SCIENCE ARTICLE

Harder Rain, More Snow

2008-05-15T20:03:00.000-07:00

Meteorologists See Future of Increasingly Extreme Weather Events

While raising average global temperatures, climate change could also bring more snow, harder rain, or heat waves, meteorologists say. Computer models based on climate data from nine countries indicate every place on the planet will be hit with extreme weather events, including coastal storms and floods.

ORLANDO, Fla. -- f you don't like the weather now ... Just wait, huge changes could be in store. Some scientists predict severe weather events will be even more extreme over the next few decades -- more snow, harder rain, and hotter heat waves.
People everywhere are noticing the changes in climate. Susan Decker, from Broomfield, Colo., says, "It seems warmer. Not as cold. We don't get the snow anymore." Rob Topolski, from Paducah, Ky., says, "We also don't have not nearly as much snow as we used to in Kentucky." Abbie Pumarejo, from Augusta, Ga., says, "It just seems like every summer gets a little bit warmer."
Gerald Meehl, from the Climate and Global Dynamics Division at the National Center for Atmospheric Research (N-CAR) in Boulder, Colo., tells Ivanhoe, "We see the biggest increase in heat waves in the Pacific Northwest where we don't presently have heat waves."
Computer models based on nine different countries' climate data indicate every country will be hit with climate change throughout this century. Meehl says: "If extreme heat bothers you that can be a problem. It could affect your utility bill. You might have to think about getting air conditioning if you don't have it."
The potential effects are far reaching; the computer models have accurately simulated past weather events and now some experts believe these simulations of future climates are likely to be correct. Scientists, however, disagree on what can or should be done, but know something needs to be done.
N-CAR scientists expect the average global temperature to increase by three degrees over this century. Three degrees may not seem like a large amount, but in a heat wave, a three-degree difference could be dangerously hot for more people and create one-foot higher storm surges.

Source : Daily Science

Our Changing Climate

2008-05-15T19:43:00.000-07:00

Source pic. www.linfield.edu

Climatologists Forecast Completely New Climates

Geographers have projected temperature increases due to greenhouse gas emissions to reach a not-so-chilling conclusion: climate zones will shift and some climates will disappear completely by 2100. Tropical highlands and polar regions may be the first to disappear, and large swaths of the tropics and subtropics will reach even hotter temperatures. The study anticipates large climate changes worldwide.

The eastern United States has a mild, humid, temperate climate, while the western United States has a dry climate, right?
Well, according to climate models, global warming could change our current world climate zones, which would affect where crops are grown and even drive some plant and animal species to extinction, all in the next 100 years.
Al Gore brought the issue to the big screen. Global warming -- what impact could it really have on our world? Geographer Jack Williams says, based on his new analyses of climate forecasting models, we're headed for major change -- fast.
"One of the things that we can definitely say that the more carbon dioxide we put into the atmosphere, the models very clearly show more of a warming that takes place in the U.S. and worldwide," said Williams, of the University of Wisconsin.
How much warming? With levels of CO2 continuing to rise, Williams suggests areas of the world that currently have a tropical climate will be much warmer and drive vegetation and animal life north. Williams believes these changes would lead to the spreading of Malaria northward, more catastrophic natural disasters and overall greater human health risks.
"Even a few degrees Celsius can make a major difference in terms of where species grow and how well they thrive," Williams said.
As North America came out of the last Ice Age, spruce trees moved northward. Williams said the same thing will happen, potentially driving plant and animal species into extinction if they can't adapt to the changes fast enough. "Species can migrate in response to climate change, but there's the question of how quickly can they migrate, and will these climate changes over the next century be so rapid that species will be unable to keep up," Williams said.
Williams said that's why we need to take action now -- because later will be too late.
The American Geophysical Union and the American Meteorological Society contributed to the information contained in the TV portion of this report.

Sources : Daily Science

Seagrass Ecosystems At A 'Global Crisis'

2008-05-15T19:23:00.000-07:00

An international team of scientists is calling for a targeted global conservation effort to preserve seagrasses and their ecological services for the world's coastal ecosystems, according to an article published in the December issue of Bioscience, the journal of the American Institute of Biological Sciences (AIBS).

Halophila ovalis in Moreton Bay, Australia. (Photo by Chris Roelfsema)

The article "A Global Crisis for Seagrass Ecosystems" cites the critical role seagrasses play in coastal systems and how costal development, population growth and the resulting increase of nutrient and sediment pollution have contributed to large-scale losses worldwide.
"Seagrasses are the coal mine canaries of coastal ecosystems," said co-author Dr. William Dennison of the University of Maryland Center for Environmental Science. "The fate of seagrasses can provide resource managers advance signs of deteriorating ecological conditions caused by poor water quality and pollution."
Among its findings, the study analyzed an apparent disconnect between the scientific community's concerns over seagrass habitat and its coverage in the popular media. While recent studies rank seagrass as one of the most valuable habitat in coastal systems, media coverage of other habitats -- including salt marshes, mangroves and coral reefs -- receive 3 to 100-fold more media attention than seagrass systems.
"Translating scientific understanding of the value of seagrass ecosystems into public awareness, and thus effective seagrass management and restoration, has not been as effective as for other coastal ecosystems, such as salt marshes, mangroves, or coral reefs," said co-author Dr. Robert Orth of the Virginia Institute of Marine Science. "Elevating public awareness about this impending crisis is critical to averting it."
"This report is a call to the world's coastal managers that we need to do more to protect seagrass habitat," said co-author Dr. Tim Carruthers of the University of Maryland Center for Environmental Science. "Seagrasses are just one of the many keys to maintaining healthy coastal ecosystems and their biodiversity."
Seagrasses -- a unique group of flowering plants that have adapted to exist fully submersed in the sea -- profoundly influence the physical, chemical and biological environments of coastal waters. They provide critical habitat for aquatic life, alter water flow and can help mitigate the impact of nutrient and sediment pollution.
The study was funded by the National Center for Ecological Analysis and Synthesis (NCEAS) through the National Science Foundation.
The University of Maryland Center for Environmental Science is the principal research institution for advanced environmental research and graduate studies within the University System of Maryland. UMCES researchers are helping improve our scientific understanding of Maryland, the region and the world through its three laboratories - Chesapeake Biological Laboratory in Solomons, Appalachian Laboratory in Frostburg, and Horn Point Laboratory in Cambridge - and the Maryland Sea Grant College.
Sources : ScienceDaily

A mysterious dark energy fills the universe... 01

2008-04-07T03:56:00.000-07:00

A mysterious dark energy fills the universe...
By Rhiannon Buck

Dark energy makes the universe fly apart like a runaway freight train and keeps space-time flat as a pancake, but what is it?

Hypothetical 'dark energy' is the most popular way of explaining why the universe is expanding at an ever increasing rate. Dark energy plays a massive part in shaping our reality however nobody seems certain of what the dang stuff actually is. Future space missions hope to solve this mystery and shake up our current understanding of the universe.

The discovery of 'Dark Energy'

In 1998 two rival groups of scientists embarked on research projects to measure the effects of gravity on the expansion of the universe. Since the Big Bang 13.7 billion years ago, the universe had been expanding. What was unknown was would this expansion go on forever. Was there too little mass in the universe to slow down the expansion - and it would continue forever? Or was the amount of mass in the universe sufficient to not only slow down the growth of the universe, but to eventually pull it all back together to one point?

Both teams got startling results. Instead of slowing or continuing at a steady rate, the universe was expanding faster and faster. A mysterious energy was causing the universe to fly apart.

We have since established that the acceleration of the expansion of the universe begun about 9 billion years ago when dark energy dominated the force of gravity and begun to push the universe apart at an ever increasing rate. These findings were understandably shocking to scientists who thought it most likely we lived in a universe which was gently slowing down due to gravitational attraction.

How do scientists determine how fast the universe is expanding?

Scientists use 'standard candles' to measure the rate of expansion of the universe. These are objects which we know always have the same total brightness. The most reliable standard candles are type 1a supernovae. These are created when a white dwarf star consumes matter from a neighbouring star until it reaches a certain critical mass and it suddenly explodes into a supernova. Because the mass of a star which becomes a Type 1a supernova is always the same, we know how bright the explosion which follows will be - and as well, the characteristic pattern of the dimming of this light.

By measuring how much fainter the light from a Type 1a supernova appears to us on earth we know how far away it must be. However, we still need a way to measure the rate at which these standard candles are moving away from us. To do this, scientists look at the redshift of the light they emitted from the parent galaxy in which the Type 1a supernova appeared. Redshift is the effect of the 'stretching' of light which has travelled a long distance to reach us.

We know that light always travels at the same speed through a vacuum - and that this speed doesn't change over time. However, the amount of energy in the light does change. If the object which emits the light is moving away from us, the wavelength of the light will be 'stretched' which means the energy of the light is decreased. An analogy for this is the change in sound you hear when an ambulance passes. When it begins to move away from you the sound waves are 'stretched' which makes the pitch of the siren lower. The faster the ambulance moves away from you, the more the pitch will change. Distant galaxies are moving away from us as the universe expands, so the light they emit is 'stretched' so it's energy is reduced. The further away the object is from us here on earth, the faster it is moving away from us so the lower the energy of the light we receive.

The scientists who were researching the expansion of the universe in 1998 found that when they compared the light from distant Type 1a supernovae to the redshift of the light in the galaxy in which it was located that it was dimmer than expected. Something was causing the expansion of the universe to accelerate! A 'dark' unknown energy was at work.

A mysterious dark energy fills the universe... 02

2008-04-07T03:53:00.000-07:00

A mysterious dark energy fills the universe...
By Rhiannon Buck

The universe is flat
Cosmologists can measure the shape of our universe by attempting to add up all of the mass and energy which we can observe. Recent measurements indicate the universe is composed of 74% dark energy, 22% dark matter, and a measly 4% ordinary matter.

Dark matter is material which we can't observe through telescopes or any other method, but we can infer it's existence by observing the rotation of galaxies outside our own. Basically some of these galaxies are rotating at speeds far greater than they should be - and the reason is that material which we can't see is present within the body of the galaxy.

As we have read, dark energy provides a neat explanation for the expansion of the universe but we also need it to solve another dilemma. The shape of our universe is explained by the existence of dark energy. So how do you find the shape of our universe?

What cosmologists mean by 'flat' is that if you were to draw an enormous equilateral triangle in space, all of the angles would add up to 180 degrees. If we imagine a space which is curved, such as on a globe, or our earth, then an equilateral triangle drawn along lines of latitude and longitude will add up to more than 180 degrees! For our universe to be flat, space cannot be curved, and so the total amount of energy and mass in the universe must add up to a particular amount. The total amount of mass and energy tied up in ordinary matter and dark matter only adds up to 26% of what we would need to keep our universe the flat shape it is. Somehow, 74% of our universe is in a mysterious form which we can not account for, dark energy.

We can see it's effects - but what IS dark energy?

We can speculate about the properties of dark energy by studying the universe around us. It has to be very evenly spread out throughout the entire universe, unlike dark matter which clumps and forms structures. It doesn't interact with anything we can measure, other then by causing the universe to expand. This makes it difficult to measure it and advance theories or disprove ideas.

The cosmological constant

There are lots of different theories about dark energy. The most popular harks back to an equation Einstein wrote in 1917 to describe the state of the universe. At the time everybody thought the universe was static - it didn't expand, or contract, it just stayed the same, so Einstein included a constant in his equation to balance the effect of gravity. This 'fudge factor' was named the cosmological constant. Soon after this, Hubble discovered that the universe was actually expanding. Einstein immediately abandoned the extra constant reportedly calling it the 'biggest blunder of his life'. What he didn't realise was that the expansion of the universe was accelerating - so an extra term was needed after all. Quantum mechanics theorises that an empty vacuum has a small amount of fundamental energy. Einstein's extra cosmological constant can be thought of as accounting for this extra energy. This energy pushes on the surrounding space-time, causing the universe to expand. The constant Einstein disregarded might hold the key to dark energy.

Quintessence

The other most mainstream theory is called 'quintessence'. The name comes from the ancient Greek for 'fifth element'. The ancient Greeks thought that a pure fifth element called the aether filled the whole universe. Quintessence differs from the cosmological constant because it changes over time and space. A special form known as 'phantom energy' increases infinitely over time. The universe would accelerate at a faster and faster rate until it tears the whole universe apart in a 'Big Rip'. The ultimate doomsday scenario would depend on the exact nature of quintessence.

Other theories

String theory is also used to explain dark energy, but has not managed to nudge the other two theories off the top spot. It is not as popular amongst the scientific community. Some scientists dismiss the whole concept of an accelerating universe as merely a failure of our current theories. Some argue that the laws of physics which apply to our small part of the universe might need amending when applied to the universe as a whole. Is it high time for some new physical information about dark energy to boost our theoretical ideas.

Future space missions

To determine which of our theories are correct we need to find out more about the properties of dark energy. Nasa are holding a competition for possible space missions to explore dark energy. At the moment there are three possible contenders which all chart the rate of acceleration of the universe using standard candles. Each spacecraft also offers it's own unique instruments which measure redshifts of light from distant stars.

The new observations from these missions will help identify whether we are dealing with a cosmological constant, quintessence or something even weirder. These missions could bring back information which shakes up modern physics and puts us back on track to formulating a fundamental theory of the universe. Embarrassingly, until then we won't know what 74% of our universe is. We live in the dark ages.

Mosquito and cucumber salad anyone? 01

2008-04-07T03:43:00.000-07:00

Mosquito and cucumber salad anyone?
By Karen Mittelstadt

Could a genetic hybrid of a mosquito and a sea cucumber spell the end of malaria - one of the World’s most deadly diseases?

Do you live in a developed country and feel unconcerned about malaria? Perhaps you should think again. With the explosion of easy international travel, imported cases of malaria are reported more frequently. And the emergence of drug-resistant strains means the disease is appearing again in areas where it was previously under control. .

There has never been a greater need for innovative preventative measures and new anti-malarial drugs. But have we found an unlikely ally in a gelatinous blob from the bottom of the Ocean.

Malaria’s deadly toll

Malaria is an infectious disease caused by the plasmodium parasite that's transmitted by mosquitoes. Although malaria is largely a preventable and treatable disease, one person dies of malaria every 30 seconds. It rivals HIV and tuberculosis as the world's most deadly infection and the majority of its victims are under five years old.

Malaria causes severe illness in 500 million people worldwide each year, and kills more than one million. It is estimated that 40% of the world’s population are at risk. Malaria transmission occurs primarily in large areas of Central and South America, sub-Saharan Africa, the Indian subcontinent, Southeast Asia and the Middle East.

In addition to an impact on individual health, malaria also has a significant socioeconomic impact. The disease causes an average loss of 1.3% annual economic growth in countries with a high incidence of infection. Furthermore, malaria has lifelong effects through increased poverty, impaired learning and decreased attendance in schools and the workplace. sted on the sky, are in reality found to be located at many different distances from earth, some closer and some further away.

How it all begins – the malaria parasite life cycle

The transmission of the parasite plasmodium begins with the female mosquito, which needs blood to make eggs. When the mosquito bites an infected human it ingests parasite sperm and eggs. These then unite in the stomach of the mosquito to form what’s known as ookinetes - cells that become embedded in the stomach wall.

These ookinetes migrate through the mosquito’s stomach wall and produce thousands of infectious daughter cells known as sporozoites. After 10-20 days they move to the mosquito salivary glands and are ready to infect another human.
Once inside the human body, the sporozoites are carried by the blood to the victim's liver where they hide from the immune system. In the liver they invade the cells and multiply into thousands of cells. After 9-16 days they return to the blood and infiltrate red blood cells where again they stay invisible to immune surveillance. Within the red blood cells they multiply once more forming parasite sperm and egg cells. This process destroy’s the victim’s red blood cells which releases the parasitic cells into the bloodstream to be ingested by a mosquito - thus renewing the transmission cycle.

Patients with malaria exhibit extreme feverish attacks, flu-like symptoms, tiredness, diarrhea, nausea, vomiting and shivering while the malarial parasite damages the liver and blood cells. The severity of the symptoms depends on several factors, such as the species (type) of infecting parasite and the patient’s acquired immunity and genetic background.

Mosquito and cucumber salad anyone? 02

2008-04-07T03:33:00.000-07:00

Mosquito and cucumber salad anyone?
By Karen Mittelstadt

Cucumbers that eat themselves alive - and malaria
The malaria parasite Plasmodium has been studied for decades, but because of its ability to evade the immune system a vaccine has been hard to develop.
Most drugs that are available are active against the parasites while they are in the human blood. However, there is an emergence of parasite strains that are resistant to many of the existing anti-malarial drugs thus making the discovery of new therapies essential.
Recently, an International team of researchers, led by Professor Bob Sinden from the Imperial College in London, has found that the sea cucumber makes a chemical that is toxic to the fatal malarial parasite.
The sea cucumber is a worm-like scavenger that feeds on plankton and debris in the ocean and is made of a tough gelatinous tissue. A slimy mass of muscular tissue, the cucumber has the unusual ability to violently expel its internal body organs during times of stress. These can later be regenerated. Another fascinating feature is their ability to slowly digest themselves to cope with periods of starvation.
Cucumbers that cure
Some varieties of sea cucumbers are said to have excellent healing properties so it may be no surprise that this creature has found medicinal use, both formally and in alternative therapies. Extracts have found their way into oils, creams and cosmetics. Sea cucumber extract has also been shown to heal wounds more quickly and reduce scarring. Other extracts from sea cucumbers inhibit blood vessel formation thus making it an excellent potential therapy for cancer.
Researchers have now found that this slug like creature also produces a protein which impairs development of the malaria parasite. Called lectin (CEL-III), this protein has been shown to damage human and rat red blood cells. Lectin is poisonous to the parasites when they are still in the early ookinete stage of development – before they migrate out of the mosquito’s stomach to produce the millions of sporozoites which end up in the insect’s saliva.
Inhibiting this ookinete development is a potential way to eliminate the transmission of sporozoites to the human host thus breaking the transmission cycle.
Part cucumber and part fly
In order to inhibit ookinete development within the stomach, the research team has developed genetically modified mosquitoes. They are just like regular mosquitoes accept for one gene. This newly introduced gene is part lectin-making gene from the sea cucumber and part gene from the mosquito that makes a substance that is released into the stomach during feeding. In this way the toxin can be introduced into the stomach where it can kill the ookinete cells.
Still no solution (of should we say ‘dressing’)
The concept of genetically modifying mosquitoes to disrupt parasite development prior to human infection is a novel approach to control the disease that is gaining recognition due to limited success elsewhere.
Currently, the only treatments against the parasite once they are in human blood are chloroquine, quinine, doxycycline, mefloquine and a few others. Unfortunately, since the most afflicted countries tend to be the poorest there has been little commercial incentive to develop new drugs. But with the disease now on our doorstep’s perhaps activity here will step up.
The rapid spread of antimalarial drug resistance over the past few decades has required more intensive monitoring to make sure there is proper management of clinical cases and early detection of changing patterns of resistance. Countries are being assisted in strengthening their drug resistance surveillance systems.
Mosquitoes have also built up resistance to insecticides which have been used in abundance.
But the deployment of super mossies that can fight off infection, like the cucumber salad, faces considerable challenges. In order to carry out this endeavor, thousands of mosquito embryos must be injected with a gene encoding for the anti-malarial protein and then the genetically modified adult mosquitoes released into the wild. And, unfortunately the toxic protein does not totally remove all parasites from all mosquitoes and as such, at this stage of development, would not be effective enough to prevent transmission of malaria to humans.
Furthermore, the genetically modified version of the mosquito would have to become the predominant species which is very difficult to achieve.
More research needs to be done but this finding is a first step toward developing a new method of preventing transmission of malaria thanks to the lowly sea cucumber

Death of the Dinosaurs

2008-04-07T03:31:00.001-07:00

By Naomi Miles
There was a time when dinosaurs thrived on Earth… What caused their demise?

Dinosaurs dominated our planet for 160 million years. Now, all that remains of these huge creatures are bones. Fossil records show that 65 million years ago, something devastated the Earth's entire ecosystem and dinosaurs suddenly died out along with around 50% of all other species. But what caused their extinction? For many years, this question has remained a mystery shrouded in speculation.

The extinction event
In the 1970s, guess work turned into real scientific research thanks to a team at the University of California, Berkley. Geologist Walter Alvarez was examining rock strata in Guppio, Italy when he came across a layer of clay between the Cretaceous and Tertiary eras called the K-T boundary. The Cretaceous rock was full of fossils but rock from the Early Tertiary era had none. This brown-black stratum was formed at the time of the K-T mass extinction event that represented the end of the dinosaurs.

Alvarez took a handful of this K-T boundary clay to his father, the late Noble physicist Luis Alvarez, for analysis. With the help of nuclear chemists Helen Michels and Frank Asaro, they discovered that it contained an abnormally high quantity of the element iridium. This element is very rare in the crust of the Earth, but levels of iridium at the K-T boundary were 200 times higher than usual. Where had it come from? Extraterrestrial bodies such as comets and asteroids are rich in iridium, and to the Alvarez team, this clay bore the distinctive signature of asteroid dust. In 1980, Luis Alvarez and his son proposed that the dinosaur's demise was caused by an asteroid impact.

Since that time, geochemists have discovered iridium anomalies at the K-T boundary at over 100 places around the world. The boundary rock in these sites contains other unmistakable signs of a meteor impact. The scarred rocks show signs of being physically altered, fractured, melted and deformed beneath the intense heat and force of an explosion. For example, shocked minerals such as quartz are common in K-T boundary rock. These form under a sudden pulse of extremely high pressure. Small glass spherules are also present, remnants of superheated melt rock at the impact site, which were blasted as droplets that fell from the sky hundreds of miles around.

An asteroid that left its wounds around the world would have been huge. But where did it hit? The search for a crater site was on.

Where did the asteroid hit?

In 1990, Alan Hildebrand, a post- graduate from the University of Arizona, was put in touch will geophysicist Glen Penfield who worked for the major Mexican oil company Petroleos Mexicanos (PEMEX). Penfield believed that he had discovered a potential impact crater site. While looking over the old survey data from PEMEX for the Yucatán region of Mexico, Penfield noticed a huge buried arc of rock. He was excited to find that the 1960s gravity maps of the region revealed another arc, which fitted together with the first to form a huge circle. Deep beneath the little Mexican village of Puerto Chixulub at the tip of the Yucután peninsular, Penfield had found a crater over 100 miles wide, one of the largest impact structures on Earth.

Penfield was aware that 50 years ago, PEMEX had been in the Yucután region looking for oil. Whilst digging an exploratory well, the workers had come across an unusual layer of igneous volcanic rock called andesite. Together, Hildebrand and Penfield re-examined the samples of andesite PEMEX had collected. Their analysis revealed that the rock contained shock- metamorphosized minerals, further evidence supporting their hypothesis that the Chixulub crater was the K-T impact site. The consensus of the scientific community is that this faded scar bears the mark of the most devastating impact the Earth has ever seen.

So it was 65 million years ago that a 2.6 billion ton asteroid the size of Mount Everest fell from the sky at 40,000 miles per hour. It slammed into the lagoons of New Mexico with the energy of 100 million megatons of dynamite, 200 times more powerful than the biggest nuclear bomb ever detonated on Earth.

A superheated shockwave rushed out from the impact faster than the speed of sound. The crash conjured ferocious fires and raised tsunamis around the Gulf of Mexico. The Earth trembled, volcanoes erupted and hurricane winds ripped through the air. Trillions of tons of debris were thrown up into the atmosphere, hurling down glowing fireballs on the Earth for hundreds of miles around.

Everything within 300 miles of the impact was instantly incinerated. But this asteroid had a global impact. Masses of dust produced by the collision blasted into the atmosphere where it blotted out the heat and light of the sun. Consequently, the Earth was plunged into a bitter darkness that lasted for months. The food chain collapsed, and the 165-million-year reign of the dinosaur came to a dramatic end. All larger creatures perished. Only a lucky 15% of land animal species survived.

This hardy minority exploded into the huge diversity of species we see today. The iridium-rich stratum divided the age of the dinosaurs and the age of the mammal. Without the 'terrible dragons' dominating the scene, mammalian life managed to get a foothold. In other words, without the K-T extinction, we might not be here now.

Holy Grail History 01

2008-04-07T03:17:00.000-07:00

Holy Grail History
By Stuart Carter

Forget Dan Brown... forget Da Vinci. For 2000 years, successive generations have been gripped by the quest for the Holy Grail, a journey that has brought people to some of the most historic and mysterious sites in Britain.
The very nature of the Holy Grail is surrounded by different stories. Some claim that it's the bowl that Joseph used to collect the blood of Jesus Christ when he was dying on the cross. Others claim that it's the cup that Christ drank from at the Last Supper. The search for the Grail has taken questors around the world, but one of the most enduring legends tells us that it was brought to Britain by Jesus Christ's great uncle, Joseph of Aramithea - a tin merchant who often travelled to Cornwall and Somerset to trade in precious metals. He is thought to have left on a voyage shortly after Christ's death, but this time is thought to have headed to Glastonbury - the Glass Isle he had been sent to find by the Archangel Raphael.
To this day, no evidence has been found and the quest continues to some of the most mysterious sites in Britain. In Glastonbury, it is said that the water flows red from the blood of Christ; Tintagel, is supposed to be the birthplace of King Arthur and home to Merlin; and the Rosslyn Chapel in Scotland, a sacred treasure trove, is thought to closely guard the holy secrets of the Grail. Where does legend end and history begin?
Buried in Glastonbury
Many people believe that Glastonbury is the most likely place where Joseph hid the Holy Grail. He is thought to have sailed with his companions to Wearyall Hill in Glastonbury - where suddenly his staff flourished into a living hawthorn bush, the Holy Thorn of Glastonbury. Joseph took this as a sign that this was the destined resting place of the Holy Grail. The 'Glastonbury Thorn' thrives to this day, and unlike any other thorn bush in the country, it flowers every Christmas and Easter. Each December, a flowering branch of the tree is cut off and sent to the Queen.
Back in the 12th century, 30 monks from the Abbey descended into the ancient tunnels underneath Glastonbury in search of the Grail. Only three came out - one struck dumb, and two deranged. The rest, it is said, were claimed by the mysterious forces of the hill. No one ever followed these monks into the labyrinth under Glastonbury, and the tunnels have long since been sealed off as the surface soil has slipped down the sides of the tor. But even today questors still dig for the warren of tunnels beneath Glastonbury, hoping to find the Holy Grail and the remains of Joseph of Aramithea.

Others are looking to the springs of Glastonbury, typically to one place where a spring runs red, according to legend, with the blood of Christ. The Chalice Well still exists today, and its water is still red, but the most likely explanation for the colour is the iron deposits in the water. Near to the Chalice Well there is another spring where the water is white - fed by underground caves beneath Glastonbury tor. Some believe that this is a much more likely hiding place where Joseph might have hidden the Holy Grail.

Holy Grail History 02

2008-04-07T03:14:00.000-07:00

Credit: Archaeology@Glasgow

Holy Grail History
By Stuart Carter
Ancient questors in Cornwall
Apart from the location of the Grail, many questors are drawn to the ultimate questor and legendary ruler of the Britons - King Arthur. He is often presented as a romantic medieval figure and arguments still rage about whether Arthur is a real or a mythical character. The first written reference to King Arthur is found in Geoffrey of Monmouth's 12th century book The History of the Kings of Britain. Most famously, Arthur, stands on the steps of Camelot Castle and dispatches his Knights on a great quest to find the Holy Grail. But the 'real' Arthur, the man who started all the legends, comes from the 5th century, a time with no written history - the Dark Ages.
Each year, over a million visitors come to the castle of Tintagel on the north coast of Cornwall in search of King Arthur and the Holy Grail. Some say Tintagel is 'Camelot' - the seat of King Arthur. Some say it belongs to Merlin, the wizard who masterminded Arthur's birth, rise to power and quest for the Holy Grail. The mysterious cave running right underneath Tintagel is said to be Merlin's Cave.
Recent excavations have revealed dramatic new evidence about Tintagel during the 5th century - the time of the 'real' Arthur. Although less than a quarter of Tintagel has been excavated, incredible amounts of Mediterranean pottery have already been found. Could there be some basis for the legend placing Arthur at Tintagel? In 1998, a 5th century drain-cover was unearthed from the castle which bore an inscription that could change legend into history. The inscription translated as "Artnou made this". Is this the clue that historians, writers and grail-hunters have been searching for? Is Artnou, Arthur? Whatever the truth behind the 'Artnou' stone, it has added greatly to the legend.
The Grail in Scotland?

Moving from the south of the U.K. to Scotland, just a few miles from Edinburgh, is the Rosslyn Chapel. Since Dan Brown's book The Da Vinci Code, hundreds of thousands of visitors have been there - but even before his book, 34,000 visitors a year made the pilgrimage to Rosslyn to look for secret messages in the chapel and for the Holy Grail. Many are drawn to the Apprentice Pillar which has drawings of Joseph of Aramithea holding the Grail and a cross carved with the shape of the Grail on it. This has caused some scholars to believe that the chalice must be hidden inside the pillar. Metal detectors have shown an object of the right size to be inside, but the Earl of Rosslyn has repeatedly refused to allow the pillar to be X-rayed. His motto is "conservation and preservation, not excavation".
For the moment, the Apprentice Pillar must remain a mystery. But even if the Holy Grail isn't in the Pillar, there are those who say it can't be far away. Rosslyn glen has been a spiritual focus for thousands of years. There are natural caves along the banks of the river - some with Bronze Age markings. There is a network of tunnels under the castle, and no one knows how many catacombs beneath the Chapel. According to legend, treasure hunters sent a piper and his dog down this tunnel to explore the labyrinth. They could hear the music as the piper moved beneath them. He travelled for a mile and then the piping stopped. He never emerged, and no one has ever entered the tunnel since.
Perhaps it's this spirit of exploration that is more important than the answer itself. On their quest to find the Holy Grail, the Knights of the Round Table would only achieve enlightenment if they asked the right question of the cup: "Whom doth the Grail Serve?" There are many who believe there is no chalice - that the Holy Grail is the quest itself; and that it is the quest, rather than the cup, which brings the gift of ultimate enlightenment.

Fossil of a Fishapod

2008-04-07T02:56:00.000-07:00

Credit: Ted Daeschler

Fossil of a Fishapod
By Jen Schripsema

A recently-discovered fossil could explain how animals transitioned from water to land over 375 million years ago.

To some, the story sounds fishy. Evolutionists believe that about 400 million years ago, animals started to make the transition from living in water to living on land. In those early days, it is thought that animals dwelling in water slowly started to evolve certain features, like limbs and lungs, which allowed them to live on land. Fossils found in Greenland in the past 15 years have shown some evidence of these creatures, but in April 2006, the discovery of a fossil called Tiktaalik roseae is the most compelling evidence to date of the transition.

The fossil was found on Ellesmere Island in Canada's Nunavut Territory by a team of scientists led by Neil Shubin of the University of Chicago. At the suggestion of Inuit elders, they named the fossil Tiktaalik which means "large shallow water fish" in Inuktitut. This creature lived about 370 million years ago during the late Devonian Period, also called the "Age of Fishes." At this time, Ellesmere Island was part of a large landmass straddling the Equator. Competition among fish in the oceans was intense, but the land was largely unexploited. Additionally, the expansion of terrestrial plants transformed the land, setting the stage for its colonization by tetrapods, or four-legged animals.

Scales and fins still qualify Tiktaalik as a fish, but several other characteristics set it apart. The bones in Tiktaalik's fins formed jointed wrists, the primary characteristic that scientists believe makes Tiktaalik a transitional species. Also, its flat skull was disconnected from its shoulders, giving it the ability to turn its neck. Based on the shape of Tiktaalik's head and its eyes positioned on the top of its head, scientists believe it probably spent most of its time in shallow water. "Tiktaalik was probably an unwieldy swimmer," John Maisey, a paleontologist at the American Museum of Natural History in New York, told Nature Online News. "Tetrapods did not so much conquer the land, as escape from the water."

The discovery of this fossil is groundbreaking because it is so well-preserved and complete. Researchers are confident that Tiktaalik is an intermediary between fish and tetrapods and they believe it will become the same kind of evolutionary icon as Archaeopteryx, the species linking reptiles and birds. Archaeopteryx lived about 150 million years ago and had fully-formed feathers, although it may or may not have been able to fly. The first Archaeopteryx skeleton was discovered in Germany in 1861.

Credit: Ted Daeschler
In terms of the evolution versus creation debate, will the Tiktaalik fossil provide the necessary proof to non-believers? Dr. Shubin's team has tried to avoid commenting on the implications the fossil has for the debate, but many other scientists have not been so quiet. They say Tiktaalik should quell the criticism by creationists, people believing that all matter and life were created by God as described in the Bible, that the fossil record lacks a transitional species. However, many creationists remain unconvinced.

In the United States, creationists make up a large proportion of the population. A Gallup poll last November showed that only one third of Americans believe there is strong evidence supporting the theory of evolution and almost half believe that God created man in his present form about 10,000 years ago. The Supreme Court ruled in 1987 that creationism was a religion and, therefore, could not be taught in schools.

However, many anti-evolutionists, including President Bush, have promoted teaching intelligent design as an alternative to evolution. This idea, pushed primarily by the Discovery Institute of Seattle, posits that the complexity of the universe and living things are best explained by an intelligent designer. Because they never specify the designer, they argue that the theory is scientific, not religious.

Most scientists are skeptical, saying that intelligent design is just creationism disguised as scientific theory. Eugenie Scott of the National Center for Science Education said to PBS, "You have this mysterious intelligent agent who, of course, is God." Of course, the debate in the U.S. over teaching evolution in schools goes back to the Scopes trial of the 1920s. The implication of discoveries like Tiktaalik for education are likely to be debated well into the future.

Therefore, most scientists are focusing primarily on the new insight into tetrapod evolution that Tiktaalik provides. This fossil fills in the gaps of prior fossil evidence, showing scientists the order in which certain structures evolved. The jaw of Tiktaalik, for example, remains very fishlike despite it having evolved limb-like structures. By knowing which features evolved first, scientists hope to learn more about the history of evolution on Earth

Genesis by Comets? 01

2008-04-07T02:40:00.000-07:00

Genesis by Comets?
By NASA

A new experiment suggests that comet impacts could have sowed the seeds of life on Earth billions of years ago.
Four billion years ago Earth was bombarded by a hail of comets and asteroids. The shattering collisions rendered our planet uninhabitable during a period scientists call the Late Heavy Bombardment.

It surely sounds like the LHB was an awful time for the beleaguered young planet -- but perhaps the pelting was a good thing after all, say researchers. Kamikaze comets could have delivered important organic molecules to Earth -- sowing the seeds for life.

Genesis by comets is a controversial idea, but it has received an important boost with the knowledge that a NASA supported experiment has revealed that complex molecules hitchhiking aboard a comet could have survived an impact with Earth.

"Our results suggest that the notion of organic compounds coming from outer space can't be ruled out because of the severity of the impact event," says Jennifer Blank, a geochemist at the University of California, Berkeley. Blank and colleagues simulated a comet collision by shooting a soda-can sized bullet into a metal target containing a teardrop of water mixed with amino acids - the building blocks of proteins.

Not only did a good fraction of the amino acids survive, but many polymerized into chains of two, three and four amino acids, so-called peptides. Peptides with longer chains are called polypeptides, while even longer ones are called proteins.

"The neat thing is that we got every possible combination of dipeptide, many tripeptides and some tetrapeptides," said Blank. "We saw variations in the ratios of peptides produced depending on the conditions of temperature, pressure and duration of the impact. This is the beginning of a new field of science."

Freezing the target to mimic an icy comet increased the survival rate of amino acids, she added.

Blank's ballistic test was designed to simulate the sort of impact that would have been frequent in Earth's earliest history when rocky, icy debris in our solar system combined to form the planets. Much of the debris would have resembled comets - dirty snowballs thought to be mostly slushy water surrounding a rocky core - slamming into Earth at velocities greater than 16 miles per second (25 km/sec).

The severity of the laboratory impact was akin to that of an oblique collision between the rocky surface of Earth and a comet coming in at an angle of less than 25 degrees from the horizon.

Benton Clark, chief scientist of Flight Systems at Lockheed Martin Astronautics, proposed in 1988 that if comets are slowed sufficiently -- by for example, drag from the Earth's atmosphere, which would be greatest at low impact angles. That some water and organic compounds might survive the collision.

"At very low angles, we think that some water ice from the comet would remain intact as a liquid puddle concentrated with organic molecules," ideal for the development of life, Blank said. "This impact scenario provides the three ingredients believed necessary for life: liquid water, organic material and energy."

Genesis by Comets? 02

2008-04-07T02:32:00.000-07:00

Genesis by Comets?
By NASA
Though comet hunter Eugene Shoemaker estimated that in Earth's early history only a few percent of comets or asteroids arrived at low enough angles, the bombardment would have been heavy enough to deliver a significant amount of intact organic material and water, according to Blank's estimates.

One well-known model for the beginnings of life on Earth posits that terrestrial life sprang from complex molecules such as amino acids and sugars produced by electrical discharges in a primeval atmosphere replete with gases such as methane, hydrogen, ammonia and water. The famous Miller-Urey experiment in 1953, conducted by Stanley Miller and Harold Urey of the University of Chicago, demonstrated that a lightening-like discharge in a test tube filled with these molecules could produce amino acids.

Other scientists believe that the building blocks of life on Earth arrived from space. Astronomers have detected many kinds of organic molecules in space, floating in clouds of gas or bound up in dust particles. They range from the simplest - water, ammonia, methane, hydrogen cyanide and alcohols, including ethyl alcohol - to more complex molecules.

Interestingly, of the more than 70 amino acids found in meteorites, only eight of them overlap with the group of 20 which occur commonly as structural components of proteins found in humans and all other life on Earth.

To test whether water and organic compounds could survive the high pressures and high temperatures of a collision, Blank and her colleagues worked for three years to design a steel capsule that would not rupture when hit with a mile-per-second (1.6 kilometre-per-second) bullet fired from an 80-mm bore cannon at the University of Chicago and later at Los Alamos National Laboratory. The target she and her team developed - a two-centimetre diameter stainless steel disk about a half-centimetre thick - was able to withstand about 200,000 times atmospheric pressure without bursting.

They filled the small cavity with water saturated with five amino acids: three from the list of 20 that comprise all proteins in humans (phenylalanine, proline and lysine) and two varieties detected in the Murchison meteorite (aminobutyric acid and nor-valine). That meteorite plummeted to the ground in 1969 in Australia and is thought to be from the core of a comet.
The liquid contents were analysed afterwards at Argonne using liquid chromatography and mass spectroscopy to determine the species and concentrations of molecules present.

The survival of a large fraction of the amino acids and their polymerization during the collision makes the idea of an extraterrestrial origin of organic compounds a strong contender against Miller-Urey style theories, Blank said.

"About one comet per year arriving in a low-angle impact would bring in the equivalent of all the organics produced in a year in an oxidizing atmosphere by the Miller-Urey electric discharge mechanism," Blank estimated. "An advantage is you get all of it together in a puddle of water rather than diluted in the oceans."

The next hitchhikers she plans to subject to a shock test are bacterial spores, which some have proposed arrived on Earth via comets to jump-start evolution.

Superbugs from Hell - Evolution Re-Visited 01

2008-04-07T02:30:00.000-07:00

Photo - Jerre Goldin

Superbugs from Hell - Evolution Re-Visited
By Paul Davies

For centuries, people thought life was created in the Garden of Eden by God. Then along came Charles Darwin with his theory of evolution, and spoilt that cosy image. Darwin gave a convincing account of how all life on Earth has gradually evolved from simple microbes. However, he left open the question of how life got started in the first place. Now scientists are sure they are close to solving that mystery too, and the answer looks set to inflame passions once again.

Chemists have long tried to make life in a test tube, by simulating the conditions of the primeval Earth. Envisaging an ancient pond laced with minerals and bathed in solar radiation, researchers pinned their hopes on finding a chain of reactions that would transform a lifeless chemical soup into a primitive organism.

Chicago chemist Stanley Miller blazed the trail in the early 1950s by zapping a noxious brew of gas and water with electricity. Others have tried different formulae. Unfortunately, after fifty years of experimentation, the results are disappointing. Some of the simpler building blocks of life, like amino acids, are readily made, but the building itself - a living cell - remains as elusive as ever.

Deep-sea Life

Now a radical new theory could explain the lack of progress. Scientists increasingly suspect that the tepid pool scenario is wrong, and that life didn't start on the Earth's surface at all. This change of mind stems from the startling discovery of bizarre micro-organisms, dubbed superbugs or extremophiles, that inhabit some of our planet's most extreme environments.

In the late 1970s, a research submarine called Alvin was sent to the bottom of the Pacific Ocean to explore a string of volcanic vents known as 'black smokers'. These chimneys on the sea floor spew forth superheated water rich in dusky chemicals. The investigators were astonished to find many exotic life forms clustered around the searing effluent in pitch darkness, including weird-looking crabs and giant tube worms.

Most remarkable of all were bacteria that inhabited the hot zone itself, thriving in the disgorging fluids at temperatures in excess of 100oC. Previously, nobody believed that any life could survive above the normal boiling point of water. These superbugs lie at the base of the food chain. They are primary producers, turning inorganic material from the hot vents directly into biomass, without the need for sunlight.

Alvin's discovery turned out to be just the tip of the iceberg. In the 1980s, Thomas Gold, an astrophysicist from Cornell University, New York, supervised an oil drilling project in Sweden. On examining the rock cores from several miles down, Gold was amazed to find unmistakable signs of life.

At the time, the idea that something could live so deep in the Earth's crust was laughed at. There have been many stories about life in the underworld, from the Greek fable of Orpheus to Jules Verne's Journey to the Centre of the Earth. Few scientists took the possibility seriously. But Gold's claim was confirmed when other drilling projects yielded similar results. Biologists in the United States began extracting live microbes from miles beneath North Carolina and the Columbia River basin. Environmentalists became concerned that subterranean superbugs might eat through containment vessels of buried nuclear waste, causing leaks.

Meanwhile, the international Ocean Drilling Programme retrieved rocks from far below the seabed, and the story was the same. The basalt of the ocean floor is teeming with microbes too. Some of them have been cultured in the laboratory by John Parkes of the University of Bristol, who believes that some species can withstand temperatures as high as 169oC. It is beginning to look as if there may be as much biomass inside the Earth as there is on the surface.

Our Ancestors?

The full significance of the deep-living microbes became clear only after their innards were analysed, following the pioneering work of Karl Stetter at the University of Regensburg in Germany. By sequencing the superbug's genes, microbiologists can construct a sort of family tree linking them with normal bacteria. The results came as a complete surprise. It turns out that the oldest and deepest branches of the tree of life are all occupied by heat-loving superbugs. In other words, the microbes residing deep within the Earth are among the world's oldest surviving organisms. In effect, they are living fossils, having changed little since the dawn of time.

To some researchers these discoveries spell out a fascinating message. It suggests that life was incubated in the volcanic depths of the Earth, in pressure-cooker conditions, and migrated to the cooler surface zone only much later. This theory neatly meshes with what we know about the Earth's history. The Solar System is four and a half billion years old. For almost a billion years after the planets formed they were pounded mercilessly by giant asteroids and comets. A record of this primordial violence is etched on the face of our nearest neighbour in space - the Moon - which is pockmarked with countless large craters.

Superbugs from Hell - Evolution Re-Visited 02

2008-04-07T02:14:00.000-07:00

Photo - NASA (Mars)

Superbugs from Hell - Evolution Re-Visited
By Paul Davies

The biggest impacts would have blasted away the Earth's atmosphere and swathed the globe in incandescent rock vapour. The heat pulses were fierce enough to boil the oceans dry and sterilise the exposed land to a depth of half a mile or more. Not even superbugs could survive such cataclysmic episodes unprotected. Yet, paradoxically, there are traces of relatively advanced life in ancient rocks from Greenland dated at over 3.85 billion years - a time before this massive cosmic bombardment had abated. But if the 'comfort zone' of heat-loving microbes was deep enough, they could shelter from the cosmic barrage in the torrid strata of the Earth's crust, beyond the reach of even the fiercest heat pulses.

Photo - NASA (Microbe)

Superbugs on Mars

If the theory is right, and life did begin deep within the Earth, it may also have got going beneath the surfaces of other planets too. Mars is an obvious candidate. When two Viking space probes landed there in 1977 they scooped up some dirt to test for biological activity. No clear evidence was found, and most scientists pronounced the Red Planet dead. With hindsight, this outcome wasn't surprising, since the surface of Mars is a freeze-dried desert bathed in ultra-violet radiation that would prove lethal to almost all known organisms. However, beneath the hostile surface, conditions may be more congenial for life. Geothermal heat will have melted the permafrost to create reservoirs of liquid brine similar to those beneath the Earth's sea bed. So there might be superbugs lurking below the harsh Martian terrain.

Although today Mars is cold and dry, in the remote past it was warm and wet, and not unlike Earth. It had rivers and glaciers and possibly a large ocean. Life may well have spread to the planet's surface and briefly flourished in the Martian spring, before the atmosphere leaked away and the temperature plunged. It's possible these ancient organisms left fossils in the surface rocks, where they may be discovered by forthcoming missions to the Red Planet.

A few years ago, some scientists claimed to find fossilised microbes within a Martian meteorite collected in Antarctica. Although the jury is still out on that, it no longer seems so fanciful to speculate that Mars has, or at least once had, some form of life.

If there is, or was, life on Mars, then it raises a fascinating possibility. Back in the early history of the Solar System, the heavy bombardment that made conditions on the planets so dangerous for surface life would also have kicked vast numbers of rocks out into space. Many Mars rocks must have reached Earth during our planet's history, and many ejected Earth rocks will have hit Mars. Could hardy superbugs dwelling within these rocks have hitched a ride through space and taken up residence on arrival?

Current evidence strongly suggests the answer is yes, and that Earth and Mars cross-contaminated each other billions of years ago. It's even conceivable that life began on Mars and travelled to Earth some time later in meteorites, colonising our planet when conditions eventually became favourable. If so, we are all descended from Martians!

The Garden of Eden – Revisited

Tantalising though these developments are, the problem remains of how the first living cell formed. What chemical magic triggered the vital spark? Whether the key process happened on Mars, Earth, or both, the puzzle of the chemical genesis of life is still unsolved. Armed with the new ideas, however, researchers are now focusing their efforts on the chemistry of hot rocks infused with sea water. Might the gases exuded by a planet's crust offer a more potent mix than those of the primordial atmosphere? Could the pores in ocean basalt play the role of tiny crucibles, in one of which was forged that microbial Adam long, long ago? Some scientists think so, and are increasingly hopeful that the key steps will soon be understood.

In many cultures the underworld has long been associated with the realm of the dead. For Christians, it is the traditional location of Hell, a place of fire and brimstone, and eternal torment. How ironical if the torrid, sulphurous depths actually harboured the cradle of life. Far from being Hell, the broiling bosom of our planet might well turn out to have been the true Garden of Eden.

Armageddon - Extinction Events 01

2008-04-07T02:09:00.000-07:00

Photo courtesy Dick Rasp/National Park Service.

Armageddon - Extinction Events
By Patrick L. Barry

250 million years ago something unknown wiped out most life on our planet. Now scientists are finding buried clues to the mystery inside tiny capsules of cosmic gas.

It was almost the perfect crime.
Some perpetrator - or perpetrators - committed murder on a scale unequaled in the history of the world. They left few clues to their identity, and they buried all the evidence under layers and layers of earth.
The case has gone unsolved for years - 250 million years, that is.

But now the pieces are starting to come together, thanks to a team of NASA funded sleuths who have found the "fingerprints" of the villain, or at least of one of the accomplices.

The terrible event had been lost in the amnesia of time for eons. It was only recently that paleontologists, like hikers stumbling upon an unmarked grave in the woods, noticed a startling pattern in the fossil record: Below a certain point in the accumulated layers of earth, the rock shows signs of an ancient world teeming with life. In more recent layers just above that point, signs of life all but vanish.

Somehow, most of the life on Earth perished in a brief moment of geologic time roughly 250 million years ago. Scientists call it the Permian-Triassic extinction or "the Great Dying" - not to be confused with the better-known Cretaceous-Tertiary extinction that signaled the end of the dinosaurs 65 million years ago. Whatever happened during the Permian-Triassic period was much worse: No class of life was spared from the devastation. Trees, plants, lizards, proto-mammals, insects, fish, mollusks, and microbes - all were nearly wiped out. Roughly 9 in 10 marine species and 7 in 10 land species vanished. Life on our planet almost came to an end.
Scientists have suggested many possible causes for the Great Dying: severe volcanism, a nearby supernova, environmental changes wrought by the formation of a super-continent, the devastating impact of a large asteroid - or some combination of these. Proving which theory is correct has been difficult. The trail has grown cold over the last quarter billion years; much of the evidence has been destroyed.

"These rocks have been through a lot, geologically speaking, and a lot of times they don't preserve the (extinction) boundary very well," says Luann Becker, a geologist at the University of California, Santa Barbara. Indeed, there are few 250 million-year-old rocks left on Earth. Most have been recycled by our planet's tectonic activity.
Undaunted, Becker led a NASA-funded science team to sites in Hungary, Japan and China where such rocks still exist and have been exposed. There they found telltale signs of a collision between our planet and an asteroid 6 to 12 km across - in other words, as big or bigger than Mt. Everest.

Armageddon - Extinction Events 02

2008-04-07T02:02:00.000-07:00

Image courtesy Luann Becker

Armageddon - Extinction Events
By Patrick L. Barry
Many paleontologists have been skeptical of the theory that an asteroid caused the extinction. Early studies of the fossil record suggested that the die-out happened gradually over millions of years - not suddenly like an impact event. But as their methods for dating the disappearance of species has improved, estimates of its duration have shrunk from millions of years to between 8,000 and 100,000 years. That's a blink of the eye in geological terms.
"I think paleontologists are now coming full circle and leading the way, saying that the extinction was extremely abrupt," Becker notes. "Life vanished quickly on the scale of geologic time, and it takes something catastrophic to do that."

Such evidence is merely circumstantial - it doesn't actually prove anything. Becker's evidence, however, is more direct and persuasive:

Deep inside Permian-Triassic rocks, Becker's team found soccer ball-shaped molecules called "fullerenes" (or "buckyballs") with traces of helium and argon gas trapped inside. The fullerenes held an unusual number of 3He and 36Ar atoms - isotopes that are more common in space than on Earth. Something, like a comet or an asteroid, must have brought the fullerenes to our planet.

image Credit Chris Scotese

Becker's team had previously found such gas-bearing buckyballs in rock layers associated with two known impact events: the 65 million-year-old Cretaceous-Tertiary impact and the 1.8 billion-year-old Sudbury impact crater in Ontario, Canada. They also found fullerenes containing similar gases in some meteorites. Taken together, these clues make a compelling case that a space rock struck the Earth at the time of the Great Dying.
But was an asteroid the killer, or merely an accomplice?

Many scientists believe that life was already struggling when the putative space rock arrived. Our planet was in the throes of severe volcanism. In a region that is now called Siberia, 1.5 million cubic kilometres of lava flowed from an awesome fissure in the crust. (For comparison, Mt. St. Helens unleashed about one cubic kilometre of lava in 1980.) Such an eruption would have scorched vast expanses of land, clouded the atmosphere with dust, and released climate-altering greenhouse gases.

World geography was also changing then. Plate tectonics pushed the continents together to form the super-continent Pangea and the super-ocean Panthalassa. Weather patterns and ocean currents shifted, many coastlines and their shallow marine ecosystems vanished, sea levels dropped.

"If life suddenly has all these different things happen to it," Becker says, "and then you slam it with a rock the size of Mt. Everest - boy! That's just really bad luck."

Was the "crime" then merely an accident? Perhaps so. Nevertheless, it's wise to identify the suspects - an ongoing process - before it happens again...

Holding Hands with Dinosaurs

2008-04-07T01:57:00.000-07:00

Paul Sereno

Holding Hands with Dinosaurs
By Stuart Carter
It’s official: humans like dinosaurs more than money. In recent months two television series have swept the television ratings world by storm.

The cliff hanging format of "Who Wants To Be a Millionaire" makes for compulsive viewing and topped the ratings in both the USA and the UK. The producers must have thought their formula of watching complete strangers win hundreds of thousands of dollars and pounds would be the television hit of the decade. But lumbering in the wings was perhaps the most unexpected hit of recent times, an animated science series about long dead creatures.
The BBC’s science documentary series ‘Walking with Dinosaurs’ has broken all television records around the globe. In Britain alone it peaked at around 19 million viewers, almost one in three of the total population. The stupendous scale of this success must have come as a great delight to the producers but for years television executives have known that dinosaurs are good box-office. It seems that all of us, children and adults alike, are obsessed with dinosaurs. Just how and why did this group of extinct reptiles get to be so popular?
Dinosaurs are members of a group of around 1300 reptiles that first appeared on our planet 210 million years ago. Mysteriously they became extinct about 65 million years ago, and just one descendant, the birds, has survived to the present. The first dinosaur remains were uncovered in England in the 1820’s. It was soon realised that some of these creatures were huge, they lived on the land and many of them could walk upright on two legs.
It was this last discovery that set the scene for the human imagination to run wild. It has led to all kinds of speculation about their locomotion, behaviour and physiology. Imagine if we had to share our planet with creatures that could run up to 26 miles an hour, weighed up to 100 tonnes and had a taste for human flesh. In reality many of them were probably vegetarian, but it’s the flesh eaters that have fuelled our fears. By the 1840s they were officially named the ‘Dinosauria’: meaning Greek for ‘terrible lizard’.

Joe Tucciarone

Dinosaur footprints reveal that many of them walked erect in a fashion similar to modern birds, putting one foot in front of the other. The earliest dinosaurs were small, light carnivores and omnivores, probably extremely quick and agile to avoid any large predators. During the Jurassic and Cretaceous periods they evolved into many different types, some of them reaching colossal size. The largest dinosaur we have ever found is Seismosaurus in New Mexico. Its fossil bones reveal an animal that may have weighed in at 30 tonnes and was up to an incredible 170 feet long; 2 times longer than today’s largest animal, the blue whale.

Joe Tucciarone
Sauropods like Argentinosaurus had long necks and reached giant proportions, weighing up to 100 tonnes. Their immense size kept them firmly on all four feet lumbering along like giant elephants. Wild elephant can be killers but frequent childhood visits to zoos have left us all with the belief that elephants are gentle, kind creatures capable of weeping. This anthropomorphic approach may not only be misleading about elephants it may be even more misleading about long extinct creatures like Diplocodus. They may have lived in harmonious groups and they may have been gentle giants, protected by their size rather than by their aggression. If they had met humans they may, like elephants, have become our best friends offering small children rides at the local zoo. But the truth is we simply don’t know. They may have been highly aggressive, intent on decimating anything in their path: monster gardeners with small brains.

Where our imagination really runs wild is with the king of the dinosaurs, the Tyrannosaurus. Just their appearance - large heads, sharp claws, backward curving, doubly serrated teeth all fill us with fear. From just a few early bones Victorian palaeontologists soon built up a picture of a powerful creature with small front limbs, massive powerful rear legs, capable of grasping its prey in its jaws and casually ripping meat off in much the same way we might tackle a chicken leg. This fearsome creature has been a story teller’s dream, a monster from our worst nightmares, a beast that already lurked in the deep primeval forest of our darkest dreams. This fear is part of our genetic makeup, part of our primal instinct. Film makers and television producers have long understood the fatal attraction we have for these creatures from hell. It’s hard to imagine but perhaps Tyrannosaurus was timid and docile and that all along we have been completely wrong. We will never know, but like the lion tamer it would be a brave person that volunteered to be in the same cage as a 6 tonne reptile most scientists agree was a ferocious carnivore.

Holding Hands with Dinosaurs 02

2008-04-07T01:44:00.000-07:00

Miami museum

Holding Hands with Dinosaurs
By Stuart Carter
The fact that dinosaurs are long extinct adds to their intrigue. Like a murder hunt it needs careful forensic work to unlock the secrets of how they walked, ate and bred. Fossil evidence tells us that like most other reptiles and birds the dinosaurs built nests and laid eggs. The remains of nests and newly hatched plant eating dinosaurs have been found in Montana in the USA. Layer upon layer of fossilised nests in the Gobi Desert suggest that the dinosaurs returned to the same nesting sites year after year. Nests, young helpless chicks and caring parents all are images that we find familiar and comforting. It reassures us that even a creature as strange and alien as a dinosaur was capable of the nurturing, social behaviour that we find so reassuring and essential in our own lives.
There is also the vexed question of whether dinosaurs were cold or warm blooded. Reptiles are cold but birds are warm blooded. But again, short of cloning a modern dinosaur from ancient original DNA molecules (as portrayed in Michael Crichton brilliant book "Jurassic Park" later turned into a Hollywood block buster by Steven Spielberg) we can never know the absolute truth. But perhaps the greatest mystery of all is how they became extinct. What force of nature was so powerful that it managed to kill off the most successful group of animals of all time? Theories about their demise range from asteroid impact, rising sea levels to today’s main contender: massive volcanic eruptions. Read our previous article

"Extinction!" which points to an intriguing balance of all three factors. Whatever killed them must have been catastrophic. A highly successful group of animals that roamed the Earth for over 150 million years, more than seventy times longer than humans, were wiped off the surface of the planet forever.
A whole branch of scientific study has grown up around the study of dinosaur fossils. An even bigger entertainment industry has jumped on to a bandwagon quite literally 'full of old bones'. Palaeontologists may have been highly imaginative in the way they have built exotic creatures from fossil fragments but the producers of the highly acclaimed television series ‘Walking With Dinosaurs’ have taken it much further by personalising and humanising these ancient leviathans wherever possible.

Paul Sereno

By brilliantly recreating the past with computer animated dinosaurs superimposed onto real life backdrops (for intimate close-ups they brought on up market hand puppets) they have made perfect natural history documentaries, telling stories of individuals and of families. They told of the perils faced by baby dinosaurs, the love of a mother for her child, the unselfish act of heroism for the needs of the herd. They painted a picture of the life and death struggle that all living creatures face - of animals capable of much more than just reaction and instinct. The reality is we can never know how this fascinating and successful group of extinct animals really behaved. The scientists have to make sure that the distinction between reality and what we would like to imagine happened remains clear and truthful.

Our fascination with dinosaurs will never diminish. Reflected in the lives of the dinosaurs we can see the same struggles that we face in our own lives. As an added bonus we can also confront the monsters hidden in our deep subconscious. New waves of technologies will improve the way we can recreate the past and breathe fresh life into our dino-mania. Soon we will be able to interact with them on the web or merge with them on giant screens in our living rooms; the land of the dinosaurs will become the ultimate virtual holiday destination. Imagine a world where we can smell, touch and be chased by monsters from our distant past...

Who Wrote the Book of Life? 01

2008-04-07T01:42:00.000-07:00

Who Wrote the Book of Life?
By Leslie Mullen

The "D'Arcy Machine" and the quest for the 'Book of Life'.

In order to effectively search for life on other planets, we first have to come to an understanding about what life IS. One way to do this is to study the forms that life can take, and this is just what NASA is currently studying with the 'Book of Life' project.
In his 1917 work, "On Growth and Form," D'Arcy Thompson altered mathematical functions in order to visualise how species changed shape over time.
Scientists are using Thompson's biomathematical studies of life forms on Earth to postulate about life forms throughout the universe. There are certain universal conditions that will always affect the shape of a life form, wherever that life may be.

"Everywhere Nature works true to scale, and everything has a proper size accordingly," wrote Thompson"Cell and tissue, shell and bone, leaf and flower are so many portions of matter, and it is in obedience to the laws of physics that their particles have been moved, moulded and conformed."
Gravity, for instance, acts on all particles and affects matter cohesion, chemical affinity and body volume. Other influences that are consistent throughout the universe are temperature, pressure, electrical charge and chemistry.

But before we can conduct a comprehensive search for unknown extraterrestrial forms of life, there needs to be an extensive classification of known life forms on Earth. The history of life on Earth provides us with a good model for how life can evolve in the universe. Fossils, even microbial fossils, can tell us a great deal about all the different life forms that have at one time or another shown their face on our planet.
"Some fossils in the ancient Burgess shale are so alien we can't determine which end of the creatures are up, and yet these monsters evolved right here on Earth from the same origins that we did," wrote Johan Forsberg, a Swedish psychologist.

By becoming forensic scientists, researchers can develop an encyclopaedia of microbial life forms that have developed on Earth. Because so many life forms need to be catalogued, the scientists are working to develop a "D'Arcy Machine" to help them create a comprehensive "Book of Life."

This Book of Life project has three phases.
Phase 1 - compiling a beginning database of microbial life forms - has already been completed. This image database is composed of 10,000 examples and distinguishes the basic microbial shapes such as rods, spheres, filaments, clusters that look like grapes (cocci), and spirochete (spirals). A computer neural network has been trained to recognise and classify these microbial life forms with 90 percent accuracy.
Phase 2 of the project will expand the basic database by using a more powerful neural network. Funds from the NASA Advanced Concepts Office provided scientists with a Beowulf-class (A Beowulf-class computer is a cluster of personal computers running LINUX, connected by its own private Local Area Network) parallel computer, to address scientific problems associated with large data sets.

Scientists have named the new parallel computer "Leibniz," after the German mathematician whose lifelong goal was to organise all human knowledge. This computer system will expand the image database by acquiring and classifying new and ambiguous images. To discriminate organic life forms from inorganic shapes, microbiologists often use the vague criteria, "Does it look alive to you?" A parallel computer using pattern recognition can make this task easier and more exact by breaking the starting image down into identifiable parts.

"Human judgement is still very much depended upon for identifying microbial life forms," says Dr. David Noever of NASA's Marshall Space Flight Centre. "Automated filters would be much like the filters commonly used to sort out useful e-mail's from useless ones. The user of the neural network would get a morning menu of microbial candidates for further detective work."
Although the trained human eye is better at recognising microbial life forms, using a computer "filter" to check for lifelike patterns could help cut the immense scale of the Book of Life project down to a more manageable size.

By Phase 3 of the project, the neural network will be so advanced in its learning that it will be able to acquire and classify new images with minimal human supervision. This network would then be equipped for future search scenarios, including the examination of meteorites found on Earth and samples retrieved from lunar or interplanetary space missions. This advanced neural network will be a fast and efficient classifier of the vast amount of microbial images that will need to be catalogued.

A Big ProblemThis speed and efficiency are extremely important due to the detail with which the samples must be analysed. Not only are there a lot of samples to study, but there are multiple dimensions to consider. D'Arcy Thompson used mostly linear and quadratic maps to compare different life forms. Linear maps between two shapes require four coefficient variables, while quadratic maps use 10 variables.
Thompson wrote in "On Growth and Form," "I know that in the study of material things number, order, and position are the threefold clue to exact knowledge: and that these three, in the mathematician's hands, furnish the first outlines for a sketch of the Universe."

Who Wrote the Book of Life? 02

2008-04-07T01:39:00.000-07:00

Who Wrote the Book of Life?
By Leslie Mullen

While Thompson and other biomathematicians used almost exclusively linear and quadratic distortions to study how life forms change over time, it is unlikely that complex life forms throughout the universe will be confined to these narrow statistical relationships. Accordingly, D'Arcy Thompsons work is being extended through the use of computers.

When D'Arcy Thompson introduced the idea of studying organisms by their geometric shapes, he could only draw figures by hand. The computers of today can take Thompson's research much further. By repeatedly comparing and contrasting learnable imagery, a D'Arcy machine would expand the chapters of the Book of Life Project and give us an interplanetary version of D'Arcy Thompson's classic "On Growth and Form."

Computers with artificial intelligence using neural networks provide more opportunities to answer complex astrobiology imaging questions. The non-linear evolution of artificial intelligence is customised to handle the learning of multiple patterns or images. Computers with artificial intelligence could accommodate various influencing variables (such as gravity) that change over scales much larger than a linear variance can include. Changes in the effects of gravity on a body can occur, for instance, when humans go into outer space. Astronauts often experience fluid retention, excessive bone loss and muscle wasting due to the effects of microgravity.

The neural network at Marshall Space Centre will be able to rapidly process the complex computations necessary for mathematically analysing the shapes of life (morphometrics). If someone continuously used a hand calculator to tabulate just linear connections, at a rate of one calculation per second it would take forty years to finish a billion calculations. The computer system speeds up this process dramatically, processing over a billion connections per second.

Writing the Interplanetary Book of Life
The powerful capabilities of a D'Arcy classification machine could also be used to study and catalogue images from the 14 known Martian meteorites. The total mass to be scanned exceeds 20 kilograms (44 lbs.), so if micron scale images are included in future projects (1 micron is 1-millionth of a metre, or 1/25,000 of an inch) the combined image handling capabilities for biogenic classification will exceed several trillion frames.

Looking for life forms in Mars rocks for example, means analysing microfossils - potentially of nanometer-size. So small that 50,000 could fit across the width of a single strand of human hair.

Based on past performance, the Antarctic meteorite (ANSMET) field teams are likely to recover at least 1,000 meteorites over the next three years. Although it is likely that only a small fraction of these meteorites will be of interest scientifically, already AMNSET has discovered 28 meteorites that are often sampled for study. Since 1976, 301 individual investigators representing 24 nations have received more than 10,800 meteorite samples.

To put this scale of computer acquisition and search in context, compare it to the challenge of creating the 1996 animated feature "Toy Story." It took nearly 3 hours for a supercomputer to process each one of that film's 140,000 frames. The challenge of classifying images of life forms constitutes a task exceeding the creation of more than 10,000 high quality computer-animated films.

Life is not an easy thing to define. Even now, we're finding life forms on Earth that we never before thought possible. Extremeophiles (bacteria that live in extreme environments) have been found living in hydrothermal vents and in high salt environments - areas once thought to be completely inhospitable to life. In 1997, Stephen Zinder of Cornell University discovered the existence of bacteria that thrive in the harsh solvents perchloroethylene and trichloroethylene that are used to clean machine parts. An acid-loving bacteria, Sulfolobus acidocaldarius, can live under conditions that would dissolve human skin in seconds.

By using a D'Arcy machine to begin a study of microbial life on Earth, someday remote and automated instruments may be able to identify life elsewhere in the universe - whatever form that life may take.

The Rise and Fall of the Mayan Empire 01

2008-04-07T01:26:00.000-07:00

Photo copyright Tom Sever.

The Rise and Fall of the Mayan Empire
By Patrick L Barry

Scientists are using space satellites to unravel one of the great mysteries of the ancient Mayan Empire.

Where the rain forests of Guatemala now stand, a great civilization once flourished. The people of Mayan society built vast cities, ornate temples, and towering pyramids. At its peak around 900 A.D., the population numbered 500 people per square mile in rural areas, and more than 2,000 people per square mile in the cities - comparable to modern Los Angeles County.

This vibrant "Classic Period" of Mayan civilization thrived for six centuries. Then, for some reason, it collapsed.

The fall of the Maya has long been one of the great mysteries of the ancient world. But it's more than a historical curiosity. Within sight of the Mayan ruins, in the Petén region of Guatemala near the border with Mexico, the population is growing again, and rain forest is being cut to make farmland.

"By learning what the Maya did right and what they did wrong, maybe we can help local people find sustainable ways to farm the land while stopping short of the excesses that doomed the Maya," says Tom Sever at the Marshall Space Flight Center (MSFC).

Sever, NASA's only archeologist, has been using satellites to examine Mayan ruins. Combining those data with conventional down-in-the-dirt archeological findings, Sever and others have managed to piece together much of what happened:

From pollen trapped in ancient layers of lake sediment, scientists have learned that around 1,200 years ago, just before the civilization's collapse, tree pollen disappeared almost completely and was replaced by the pollen of weeds. In other words, the region became almost completely deforested.

Without trees, erosion would have worsened, carrying away fertile topsoil. The changing groundcover would have boosted the temperature of the region by as much as 6 degrees, according to computer simulations by NASA climate scientist Bob Oglesby, a colleague of Sever at the MSFC. Those warmer temperatures would have dried out the land, making it even less suitable for raising crops.

Rising temperatures would have also disrupted rainfall patterns, says Oglesby. During the dry season in the Petén, water is scarce, and the groundwater is too deep (500+ feet) to tap with wells. Dying of thirst is a real threat. The Maya must have relied on rainwater saved in reservoirs to survive, so a disruption in rainfall could have had terrible consequences.

(Changes in cloud formation and rainfall are occurring over deforested parts of Central America today, studies show. Is history repeating itself?)
Using classic archeology techniques, researchers find that human bones from the last decades before the civilization's collapse show signs of severe malnutrition.

"Archeologists used to argue about whether the downfall of the Maya was due to drought or warfare or disease, or a number of other possibilities such as political instability," Sever says. "Now we think that all these things played a role, but that they were only symptoms. The root cause was a chronic food and water shortage, due to some combination of natural drought and deforestation by humans."

The Rise and Fall of the Mayan Empire 02

2008-04-07T01:18:00.000-07:00

Photographed by Daniel Irwin

The Rise and Fall of the Mayan Empire
By Patrick L Barry

Today, the rain forest is again falling under the axe. About half of the original forest has been destroyed in the last 40 years, cut down by farmers practicing "slash and burn" agriculture: a section of forest is cut down and burned to expose soil for planting crops. It's the ash that gives the soil its fertility, so within 3-5 years the soil becomes exhausted, forcing the farmer to move on and cut down a new section. This cycle repeats endlessly ... or until the forest is gone. By 2020, only 2% to 16% of the original rain forest will remain if current rates of destruction continue.

It seems that modern people are repeating some of the Maya's mistakes. But Sever thinks disaster can be averted if researchers can figure out what the Mayans did right. How did they thrive for so many centuries? An important clue comes from space:

Sever and co-worker Dan Irwin have been looking at satellite photos and, in them, Sever spotted signs of ancient drainage and irrigation canals in swamp-like areas near the Mayan ruins. Today's residents make little use of these low-lying swamps (which they call "bajos," the Spanish word for "lowlands"), and archeologists had long assumed that the Maya hadn't used them either. During the rainy season from June to December, the bajos are too muddy, and in the dry season they're parched. Neither condition is good for farming.

Sever suspects that these ancient canals were part of a system devised by the Maya to manage water in the bajos so that they could farm this land. The bajos make up 40% of the landscape; tapping into this vast land area for agriculture would have given the Maya a much larger and more stable food supply. They could have farmed the highlands during the wet season and the low-lying bajos during the dry season. And they could have farmed the bajos year after year, instead of slashing and burning new sections of rain forest.

Could today's Petén farmers take a lesson from the Maya and sow their seeds in the bajos?

It's an intriguing idea. Sever and his colleagues are exploring that possibility with the Guatemalan Ministry of Agriculture. They're working with Pat Culbert of the University of Arizona and Vilma Fialko of Guatemala's Instituto de Antropología e Historia to identify areas in the bajos with suitable soil. And they're considering planting test crops of corn in those areas, with irrigation and drainage canals inspired by the Maya.

Life at the Extremes 01

2008-04-06T22:36:00.000-07:00

Credit:carleton.ca

Life at the Extremes
By Rachel Dodds
Some living species are able to thrive in inhospitable environments. How do they do it?

Life has flourished here on Earth. Typically, living things are found in warm, wet, sunlit zones, at pressures similar to those at sea level and in conditions that are neither acidic nor alkaline. But living cells have also been found in areas that seem inhospitable to life: in hot springs, lying dormant buried in ice, in acid-filled caves and in the depths of the ocean. By exploiting new environments, these pioneering organisms gain a competitive advantage that allows them to proliferate. How are they able to tolerate these conditions?

Normal versus extreme

Life is inextricably linked to water and is usually found within the range of temperature and pressure where liquids can exist. Organisms that live on land tend to favour a temperature range of 10 degrees C to 48 degrees C, while life in the ocean exists at around 2 degrees C year round. At higher temperatures, vital long chain carbon molecules acquire too much energy from their surroundings and lose their important 3D shapes. At lower temperatures, chemical reactions slow down, making it difficult to sustain metabolism. At subzero temperatures, water inside living organisms can form ice crystals which damage the delicate internal architecture of cells.

Low pressure environments are rare, even at the top of the tallest mountain ranges. High pressure is a much more common stress factor, particularly at the bottom of oceans where the weight of the water generates a crushing force up to 1,100 times the pressure at the surface. There is also a lot of pressure inside rocks and sediments beneath the surface of the Earth where some bacterial species have been found.

In addition to these physical constraints, chemical stress factors like salt concentration and pH, a measure of how acid or alkali an environment is, also affect what can survive in an environment. All living things separate themselves from the outside world with a cell membrane. This allows them to control the concentrations of important or dangerous chemicals within their cells. In very salty conditions, cells struggle to retain their water as it floods out to dilute the salt outside the cell. Many of the problems associated with salty environments are due to lack of water.

The pH of an environment also has many consequences for cells. Since most biological processes occur in the neutral range of the pH scale, biological molecules lose their function in both acid and alkali environments (low and high pH respectively).

Surviving extreme conditions

Every living organism has a range of conditions over which it is able to undergo normal activity, and when it is pushed to its limits, it struggles to survive. Some species that survive in extreme environments are true extremophiles and do not seem to find the conditions harsh at all. But in most cases, living things develop elegant tolerance mechanisms that help them adapt to their surroundings.

Animals seem to have developed three basic tolerance strategies. The first involves slowing down and sitting it out: animals often reduce their metabolism and sometimes enter into hibernation. Others may find a more favourable environment, like animals that migrate to avoid seasonal extremes. Living things sometimes also launch a counterattack, like wood frogs that produce antifreeze proteins to prevent ice crystals forming in their cells in the extreme cold.

Life at the Extremes 02

2008-04-06T22:19:00.000-07:00

Courtesy of the NOAA

Life at the Extremes
By Rachel Dodds

However, these tactics usually only work for occasional exposure and to flourish, major adaptations are required at the biochemical level. For the most part, micro-organisms, like bacteria, archaea and fungi, have achieved these more complex adaptations.
Super cells

Proteins are large complex molecules made up of amino acids that perform many diverse and essential functions within living cells; enzymes, for example, enable chemical reactions to take place. Their function is directly a consequence of the 3D arrangement of their amino acid chains in space. Physical and chemical stress factors interact with proteins to alter their structure and consequently, their function.

Whether cells can isolate themselves from their environment and protect themselves depends on the type of conditions they are exposed to as well as the properties of their cell membranes. Extreme environments that are mediated through chemicals (pH and salty environments) can be manipulated by cells so that their internal biochemistry need not be rewritten. For example, there is usually a difference of 2 pH units between the outside and inside of cells in an acid or alkali environment. Cells can achieve this by actively pumping ions out of the cell through specialised membrane protein channels.

Temperature and pressure cannot be restricted to the outside of the cell; consequently, organisms that live in extreme conditions must adapt their biochemistry. Some of the most common adaptations to extreme environments are made to membranes and enzymes to ensure their continued function.

Models for extraterrestrial life?

So far, the extreme conditions considered here have been those found on our own planet. But environments found elsewhere in the Solar System are much more inhospitable. Could life as we know it survive beyond Earth and what form might this life take? Study of extreme environments has led many experts to believe that extraterrestrial life may resemble the pioneering single-celled extremophiles.

The planet Mars is the most similar to Earth and a favourite candidate for extraterrestrial life. Slightly further from the sun than Earth, it is colder with a surface temperature range of -10 degrees C to -76 degrees C. Beneath the surface, temperatures are likely to be much warmer and liquid water may exist.

Europa is one of Jupiter's largest moons. Surface temperature is an icy -145 degrees C, but 1-10 km underground there appears to be a very deep ocean of liquid water. Scientists believe that the ocean is warmed by volcanic and tidal activity caused by the gravitational pulls of nearby Jupiter and other moons. Some even speculate that there are hydrothermal vents at the bottom of Europa's ocean. If this is the case, life on the moon seems much more likely.

Astronomically speaking, there are only two candidates for extraterrestrial life within our own neighbourhood. But the discovery of planets beyond our own Solar System has re-ignited interest in extraterrestrial life. Such discoveries are accelerating due to advances in detection, and to date over 200 have been documented. At this point in time, we can only speculate about conditions on these worlds, and the life that may inhabit them.

What's In A Breath of Fresh Air?

2008-04-06T22:05:00.000-07:00

What's In A Breath of Fresh Air?
By Rhiannon Buck

Do the ions produced by sea spray improve the health of surfers and beach goers? Scientists and homeopaths are still arguing about the possible curative effects of negative ions.

When ocean waves crash onto a beach, they could be doing more than entertaining beach goers. Moving water, moving air and sunlight all cause air molecules to break apart, releasing charged atoms, or ions, into the atmosphere. Some scientists claim that there is an abundance of negatively charged ions in sea air and that they could have health benefits which range from better circulation to improved moods. A lot of people have enough faith in these effects to purchase negative ion generators for their homes. But have these curative claims ever been satisfactorily verified?

Ions in Sea Air

Ocean air contains a high percentage of ions which a surfer will inevitably encounter in their quest to find the perfect wave. These mainly come from ions of sodium, magnesium, chloride and sulphate present in sea water.

Sodium, the main positive ion found in sea water, is also found in extra-cellular fluids in our bodies. These fluids, such as blood plasma, bathe cells and carry out important transport functions for nutrients and waste. Positive magnesium ions are also used by the body and are an ingredient of some medicines like Epsom salts, which are commonly used to treat aches and pains. Negative chloride ions also play an important physiological role in the central nervous system and in transporting protein around the body.

But do these ions actually change the way we feel? The theories advocating the medicinal properties of ions tend to focus on the effects of breathing them in. It is thought that the extra charge helps our bodies take in oxygen and thus increases oxygen flow to the brain.

Alternative thinking or hard fact?

Opinions on the physiological effects of ions seem to be incredibly polarised between the ardent skeptic and the avid believer. Research seems to be centered around the effect of ionizers, which create a negatively charged atmosphere similar to the relaxing natural environments near waterfalls, on mountains, in forests or by the sea.

It is widely accepted that negative ion generators remove dust particles from the air, which can help alleviate the symptoms of patients with respiratory difficulties. Similarly, scientists at St James's University Hospital in Leeds managed to entirely eliminate common bacterial infections by installing ionizers in their intensive care unit. The team explained that the ions collided with the suspended particles and gave them a charge. The charged particles then clustered together and fell out of the air, disinfecting the atmosphere.

At the New York State Psychiatric Institute, researchers found that negative ion therapy helped to alleviate the symptoms of Seasonal Affective Disorder (SAD), a type of winter depression. During a trial, people were exposed to high and low rate flows of negative ions while they slept. Many of the patients that were exposed to a higher density of negative ions showed an improvement in their symptoms.

Negative ions are thought to alleviate depression because of their effect on serotonin, a neurotransmitter in the brain believed to play an important role in regulating mood. Studies in the 1970s reported that levels of serotonin could be affected by the type and concentration of ions breathed from air. The recent study at the New York State Psychiatric Institute found that devices emitting negatively charged oxygen particles had a similar effect to sunlight, which helps the body produce serotonin and ease seasonal depression.

The general consensus in the homeopathic community seems to be that negative ions have beneficial effects whereas positive ions are harmful. It is thought that positive ions cause a massive overproduction of serotonin in the blood which triggers the release of adrenaline into the brain. Although this should not cause any short term problems, if the body produces too much serotonin for long durations then it will not be able to keep up with the production of adrenaline. The sudden rush of adrenaline can cause anxiety and nervousness followed by a tired low as the body struggles to keep up.

Other factors to consider?

Ionizer manufacturers often state that their products are emulating the negatively charged atmosphere found in forests and by the sea. However, there is no hard evidence that the therapeutic effect of nature is caused by negative ions and skeptics claim that there could be other factors at work.

Scientists at the University of East Anglia have put the distinctive seashore smell down to dimethyl sulphide (DMS), a strong-smelling gas that is emitted by marine microbes. Their research also stresses that inhaling DMS, which is an irritant, is not necessarily healthy, although it is usually present in such low concentrations that it isn’t particularly harmful either.

In Japan, many people seem to believe that ionizers provide health benefits. Many personal products like toothbrushes, washing machines and refrigerators have been adapted to emit ions. Forest bathing, or shinrinyoku, is a popular Japanese therapy and involves being guided through a forest and taking deep breaths of the air, which is rich with particles emitted by the trees. However, forest bathers mostly agree that the improvement in their wellbeing is caused by breathing in phytoncides released by the trees. Phytoncides are organic compounds that are emitted from some plants to prevent them from rotting or being eaten by certain animals or insects.

Although the effect of ions on human health is still being debated, most people would agree that breathing fresh, clean air is good for one’s health. Polluted city air and dusty indoor locations are unpleasant for most people, especially those with asthma and other respiratory conditions. Whether this has to do with ions in the air or not, there is no doubt that spending time out in nature contributes to a healthy lifestyle.

Urban Possum: Friend or Foe? 01

2008-04-06T22:01:00.000-07:00

Credit: Peter Firminger

Urban Possum: Friend or Foe?
By Daniela Binder

Brush-tailed possums are now common in Australian urban areas and researchers are looking at whether they could be spreading diseases to humans and livestock.

Brush-tailed possums used to be a common site in the Australian bush. Recently, their populations in the wild have been declining and many are now found in urban areas, showing a remarkable ability to adapt to city life and breed successfully. But for many humans who live close to the possums, they are not the cute and cuddly creatures they appear to be. Rather, they prove to be destructive pests who damage property, trees and vegetable patches. Even more troubling are the claims that possums are spreading disease to humans and livestock. Are possums in fact transmitting diseases to other species?

Disease carriers?

At Macquarie University, in Sydney, Australia, doctoral student Nichola Hill and a team of researchers in the department of marsupial immunology are investigating whether brush-tailed possums could be carrying zoonotic pathogens - disease producing agents that are infectious to both animals and humans. They are studying possums living in the grounds of Sydney’s Taronga Zoo and are screening the possums for a range of these pathogens. There are growing concerns that the increasing urbanisation of wild habitats may facilitate the exchange of diseases between humans and the wildlife that live near urban boundaries.

On four days out of every month, the researchers trap several of the zoo’s 150-180 resident possums. They are scanned to see if they have already been microchipped, and thus previously examined, and faecal samples are collected at the site for later analysis.

Urban Possum: Friend or Foe? 02

2008-04-06T20:45:00.000-07:00

Source: FirtsScience.com

Urban Possum: Friend or Foe?
By Daniela Binder

The possums are then driven to the veterinary clinic for examination. With the help of a veterinary nurse, they are anaesthetized and their temperature, heart rate, and respiratory rate are noted. Hill also records their weight and size and checks the state of their teeth, often a good indicator of the animal's age.

The possums are then inspected from the outside for injuries and illnesses and hair, blood and faecal samples are collected. Hill delights in finding fleas, ticks, and other parasites on the possums’ coats which she studies under her microscope. Once the animals are examined, they recuperate in separate cages, a necessary condition since possums are very territorial. They are fed apples, bananas, and home-made muesli bars before being released later in the evening in the same place that they were found.

Tracking the diseases

Back in the lab, Hill analyses the data she has collected. By identifying antibodies in the possums’ blood plasma, she can find out which diseases they could be carrying. Hair and faecal samples are viewed under the microscope to identify other potentially harmful microorganisms and external parasites.

Hill has found that possums do carry a range of parasites and pathogens. However, most of them exhibit host-adaptation, which means that the diseases have become suited to possum hosts and would not be able to thrive in humans. The evolutionary divergence of marsupials and humans has left few pathogens that are able to swap hosts and survive. ‘At this stage of my research, I would say that possums are unlikely to act as a reservoir for zoonotic disease in urban areas,’ says Hill.

Sick possums

Ironically, research has shown that possums themselves are prone to catching fatal infections like toxoplasma from domestic cats. ‘Possums have adapted their biology to exploit the higher concentration of resources in urban areas, but there is a flip side in that they have to live in an environment where there is a range of introduced pathogens,’ explains Hill. As the possums have not co-evolved with these pathogens, they often have not developed immune protection, and can die from the infections.

In the future, Hill will track possums with Global Positioning System (GPS) collars to determine the extent of their movement into urban areas. She also hopes to find out how dependent these animals are on human resources of food and shelter. Although possums seem to be at home in urban areas, there is still ground to cover to ensure they survive in the long term. ‘We need to limit the interaction of domestic pets and native fauna by restricting the ranging behaviour of pets at night and doubling our efforts to control feral cat and dog populations,’ Hill says.

Herbal Remedies Reviewed 01

2008-04-06T20:33:00.000-07:00

Photo courtesy of Luke Hansen

Herbal Remedies Reviewed
By Jen Schripsema

Herbal remedies can be a more natural alternative to treating medical problems, but they also have their dangers.

Many people are now choosing to cut out the middleman by treating their medical problems themselves with herbal supplements. The face of herbal medicine, once dominated by patchouli-scented hippies and gauzy New Age types, is changing. Soccer moms are treating their children's colds with chicken soup and echinacea and college students fuel all-night study sessions with energy drinks boasting ginkgo and ginseng. Even in your local convenience store, snacks and drinks touting herbal ingredients are slowly encroaching on traditional junk food territory.
Every year, the Centers for Disease Control and Prevention (CDC) conduct a health survey of American households and a variety of other groups may request supplemental surveys as well. In 2002, the National Center for Complementary and Alternative Medicine, which studies everything from yoga to acupuncture, sponsored a supplemental survey to measure herbal and dietary supplement use.
What the Survey Said
Jae Kennedy of Washington State University used this information to provide the first detailed national portrait of herbal medicine in the U.S., which was published in Clinical Therapeutics in January 2006. He found that echinacea, ginseng, ginkgo and garlic were, in that order, the most common herbs regularly taken by Americans. Nearly one fifth of Americans (38.2 million people), regularly took at least one type of herbal or dietary supplement. This number had doubled in only three short years since the previous survey in 1999 and is likely to be even higher now.
Kennedy found that regular herbal and dietary supplement use was higher among women, middle-aged adults, and college graduates. People with multi-racial, Asian, or Native American backgrounds also reported a higher usage. Using herbs and dietary supplements seems to be part of a concerted effort to improve health: generally, herbal supplement users exercise regularly, no longer smoke cigarettes, and report being in good or excellent health.
Kennedy's findings also show that most people use herbal medicine to complement conventional medicine, not to replace it. "For some conditions like depression and chronic pain, herbs might be a less toxic, less extreme kind of solution," says Kennedy. "These kinds of conditions are tough to treat effectively with conventional drug treatment."

The evidence suggests that many people are satisfied with alternative treatments of chronic conditions. A study from Harvard researchers published in 2001 in the Annals of Internal Medicine showed that almost half of the people who had tried some type of complementary or alternative medicine were still using it 11 to 20 years later.

Not So Safe

There are, however, a number of concerns about the use of herbal medicine. "Of all the complementary and alternative medicines, herbal medicine has, I think, the most potential but also the most risk to patients," says Kennedy. "There's this impression that herbs are safe and natural. But they can interact with other drugs and other herbal products and cause serious health consequences." Unfortunately, most people and even many physicians are not aware of the potential dangers.

For example, St. John's Wort can decrease the effectiveness of birth control pills. Feverfew, garlic, ginkgo, ginseng, and ginger all thin the blood; using any of these herbs in combination with prescription blood-thinners can lead to uncontrolled bleeding. Ginseng alters blood glucose levels and should never be used by people with diabetes.

Herbal Remedies Reviewed 02

2008-04-06T20:21:00.000-07:00

Photo courtesy of Jen Schripsema

Herbal Remedies Reviewed
By Jen Schripsema

The perceived safety of herbal supplements leads many people to use them without supervision. Only 5% of those taking herbs were doing so under the care of an alternative medicine provider. Additionally, two-thirds of people using herbal supplements did not tell their physician.

Herbal medicine use may also reveal fundamental problems with access to healthcare. Kennedy is currently involved in research that shows that St. John's Wort use is higher in people without insurance or a primary care physician. "They are self-treating with cheap, unregulated alternatives because they can't afford to pay for prescription medications and psychiatry visits," says Kennedy.

The U.S. Food and Drug Administration (FDA) classifies herbal supplements as a food, not a drug. They are, therefore, not subject to the same testing, manufacturing, and labeling standards as prescription and traditional over-the-counter drugs. "There is no enforcement using current regulation," says Kennedy. "When you've got for-profit companies selling these products and treating them as benign dietary supplements instead of drugs, that's potentially a problem."

Companies may mislabel, misidentify, or adulterate the products they sell. A study published in May 2006 in the Journal of Agricultural and Food Chemistry underscored the extent of this problem. Researchers from Columbia University and the City University of New York tested 11 commercially available brands of black cohosh, used to treat symptoms of menopause, and found that three of those products contained no black cohosh at all.

Even when products are properly labeled, important information is often missing. "They are not sold with any warnings. The dosage is indeterminate," says Kennedy. "There's no clinical studies for the most part on appropriate dosing. There's certainly no placebo testing of herbal medicines, which is the gold standard for testing pharmaceutical products."

However, obtaining funding for this research can be difficult. "Since you can just go out and pick this stuff, the pharmaceutical industry isn't going to be interested in bringing things to market and identifying the active agents and synthesizing them. So there's no business funding for the kind of clinical trials we get for a lot of prescription drugs," says Kennedy. Governmental funding is available but limited and he says that since The National Center for Complementary and Alternative Medicine is a tiny component of the National Institutes of Health, they are trying to do a lot with a little budget.

Kennedy has suggested that future research should investigate the role of pharmacists in patient education about potential risks and benefits of herbal medicines. But until more research is conducted and stronger regulations are put in place, the advice "buyer beware" rules herbal medicine.

Kennedy envisions a future where patient care is a cooperative effort. "We're trying in this field to encourage at least informing your physician, but ideally moving towards an integrative medicine model where the physician, and the patient, and any complementary and alternative medical providers are working as a team."

Feeling Seasick? 01

2008-04-06T20:10:00.000-07:00

Courtesy of Alvin Smith

Feeling Seasick?
By Jen Schripsema
A virus originating from the ocean has been found in human blood samples.

Oceans cover most of our planet, yet we know very little about marine ecosystems and even less about their pathogens and how they might infect us. When virologist Alvin Smith was working as a veterinarian for the U.S. Navy, he found that one marine virus called Vesivirus was causing a multitude of symptoms in a very wide range of animals - and could also spread from animals to humans. More recently, along with a team of researchers from Oregon State University, Eastern Virginia Medical School and AVI BioPharma, he has been studying how prevalent Vesivirus is in the general human population.

Vesivirus can infect a broad range of species due to an adaptive trait that has developed based on its replication mechanisms. Part of a family of viruses called Calciviruses, its genetic information is coded with RNA, not DNA. RNA replication lacks the proofreading inherent in DNA replication, making it very error-prone. Every virus replicated will have one to ten mistakes in the genetic code. Thus, the children from a single parent will virtually all be unique variants.

Although Vesivirus is present in the ocean, it can easily get to the surface. Much like the spray that comes off a freshly poured glass of soda, it can become airborne by erupting in bubbles at the surface of the water. "If you think about it, the ocean is a much easier place for a virus to get around anyway," says Smith. "When the viruses are shed, they're in basically a big bag of saline, so they can move around pretty freely and don't decay nearly as rapidly as they might on land."

Smith's theory was that many people could be unknowingly infected by the virus. It does not have a specific set of symptoms and can sometimes manifest itself simply as a blister - as exemplified by two scientists a few years ago who contracted the virus, one in the lab and one by working with marine mammals in the field. "If you don't know it's there, and you don't know to test for it, then it simply doesn't exist," says Smith.

To test how widespread the virus really is, the researchers decided to examine many samples of human blood. They obtained over 700 blood samples from a laboratory processing blood donations intended for transfusion - and looked for the presence of Vesivirus as well as for antibodies to Vesivirus which would indicate a previous infection

Feeling Seasick? 02

2008-04-06T19:21:00.000-07:00

Courtesy of Alvin Smith

Feeling Seasick
By Jen Schripsema

The results showed an interesting correlation with liver damage. Among normal blood donations, 12% had antibodies to the virus but in donors with liver damage, 21% had antibodies. Based on this preliminary data, the researchers obtained blood samples from patients with clinical hepatitis, or inflammation of the liver, and found that 29% of those samples had antibodies. Finally, in people who developed hepatitis from an unknown cause after being transfused - 47% had antibodies to Vesivirus.

Further testing that looked for the presence of the actual virus also showed a higher proportion of infections among people with liver damage. Eleven percent of people with liver damage had the virus, compared to only 5% for normal blood donors.

Although this study doesn't prove that Vesivirus infection causes hepatitis in humans, Smith says that there is no reason to believe that it doesn't. He is currently working on strengthening the evidence of a link between Vesivirus and hepatitis so he can push for Vesivirus screening of the blood supply.

Environmental exposure may put some people at risk of contracting Vesivirus, and it is always wise to keep a safe distance from sickly-looking animals, but researchers believe the biggest danger is probably contaminated meat, seafood, or drinking water. Smith advises against eating undercooked or raw seafood.

For those who are infected, biotech company AVI BioPharma is investigating the use of their proprietary NeuGene antisense compound as an anti-viral treatment for Vesivirus. The technology uses a synthetic compound that binds closely with points along the code of the RNA sequence that tell the virus to begin replication. "It's like blocking a zipper," says Smith.

NeuGene drugs developed using this technology successfully stopped an outbreak of fatal Calicivirus in cats. The company is developing several other drug candidates for treatment of other RNA viruses including hepatitis C, influenza, and West Nile virus. This technology may signal the beginning of the end of the "wait and see" approach to viral infection treatment.

Aquatic Culture - Dolphins Communication 01

2008-04-05T05:46:00.000-07:00

Wild Dolphin Project

Aquatic Culture - Dolphins Communication
By Denise L. Herzing

Dolphins and the Possibility of Interspecies Communication
In 1985 I began a long-term project in the Bahamas to observe and study, underwater, a resident group of Atlantic spotted dolphins, Stenella frontalis. Over the last 16 years we've recorded life history information, communication (visual and postural) signals during fighting, foraging, and play, and how mothers teach their calves to hunt, fight, and babysit younger dolphins.

The richness of behavior we've observed over 16 years at sea speaks of a culture of intelligent aquatic beings, with complex communication and flexible coping strategies in the world. Dolphins are the aquatic equivalent of an advanced terrestrial culture. Such observations reinforce the idea that perhaps dolphins would be good candidates with the motivation to interact with, and potentially communicate with humans.

The possibility of communicating with nonhuman animals has long fascinated humans as long ago as Aristotle. Interspecies interaction, specifically human/dolphin, is a very old phenomenon but a reemerging field of scientific inquiry. The more we inquire into the lives and minds of dolphins, and other toothed whales, the more we find evidence of complex societies, communication, and cultures. Only recently have we begun to search in the wild for such evidence and opportunities to work. This interest stems from years of exploring the possibilities of communication with other species, usually in non-wild environments.

Our History Exploring Dolphin Communication
Many of our popular beliefs about dolphins come from the work and writings of John Lilly. Originally a neurophysiologist with an interest in the dolphin brain, Lilly began to understand that dolphins were too intelligent to experiment on, and forged his own path to interspecies communication. Although his later work remains controversial, many of his original ideas remain intriguing. Lilly pursued a controversial career, trying to teach dolphins English and matching vocal output by the dolphins to humans. Although able to mimic the prosodic aspects of human speech such as rhythm and intensity, the dolphins were unable to produce consonants involved in the production of English sounds, most likely due to the lack of necessary anatomy.

Since Lilly's time a picture has emerged from long-term research projects around the world. Ken Norris and his colleagues in Hawaii have studied spinner dolphins, Stenella longirostris, Randall Wells and his colleagues in Sarasota, Florida continue to study bottlenose dolphins, Tursiops truncatus, and my ongoing work in the Bahamas studying Atlantic spotted dolphins, Stenella frontalis. We know many realistic aspects about life as a dolphin in the wild both biologically and ecologically. But what will it really take to break the code, to build a bridge between species, in this case an aquatic mind evolved over a 30 million year old aquatic in a socially complex environment?

Picture : Wild Dolphin Project

What have we learned?
In captive settings, giving the dolphins control over the choice of reinforcement and social interaction with nonhuman subjects has been paramount in the investigation of interspecies communication. Success has often been determined by the selection of the appropriate sensory modality within which to communicate and work. Participatory research, in combination with observations of a species natural communication system, may be a fresh method of investigation available to us.

We can see parallels from primate researchers over the years who have focused on training their nonhuman subjects with artificially derived codes. This mutual system of approach, or two way communication methodology, has often been chosen because of the difficulty of comparing and deciphering the complexities of nonhuman natural systems.

Communicating with our nearest relatives.
In the history of work with captive primates there is a continuum of methodologies researchers have used, from very objective and strict, to more interactive, involving bonding with the animals under study. One of the first studies, by David Premack, was a chimpanzee named Sarah who was acquired from the wild. She was trained with the use of a board, testing her ability to discriminate "same and different" objects. Premack used an interrogative concept and remained separate and "objective" during his work with Sarah. His work could be considered on the far end of the continuum.

Aquatic Culture - Dolphins Communication 02

2008-04-05T05:37:00.000-07:00

Picture ; Wild Dolphin Project

Aquatic Culture - Dolphins Communication

By Denise L. Herzing

Duane and Sue-Savage Rumbaugh brought an interactive approach to their work with two other chimpanzees, Sherman and Austin. The researchers invested time developing rapport with Sherman and Austin, and also tried to develop experiments that included referents or objects that were important to chimpanzees themselves. Allowing Sherman and Austin to work as a team, possibly mimicking the way communication systems evolved under natural conditions, was also very successful. In later years they started working with Kanzi, a pygmy chimpanzee, the most closely related primate to humans. Using a portable keyboard and a semi-natural environment, Kanzi is skilled at understanding complex symbolic associations.

Another innovated approach to interspecies communication has been the work with chimpanzee Washoe. The key to this work was trying sign language, which Alex and Beatrice Gardner, and then Roger and Debbie Fouts, believed was close to the chimpanzees' natural gestural abilities. Washoe could express herself with gestures and this proved the key to the interspecific communication between chimpanzees and humans. Roger Fouts also reasoned that the chimpanzees would be much more interested in working with humans if they liked them and found them interesting. This would provide the social motivation for expressing themselves, to communicate with someone they liked, about something they desired or wanted to express. His study would later document the spread of sign language from chimp to chimp, without human intervention, as an example of cultural transmission within the chimp society itself.

Lessons about our approach!
Some of the controversies around nonhuman animal communication has centered around the "Clever Hans" story. Clever Hans was a horse that was taught to "count", among other skills, by his trainer. When a psychologist observed this interaction, he noticed that the trainer was giving Hans subtle cues, everything from face nods to slight movements. Without these "cues", Hans could not perform properly. When the "double blind" method, not allowing the trainer or experimenter the knowledge of the answer, was applied to avoid the suspected exchange of subtle cues from trainer to animal, Clever Hans could not perform.

What does the Clever Hans phenomenon suggest about biological communication in general? Could it be that these "cues" are information bits that create complex communication in the first place? If so, then we are asking nonhuman animals to do what we cannot; to be restricted to one modality, such as gestural signs or acoustic cues, and learn a multi-modal language that involves these exact subtle cues. This perhaps, could be our biggest lesson about communication and might result in the creation of a more interactive and functionally expressive methodology for interspecies communication in the future.

Despite the continuum of methodologies in all primate interspecies work, most researchers agree that creating rapport with nonhuman subjects is critical to the animal's motivation for interacting and expressing themselves. Other species are capable of interacting and communicating on a variety of levels. Perhaps it is our human challenge to develop methodologies and sensitize ourselves to the motivation of other species to maximize our opportunity to make a connection.

Perhaps the similarities we find between species may turn out to be more critical than the differences. We might find levels of mental and social continuity and convergence across social species on our very own planet, Earth.

Source : FirstScience

Lion Mane Myths

2008-03-29T06:44:00.001-07:00

Photo courtesy of Bruce Patterson

Lion Mane Myths
By Virginia Hughes

New research shows that lion manes do not help protect fighting lions as was commonly thought.

The purpose of the male lion's mane has long perplexed biologists. Because female lions roam in groups of three or four, and allow only one male to reside with them, competition between males is fierce. Rival males often fight to the death-with their enormous teeth and claws-to gain coveted access to a pride. This led many biologists - including Charles Darwin - to assume that the function of the thick manes was to make it harder for attackers to reach the vulnerable throat area. But over the years this assumption has been questioned by field biologists who actually saw lions fight and noticed that the mane area was rarely targeted.

Evolutionary biologist Peyton West and her colleagues from the University of Minnesota used life-size lion dummies to test if manes indeed offered protection. The researchers first lured some lions to the testing area by playing tapes of hyenas feeding at a kill, then presented them with the fake rivals. "Of course we worried that the lions wouldn't be fooled," West says. But many of the real lions attacked the fakes with a vengeance. Sometimes the fakes worked so well in fact, that even after the real lions knocked them over, they tended to stick around and maul them some more.

The real lions didn't attack the models at the neck, but on the back and hindquarters, putting a serious snarl in the protective mane hypothesis. To see if the males were avoiding the neck because the mane was acting as a shield, the researchers repeated the tests with "maneless" fakes. But even with these exposed-neck models, the real lions went first for the backside. "We were pretty surprised to find so little evidence for protection," West says. "It's so intuitive that the mane would work that way."

But it turns out those shaggy manes are used for attracting females. In previous research published in 2002, West had shown that males with longer and darker manes were older, better fed, and better fighters. And because females rely on males to protect their cubs, it makes sense that females would prefer males with large manes. "Just as songbirds can advertise their quality though visual cues, so, apparently, do lions," says field biologist Jon Grinnell of Gustavus Adolphus College in Minnesota. Grinnell says that West's study is new and interesting because it forces us to look at lions differently.

Photo courtesy of Peyton West

Even though today manes don't seem to offer protection, West says a protective role could have been the reason the trait evolved in the first place. In the early evolution of the trait, males may have gone straight for the neck, making individuals with manes harder to attack and thus more favored by natural selection. As evolution continued and more and more males developed manes, attacking the neck area would no longer have been an effective fighting strategy, causing lions to try for the back side instead.

But the natural selection theory has recently been contested by a new study. Research led by Dr Bruce Patterson from The Field Museum shows that a lion's mane can vary in thickness depending on the local climate and is not a result of evolution. Although useful for attracting a mate, a thick mane also comes at a price: it takes energy to grow and maintain, is cumbersome, makes a lion more visible and therefore can attract prey, can harbor parasites and most importantly, retains heat. In a northern climate, it helps a lion keep warm but in hotter areas, the lion risks overheating and so differential hair growth keeps the mane thinner.

After studying 19 lions in zoos across the United States covering a variety of climates, the researchers found that there was a correlation between mane variation and temperature, most significantly in cold weather where manes were seen to change the most. These results may cause scientists to reevaluate the lion family tree, since lions have largely been classified based on their physical appearance and the length and thickness of their mane.

The adaptability of the lion mane gives hope for lions' survival in the wild. A better understanding of their physionomy and behaviour will also help conservationists reestablish dwindling populations. "The lion is an intensively studied species and probably the best known wild cat on earth," says field biologist Luke Hunter of Wildlife Conservation Society-International, "but good science is still revealing new things about the species and turning over popular misconceptions."

Photo courtesy of Bruce Patterson

Designer Strawberries

2008-03-29T06:35:00.000-07:00

Photo courtesy of Barry Whyte

By Meagan White

Genetically-modified strawberries are paving the way to more vitamin-rich fruit.

The food pyramid is a guideline, but considering the ridiculously low amounts of fruits and vegetables people are eating in the Western world, it may have more in common with the ancient monuments in Egypt. In 2000, 81% of men and 73% of women in the United States reported eating fewer than the recommended five servings of fruits and vegetables a day. Changing people's eating habits is one way of dealing with the problem, but some molecular biologists are taking a different approach: they are developing a way to transfer genetic material into the genome of fruits to increase the health benefits of even the fewest bites.

The scientists are specifically looking at strawberries, although the method can be applied to a variety of crops. Like all fruits, strawberries provide compounds that are essential to life. They are a major source of phytochemicals, antioxidants that are thought to reduce the risk of cancer, and they also happen to be an especially important source of vitamin C.

But although strawberries already have a high nutritional content, scientists claim that these fleshy, red fruits could be engineered to be even better for our health. Until now, it has been possible to engineer foods like corn and soybeans, but scientists haven't been able to manipulate the genome of the commercial strawberry in the way that they would like. The first step involves identifying the different genes in the strawberry and understanding their function and this requires a process called transformation to occur in the fruit. Transformation involves introducing foreign DNA from one type of cell into cells of a different organism with a different genome and to do this, scientists must engineer small, independent DNA molecules called plasmids to carry genetic information to the new host genome. The process is successful when genes from the foreign DNA are incorporated into the genome of the host, in this case the strawberry, causing a permanent change in its properties. So far, attempts at transformation in different varieties of strawberries have proved to be unsuccessful.

Photo courtesy of Barry Whyte

This month, however, molecular biologists at the Virginia Bioinformatics Institute and the Department of Agriculture at Virginia Tech reported that they have developed a method of transformation that's both fast and thorough, transforming 95% of strawberry plants studied and generating a mature new plant in just four months. The biologists used a simpler berry, the Alpine strawberry, which has two sets of chromosomes instead of the eight sets in the commercial strawberry, Fragaria ananassa. It also has a shorter reproductive cycle, 14 to 15 weeks, which allowed them to produce more mutant plants in a shorter period of time.

To make the transformation process more efficient, the biologists used used a more aggressive strain of Agrobacterium, the cellular shuttle that introduces foreign DNA into the strawberry genome, to guarantee rapid infection. In transforming any given species-whether a fruit, vegetable, or slug- scientists need to know if the foreign DNA has been taken up and integrated. They ensured that very few non-transformed plants slipped through the selection process by using an antibiotic marker called hygromycin piggy-backed with a gene that codes for a specific marker protein known as Green Fluorescent Protein. By looking at the plant tissue under a fluorescent microscope, they were able to see clearly what tissue glowed green and therefore if the plants had been transformed or not with the DNA of interest.

"This method's efficiency is crucial for generating the large numbers of mutants we need to study the function of strawberry genes," said Dr. Janet Slovin, a molecular biologist at the United States Department of Agriculture in Beltsville MD. "It's a major step in developing a system that will allow scientists to identify commercially-important genes, like those that convey health benefits."
The method used by these scientists could also lead to modifications in other fruits of the Rosaceae family, which includes peaches, pears, plums, apples, cherries, raspberries and almonds. The consumption of this family of fruits ranks third in temperate regions.

Source: FirstScience

Nesting wars

2008-03-29T06:31:00.000-07:00

Photo courtesy of Steve Baldwin

Nesting Wars
By Elizabeth Quinn

Monk parakeets that have returned to the wild are causing problems for utility companies.

Since 1970, New York City has been home to a different species of immigrant: the monk parakeet. Usually a common sight in pet stores, these birds started being spotted around the city and now Brooklyn is home to the largest population. For the residents, they are an exotic addition to the natural environment, but the utility companies have deemed them a nuisance since their huge nests, often built on electrical poles, can catch on fire or cause blackouts if they are built too close to a transformer. In some states, the problem is dealt with by killing the parakeets, but in New York, some people are trying to find a less drastic solution.

Dr Eleanor Miele, a professor of elementary science and environmental education at Brooklyn College, has been studying the monk parakeets in the area for the past seven years. They are native to Argentina and Brazil and she believes that the majority of these birds were introduced to the New York City environment when a shipment of parakeets being sent out of the country was accidentally released in 1967. A small percentage of the parakeets are former pets that escaped or were released and joined this main group. Parakeets typically live about 30 years and Miele claims that some of the birds now living around the college are from the original flock.

Although monk parakeets are small birds, on average 29 cm long, their nests are hard to miss. They can be quite monstrous, sometimes reaching the size of a small car and weighing up to 2,000 pounds. Parakeets are highly social and live in colonies where up to 200 couples can share the same nest with separate entrances for each pair. Each couple's "apartment" is quite sophisticated and contains an area for laying and incubating eggs, a living area for the hatched chicks and a lookout point for the parents to guard the nest. Among parrots, they are the only species to even make a nest since other species simply find a hole to lay and incubate their eggs.

It is obvious that the size and weight of parakeet nests can make them highly destructive. In Connecticut, monk parakeets are blamed for having caused about a dozen power outages per year and four fires in the past four years. In December 2005, United Illuminating, the electric power company, used nets to trap parakeets living in 103 nests on power poles and turned them over to the U.S. Department of Agriculture where they were gassed with carbon dioxide. In Brooklyn, Consolidated Edison is responsible for electric power and they have been removing the nests without capturing the birds. However, this has to be done periodically and isn't a permanent solution to the problem.

Photo courtesy of Steve Baldwin

Nesting Wars 01

2008-03-29T06:25:00.000-07:00

By Elizabeth Quinn
According to Miele, there are better ways to deal with the nests without harming the parakeets. One option is to create a barrier around areas where they would cause serious damage or putting platforms on the poles so that the birds could make their nests away from the transformers. Having lower wires is also a possible solution since the parakeets are capable of building nests in trees, but choose the electrical wires as an alternative when they are high up.

In Florida, people have managed to trap wild parakeets and return them to the pet trade, but Miele does not think they need to be removed from natural environments. "It's a natural process, so unless there is a hazard to human health, I prefer to let nature take its course," she says. When parakeets are kept in captivity they are not as healthy, nor as brightly-colored and vigorous, as when they're in nature.

Other conservationists are in favour of a more creative solution to the nesting problem: the "monk bunker". Designed by Marc Johnson from Connecticut, it's a free-standing polyvinyl chloride pipe that can be inserted into the ground and has a multi-chambered wooden box attached to it. Chicken wire and twigs are wrapped around the box which the birds can add to to make their nests. These structures can be installed on private properties for the birds to nest in, detracting them from the power lines. The first monk bunker was tested in the garden of Julie Cook, a woman who was arrested last December for protesting against the killing of the parakeets in Connecticut. It proved to be successful and many parakeets are now nesting there.

Although they are not yet widely available to the public, monk bunkers are expected to be marketed soon on the web site monkbunkers.com. Steve Baldwin, a resident of Brooklyn and parakeet enthusiast, has already attended a grassroots session in his area to help build the nesting structures. He hopes to help Johnson develop an e-book that will be distributed free online about how to build a wild monk parrot nest. "We've proven there's a humane way of getting them off the electrical infrastructure. We have done what the scientific community has not" Baldwin says.

Photo courtesy of Steve Baldwin

Prozac for Plants

2008-03-29T06:04:00.000-07:00

Photo by the Viking Orbiters.

Prozac for Plants
By Karen Miller

How do you get plants to grow on Mars? The first step: relieve their anxiety.

Anxiety can be a good thing. It alerts you that something may be wrong, that danger may be close. It helps initiate signals that get you ready to act. But, while an occasional bit of anxiety can save your life, constant anxiety causes great harm. The hormones that yank your body to high alert also damage your brain, your immune system and more if they flood through your body all the time.

Plants don't get anxious in the same way that humans do. But they do suffer from stress, and they deal with it in much the same way. They produce a chemical signal - superoxide (O2-) - that puts the rest of the plant on high alert. Superoxide, however, is toxic; too much of it will end up harming the plant.

This could be a problem for plants on Mars.

According to the Vision for Space Exploration, humans will visit and explore Mars in the decades ahead. Inevitably, they'll want to take plants with them. Plants provide food, oxygen, companionship and a patch of green far from home.

On Mars, plants would have to tolerate conditions that usually cause them a great deal of stress - severe cold, drought, low air pressure, soils that they didn't evolve for. But plant physiologist Wendy Boss and microbiologist Amy Grunden of North Carolina State University believe they can develop plants that can live in these conditions. Their work is supported by the NASA Institute for Advanced Concepts.

Stress management is key: Oddly, there are already Earth creatures that thrive in Mars-like conditions. They're not plants, though. They're some of Earth's earliest life forms - ancient microbes that live at the bottom of the ocean, or deep within Arctic ice. Boss and Grunden hope to produce Mars-friendly plants by borrowing genes from these extreme-loving microbes. And the first genes they're taking are those that will strengthen the plants' ability to deal with stress.

Ordinary plants already possess a way to detoxify superoxide, but the researchers believe that a microbe known as Pyrococcus furiosus uses one that may work better. P. furiosus lives in a superheated vent at the bottom of the ocean, but periodically it gets spewed out into cold sea water. So, unlike the detoxification pathways in plants, the ones in P. furiosus function over an astonishing 100+ degree Celsius range in temperature. That's a swing that could match what plants experience in a greenhouse on Mars.

Pyrococcus furiosus, photographed by Henry

The researchers have already introduced a P. furiosus gene into a small, fast-growing plant known as arabidopsis. "We have our first little seedlings," says Boss. "We'll grow them up and collect seeds to produce a second and then a third generation." In about one and a half to two years, they hope to have plants that each have two copies of the new genes. At that point they'll be able to study how the genes perform: whether they produce functional enzymes, whether they do indeed help the plant survive, or whether they hurt it in some way, instead.

Eventually, they hope to pluck genes from other extremophile microbes - genes that will enable the plants to withstand drought, cold, low air pressure, and so on.

The goal, of course, is not to develop plants that can merely survive Martian conditions. To be truly useful, the plants will need to thrive: to produce crops, to recycle wastes, and so on. "What you want in a greenhouse on Mars," says Boss, "is something that will grow and be robust in a marginal environment."

In stressful conditions, notes Grunden, plants often partially shut down. They stop growing and reproducing, and instead focus their efforts on staying alive - and nothing more. By inserting microbial genes into the plants, Boss and Grunden hope to change that.

"By using genes from other sources," explains Grunden, "you're tricking the plant, because it can't regulate those genes the way it would regulate its own. We're hoping to [short-circuit] the plant's ability to shut down its own metabolism in response to stress."

If Boss and Grunden are successful, their work could make a huge difference to humans living in marginal environments here on Earth. In many third-world countries, says Boss, "extending the crop a week or two when the drought comes could give you the final harvest you need to last through winter. If we could increase drought resistance, or cold tolerance, and extend the growing season, that could make a big difference in the lives of a lot of people."

Their project is a long-term one, emphasize the scientists. "It'll be a year and a half before we actually have [the first gene] in a plant that we can test," points out Grunden. It'll be even longer before there's a cold- and drought-loving tomato plant on Mars - or even in North Dakota. But Grunden and Boss remain convinced they will succeed.

"There's a treasure trove of extremophiles out there," says Grunden. "So if one doesn't work, you can just go on to the next organism that produces a slightly different variant of what you want."

"Amy's right," agrees Boss. "It is a treasure trove. And it's just so exciting."

Source : FirstScience

Jellyplants on Mars 01

2008-03-29T05:28:00.000-07:00

Picture by: Rob Ferl.
Jellyplants on Mars
By Karen Miller and Dr Tony Phillips

Scientists are creating a new breed of glowing plants - part mustard and part jellyfish - to help humans explore Mars.

The first colonists on Mars probably won't be humans. More likely, they'll be plants. And the prototypes of these leafy pioneers are under development right now.

As part of a proposed mission that could put plants on Mars as soon as 2007, University of Florida professor Rob Ferl is bioengineering tiny mustard plants. He's not altering these plants so that they can adapt more easily to Martian conditions. Instead, he's adding reporter genes: part plant, part glowing jellyfish - so that these diminutive explorers can send messages back to Earth about how they are faring on another planet.

The plants can be genetically wired to glow with a soft green aura when they encounter problems. Within a garden grouping, some plants could report (by glowing) low oxygen levels, while others might signal low water or, say, the wrong mix of nutrients in the soil.

"Just like humans, plants must learn how to adapt to any new environment," Ferl says. On Mars they would encounter extreme temperatures, low air pressure, exposure to harsh ultraviolet light, and generally inadequate soil. "We are using genetics to create plants that can give us data we can use to help them survive."

Learning to grow plants on Mars will be an important precursor to humans living there. Future explorers will need oxygen, food, and purified water - items too costly to ferry from Earth to Mars on a regular basis. But plants can help provide those essentials inexpensively and locally as part of a self-contained "bioregenerative" life support system.

Bioregenerative life support means humans, plants, and microbes working together in a renewable system. Humans consume oxygen and produce carbon dioxide. Plants take carbon dioxide and turn it back into breathable air. Human waste (after processing by suitable microbes in bioreactor tanks) can provide nutrients for growing plants, which will, in turn, produce food for people.

Such life support systems on Mars will probably involve growing crop plants in Martian soil within specially designed greenhouses, says Andrew Schuerger, a manager of Mars projects with Dynamac Corporation at the NASA's Kennedy Space Centre.

Ferl, Schuerger, and Chris McKay of NASA's Ames Research Centre. want to test the greenhouse concept by sending bioengineered plants to Mars on board a small NASA spacecraft - a "Mars Scout." They envision a seed-bearing lander that would scoop up a portion of Martian soil, add buffers and nutrients, then germinate the seeds to grow within a miniature greenhouse.

Thriving plants won't glow at all. They'll look like normal mustard. But plants struggling to survive will emit a soft green light, a signal to researchers that something is amiss. A camera onboard the lander would record the telltale glows and then relay the signal back to Earth. No humans are required on the scene - a big advantage for such a far away experiment.

The plants' designer genes consist of two parts: a sensor side to detect stress and a reporter side to trigger the glow.
Source: FirstSciece

Jellyplants on Mars 02

2008-03-29T05:16:00.000-07:00

Picture by: C.E. Mills

By Karen Miller and Dr Tony Phillips

The sensor side of the gene comes from the plant itself - Arabidopsis thaliana, a member of the mustard family also known as thale cress. Ferl and his colleagues picked Arabidopsis because three attributes suit it well for a Mars mission: Its maximum height is about 6 inches, so it can fit inside a small greenhouse, its life cycle is only six weeks, and its entire genome has been mapped. (For these same reasons Arabidopsis plants are already orbiting Earth on board the International Space Station as part of an independent experiment to learn how plants react to free fall.

The reporter side of the gene comes from Aequorea Victoria, a jellyfish common along the Pacific coast of North America. Aequorea live about six months, grow to 5 or 10 cm, and can glow soft-green along the rim of their bell-shaped bodies. Scientists aren't sure why they glow - Aequorea Victoria do not flash at each other in the dark, nor do they glow continuously. But the touch of a human hand, for example, can stimulate the jellyfish to "light up."

Once the sensor and the reporter gene fragments are stitched together, Ferl uses a bacteria to move the newly-constructed gene into the plant.
Because plants are sessile - that is, they can't get up and walk away from stressful situations - they can survive only by adapting to whatever their environment offers. So, they've developed an exquisite variety of sensing mechanisms to monitor their surroundings and trigger appropriate responses to stressors. By adding phosphorescent reporters to those sensors, Ferl says, "we can learn not just whether the plant is surviving, but whether it's struggling to survive, and whether it's surviving because it's mounting specific responses to the Mars environment."

Ferl offers this example of an adaptive response to hard times: Here on Earth when plants are flooded by water, they have access to less oxygen. The plants respond by changing their metabolism to generate energy anaerobically (without oxygen) - a less efficient pathway, but one that is available to them. On Mars plants might adopt the same response to survive in the thin oxygen-poor atmosphere.

Water on Mars will also be very scarce, and plants will need to conserve every bit. The leaves of all plants contain stomata, little holes that let gas molecules in and out. Plants have the ability to open and close stomata as conditions demand. "One can imagine plants [living on the surface of Mars in the distant future] that might adapt by means of fewer stomata in their leaves: that means fewer opportunities for water vapour to leave, and maybe that would be a positive adaptation," says Ferl.

The plants might also be exposed to Martian light, which could be piped into the greenhouse (inside the lander) through fibre optics, and to a moisture-added, oxygen-enhanced version of the Martian atmosphere. But the project's primary goal is determining whether plants can thrive in Martian soil - an experiment best done on Mars itself!

As important as it is to know whether plants can actually grow on the Red Planet, this project also has a philosophical purpose, says Chris McKay, the principal investigator of the proposed Scout mission. "It will be a symbolic step," he says, "of life from Earth, leaving Earth, and growing somewhere else." And when this little plant grows on Mars, he believes, it's going to be a major awakening of our interest in our future in space.

Source : FirstScience

Life in The Dark 01

2008-03-27T04:01:00.000-07:00

Life in the Dark - Deep Sea Ecosystems
By Patrick L.Barry

Biologists always thought life required the Sun's energy, until they found an ecosystem that thrives in complete darkness.

Dr. Cindy Van Dover manoeuvres her robotic craft closer to the strange, rocky landscape below. It's totally dark, except for lonely circles of light where she points her flood lamps. Back on the mother ship her monitor reveals tall, thin towers of craggy rock billowing black smoke from their peaks. Very strange!

All around the towers stand dozens of red-and-white, tube-like organisms. These bizarre, 3-foot-long, wormish creatures have no mouth, no intestines, and no eyes. Stranger still, they derive their energy from the planet itself, not from the light of the nearby star -- a feat most biologists didn't believe possible until these creatures were found.

She steers toward the worms and uses the robotic arm to reach out and take a sample for later examination.

Is this a science fiction tale? No. Is the intrepid Dr. Van Dover truly exploring another world? Yes!

Van Dover is as real as is the alien world she's discovering. And both are right here are Earth!

Cindy Van Dover, a marine biology professor at the College of William and Mary in Williamsburg, Virginia, is one of some 60 scientists, technicians and sailors who sailed aboard the research vessel Knorr from the Woods Hole Oceanographic Institution between March 27th and May 5th 2001. This 40-day expedition sent a 1-ton robotic submarine named JASON 2,000 metres down to explore the peculiar sunless world of deep-sea hydrothermal vents.

"I really never thought that one could be an explorer in this day and age," said Van Dover, chief scientist for the expedition and a member of NASA's Astrobiology Institute. "But in the ocean, it's absolutely true," she added. "You're going places that nobody's ever been before!"

Life in The Dark 02

2008-03-27T03:45:00.000-07:00

Pic.Source treehugger.com

Life in the Dark - Deep Sea Ecosystems
By Patrick L.Barry

The hydrothermal vents - which are essentially geysers on the sea floor - support exotic chemical-based ecosystems. Some scientists think the vents are modern-day examples of environments where life began on Earth billions of years ago. And the vents might also hold clues to life on other planets.

The thriving communities of life that surround these hydrothermal vents shocked the scientific world when the first vent was discovered in 1977.

Before 1977, scientists believed that all forms of life ultimately depended on the Sun for energy. For all ecosystems then known to exist, plants or photosynthetic microbes constituted the base of the food chain.

In contrast, these vent ecosystems depend on microbes that tap into the chemical energy in the geyser water that billows out from the sea floor -- energy that originates within the Earth itself.

Because they offer an alternative way for life to meet its fundamental need for energy, these vent ecosystems have piqued the interest of astrobiologists - scientists who study the plausibility of life starting elsewhere in the universe.

"It's the only system we know of on Earth where life can thrive in the complete absence of sunlight," said Bob Vrijenhoek, senior scientist at the Monterey Bay Aquarium Research Institute in Moss Landing, California. Vrijenhoek will conduct DNA analysis on the samples gathered by the expedition.

One chore that astrobiologists have struggled with for years is to define the range of conditions (temperature, salinity, irradiation, chemical composition, etc.) in which "life as we know it" could exist. The discovery of hydrothermal vent ecosystems expanded that range.

"It (the life around the vents) was the first discovery of 'life as we don't know it,'" Vrijenhoek said.

Hydrothermal vents form along mid-ocean ridges, in places where the sea floor moves apart very slowly (6 to 18 cm per year) as magma wells up from below. (This is the engine that drives Earth's tectonic plates apart, moving continents and causing volcanic eruptions and earthquakes.) When cold ocean water seeps through cracks in the sea floor to hot spots below, hydrothermal vents belch a mineral-rich broth of scalding water. Sometimes, in very hot vents, the emerging fluid turns black -- creating a "black smoker" -- because dissolved sulphides of metals (iron, copper, and several heavy metals) instantaneously precipitate out of solution when they mix with the cold surrounding seawater.

Images courtesy Woods Hole Oceanographic Institution

Deep-sea bacteria form the base of a varied food chain that includes shrimp, tubeworms, clams, fish, crabs, and octopi. All of these animals must be adapted to endure the extreme environment of the vents -- complete darkness; water temperatures ranging from 2°C (in ambient seawater) to about 400°C (at the vent openings); pressures hundreds of times that at sea level; and high concentrations of sulphides and other noxious chemicals.

The ability of life to tap such geothermal energy raises interesting possibilities for other worlds like Jupiter's moon Europa, which probably harbour liquid water beneath its icy surface. Europa is squeezed and stretched by gravitational forces from Jupiter and the other Galilean satellites. Tidal friction heats the interior of Europa possibly enough to maintain the solar system's biggest ocean. Could similar hydrothermal vents in Europa's dark seas fuel vent ecosystems like those found on Earth? The only way to know is to go there and check.

Astrobiologists are increasingly convinced that life on Earth itself might have started in the sulphurous cauldron around hydrothermal vents. Vent environments minimise oxygen and radiation, which can damage primitive molecules. Indeed, many of the primordial molecules needed to jump-start life could have formed in the subsurface from the interaction of rock and circulating hot water driven by hydrothermal systems.

If this idea proves true, then the next time Van Dover gazes through the submarine's camera at the vents on the floor of the Indian Ocean, she may be seeing both a portrait of life's genesis in Earth's distant past - and a glimpse of alien life yet to be discovered.

Extreme Ecosystems 01

2008-03-27T03:20:00.000-07:00

Extreme Ecosystems - A Tough Bunch of Microbes!
By Ron Koczor

Microbiologists have found an ecosystem of extreme-loving microbes working together to survive at the bottom of California's strange Mono Lake.

Humans don't like being alone. So when Richard Hoover, a microbiologist at the NASA Marshall Space Flight Center, travels, he looks to see where the locals hang out. Not in hotels, though, or in restaurants or nightclubs. The places he looks are more exotic: Deep mines under the permafrost of Alaska and Siberia, the high mountains of Antarctica, and the salty, alkaline bottom of California's Mono Lake.

And what does he find? Life. In abundance.

A false colour photomicrograph of the new extreme-loving microbe,

Desulfonatronum thiodismutans, recently discovered in Mono Lake

by Richard Hoover and colleagues. Note the flagellum (lower left),

which it uses for movement.(FirstScience)

Richard Hoover is an extremophile hunter. He searches the most inhospitable places for lifeforms that love extremes: scalding heat, freezing cold, salt, lye, darkness. And like other researchers exploring the limits of life on our planet, he's found a surprising variety of species ranging from simple bacteria to plants and animals.

He also finds that species of extremophiles depend on each other to make a living-much like ordinary lifeforms do.

"The diversity of life on Earth boggles the mind," marvels Hoover. There are hundreds of thousands of green plant species. Green algae alone comes in thousands of different varieties, he says. There are millions of species of animals. More than 6,000 species of bacteria and 3,600 viruses have been named. Researchers suspect there are more than a million species of fungus, although only 70,000 or so have been identified.

Few (and perhaps none) of these species live in splendid isolation. They depend on others. Plants use sunlight, carbon dioxide, and minerals to create organic compounds (sugars, proteins, fats, etc.). Animals take these compounds for their own needs. When animals die, they return to minerals and carbon dioxide and the cycle renews.

Cooperation between species is common. For example, the tropical African Gray Parrot eats fruit from trees. For reasons no one understands, these birds sling bits of fruit containing seeds far from the tree. This helps the trees spread their seeds and reproduce. Many instances are well documented of other animals helping spread plants through their droppings. At the complex plant/animal level in a biologically rich environment, interdependence of species seems to be conducive to life.

But what about simpler lifeforms found in extreme environments? Do they too exhibit such interdependent life styles? NASA is interested because the agency is tasked to explore for life in the Universe. Many scientists expect the first signs of life confirmed off Earth - on Mars, within comets, or in the suspected oceans of Europa - will be unicellular lifeforms such as bacteria, archaea, or diatoms rather than complex technological species. Understanding how these species live in extreme conditions is vital to NASA's mission.

Extreme Ecosystems 02

2008-03-27T03:05:00.000-07:00

Richard Hoover collects samples from the mud of Mono Lake (DirectScience)

Extreme Ecosystems - A Tough Bunch of Microbes!
By Ron Koczor
Hoover and microbiologist Elena Pikuta of the University of Alabama in Huntsville are working to answer some of these questions by studying lifeforms in California's Mono Lake. They recently announced the discovery of a third new species of bacteria, Desulfonatronum thiodismutans, living in the lake in the International Journal of Systematic and Evolutionary Microbiology. All three of Pikuta and Hoover's new species are extremophiles. The bacteria thrive in the dark mud of Mono Lake, devoid of oxygen with 3 times higher salinity than sea water and alkalinity that approaches lye.

This third new species is particularly interesting because of its niche in the extreme ecology of the lake. This bacterium obtains its energy from sulfur and other inorganic compounds. It does not require sunlight or other organic materials to thrive and is a type of organism known as a chemolithotroph. Hoover and Pikuta's two previous new species, Tindallia californiensis and Spirochaeta americana are also extremophiles from Mono Lake, but ingest organic materials. These organisms are known as organotrophs. Together they paint a picture of interlinked and interdependent life, even under extreme conditions.

For example, D. thiodismutans gets its energy from hydrogen and sulfur compounds in the minerals of the lake mud. From these it creates sugars and other organic materials. T. californiensis can consume simple amino acids and other chemicals and also produces complex organic compounds such as sugars, fats, proteins, etc. S. americana ingests the complex organic compounds and excretes hydrogen and other gases. When it dies, it returns to minerals and the cycle is complete.

Unlike the plant/animal cycle in our "normal" environment, this bacterial cycle does not necessarily need visible energy from sunlight to drive photosynthesis. It can be driven completely by the chemical energy of the reactions. So in a dark, extreme environment, life appears to develop the same interdependent strands, with different species finding the niche that allows each to thrive.

One day, perhaps, lifeforms like these will be found on other worlds. The work of Hoover and Pikuta is telling us that if we find one species, we should look for more. Extremophiles, like "ordinary" lifeforms, don't like being alone.

Greenhouses For Mars 01

2008-03-27T02:31:00.000-07:00

Greenhouses For Mars
By Karen Miller

When humans go to the moon or Mars, they'll probably take plants with them. NASA-supported researchers are learning how greenhouses work on other planets.

Confused? Then you're just like plants in a greenhouse on Mars.

No greenhouses exist there yet, of course. But long-term explorers, on Mars, or the moon, will need to grow plants: for food, for recycling, for replenishing the air. And plants aren't going to understand that off-earth environment at all. It's not what they evolved for, and it's not what they're expecting.

But in some ways, it turns out, they're probably going to like it better! Some parts of it, anyway.

"When you get to the idea of growing plants on the moon, or on Mars," explains molecular biologist Rob Ferl, director of Space Agriculture Biotechnology Research and Education at the University of Florida, "then you have to consider the idea of growing plants in as reduced an atmospheric pressure as possible."

There are two reasons. First, it'll help reduce the weight of the supplies that need to be lifted off the earth. Even air has mass.

Second, Martian and lunar greenhouses must hold up in places where the atmospheric pressures are, at best, less than one percent of Earth-normal. Those greenhouses will be easier to construct and operate if their interior pressure is also very low - perhaps only one-sixteenth of Earth normal.
The problem is, in such extreme low pressures, plants have to work hard to survive. "Remember, plants have no evolutionary preadaption to hypobaria," says Ferl. There's no reason for them to have learned to interpret the biochemical signals induced by low pressure. And, in fact, they don't. They misinterpret them.
Low pressure makes plants act as if they're drying out.
In recent experiments, Ferl's group exposed young growing plants to pressures of one-tenth Earth normal for about twenty-four hours. In such a low-pressure environment, water is pulled out through the leaves very quickly, and so extra water is needed to replenish it.
But, says Ferl, the plants were given all the water they needed. Even the relative humidity was kept at nearly 100 percent. Nevertheless, the plants' genes that sensed drought were still being activated. Apparently, says Ferl, the plants interpreted the accelerated water movement as drought stress, even though there was no drought at all.
That's bad. Plants are wasting their resources if they expend them trying to deal with a problem that isn't even there. For example, they might close up their stomata - the tiny holes in their leaves from which water escapes. Or they might drop their leaves altogether. But, those responses aren't necessarily appropriate.

Greenhouses for Mars 02

2008-03-26T22:48:00.000-07:00

Greenhouses For Mars
By Karen Miller

Fortunately, once the plants' responses are understood, researchers can adjust them. "We can make biochemical alterations that change the level of hormones," says Ferl. "We can increase or decrease them to affect the plants' response to its environment."

And, intriguingly, studies have found benefits to a low pressure environment. The mechanism is essentially the same as the one that causes the problems, explains Ferl. In low pressure, not only water, but also plant hormones are flushed from the plant more quickly. So a hormone, for example, that causes plants to die of old age might move through the organism before it takes effect.

Astronauts aren't the only ones who will benefit from this research. By controlling air pressure, in, say, an Earth greenhouse or a storage bin, it may be possible to influence certain plant behaviours. For example, if you store fruit at low pressure, it lasts much longer. That's because of the swift elimination of the hormone ethylene, which causes fruit to ripen, and then rot. Farm produce trucked from one coast to the other in low pressure containers might arrive at supermarkets as fresh as if it had been picked that day.

Much work remains to be done. Ferl's team looked at the way plants react to a short period of low pressure. Still to be determined is how plants react to spending longer amounts of time - like their entire life - in hypobaric conditions. Ferl also hopes to examine plants at a wider variety of pressures. There are whole suites of genes that are activated at different pressures, he says, and this suggests a surprisingly complex response to low pressure environments.

To learn more about this genetic response, Ferl's group is bioengineering plants whose genes glow green when activated. In addition they are using DNA microchip technology to examine as many as twenty-thousand genes at a time in plants exposed to low pressures.

Plants will play an extraordinarily important role in allowing humans to explore destinations like Mars and the moon. They will provide food, oxygen and even good cheer to astronauts far from home. To make the best use of plants off-Earth, "we have to understand the limits for growing them at low pressure," says Ferl. "And then we have to understand why those limits exist."

Ferl's group is making progress. "The exciting part of this is, we're beginning to understand what it will take to really use plants in our life support systems." When the time comes to visit Mars, plants in the greenhouse might not be so confused after all.

Almost Like a Whale 01

2008-03-26T22:38:00.000-07:00

Amersham Pharmacia Biotech Ltd 1998
Almost Like a Whale
By Steve Jones

Birdwatchers and ornithologists are not at all the same. To the latter, everything about birds is of interest - how they migrate, where they breed, or what they eat. Birdwatchers have a single concern, which is to see as many kinds as they can. Once seen, as soon forgotten, or, at least, ticked off and added to the Life List that is the basis of their self-esteem.

I went through the same phase. After the usual interest in stamps and an eccentric deviation into cheese labels, I was given a pair of binoculars. At the age of twelve I eavesdropped on a group of excited amateurs (twitchers, as they call themselves nowadays) as they peered at some gulls bobbing, on a dim winter day, on the then filthy waters of the River Mersey. All agreed: one of the birds was not an ordinary herring gull, but the much scarcer glaucous gull, seldom seen so far south. My problem was that I could not see any difference. A member of the flock was a rarity, but which was it? Did it count? Could I check the box in my bird book? It was my introduction to the ethics of science. I admit it: I made the tick, but then I rubbed it out.

Twitchers, like scientists, belong to a fellowship of faith. They play cards against Nature. It is possible to win every time by faking one's hand, but to do so removes the point of the game. That is the strength of science, and its greatest weakness. Without collective trust it could not work. Instead there would be the dismal apparatus of mutual suspicion familiar to every accountant.

Birding is refreshingly free from fraud. It has had its scandals, such as the notorious case of the Hastings Rarities (a set of bizarre sightings on the South Coast in Edwardian times), the dubious claim of a Dalmatian pelican in Colchester in the 1960s, and more. Even so - and whatever the rivalry amongst the twitching fanatics - most of those involved in the sport play by the rules.

One problem baffles the most ethical birdwatcher. Stamps (or cheese labels) are easy. The 1853 One Shilling Cape of Good Hope Triangular (or the 1954 Vache qui Rit) is, or is not, genuine. Fakery apart, there is no reason to question the object itself. But what if it is ambiguous? Then opinion, the enemy of science, creeps in. Is one kind of bird really unlike another? How different does it have to be to count as distinct? What, indeed, is a 'species' in the first place? Does it have a scientific definition, or is it all in the eye of the beholder?

Most people can tell gulls from terns. Many can separate the herring gull from the lesser black-backed (look at the back, which is pale in the first and dark in the other). My friend the glaucous gull is more subtle - as large as a greater black-backed, but as pale as a herring gull, without its black wingtips. A real expert can even sort out the Iceland gull (like a small glaucous, with longer wings). Birders still argue about the existence of the yellow-legged gull as a distinct entity, but its 'bold, confident look' is said to be diagnostic.

But how to deal with variation within each bird? Herring gulls from Estonian bogs had, some say, yellow legs, but these have now disappeared in favour of the pink legs found everywhere else. Those from the Atlantic islands are on occasion blown to Britain. Their backs are almost as black as those of lesser black-backeds. A 'generally stouter bill' might help, but what use is a generalization when an individual must be sorted out? If the despondent twitcher were to travel to Iceland he would be frustrated by hybrids between the Iceland gull and its commonplace relatives. Where does he put his tick?

Species and nations have a lot in common. What, for example, is a German? The tribe has a shared and guttural means of communication that interrupts intercourse of most kinds, but the character is equivocal, for Austrians speak the same language. Since 1913, the country has defined its own citizens by descent, by German blood (whatever that might be). It includes within the realm the remnants of the Saxon diaspora (many of whom - Romanians included - cannot speak German at all), but cuts out children born in Berlin of Turkish parents. One badly behaved teenager was deported to Turkey even though he was born in Germany; while at the same time a hundred thousand Romanian-speakers of approved blood were allowed in. Until the fall of the Berlin wall, indeed, a geographical barrier made many German citizens more alien to each other than Westerners or Easterners were to the French or the Poles. A century ago German identity itself meant little, as there were only Prussians, Bavarians and Rhinelanders, political entities of their own, each now reduced to variants in some greater Teutonic whole.

Almost Like a Whale 02

2008-03-26T22:29:00.000-07:00

Cracow University of Technology

Almost Like a Whale
By Steve Jones

The problem of how to define Germans, or any nation, arises because the question is ambiguous: does it turn on shared appearance and behaviour, on geography, or on descent? Is a country an historical entity, or should it be identified only on criteria that apply today? How much can frontiers be allowed to leak before a nation loses its essence? When will Germans be seen as Europeans, as Prussians have become German?

Such problems of identity turn on natural variation, the raw material of evolutionary change. Like a politician, the twitcher has to deal not just with differences among individuals but with the subtle distinctions that separate each kind. The difficulty of how to define domestic breeds has been magnified and transferred to the world as a whole. Twitchers are asking a question older than the theory of evolution. How should they deal with forms that possess in some considerable degree the nature of species but are not classified as such?

Taxonomy, the science of ordering life, has to worry about that problem. Needless to say, many animals and plants are easy to tell apart. If they were not, birdwatching and natural history museums would each go out of business. One tribe in New Guinea recognizes a hundred and thirty-six kinds of bird, just one fewer than that accepted by the experts. Experts and tribesmen have the same philosophy. Each needs an archetype, a gold standard, to allow their specimens to be put in the correct cabinet.

Once all taxonomists worked in the same way. An animal was killed and its remains stuffed, pinned or bottled. Then, it was described in the scientific literature. The cadaver was the 'type' against which others could be checked. In 1868, in China the French missionary Pere Armand David saw the skin of a black-legged white bear. It resembled animals shown in ancient works of art and until then assumed to be polar bears brought back from the north by hunters. The first specimen of the mysterious beast was collected in 1929 by Theodore and Kermit Roosevelt, the sons of the President. They shot a giant panda asleep under a tree. Its body gave the animal entry to the pantheon of mammals as Ailuropoda melanoleuca. It joined the world of science as had all its relatives, as a corpse.

Amersham Pharmacia Biotech Ltd 1998
Now, fewer than a thousand pandas are left. In China, to kill one means the death penalty. Taxonomists. too, are more careful with their material than once they were. The essence of a species can now be (or so the museum-keepers believe) be preserved not in its bones but in its genes. The Bulo Burti boubou shrike of Somalia was recognized in 1991 on the basis of the DNA sequence in a feather shed by a captive bird. The type specimen - the very substance - of this new form is a set of dark bands on a photographic plate. The rest of the bird was released.

Not all pandas - or Bulo Burti boubou shrikes - are alike. They may look the same but are, like whales, dogs, or viruses, full of diversity. Classifiers hence face a fatal temptation: to split their animals into too many groups. As in the Kennel club or the United Nations, quarrels break out between those who like to subdivide the world and those who hope to unify it.

A rich nineteenth-century collector, Isaac Leigh, was interested in the freshwater mussels of North America. He named more than a thousand kinds on the basis of tiny variations in shell-shape and size. Now the number has been reduced by two-thirds. A hundred and two of his types are classified as one. Isaac Leigh was too enthusiastic about his varieties. His cherished diversity was no more than that between people with brown or blue eyes or between the pink- and yellow-legged herring gulls that once infested Estonian marshes. He had, nevertheless, put his finger on a problem that still plagues museums. How should they fix the frontiers between supposed entities when each is filled with variation?

Genetics, the science of differences, has not made their job any easier. Before it began it had often been asserted - but the assertion was quite incapable of proof - that the amount of variation under nature is strictly limited in quantity. Now, the claim can be tested, and it fails.

Most members of most species do not look much different one from the next. Any fruit-fly is much like another, and even their best friends find it hard to tell mice apart. In spite of some exceptions - the colourful snails or butterflies that come in dozens of forms and are still studied by a few outmoded naturalists - to share a Latin name imposes, almost by definition, a certain uniformity upon those who bear it. That comforts both creationists and experts on taxonomy. They like to see existence as a set of neat ideals, each filled with some pure Platonic essence. However, a great deal is hidden within even the most uniform creature. Genetics shows that no one - not even the glorified chemists which most biologists have become - can any longer suppose that all the individuals of same species are cast in the very same mould.

Moon Trees 01

2008-03-10T20:37:00.000-07:00

Moon Trees
By Dr Tony Phillips

Hundreds of trees have been to the Moon. How they got there and back again is a curious tale.

Scattered around our planet are hundreds of living things that have been to the Moon and back again. None of them are human. They outnumber active astronauts 3:1. And most are missing.

They're trees. "Moon Trees."

NASA scientist Dave Williams has found 40 of them and he's looking for more. "They were just seeds when they left Earth in 1971 onboard Apollo 14," explains Williams. "Now they're fully grown. They look like ordinary trees - but they're special because they've been to the Moon."

How they got there and back is a curious tale.

It begins in 1953 when Stuart Roosa parachuted into an Oregon forest fire. He had just taken a summer job as a US Forest Service "smoke jumper," parachuting into wildfires in order to put them out. It was probably adventure that first attracted Roosa to the job, but he soon grew to love the forests, too. "My father had an affinity for the outdoors," recalls Air Force Lt. Col. Jack Roosa, Stuart's son. "He often reminisced about the tall Ponderosa pine trees from his smoke jumping days."

Thirteen years later, NASA invited Roosa, who had since become an Air Force test pilot, to join the astronaut program. He accepted. Roosa, Ed Mitchell and Al Shepard eventually formed the prime crew for Apollo 14, slated for launch in 1971.

"Each Apollo astronaut was allowed to take a small number of personal items to the Moon," continued Jack. Their PPKs, or Personal Preference Kits, were often filled with trinkets - coins, stamps or mission patches. Al Shepard took golf balls. On Gemini 3, John Young brought a corned beef sandwich. "My father chose trees," says Jack. "It was his way of paying tribute to the US Forest Service."

The Forest Service was delighted.

"It was part science, part publicity stunt," laughs Stan Krugman, who was the US Forest Service's staff director for forest genetics research in 1971. "The scientists wanted to find out what would happen to these seeds if they took a ride to the Moon. Would they sprout? Would the trees look normal?" In those days biologists had done few experiments in space; this would be one of the first. "We also wanted to give them away as part of the Bicentennial celebration in 1976."

Krugman himself selected the varieties: Redwood, Loblolly pine, Sycamore, Douglas Fir and Sweetgum. "I picked redwoods because they were well-known, and the others because they would grow well in many parts of the United States," he explained. "The seeds came from two Forest Service genetics institutes. In most cases we knew their parents (a key requirement for any post-flight genetic studies)."

On January 31, 1971, Apollo 14 blasted off. Only Shepard and Mitchell actually walked on the Moon. On Feb. 5th they landed the lunar module Antares in Fra Mauro - a hilly area where Shepard famously launched his golf balls using a geology tool as a makeshift driver. Roosa remained in orbit as pilot of the mission's command module Kitty Hawk. Inside his PPK was a metal cylinder, 6 inches long and 3 inches wide, filled with seeds. Together they circled the Moon 34 times.

Apollo 14 was a success. Scientists were delighted with the mission's geology experiments and they were eager to study the 43 kg of Moon rocks collected by Shepard and Mitchell. Krugman was just as eager to study the seeds.

"We had a bit of a scare," Krugman recalls. During decontamination procedures, the seed canister was exposed to vacuum and it burst. The seeds were scattered and traumatized. "We weren't sure if they were still viable," he says. Working by hand, Krugman carefully separated the seeds by species and sent them to Forest Service labs in Mississippi and California. Despite the accident, nearly all of them germinated. "We had [hundreds of] seedlings that had been to the Moon!" Thirty-one years later, Krugman still sounds excited.

Source: FirstScience

Moon Trees 02

2008-03-10T20:30:00.000-07:00

Moon Trees
By Dr Tony Phillips

During the years that followed, the trees thrived as scientists watched. "The trees grew normally," he continued. "They reproduced with Earth trees and their offspring, called half-Moon trees, were normal, too." (He notes, however, that DNA analysis wasn't routinely done in the early '70's, and so the Moon trees weren't tested in that way. There might be subtle differences yet to be discovered.)
Finally, in 1975, they were ready to leave the lab. "That's when things got out of hand," he says.
Everyone wanted a Moon tree. In 1975 and '76, trees were sent to the White House, to Independence Square in Philadelphia, to Valley Forge. "One tree went to the Emperor of Japan. Senators wanted trees to dedicate buildings. We even did some plantings in New Orleans because the mayor there, Mayor Moon, wanted some," says Krugman. There were so many requests that "we had to produce additional seedlings from rooted cuttings of the original trees."
No one kept systematic records, notes Dave Williams. That's why the whereabouts of the trees today are mostly unknown.

One of the them went to a Girl Scout camp in Cannelton, Indiana, where 3rd grade teacher Joan Goble found it in 1996. (She knew it was a Moon Tree because a sign said so. Most Moon trees were planted with ceremony; there's usually a sign or plaque nearby that identifies them.) "My students love it," she says. "It looks like an ordinary tree, but they feel it's special anyway because of its trip to the Moon." Jack Roosa has since become a pen pal of Goble's class, encouraging the students to explore and learn as his father did.
When Goble contacted Dave Williams to ask for more information about Moon trees, "I was clueless," Williams admits. Like many people who were young in the 1970's, Williams had never heard of such trees, but he soon became an enthusiast. "I found one Moon tree right here at Goddard near my office," he laughs. "I had no idea it was there."

Often that's how they're encountered - by accident. Williams now maintains a

web site listing all known Moon trees. If you stumble across one then contact him. He'll investigate the find and add it to the collection if it's authentic.
Moon trees are long-lived, adds Krugman. The redwoods could last thousands of years, and the pines have a life expectancy of centuries. Indeed, they've already outlived Stuart Roosa and Al Shepard - two of the humans who took them to the Moon.

Says Jack, "I think my father always knew that these trees would serve as a long-lasting, living reminder of mankind's greatest achievement - the manned missions to the Moon." Of course, if humans don't return soon, Moon trees could become the only living things on our planet that have been to the Moon. That's probably not what Stuart had in mind.
Jack, however, is optimistic: "These trees will be here 100 years from now," he says. "By then I believe we'll be planting Mars trees right beside them."
Source: FirstScience

Ecology Ablaze 01

2008-03-10T20:14:00.000-07:00

Ecology Ablaze
By Patrick Barry

The rich diversity of wildlife in southern Mexico and Central America is in peril. Local governments are using satellites to get a grip on a vast "corridor" system of protected lands.

Central America is on fire.

In an area of rich bio diversity, where 7% of our planet's terrestrial species are packed onto less than 1% of the planet's land, a rapidly growing human population is struggling with widespread poverty that affects more than 20 million people. Many of these people survive through unsustainable "slash and burn" agriculture, putting themselves and the rain forest on a collision course with catastrophe.

Simultaneously promoting the local economy while protecting forests and wildlife is the ambitious goal of an international project called the Mesoamerican Biological Corridor (CBM is the acronym for the name in Spanish).

The largest "sustainable development" effort of its kind in the world, the CBM is a sprawling web of protected and semi-protected lands that stretch the entire length of Central America from southern Mexico to the border of South America - a region known as "Mesoamerica." The lands of the CBM are collectively managed by the governments of the seven Central American countries and Mexico. Together, these governments preserve some areas of the CBM and in others promote limited, "sustainable" economic use of the land.

Image courtesy CBM.

"The human dimension is now one of the most important factors for not only conservation but also sustainable economic development," says Daniel Irwin, a research scientist who has worked and lived in Central America much of his life.

"It's not just a matter of fencing off animals and keeping it separate, because there are so many people who live in the region," Irwin says.

Sustainable development is a relatively new direction in environmental thinking. It acknowledges that people need to use nature's resources to survive, but it also asserts that people must do so in an ecologically sensitive way, or else those resources may not be there for future generations.

For example, farmers might be encouraged to enrich the nitrogen in their existing fields by planting legumes such as alfalfa, rather than cutting and burning more forest when the soil becomes depleted. Another popular approach is to use tax incentives to motivate a land owner to set aside some of the forest on their property rather than developing it.

To maximize the ecological benefit of saving these forests, the CBM maintains strips of land connecting the forested areas - another relatively new idea in wildlife conservation called "corridors."

Photo courtesy CBM.

Animals and plant seeds can then move between the areas, reducing the threat of inbreeding or local disasters wiping out a species. And they provide more space for top carnivores such as jaguars who range long distances to survive. That's why the network of connected areas as a whole has more ecological value than the sum of its parts.

"Because you don't have intense migrations like in the African savannah, your corridor can serve its purposes and still allow certain kinds of human uses," explains Archie Carr III, a veteran conservationist who leads the Wildlife Conservation Society's projects in the Caribbean. Carr led a project between 1990-95 called the Paseo Pantera (Spanish for "path of the panther") that originally established the corridor system that later became the CBM.

Coffee, for example, had traditionally been grown under the shade of trees. This kind of coffee field mimics the structure of a natural forest and thus provides good habitat for wildlife.

"Some of this shade-grown coffee would provide corridor functions probably perfectly well for an enormous number of tropical creatures," Carr says.

But in modern times, a more productive, sun-tolerant strain of coffee was introduced to the region, leading to treeless coffee fields with little habitat for wildlife. Various organizations including the CBM and the Rainforest Alliance are now trying to persuade coffee farmers to return to the more ecological, shade-grown system.

Ecology Ablaze 02

2008-03-10T19:27:00.000-07:00

Ecology Ablaze
By Patrick Barry

It's not easy for the region's environmental managers to keep an eye on such a large area of land, though. That's why the intergovernmental agency in charge of the corridor, called the Central American Commission for Environment and Development (CCAD), has recruited the bird's-eye view of NASA satellites to help out.

"The landscape-wide perspective that satellites provide is essential for doing a large-scale conservation project like this," Irwin says.
"The rain forest is so thick in many places that you can hardly see 10 feet in front of your face," Irwin says. "Trying to survey such large areas on foot is nearly impossible."
To get the job done, Irwin and his colleagues use data from an assortment of satellites. For assessments on the scale of entire countries, they use data from the Moderate-resolution Imaging Spectrometer (MODIS) on NASA's Terra and Aqua satellites. This sensor takes images whose pixels each cover 250 meters of ground, suitable for looking at such large scales. Landsat, on the other hand, has a resolution of 30 meters, and is more useful for closer looks.

Photo was taken in Petén, Guatemala, by Daniel Irwin.

NASA signed an agreement with CCAD in 1998 to use its Earth-watching satellites - called the Earth Observing System - to help the corridor project. One outcome of this collaboration was a study using Landsat data from the 1990s that showed that the corridor was indeed protecting the forests. About 80% of forests inside the CBM still remained, compared with only about 31% outside the corridor. And annual forest clearing rates were 5.5 times higher outside the corridor than inside (1.44% versus 0.26%).
With help from the World Bank, the team also assembled an ecosystem map for all of Mesoamerica. The first of its kind to cover the entire region, this map shows in detail where the rain forests, lowlands, and croplands all lie - an invaluable tool for those managing the CBM.
These managers use the satellite data in other ways as well. For example, data from MODIS shows the location of burning fires in the entire region in near real-time (as in the image at the top of this article).
So far, however, the principal use of the satellite data has been as a political tool, according to Jorge Cabrera, the CCAD official in Central America handling the collaboration with NASA.
"In the case of the fires in the Petén and Yucatan regions this year, giving this information to the media succeeded in mobilizing more political, institutional, and public interest in the magnitude of the disaster," Cabrera said in an e-mail interview (translated from Spanish).

In December, NASA signed a new agreement with the CCAD and the World Bank to continue the use of satellites for the corridor project, and to look into an innovative new way of making the satellite data available.
The concept they're considering is a live "dashboard" showing the state of the environment in Central America as seen by NASA satellites in near real-time, just as the dials on a car dashboard show the state of the car. A computing "pipeline" would be designed that would automatically gather the latest data from the satellites, process the raw data into a relevant and useful form, and present this user-friendly information to the people who need it: Central American politicians, civic leaders, and even local students.
"The information would be available in a timely manner for the Central American decision makers - the ministers, the people who are really making the calls about the environment down there," Irwin says.
After all, when the fires are ablaze, time is of the essence.

Article Source : FirstScience

DNA Secrets of a Salty Survivor 01

2008-03-01T03:39:00.000-08:00

DNA Secrets of a Salty Survivor
By Patrick L Barry

A microbe that grows in the Dead Sea is teaching scientists about the art of DNA repair.
You can learn a lot from a microbe. Right now, a tiny critter from the Dead Sea is teaching scientists new things about biotechnology, cancer, possible life on other worlds. And that's just for starters:
This microbe, called Halobacterium, may hold the key to protecting astronauts from one of the greatest threats they would face during a mission to Mars: space radiation. The harsh radiation of interplanetary space can penetrate astronauts' bodies, damaging the DNA in their cells, which can cause cancer and other illnesses. DNA damage is also behind cancers that people suffer here on Earth.
Halobacterium appears to be a master of the complex art of DNA repair. This mastery is what scientists want to learn from: In recent years, a series of experiments by NASA-funded researchers at the University of Maryland has probed the limits of Halobacterium's powers of self-repair, using cutting-edge genetic techniques to see exactly what molecular tricks the "master" uses to keep its DNA intact.
"We have completely fragmented their DNA. I mean we have completely destroyed it by bombarding it with [radiation]. And they can reassemble their entire chromosome and put it back into working order within several hours," says Adrienne Kish, member of the research group studying Halobacterium at the University of Maryland.
Being a virtuoso at repairing damaged DNA makes Halobacterium one hardy little microbe: in experiments by the Maryland research group, Halobacterium has survived normally-lethal doses of ultraviolet radiation (UV), extreme dryness, and even the vacuum of space.

Credit: Purdue University
The Dead Sea is not so dead
But why is Halobacterium such a tenacious survivor? What caused it to evolve such dexterous DNA repair mechanisms? And how do those mechanisms work?
Jocelyne DiRuggiero, leader of the Maryland research group, has been exploring these questions for the last five years. She believes the answer stems from the fact that Halobacterium naturally lives in some rather inhospitable places: ultra-salty bodies of water such as the Dead Sea.
Most sea life would quickly shrivel up and die in the Dead Sea's briny water, which is 5 to 10 times saltier than normal seawater. The extreme saltiness damages an organism's cells, and especially the DNA inside those cells. This happens because DNA molecules are accustomed to being surrounded by a dense swarm of water molecules, and the DNA actually depends on the influence of these water molecules to keep its double-helix structure intact and to avoid damage. But in ultra-salty waters, the dissolved salt crowds out the water molecules. Partially deprived of the contact with water they need, the long strands of DNA suffer damage and even break, causing the cell to malfunction or die.

Evolving to cope with a salty lifestyle could explain why Halobacterium is so good at surviving radiation and other ravages, DiRuggiero reasons:
"High salt concentrations lead to the same type of lesion in the DNA that does radiation," she explains. "So if the organisms are adapted to extreme saltiness, they have the machinery to repair those lesions when they encounter radiation."

DNA Secrets of a Salty Survivor 02

2008-03-01T03:27:00.000-08:00

DNA Secrets of a Salty Survivor
By Patrick L Barry

DiRuggiero and her research group have begun revealing this DNA-repair machinery in a recent series of experiments funded by NASA's Exploration Systems Mission Directorate.
In some experiments, they exposed Halobacterium cells to beams of intense UV radiation. "We used UV-C at 254 nm, which is the most lethal UV wavelength," says DiRuggiero. Most microbes, like E. coli that lives in the human gut, would have been completely exterminated, yet 80% of the Halobacterium cells survived. Indeed, they went on living and reproducing just fine.

Image credit: Albert Lau
In other experiments, the researchers used a vacuum chamber at NASA's Goddard Space Flight Center to expose cells of Halobacterium to a space-like vacuum (1 millitorr). Here, living in very salty water proved to be Halobacterium's saving grace: as the vacuum caused the water to evaporate away, the salt was left behind, forming salt crystals. The tiny cells of Halobacterium became trapped inside these crystals, along with a bit of entrapped water.

"The salt crystal is like a little house in which the cells are protecting themselves from additional desiccation," DiRuggiero explains. The cells can live in a semi-dormant state within the crystals for a long time. When dissolved back into water, the cells spring to life again, repair all the damage to their DNA caused by the partial desiccation, and go right on living.

Some scientists even claim to have found living cells of Halobacterium encased in salt deposits that are 250 million years old. (see journal references below) The claim is controversial, but if true, it could have some profound implications for the hunt for microbial life on Mars. Evidence from the Mars Exploration Rovers, Spirit and Opportunity, announced in March suggests that the Martian surface once had pools of salty water, which slowly evaporated away.

Image credit: James Smiley

Reading the "book of life"
To understand how these cells of Halobacterium managed to survive in their experiments, DiRuggiero's team sent the "victims" of their tests to the Institute for Systems Biology in Seattle. There, scientists used a modern genetics tool called a "DNA microarray" to see a complete picture of Halobacterium's response to being damaged: the full set of molecular tools that spring into action in the wake of a UV dose or exposure to space-like vacuum.
These "molecular repair tools" belong to a category of proteins called enzymes. Enzymes are the workhorses of all living cells: they catalyze the thousands of chemical reactions necessary for life, such as breaking down food or repairing flaws in DNA. Halobacterium always keeps a certain amount of repair enzymes on hand, so when a radiation dose occurs, this stash of enzymes can quickly administer "first aid" to the DNA. But then it must also ramp up production of other repair enzymes to continue the repair, activating the genes that produce those enzymes. It's that boost in gene activity that the microarray tests can detect, thus showing which enzymes are important for Halobacterium's remarkable DNA-repair abilities.

From those microarrays, DiRuggiero's team has learned that when it comes to DNA repair, Halobacterium is something of a "Renaissance bug." It dabbles in a bit of everything. Its genome of only 2,400 genes contains several distinct sets of DNA-repair mechanisms. Some of these sets of tools are like the DNA-repair tools found in plants and animals, other sets are more like those of bacteria, and still others are characteristic of a lesser-known group of life called "Archaea" (the group that Halobacterium belongs to). Halobacterium has them all. Beyond even that, Halobacterium has a few novel DNA-repair mechanisms that no one has ever seen before!
Learning how all these repair mechanisms work could teach scientists a lot about how DNA repair occurs in humans, and perhaps point to ways to enhance people's natural ability to cope with damage to their DNA - a possible boon to astronauts.

"Many of the repair proteins in the Archaea are very similar to that of Eukarya - [the group of life that includes] you and me - and therefore Archaea can be used as a simple model system to study the more complex processes that occur in eukaryotes," DiRuggiero explains.
Some of these novel molecular tools could also prove to be useful for industry and biotechnology, DiRuggiero suspects. After all, it was in studying a cousin of Halobacterium - a heat-loving microbe - that scientists found the DNA-copying protein that made it possible to sequence entire genomes. The Human Genome Project would have never happened without it.

Malaria No More

2008-03-01T01:21:00.000-08:00

Malaria No More
By Hugh Sturrock

A common fungus could be the weapon needed to fight malaria
It’s called Beauveria bassiana and it’s probably found in your soil. This common fungus is known to be an insect killer: when the skin of locusts and beetles comes into contact with it, it enters their body, feeds off their insides and eventually kills them.

Its reputation as an insecticide is what led a team of scientists from Imperial College and Edinburgh University, headed by Dr. Matt Thomas and Professor Andrew Read, to investigate its effect on malaria-carrying mosquitoes. If it could kill these mosquitoes before they infected a human, then it would be a huge step forward in controlling the spread of malaria, of which there are more than 300 million new cases globally each year and about a million deaths.

Mosquitoes often get into people’s homes, resting on ceilings, walls and bed netting after a bloody meal. Researchers wanted to recreate this environment for their study, so to simulate the inside of a house, they placed mosquitoes in old ice cream pots covered in bed netting. The inside surfaces of the pots were sprayed with oil containing Beauveria bassiana fungus and mosquitoes were allowed to rest inside for 24 hours.

Tall Tales

2008-03-01T00:43:00.000-08:00

Tall Tales: Giant Squid
By Hayley Birch
Are the oceans hiding monsters of epic proportions? And will they survive long enough for us to track them down?

Hemmed in on all sides by two metre-long, tentacled sea demons, Scott Cassell must have thought he’d breathed his last...
30 minutes later he emerged from what would have been his watery grave, just off the coast of Mexico, saved only by his armour-plated diving suit.

A veteran deep sea film maker, Cassell was on a mission to get an image on camera of the Mexican Rojo Diablo, the 'red demon' or Humboldt squid. At up to 50 kilograms, these vicious sea beasts can throw enough weight to do some serious damage to an unprotected diver. Cassell was anything but unscathed after his own terrifying encounter. “I later discovered bruises on me the size of oranges, as well as several scratches in my anti-squid armour suit,” he says.

Undeterred, Cassell has returned to squid-infested waters on numerous occasions since his lucky escape. Most recently, in November 2007, the History Channel aired his new documentary in which he and his team manage to saddle a Humboldt squid with an underwater camera. The images they return hint at something much, much larger lurking in the deep. A squid, perhaps, of such epic proportions that it would dwarf anything previously hauled in by squid hunters.

What haunts the deepest, darkest recesses of the ocean has alternatively fascinated and terrified our sea-faring ancestors for centuries. Writing in 1755, the bishop of Bergen in Norway, painted a picture of a monster a mile long, which he called a ‘Kraken’. And in 1770, the Royal Society heard Charles Douglas’ account of “an animal of 25 fathoms long”, related to him by a Norwegian sea captain. Among the fables and fabrications, however, there may just lie an inkling of the truth.

The one that got away
Cassell’s giant, which he claims may have measured anything up to 30 metres in length – as big as a blue whale – was most likely a cousin to his old enemy, the Humboldt. So-called giant and colossal squid belong to the same family of backboneless sea creatures, falling under the general umbrella of cephalopods. It is only relatively recently, however, that scientists have begun to understand anything about the lives of these much larger cephalopods, which are notoriously elusive. “With giant squid, we catch so few - it’s not like working on something like an earthworm where you can dig up a million and compare them all,” says Louise Allcock, a cephalopod expert at the University of Aberdeen. “We’re getting a couple a year if we’re lucky.”

It may not be so difficult to appreciate why such enormous entities should be so difficult to run into. Firstly, they dwell far below the water’s surface, sometimes as deep as a kilometre. And secondly, they don’t easily fall for our tricks. “They are very smart, very fast, they hunt, they live in mid-water and they rarely come to you,” says Alan Jamieson, a researcher developing deep sea observation systems at the University of Aberdeen.

Jamieson spent part of last year with the Japanese Marine Science and Technology Center (JAMSTEC) in Tokyo, where researchers shot the first ever footage of a live giant squid in its home environment in 2005. But they had to try every trick in the book to get it, eventually resorting to an elaborate system of buoys, cables and hooks, dangling a camera and some shrimp bait. Squid like their prey alive and tend not to be drawn by the static observation vehicles often deployed by scientists. “Short of catching a live fish and strapping some poor guy in front of a camera like a sacrificial lamb, they are only seen as chance encounters,” says Jamieson.

These encounters have been so rare that even basic information about larger species of squid is missing from the marine biologist’s manual. “There is much we have to learn about these animals,” says Steve O’Shea, Director of Auckland University of Technology’s Earth and Oceanic Sciences Research Institute in New Zealand. “Life cycle, growth rate, distribution and abundance all have yet to be determined.” According to O’Shea there is enough work to be done to occupy squid specialists for generations.

Science Out of Africa

2008-02-29T06:00:00.000-08:00

By Patrick L.Barry

In this story a scientist describes his down-to-earth encounters with poisonous snakes, charging elephants and more ... as he tested a high-flying satellite from the wilds of Africa.

You're awake at 5 a.m. After dressing, you wait for the game guard to show up with his .50-calibre elephant rifle. He's going to escort you from the gate in the electrified fence -- the one that keeps the lions out at night -- to your waiting truck.

As you drive along, avoiding crater-like pot holes and reckless cab drivers, you spot a few zebras crossing the road ahead. To keep a safe distance you slow down -- but not for long. A few kilometres later, you're frantically accelerating to outrun a charging elephant.

Photos by Mark Helmlinger.

Talk about rush hour traffic!

When you finally arrive at work (50 miles and a couple of detours later) you're careful to lock the truck. That way baboons can't get inside and tear things up.

There's not much time to lose now. The instruments have to be ready before 10:30 a.m. That's when the satellite passes overhead.

Despite a close encounter with a poisonous snake, you have everything assembled and ready to go half an hour early.

Then, one of the scientists from the airfield radios to say the reconnaissance planes are grounded -- bad weather strikes again. They've cancelled today's mission. Oh well, there's always tomorrow! Another day, another adventure for NASA researcher Mark Helmlinger.

Mark, who works for NASA's Jet Propulsion Laboratory, is one of hundreds of researchers involved in SAFARI 2000, an international campaign to study the impact of human activities on southern Africa's unusually self-contained environment. Using instruments on the ground, on airplanes, and on satellites, the scientists hope to understand how gases released into the atmosphere by industrial and biological sources affect phenomena ranging from regional crop productivity to global climate change.

But first, people like Mark must go out in the field to gather the data.

"You learn really quickly the extraordinary means you have to go through to get the job done," Mark said.

Coping with the dangers of African wildlife kept Mark on his toes. His team conducted some of their experiments at an instrument tower in Krugar National Park in South Africa. The park offered favourable conditions for the measurements, but working there meant dealing with the ever-present threat of lions.

"The lions own the place," Mark said. "You don't get out of your car at all, and you don't go out at night."

"When I went out to the tower site, I had to park the car some distance away so that the instruments were not measuring the car. I had to hire a game guard -- a big guy with a big gun -- and his job was to keep his eyes open and scare off any big game."

Even when travelling outside of wildlife preserves, Mark and his colleagues would pitch their tents on top of their truck just to be safe.

"The tents are on top so that lions don't get you when you go camping across the countryside," he said. "They won't climb the ladders. Lions don't like to climb things, and they haven't figured out yet that tents have yummy things inside."

With so many lions about, one thing you don't want to run short of is gasoline.

"Unleaded gas is not very common in that part of the world," he recalled, "and the rental company rented me a truck that ran only on unleaded gasoline. Boy, was that a pain! I had to take some empty 55-gallon drums from the airstrip [all the way] to a gas station 100 kilometres away, fill them all up, and bring them back so I could have my own fuel dump."

Far from home "you get into situations where one crucial thing that you need just isn't there, and you have to go way out of your way to make do with something else. So you've got to be clever."

On top of all the logistical challenges and the constant distraction of wildlife, Mark and the rest of the scientists still had to do their science -- itself a logistical nightmare.

The tricky part was that scientists wanted to measure the same aspects of the environment from the ground, from airplanes, and from space, all three at the same place and at the same time. Imagine all that complex technology coming together with perfect timing to pull off such a feat!

"That means all of your instruments have to be installed and working on the ground, the airplane has to be able to make it to the site with all of its instruments running -- and there are usually several airplanes -- and then of course the space platform, Terra, must be overhead," Mark explained.

"The metaphor that Dr. Jim Conel, a colleague of mine at JPL, uses is that it's like trying to balance several pencils on top of each other on the end of your finger -- each pencil representing one of the factors that has to go right before the whole thing gets pulled off."

When the weather co-operates and everything goes just right, the scientists called it a "Golden Day."

"In this business, if you get one Golden Day a month you're doing good," said Mark, "even though you had every day of that month as an opportunity to do your mission."

During his most recent trip to Africa, Mark's project enjoyed three Golden Days.

Dealing with potentially life-threatening circumstances for months to obtain just three days of peak data certainly reflects the commitment these scientists have for the work they do.

"A lot of these professionals could be making a whole lot more money somewhere else," Mark said. "But they're studying a problem that's ultimately for the benefit of humanity. I think to a small extent that's in the back of everyone's mind, and that's kind of what holds everybody together and keeps us focused."

That and a charging elephant will do wonders for your concentration!

Space Seeds Return to Earth 01

2008-02-26T03:01:00.000-08:00

Space Seeds Return to Earth
By . Dr Tony Phillips and Patrick L. Barry

Seed pods from a commercial gardening experiment aboard the ISS are back on our planet. The far-out pods could hold the key to long-term habitation of space.

When the space shuttle Atlantis returned to Earth in July 2001, it brought home some unusual cargo - seed pods grown in space. They were the harvest of an 8-week-long commercial gardening experiment on board the International Space Station (ISS). Astronauts on the ISS have been tending a batch of fast-growing Arabidopsis plants (better known as "mustard weed") to discover whether plants can complete their entire seed-to-seed life cycle in a weightless environment.

Video from the experiment shows that seed pods were produced by the space-borne plants. But scientists aren't yet certain what's inside the pods.

"We are waiting for retrieval of the payload to see whether or not seeds are indeed inside the seed pods," says Weijia Zhou, Principal Investigator for the ADVANCED ASTROCULTUREtm plant growth chamber that harboured and nourished the seedlings on the ISS. "Personally, I have a very high confidence level that they will have seeds," he added.

Zhou is the Director of the Wisconsin Centre for Space Automation and Robotics (WCSAR), a NASA Commercial Space Centre that built the growth chamber. "This research is a joint endeavour between WCSAR and Space Explorers, Inc. (SEI)," explains Zhou. SEI is a private company specialising in the development of educational products for schools. Data from the ADVANCED ASTROCULTURETM experiment will allow SEI to complete an Internet-based multimedia program called Orbital Laboratory, which students and educators can use to study plant biology in classrooms.

If normal, healthy seeds were produced as Zhou suspects, the experiment will be a good sign that future astronauts can grow multiple generations of plants in space. Such self-perpetuating gardens will be a practical necessity for humans as they explore and colonise the solar system. Hardy space plants could provide fresh food, oxygen, and even clean water for explorers living for long stretches aboard orbiting outposts or on the Moon and Mars.

Image courtesy NASA Marshall Space Flight Centre.
Now that the plants are back on Earth, scientists at WCSAR will analyse them to learn if growing in the weightless environment of free-fall had any ill effects

"Most importantly, we need to see how many seeds were produced," Zhou says. Comparing the fecundity of the space-grown plants to a control group grown under identical conditions on the ground will tell researchers whether the conditions of growth - such as temperature, moisture, and fertiliser concentrations - were indeed optimal.

"The second thing we need to do is conduct a final chemical analysis of the seeds to find out if there was a different phytochemistry involved," Zhou says. (Phytochemistry is a term for the chemical make-up of a plant.) If there is a difference, it would likely be caused by the weightless environment where the plants were gardened, he added.

These seeds will be preserved for use in a similar experiment to be flown to the ISS by a shuttle flight currently scheduled for November 2001. Half of the seeds in that experiment will be from this space-grown batch, and the other half will be regular Earth-grown seeds. Comparing the plants and seeds produced in this follow-up experiment will tell scientists whether the conditions of space have any effect on subsequent generations of plants.

Eventually gardens could become a routine part of space travel. "NASA has announced a plan to sustain a long-term human presence in space," notes Zhou. What are those astronauts going to eat? "Are they going to eat all dehydrated food, or are they going to get some fresh salad crops?" he asks.

Salads and vegetables are not only good nutrition, but they could also offer an important psychological boost to diners who have spent a long time in space. Eating reconstituted foods from plastic bags is bound to grow tiresome eventually. Fresh lettuce or broccoli might be a welcome change - even for kids.

Space Seeds Return to Earth 02

2008-02-26T02:58:00.000-08:00

Space Seeds Return to Earth
By Dr Tony Phillips and Patrick L. Barry

Plants in space won't only be a source of food -- they'll have other jobs to do as well, playing a critical role in cutting-edge life support systems.

On Earth, photosynthetic organisms like plants and algae provide a natural life support system for the planet's many life forms. Plants and algae use energy from light to split water molecules into hydrogen and oxygen. Then they combine the hydrogen with carbon dioxide to make sugars, which serve as food. Oxygen is released into the air as "waste." This serves as a perfect compliment to other life forms such as animals and fungi, which use the oxygen and respire carbon dioxide.

Taking a cue from nature, scientists at NASA's Johnson Space Centre and Kennedy Space Centre are pioneering next-generation "bioregenerative" life support systems, which use plants rather than machines to perform the chemistry of life support.

Not only do plants release precious oxygen, they can also help recycle drinking water. After some processing, nutrient-rich waste-water can be used to water and fertilise the plants. Much of the water absorbed by the roots will evaporate from the leaves as pure water vapour. Condensing this water vapour. out of the air creates virtually pure, distilled water that can be used for drinking.

While elegant in theory, the fine details of such a system must be worked out before plants and people can live in a successful space-symbiosis. Learning to grow many generations of plants in space is an early step toward that goal.

Many research teams at NASA and NASA-sponsored university projects are experimenting with plant growth for space missions, but Zhou's team is the only one at the moment that's actually growing plants in space from seed to seed.

"What WCSAR and industry are doing is rather unique," Zhou says. But researchers hope it will soon be common. Fast-growing plants that thrive from generation to generation in orbit will surely produce the seeds from which human exploration of space will spring.

Perfumes - Space Scents 01

2008-02-10T03:18:00.000-08:00

Perfumes - Space Scents
By Karen Miller and Dr Tony Phillips

Researchers hunting for new and profitable perfume fragrances will soon send a pair of flowers into Earth orbit.
"That which we call a rose, by any other name would smell as sweet."
Shakespeare knew a few things about romance ... and roses. But here's something he never considered: roses in space. Would they smell as sweet in Earth orbit?
It's not as silly as it sounds - at least perfume industry giant International Flavours& Fragrances (IFF) didn't think so. New perfume ragrances are much sought after in the competitive perfume industry. Some years ago IFF researchers began to wonder, Could space-travelling flowers yield something new and exotic? The answer might prove profitable, they figured.
And so began perhaps the most romantic space experiment ever done.
In 1998, IFF teamed with the Wisconsin Centre for Space Automation and Robotics (WCSAR), a NASA Commercial Space Centre (CSC) at the University of Wisconsin. WCSAR's job is to help companies research new products in space. NASA's Space Product Development program at the Marshall Space Flight Centre supports 15 such CSC's around the country.
WCSAR researchers had developed a plant growth chamber called ASTROCULTURETM for the middeck of the space shuttle. It provides plants with the appropriate temperature, humidity, light, and nutrients during spaceflight, explains Dr. Weijia Zhou, WCSAR director. ASTROCULTURETM was perfect for IFF's purpose, and so on Oct. 28, 1998, a tiny rose selected by IFF was able to leave Earth for a 10-day flight onboard the shuttle Discovery (STS-95).

Credit: International Flavours and Fragrances.
Fragrance, in flowers, is a variable and elusive commodity, evolved solely to help plants reproduce by attracting the insects and animals they need to spread their pollen, or sperm, around. Although we tend to think of floral smells as sweet and appealing, flowers produce a variety of odours, depending on the preferences of their pollinators. If bees are lured by the same kinds of smells that we like, carrion flies, for example, may be drawn by ranker odours, like that of skunk cabbage.

But whatever they smell like, the odours themselves come from "volatile oils," also known as essential oils, because they carry the essential fragrance of the plant. These highly concentrated plant extracts all share certain traits: For example, they readily bind to receptors in olfactory neurons. They also tend to be soluble in alcohol, but not water, and they often feel oily. Most important is that they evaporate at room temperature. Indeed, the fragrances used in perfumes are classified on a scale from 1 to 100, according to how readily they dissipate.

A plant's production of volatile oils is strongly affected by its environment, explained Dr. Braja Mookherjee, who, until his recent death, was Director of Global Natural Products at IFF. Some plants, for example, produce more oils at night when their pollinator is active, and some produce more in the daytime. Temperature, humidity, and the age of the flower are influential, too.

It's no wonder, said Mookherjee, that low-gravity should affect a flower's smell just as other environmental factors do.

The flower that flew on STS-95 was a miniature rose called "Overnight Scentsation" - a plant no more than seven inches high, with two buds just ready to open. The rose needed to be small to fit inside ASTROCULTURETM, which is a 17 by 9 by 21 inch enclosure.

"Ninety-nine percent of miniature roses have no odour," said Mookherjee, but Overnight Scentsation is an exception. It emits a fragrance, which Mookherjee described as "a very green, fresh rosy note."

Perfumes - Space Scents 02

2008-02-10T03:15:00.000-08:00

Perfumes - Space Scents
By Karen Miller and Dr Tony Phillips

In low gravity, said Mookherjee, the rose actually produced fewer volatiles than it did on Earth. But the fragrance that it did generate was critically altered. The flower in space had a more "floral rose aroma," which is aesthetically pleasing.

And, no, the astronauts didn't just sniff the flower.

Credit: International Flavours& Fragrances

To collect the scent, they reached into the ASTROCULTURETM chamber and touched the rose using a tiny silicon fiber. Less than one centimetre long, and only 1 to 2 millimetres in diameter, the fiber was coated with a special liquid to which molecules around the flower petal adhere. After the shuttle returned to Earth, IFF researchers took the fiber and analysed the molecules they found on it.

"We identify the constituents, we know the quantity, and then we can synthesize [the fragrance] here in the lab," explained Mookherjee. The fragrance of a rose is made up of nearly 200 different compounds, he added.

The rose was sampled four times throughout the STS-95 shuttle mission. Each time, says Mookherjee, they got a different result. The scent that they finally arrived at was the average of those samplings, and the new fragrance has since been incorporated into "Zen", a perfume produced by the Japanese company Shiseido.

The collaboration between IFF and WCSAR will continue on STS-107, a shuttle mission slated for launch in January 2003. This time the plan is to send up two different plants - a rose and an Asian rice flower - again placed in the ASTROCULTURETM facility. Like Romeo and Juliet, the flowers will touch each other. This as well as the low gravity, said Mookherjee, will alter the molecules they emit.

The ability to do research in space, concluded Mookherjee, gives a whole new dimension to the field of fragrance studies. "It's a fantastic opportunity," he said ...one that the Bard himself might have appreciated.

Form Follows Sequence 01

2008-02-01T02:44:00.000-08:00

Form Follows Sequence
By Paul Preuss

Ever since James Watson and Francis Crick solved the double helix structure of dna in 1953, biology's most formidable structural challenge has been the "protein folding problem" - learning how nature gets from a gene, a length of dna that encodes the order of amino-acid residues in a string, to a working protein, that same string intricately folded into all the pockets and creases and knobs essential to the physics and chemistry of life.

While protein structures are being collected at a steadily increasing pace, knowledge of gene sequences is exploding. The Human Genome Project, begun by the Department of Energy and the National Institutes of Health less than ten years ago, have finished a draft of all 50,000 to 100,000 human genes - all three billion base-pairs. The majority of the proteins these myriad genes code for do not resemble any already known.

"The more information you have, the more kinds of information you need to make sense of it," says Daniel Rokhsar, head of the Computational and Theoretical Biology Department in the Lab's Physical Biosciences Division and a professor of physics at the University of California at Berkeley. "Without a simultaneous explosion in computation-powerful computers and flexible programs-we'll be overwhelmed."

The Garden of Converging Paths

One way to test ideas about how proteins fold is to start with a shape smaller and less intricate than most proteins, made from units less complicated than amino acids. Supercomputers simulate the behavior of model polymers, which in their native structure-analogous to the thermodynamically stable conformation of a fully folded protein-resemble jungle gyms made from Tinker-Toy-like sticks and balls.

Instead of the varying angles between amino-acid residues in a real protein, the stick-and-ball units, or mers, in a lattice model bond to their neighborsonly at right angles or straight ahead; instead of a real amino acid's complex of properties, a mer can be assigned just a few.

"Lattice models aren't meant to model specific proteins," says Rokhsar, "but they give a good representation of certain aspects of real processes in manageable time." Using the Cray T3E at the National Energy Research Scientific Computing Center (nersc), Rokhsar and Vijay Pande, an assistant professor of chemistry at Stanford University, discovered unsuspected regularities in the folding pathways of model polymers.

When the simulated temperature was raised high enough, their lattice model unfolded completely; when the temperature was lowered, the model refolded, writhing through almost a million different positions before settling into its native, low-energy structure. Even with a 48-mer model-roughly equivalent to a small protein-the possible initial conformations are astronomical, and each path to stability is potentially unique.

To see how different properties of the components may affect transition states and pathways, Rokhsar, Pande, and graduate student Nicholas Putnam designed three other small, 27-unit polymers with the same native-state conformation, based on three widely used types of lattice models.

In the simplest version, only mers that touched in the native state attracted each other-all others were energetically neutral. A more complex model had three kinds of mers in competition, with like types attracting one another more strongly than unlike types. The most complicated lattice model used mers with 20 discrete values derived from those of real amino-acid residues.

"In the two simpler cases, we found that folding pathways could pass through just two distinct core transition states," says Rokhsar. "The more complex model had only a single transition state. Both these behaviors are observed in the folding of some small natural protein structures."

Knowing more about the transitional structures that a folding protein must pass through sheds light on which positions in the chain of amino-acid residues are most critical for a flawless fold-those positions where mutations that substitute one amino acid for another are likely to have the greatest effect on a protein's shape, for better or worse.

Water, Water, Everywhere

Proteins don't exist as ideal Platonic forms; their real environment consists mostly of a warm solvent, namely water. By combining theoretical and computational approaches, such as lattice models, with data from experiments, physical chemist Teresa Head-Gordon of the Physical Biosciences Division and her colleagues have detailed water's essential role in driving protein folding and stabilization.

Form Follows Sequence 02

2008-02-01T02:33:00.000-08:00

Form Follows Sequence
By Paul Preuss

One important measure of amino acids is their varying degrees of hydrophobicity, or "fear of water." Oil is hydrophobic-that's why oil drops remain separate in water-while hydrophilic ("water-loving") substances readily dissolve in it. Many proteins have a hydrophobic core and a hydrophilic surface.

By measuring the intensities of x-rays or neutrons scattered by water molecules alone - and then by leucine molecules dissolved in water-Head-Gordon and her colleagues were able to analyze the structure of water near the leucine. They conjectured that these water structures, much more highly ordered than water in bulk, give rise to forces that differ among different kinds of amino acids and thus influence folding pathways.

When Head-Gordon and her colleagues applied what they had learned from scattering experiments to lattice models of polymers, they found that by including accurate solvation forces they could go a long way toward making the models more realistic mimics of actual proteins. Some models were swiftly eliminated, and the performance of others was improved to exhibit faster folding and more cooperative folding transitions. In addition to a basic understanding of the folding of all proteins, such studies may lead to specific insight into classic sequences such as the "leucine zipper" that joins secondary protein structures into dimers through hydrophobic attraction-a sequence that, when mutated, may play a prominent role in activating cancer-causing genes.

SCOPing Out Folds

Simple theoretical models bolstered by experimental data are one approach to faster protein-structure prediction. Another way to use computers to translate dna sequences into protein structures is to work directly from a growing library of known folds.

Describing her method of predicting the folds of unknown proteins, Dubchak explains that "traditional methods compare unknown gene sequences to known protein sequences or structures residue by residue, searching for correspondences. But what happens when no similar sequence exists? I decided to tackle the problem differently, from a taxonometric perspective."

Dubchak assessed the physical properties of each of the 20 amino acids found in proteins-such characteristics as hydrophobicity, polarity, van der Waals radius (size), and the like-and reduced these to a number of vectors representing the residue's cooperative influence on a fold.

Taken together, the vectors of an unknown sequence do not specify an exact shape so much as they suggest one that may or may not resemble a fold already included in the Structural Classification of Proteins (scop), a library of experimentally observed folds developed by the Medical Research Council's Laboratory of Molecular Biology in Cambridge, England.

Dubchak "trains" neural networks, built with computer processors, to recognize sequences that produce scop-like folds; at present, about a fourth of new sequences can be matched confidently to folds already in the library. Those that don't match known shapes represent folds that have not yet been discovered (or they signal that the neural network doesn't have enough information or hasn't yet learned to recognize the relationship).

Armed with the knowledge that the fold of a new protein resembles familiar folds, biologists can hypothesize the new protein's evolutionary relationships and biological functions, as well as how it may bind to other proteins and to specific chemicals, including drugs.

However, because entirely different dna sequences may produce structures of similar topology, large uncertainties remain. For example, the resolution of a neural-network fold prediction may be limited to several times the typical distance between atoms-and two structures possessing the same fold may be significantly different in size.

Teresa Head-Gordon seeks to reduce these uncertainties by invoking the gospel-that is, "global optimization strategies to probe energy landscapes." Head-Gordon's goal is to find, within the range of possibilities, the protein structure corresponding to a specific sequence that has the lowest energy.

Neural-network predictions such as Dubchak's supply "soft constraints" on shape and specify known secondary structures such as alpha helices and beta sheets. By applying gospel - using force-field models such as amber and charmm, and descriptions of aqueous solvation learned from theory and experiment-vaguely defined "coil" structures, which are more challenging, can also be resolved.

In the course of comparing candidates, the algorithm applies these empirically derived functions to areas of the fold accessible to water; it imposes an extra energy penalty on structures with exposed hydrophobic surfaces. Repeated perturbations of amino-acid positions use gospel to lower the energy further, homing in on the lowest possible total energy.

Global optimization is a voracious consumer of computer power and time. Using the Cray T3E-900 at nersc, Head-Gordon and her colleagues have tested their algorithm against simple "target" proteins. In the case of 1pou, for example, a dna binding protein with 72 amino acids arranged as several alpha helices, the structure predicted by gospel from sequence gave a reasonable estimate of the fold but had some six percent higher binding energy than the known structure derived from nuclear magnetic resonance imaging.

"We have still not reached crystal structure energy yet, so further improvements in structure are still possible!" Head-Gordon exclaims.

Form Follows Sequence 03

2008-02-01T02:16:00.000-08:00

Form Follows Sequence
By Paul Preuss
Nevertheless, while improvements in the underlying model are needed, global-optimization results have been sufficiently encouraging to attempt larger proteins with more complex structures, including pure beta sheets and mixed alpha-helix, beta-sheet proteins.

Bundles and Beads and Barrels and Saddles

Proteins are like strings of beads wound into bundles. Their structure is described at increasingly intricate levels. Primary structure is a chain of amino-acid residues, chemical units linked to their neighbors by peptide bonds, like snap-together plastic beads. The 20 amino acids that can form proteins differ in size, shape, electric charge and polarity (which affects interaction with water), hydrophobicity ("oiliness"), and other properties. Researchers have assigned single-letter designations to each, from A for alanine through Y for tyrosine; thus primary structure, the polypeptide chain, is given by a string of letters, e.g., MEIMKKQNSQINEINKDEIFV. . . .

Secondary structure results from the angles between amino acids, plus the hydrogen bonds that may form from one residue to another. Repeating bonds and angles commonly form alpha helices and beta sheets (or sometimes variations of these) and their hairpin or crossover connections-plus a variety of turns, which often expose active chemical groups on the protein surface, and a few other structures such as loops and "paperclips."

Tertiary structures are made from helices, sheets, and other secondary elements. A particular configuration of these is called a fold. There are roughly 500 known folds, a dozen of which occur very commonly, some with names like "barrel" or "sandwich" or "saddle"-out of some 6,000 to 10,000 predicted to exist. Remarkably, many proteins that have completely different sequences of amino acids are structurally identical-a strong hint that this structure has inherent evolutionary advantage.

While a protein may consist of a single polypeptide strand incorporating a particular fold, others are built from separate strands. A famous example of quaternary structure is hemoglobin, which combines two pairs of identically folded chains in a single molecule capable of snapping up, carrying, and releasing oxygen in the bloodstream and tissues of the human body.

In vivo, In vitro, In silico

Models that derive values from real amino-acid residues and realistic watery environments can help us understand the folding of real proteins, and the shapes and functions of many unknown proteins can be deduced from libraries of known folds. These and yet more sophisticated and powerful computer techniques are essential, for a functioning protein is dynamic, while the protein structures determined by crystallography are static-and even at the present rapid experimental clip it could take another century to decipher the full atomic structures of all the proteins in cells by experiment alone.

Daniel Rokhsar and his colleagues have also studied the molecular dynamics of a real protein structure, not under natural conditions or in an experimental set-up, but in silico, using a fully realistic "all-atom" computer model in which the properties of every atom in every amino acid are represented, and thousands of water molecules are explicitly treated.

"Even in long runs on powerful computers, with all-atom calculations it's only practical to model a few nanoseconds of real time," says Rokhsar, "yet real proteins typically fold up in a few milliseconds"-a million times longer. "So we modeled a very small part of a real protein, a common structure called a beta hairpin. Instead of trying to watch it fold up, we watch it unfold, which at the high temperatures of the simulation is a much quicker process."

Unfolding occurs in a series of discrete steps which always happen in the same order. Each represents the dissolution of a specific part of the hairpin structure, recalling the transition states of lattice models.

Much faster and more manageable supercomputers will be needed to study larger protein structures at the atomic level. The largest yet studied in silico, with 36 residues and 12,000 atoms, was tracked over the course of a single microsecond by researchers at the University of California at San Francisco; the simulation took a Cray T3D and a Cray T3E-600 running for two months each, and the model did not reach the real protein's native conformation.

To rationally design drugs that can attack specific disease mechanisms, to create novel industrial enzymes, to engineer new organisms that can increase food production, clean up waste, and restore the environment-these potential benefits all depend upon accurate, intimate knowledge of a wide range of protein structures and their possible mutations. Every scrap of experimental knowledge, every advance in calculating the molecular dynamics of model proteins, all are essential to the solution of the protein folding problem, a goal that still glimmers in the future.

The Science of Shark Attacks 01

2008-01-26T01:02:00.000-08:00

The Science of Shark Attacks
By Stuart Carter

Every year there are over 100 shark attacks worldwide. Those who come face to face with the ultimate predator rarely escape unscathed. Understanding how and why they attack is our only chance of surviving this natural born killer. But can we predict their behaviour and avoid their attack?

Near Cape Town, on the Southwest tip of South Africa, the coastline pounded by the planet's most violent sea. Here, the Indian Ocean meets the Atlantic, creating the notorious Cape of Good Hope feared by mariners worldwide. But beneath the waves, lies a greater danger. There are over 350 different species of shark that patrol our seas, but three are especially dangerous to man. The Bull, the Tiger and perhaps the most feared of all the Great White. Growing to over 20 feet in length and weighing over 3 tones- Great Whites have few enemies.

33 year old local, Craig Ferreira, has been fascinated with the behaviour of the Great White for nearly all of his life.

"If we can really learn enough about the white shark's interaction with humans, we can provide positive input or really substantial information to the general public that use the ocean."

Craig hunts for Great Whites in a stretch of sea known as 'shark alley', 10 miles off the southerly tip of Cape Town. Already a veteran of cage diving, Craig now pushes the envelope even further. He dives with the Great White unprotected to study how they react to humans in open water. It's a high-risk experiment. Great White's are intelligent hunters and pick their prey carefully - they don't get to grow to 20 feet in length by being reckless…or too timid.

"What you've got to remember when diving with them is that these animals take out huge seals, they take out other large sharks, they eat and kill big sharks, so if that shark decides to do something, you've got absolutely no chance at all, and obviously as a result you do have close encounters."

The Science of Shark Attacks 03

2008-01-24T03:48:00.000-08:00

The Science of Shark Attacks
By Stuart Carter
As Laurie approached the buoys, her premonition became a reality. She was hit from the backside and knocked out of the water.

"The actual bite itself was excruciating, and the only way I can describe it is to say that when you have a piece of glass in your finger it's, it, you're very uncomfortable. Well you can imagine having a thousand pieces of glass in your backside."

As she struggled to push the Tiger shark away, her hands tore against the razor sharp serrated teeth.

"I raised my hands up in front of my face and I saw pieces of flesh hanging down to my palms."

Although Laurie's hands had only been in contact with the teeth for a second, the damage was enormous. Flesh was torn from the bone. Nerves and tendons were shredded. But nothing could prepare the surgeons for the full extent of her injuries. They found the entire right buttock missing. The teeth had bitten a hole 16 inches in diameter. Saving Laurie's life was a race against time. The shark's teeth had sliced through arteries and she needed over 20 pints of blood just to keep her alive. Three years on Laurie has made a full recovery, but like others who've come face to face with oceans greatest killer - she still bears the scars.

But why did the shark attack her? Was it because she was swimming on the surface or that women are at greater risk then men? It seems highly unlikely that sharks can distinguish women from men and there is certainly no statistical evidence to back this up. It is far more likely that she was attacked because she was thrashing about on the surface. Surfers get attacked the most. One reason why surfers might get attacked so often is that they spend more time in the water than any other user group. They spend more time in than bathers, divers and windsurfers together - they spend a huge amount of time in the water.

Like many teenagers who live on the island of Hawaii, Jesse Spencer spends hours in the ocean waiting for that next big breaker. On the afternoon of October 1st 1999, he was at his favourite surf beach paddling into deep water. He was about to learn of a shark's attraction to movement on the surface and their readiness to have a quick taste. Like most shark attacks, Jesse's strike came out of the blue.

The Science of Shark Attacks 02

2008-01-22T02:40:00.000-08:00

The Science of Shark Attacks
By Stuart Carter

On the other side of the world on the west coast of Australia, a group of swimmers confrontation with a Great White revealed how selective a shark can be when choosing its prey. In Perth there is a local swimming group called the Pod. One of their members was businessman Ken Crew. The morning of November 6th 2000 started like any other. The 'pod' met on the beach for their usual 6.30am swim. At the end of the swim over a dozen of the members stood chest deep water. Then suddenly someone yelled 'Shark! Get out of the water!' The swimmers fled for their lives. The Great White caught Ken in its massive jaws. The shark had bitten off his right leg, slicing through a major artery. He'd bled to death in seconds. But how and why did the shark single out Ken Crew, in the middle of such a large group of swimmers?
Something about the movement and position of Ken Crew made him more vulnerable then the other swimmers. The Great White has better colour vision than any other shark - it's this hunter's greatest asset. It may have watched him from several hundred yards offshore. It can stalk its prey with one eye above the water's surface, picking the moment to close in and strike. As it approaches, a Great White rolls its eyes back into their sockets. Now attacking blind the Great White switches to electro detection. The human body is full of electrolytes and our breathing creates electrical fields that the shark can home in on. Sensitive capillaries on the snout can detect currents as low as one 5 billionth of a volt. In the attack on Ken Crew, the electrical activity from his beating heart may have been enough for the shark to home in on.

But Australia and South Africa are not the only place with a treacherous coastline. Around the world there are 14 shark attack hot spots. Danger zones where people are at greatest risk. As our fascination with using the sea for leisure increases, so do the number of attacks. 98 of them have happened in the warm tropical waters of Hawaii.

Three years ago housewife Laurie Boyette decided to take the long trip from Rhode Island to Kona, Hawaii for a family vacation. She went swimming in the sea with her nephew; both were strong swimmers.

"I actually had a premonition that if there was a shark this is where it would be and at that point I was a little bit past a raft which was maybe a 150 yards out. And I thought that was a very strange thought to have but it didn't scare me I just wondered where it came from."

The Science of Shark Attacks 04

2008-01-21T04:53:00.000-08:00

The Science of Shark Attacks
By Stuart Carter

"I just felt a big bump. As I was turning my head I was thinking maybe a turtle another surfer. I don't think a turtle could bump me that hard. So then I turned and sort of saw the shark pop up and went over my arm and I went under water. I could feel the tips of the teeth pretty sharply. They first touched my skin and then went through, and I couldn't feel anything."

The shark that attacked Jesse was a Tiger and like most species its teeth are perfectly adapted for cutting through tough skin and muscle. Jesse was bitten and let go - the shark clearly didn't want to make a meal of him. So why was he attacked? Was it a case of mistaken identity? Some scientists believe that if the animal's motivated to feed then what's the risk in going up and taking a little taste. Jesse's attack took place in open deep water. He had no defence against the shark that struck him silently from below. The bite left Jesse's arm so badly mutilated it's still on the road to recovery. After 2 years, he still doesn't have full mobility.

With over to 100 attacks and 10 deaths a year, protecting ourselves from shark attacks is becoming ever more important. Over the last few years the largest increase in shark attacks has been along the eastern coast of America. The summer of 2001 witnessed sharks moving in to shallow waters and striking swimmers near the shoreline. In just 3 weeks there were 20 attacks and 2 deaths - often in water no more than 3 feet deep. Everyone wants to know if it was because there were more people in the water or because the sharks were becoming more aggressive?

We may never know the answer but scientists from State Longbeach believe we could reduce the number of attacks if we knew more about their feeding habits. Their research could help us judge what times of the day it's most dangerous to get in to shark-infested waters. The scientists are not convinced by the popular theory that sharks only feed at the beginning and end of the day. The sharks' stomach contains acid that varies in concentration depending on how hungry they are. The weaker the strength, the bigger their appetite. Using a metal probe, packed with microelectronics, they plan to look into the digestive habits of a shark. They plan to feed the probe to a shark and record the times of the day when stomach acid levels are at their weakest. Then they'll know when the shark is hungriest and most dangerous. By gutting a squid and hiding the probe inside, they hope to fool the shark into swallowing it whole. Then by tracking and down loading data remotely, they'll be able to pin point exact feeding times on any shark.

There's still much to learn about the science of shark attacks. Those who have lived through the nightmare have drawn their own conclusions about when it's safe to swim. Science and technology may be able to help us - but one fact is certain. As more and more of us take to water, the number of shark attacks is going to increase.

Mars Mice 01

2008-01-10T21:55:00.000-08:00

Mars Mice
By Karen Miller

In 2006 a group of mice-astronauts will orbit Earth inside a spinning spacecraft. Their mission: to learn what its like to live on Mars.

Humans need gravity. Without it, as astronauts have vividly demonstrated, our bodies change strangely. Muscles lose mass, and bones lose density. Even the ability to balance deteriorates.

From long experience on the space shuttle and various space stations, we have some knowledge of how mammals, especially people, respond to 0-g. We have even more experience with 1-g on Earth. But we still don't know what happens in between.

What, for example, will happen to humans on Mars where the surface gravity is 0.38-g? Is that enough to keep human explorers functioning properly? And, importantly, how easily will they readapt to 1-g, once they return to Earth?

A team of scientists and students from the Massachusetts Institute of Technology (MIT), the University of Washington, and the University of Queensland, in Australia, plans to explore these questions. They're going to do it by launching mice into orbit.

"What we're doing," explains Paul Wooster, of MIT, and program manager of the Mars Gravity Biosatellite project "is developing a spacecraft that is going to spin to create artificial gravity." The satellite will spin at the rate of about 34 times each minute, which will generate 0.38-g - the same as gravity on Mars.

The team hopes to launch the Biosatellite in 2006. The mice will be exposed to Mars-gravity for about five weeks. Then, says Wooster, they'll return to Earth alive and well. The mice will descend by parachute and land near Woomera, Australia, inside a small capsule reminiscent of NASA's old Apollo capsules.

The Biosatellite project is the first investigation conducted at this gravity level, says Wooster. Financed in part by NASA, the project is also unique "due to the heavy involvement of students in all aspects of the work, including planning the science, designing the spacecraft, raising the funds, and managing the overall effort," he adds.

The research will focus on bone loss, changes in bone structure, on muscle atrophy, and on changes in the inner ear, which affects balance. "The main thing we're trying to do," says Wooster, "is to chart a data-point between zero-gravity and one-gravity."

As they orbit the earth, the mice, each in its own tiny habitat, will be painstakingly observed. Each habitat will have a camera, so that the researchers can monitor mouse activity. Each will have its own pump-driven water supply, so that each mouse's water consumption can be tracked.

Mars Mice 02

2008-01-10T21:45:00.000-08:00

Science NASA

Mars Mice
By Karen Miller

Each mouse's wastes will be collected in a compartment beneath its habitat; the compartment will contain a urinalysis system checking for biomarkers that indicate bone loss.

Each habitat will also be equipped with a body mass sensor, which will take frequent readings. This will also allow the researchers to track how the weight of the mice changes over the course of the five weeks.

Each mouse will also have toys to keep it busy. "We may give them a wooden block to chew on," says Wooster. That'll keep them happy, and will also prevent them from chewing on the habitat. They might have a small tube to run through.

No wheels, though, says Wooster, because NASA has learned that exercise can counteract some of the effects of low-gravity on astronauts. A mouse with a wheel in its cage can actually run several miles a day. "We don't want to give the mice a countermeasure in terms of exercise."

The students will be using only female mice, says Wooster. That's partly because female mice eat slightly less than male mice, decreasing the mass that must leave Earth. But more importantly, some studies suggest that females are affected more strongly by lowered gravity than the males.

Those studies, though, weren't conducted in true partial gravity. Rather, they were done by suspending the hind legs of the animals, so that the mice are only able to feel part of their weight on the ground. The simulated Mars gravity inside the Biosatellite will be much more realistic.

Through the three participating universities, more than 250 students have been involved in the Biosatellite project. The project is being led and coordinated by MIT, which is also managing the animal habitats and life support systems. The University of Washington is in charge of providing electrical power, propulsion, attitude control, thermal control, and all the communications to the ground. The University of Queensland is in charge of the entry, descent, and landing systems, including the heat shields and parachutes.

"I think that one of the big contributions of the Biosatellite," says Wooster, "is the educational benefit for the students involved." So many people, he says, have been inspired by this project, and have learned from it. "Plus we're going to be getting back information that nobody's ever had before, data that have been missing in the planning of human missions to Mars."

How might humans respond to gravity on Mars?

With the successful landing of NASA's rover Opportunity, that question seems closer and closer to one we'll need to solve.

Sowing Seeds in a Magnetic Field 01

2008-01-01T22:14:00.000-08:00

Image courtesy NASA.

Sowing Seeds in a Magnetic Field
By Patrick Barry and Dr Tony Phillips

Scientists hope that an unusual experiment slated for launch on the space shuttle this summer will reveal how plants know up from down.

When gardeners poke a seed into the ground, they never worry in which direction it lays. Give it enough water and food and care, and sure enough, its root will grow downward and its stem will sprout upward - every time! Lay the seed upside-down, and the root and stem would still find their proper positions.

Everyone knows that plants grow toward light, but there must be more to it than that. Trees in northern forests, for example, grow straight up even though the Sun is never directly overhead, and the first stem emerging from a buried seed grows upward through dark soil.

It's clear that gravity must play some role, too. Indeed, scientists know that the direction of gravity's pull is behind many plant behaviours, such as corn crops righting themselves after being flattened by a storm. What's unclear is exactly how plants "feel" gravity and respond to it. What part of a plant senses the direction of gravity's pull? And how is that pull translated into a chemical response that alters the plant's growth?
No one knows the answers.
But scientists do know enough to suggest two possibilities. First, when the fluid contents of plant cells (called the "protoplasm") are pulled downward by gravity, the pressure exerted on the cell walls might serve as a signal that helps plants distinguish up from down. Second, plant cells contain starch grains which, like protoplasm, drift down when gravity is present. Scientists suspect this might act as a cue to plants, too.

But which is it? A novel experiment slated to fly aboard the space shuttle might reveal the answer.

Karl Hasenstein, principal investigator for the BioTube/Magnetic Field Apparatus experiment, explains: The shuttle will carry a payload of flax seeds to orbit. Once there, a computer-controlled dose of water will start them growing. Unlike flax sprouts growing on Earth, these won't feel the usual pull of gravity. The protoplasm and the starch grains within their cells will float rather than sink.
Plants have been grown in space before. But this experiment will be the first to subject plants to an "artificial gravity" created by magnets.
The experiment will have a high-gradient magnetic field in the plant growth chamber. Within the cells of the plants, the protoplasm will be essentially unaffected by the magnet, but the starch grains will feel the magnetic force. They will sink to the bottom of the cell as if drawn there by gravity.

Sowing Seeds in a Magnetic Field 02

2008-01-01T22:09:00.000-08:00

Image; Univ. of Wisconsin-Madison

Sowing Seeds in a Magnetic Field
By Patrick Barry and Dr Tony Phillips

Starch grains are not magnetic in the usual sense - if you held one against your refrigerator it wouldn't stick. But the grains are "diamagnetic," which means they develop a weak magnetic field when other magnets are nearby. The diamagnet's field will naturally oppose that of the nearby magnet - hence the prefix "dia" - so the starch grains will be repelled. Although the effect is weak, this diamagnetic response allows researchers to use magnets to move the starch grains.

"By changing only the internal displacement of the starch grains, we can put one of these two arguments to rest," explains Hasenstein, a professor at the University of Louisiana at Lafayette. "If the starch grains are the gravity-sensing trigger, we should see the flax-seed roots curve along the magnetic gradient. And if the pressure on the cell walls triggers the curvature, we should see no response."

Infrared cameras will automatically photograph the germinating roots. Regular cameras can't be used because the chamber will be kept completely dark. The darkness allows scientists to know that the seeds are responding to the magnetic fields, not just growing toward a light source.

Don't bother trying this experiment at home with ordinary refrigerator magnets. Only special "high-gradient" magnetic fields will do. Hasenstein's experiment uses magnets about 50 times more powerful than a typical refrigerator magnet. The magnets have ferromagnetic wedges attached to them, which focus a strong magnetic field into a small area. Around that area, the strength of the field tapers off quickly, creating the "gradient" of field strength that moves the starch grains.
High-gradient magnetic fields will be used in two chambers of the experiment, while a third chamber will use a homogeneous magnetic field as a "control."

The lessons learned won't only apply to flax seeds (which were chosen for their small size and their quick, reliable germination). All normal plants have these starch grains, so the results of this experiment will add to our basic understanding of plants in general.
Starch grains or protoplasm? No matter which proves correct, researchers will have lingering questions. For example: "how does the mechanical trigger (e.g., starch grains drifting downward) produce a biochemical response?" BioTube/MFA won't provide all the answers right away, but it is an important first step - one that will teach us something fundamental about the leafy-green life all around us.