January 10, 2006, 7:41 PM CT

Map Of Ozone Hole

NASA researchers, using data from the agency's Aura satellite, determined the seasonal ozone hole that developed over Antarctica this year is smaller than in prior years.

NASA's 2005 assessment of the size and thickness of the ozone layer was the first based on observations from the Ozone Monitoring Instrument on the agency's Aura spacecraft. Aura was launched in 2004.

This year's ozone hole measured 9.4 million square miles at its peak between September and mid-October, which was slightly larger than last year's peak. The size of the ozone hole in 1998, the largest ever recorded, averaged 10.1 million square miles. For 10 of the past 12 years, the Antarctic ozone hole has been larger than 7.7 million square miles. Before 1985, it measured less than 4 million square miles.

The protective ozone layer over Antarctica annually undergoes a seasonal change, but since the first satellite measurements in 1979, the ozone hole has gotten larger. Human-produced chlorine and bromine chemicals can lead to the destruction of ozone in the stratosphere. By international agreement, these damaging chemicals were banned in 1995, and their levels in the atmosphere are decreasing.

Another important factor in how much ozone is destroyed each year is the temperature of the air high in the atmosphere. As with temperatures on the ground, some years are colder than others. When it's colder in the stratosphere, more ozone is destroyed. The 2005 ozone hole was approximately 386,000 square miles larger than it would have been in a year with normal temperatures, because it was colder than average. Only twice in the last decade has the ozone hole shrunk to the size it typically was in the late 1980s. Those years, 2002 and 2004, were the warmest of the period.........

Posted by: Tyler      Permalink


January 10, 2006, 7:30 PM CT

Best-ever Antarctic Maps

Researchers using satellite data have now created the most detailed maps ever produced of the vast snow-covered Antarctic continent. The maps reveal unprecedented views of surface features that provide clues to how and why the continent's massive ice sheets and glaciers are changing.

Scientists can now decipher the intricate history of ice movements in the just-released "Mosaic of Antarctica," which uses images from the Moderate Resolution Imaging Spectrometer onboard NASA's Terra and Aqua satellites. The map is the result of a partnership between NASA's Goddard Space Flight Center, Greenbelt, Md.; the University of Colorado's National Snow and Ice Data Center (NSIDC), Boulder; and the University of New Hampshire, Durham.

A second map to be released early next year will provide the most complete and accurate topographical survey of the continent ever undertaken, with more than 65 million points surveyed from space by the Geoscience Laser Altimeter System orbiting on NASA's Ice, Cloud and Land Elevation Satellite (ICESat). This "digital elevation model" produced at Goddard will be distributed by NSIDC in a format compatible with the Mosaic map.

"The Antarctic Mosaic shows a lot of very subtle changes in the slope of the terrain that you cannot see from the ground," says Robert Bindschadler, chief scientist of Goddard's Hydrospheric and Biospheric Sciences Laboratory. "These subtle variations are important because they tell us the direction the ice is flowing now and they indicate where it has gone in the past. The surface roughness also tells us about the bed underneath the ice and whether the ice is sliding over the bed or frozen to it".........

Posted by: Tyler      Permalink


January 10, 2006, 6:53 PM CT

Plankton Populations Reflect Ocean Warming

Sediment cores collected from the seafloor off Southern California reveal that plankton populations in the Northeastern Pacific changed significantly in response to a general warming trend that started in the early 1900s. As ocean temperatures increased, subtropical and tropical species of small marine organisms called foraminifera (forams) became more abundant. Forams that live in cooler waters decreased, particularly after the mid-1970s. These changes are unlike anything seen during the prior 1,400 years. Oceanographer David Field discovered these dramatic changes during his Ph.D. work at Scripps Institution of Oceanography at the University of California, San Diego. He currently works as a postdoctoral fellow at the Monterey Bay Aquarium Research Institute (MBARI). Field and his co-authors describe their findings in the current issue of Science magazine.

Foraminifera are small, amoeba-like organisms that live inside tiny shells ("tests") several of which might fit on the head of pin. Most forams live near the surface of the world's oceans. Different species of forams live in ocean waters of different temperatures. When forams die, they sink to the seafloor, where their shells are often preserved as fossils in seafloor sediments.

Field studied fossilized forams in one- to three-meter-long sediment cores collected at the bottom of the Santa Barbara Basin, off Southern California. In this area, dead plankton and sediments settle onto the seafloor to form distinct annual layers similar to growth rings in a tree. At 600 meters beneath the ocean surface, seawater in the Santa Barbara Basin contains very little oxygen, so few bottom-dwelling animals disturb the sediments and the annual layers remain relatively intact.........

Posted by: Tyler      Permalink


January 8, 2006, 12:09 AM CT

Fallen Leaves Play a Role in the Food Chain

The watery plants form the base of the food chain. Energy these watery plants create supports, of the invertebrates to largest fish of sport. Now, a study proves that the watery plants receive assistance from the trees. In a recent issue of the journal Nature, Michael Pace and Jonathan Cole of the Institute of Ecosystem Studies in Millbrook, New York, along with colleagues from Wisconsin and Sweden, indicate that the terrestrial organic matter, which starts on the shore, supports a significant part of the watery food chain.

A building block of life, organic carbon is essential to aquatic food webs. In lakes, aquatic plants produce organic carbon by harnessing the sun's energy (photosynthesis); some of this carbon supports the growth of fish and invertebrate populations. Researchers have long suspected that organic carbon from land is also significant to aquatic life, but the idea is difficult to demonstrate. By tracing the fate of carbon through large-scale lake manipulations, Pace, Cole, and their colleagues have revealed that in some waters terrestrial organic carbon significantly subsidizes the aquatic food web.

"These researchers have found an ingenious method of teasing apart the carbon cycle of lakes," says James Morris, program director in the National Science Foundation (NSF)'s division of environmental biology, which funded the research. "Their study reveals a surprising degree of dependence of lake food webs on sources of organic matter transported into the lakes from the surrounding watershed. These findings reinforce the concept that the ecology of lake ecosystems is tightly coupled with that of the surrounding terrestrial landscape".........

Posted by: Ashley      Permalink


December 30, 2005, 4:47 PM CT

Unravelling a rainforest food web

Is your enemy's enemy your friend? Not if you're an insect in the tropical rainforest in Belize. Researchers at Oxford University and Imperial College London investigating what happens to one species when another species with a shared natural predator disappears have found that the population of the remaining species increases.

Dr Owen Lewis in Oxford's Department of Zoology, with Dr Becky Morris and Professor Charles Godfray from Imperial College, studied different species of leaf-miner insects in Belize. Leaf-miners in the larval stage live within leaves, munching their way through the inside of the leaf as they grow. At maturity they develop into beetles, moths or flies. The larvae of leaf-miners are often preyed on by parasitoid wasps which develop inside the leaf-miner, eating it alive and eventually killing it.

The scientists removed one species of leaf-miner from experimental plots within the rainforest to see what would happen to the remaining species of leaf-miner. As they had predicted, the parasitoids decreased in number as a result of one of their food sources being taken away, and so the remaining leaf-miners increased.

'Instinctively you might expect that if you shared an enemy with another species and that species were removed, then your enemy - in this case the parasitoid - would focus on you, and your species would suffer as a result,' said Dr Lewis. 'But in fact, though that might happen in the very short term, removing a source of the parasitoid's food can in the long run decrease the number of parasitoids, to the benefit of other species.........

Posted by: Tyler      Permalink


December 30, 2005, 4:08 PM CT

Inner Working of Volcanoes

While volcanologists can see the dome of the Soufriere Hills Volcano on the island of Montserrat grow and collapse, it takes instrumentation to delve beneath the surface. Now, Penn State geologists, using tiltmeter measurements, have investigated a shallow area under the dome and what they found was not quite what they expected.

"The Soufriere Hills Volcano has been building a lava dome, collapsing and rebuilding a dome since 1995, when it first erupted," says Dr. Christina Widiwijayanti, postdoctoral researcher in geosciences, working with Dr. Barry Voight, professor of geosciences."We are working with data collected from tiltmeters in 1997 to try to understand the volcano's behavior and what is happening inside".

Voight had placed several tiltmeters around the crater rim of the volcano in 1996-97, but no more than two were ever working at once and during the important June 25, 1997 dome collapse, only one was operational. However, from a record the prior month, two tiltmeters recorded the cycle of pressurization and depressurization that took place under the dome on a 3 to 30-hour cycle.

A tiltmeter, like a carpenter's level, measures the local angular movement of the Earth. With synchronized data from two tiltmeters, the researchers, who included Dr. Amanda Clarke a former Penn State graduate student who is now an assistant professor at Arizona State University, and Dr. Derek Elsworth, professor of energy and geo-environmental engineering, could determine the depth of the source region causing the tilting near the dome. They reported their work in a January issue of Geophysical Research Letters.........

Posted by: Jaison      Permalink


December 26, 2005, 11:35 PM CT

Hidden Invaders In A Hawaiian Rain Forest

By applying novel measurement techniques from a high-altitude aircraft, researchers detected two species of invading plants that are changing the ecology of rain forest near the Kilauea Volcano in the Hawaii Volcanoes National Park. Lead author, Dr. Gregory Asner of the Carnegie Institution's Department of Global Ecology, explained: "We found chemical fingerprints from the plant leaves and used them to tell which species dominated specific areas. We employed the recently upgraded NASA Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) to measure leaf nitrogen and water content from the aircraft, and corroborated the data on the ground.

The fingerprints showed where the native dominant tree 'ohia' (Metrosideros polymorpha) has been taken over by the invading Canary Islands tree, Myrica faya, and more importantly identified areas where Myrica invasion is in its early stages. The aircraft imagery also showed us how the forest canopy chemistry is changing as a result of the invader." The study is published in the March 7-11, 2005, early online edition of the Proceedings of the National Academy of Sciences.

The new methods are exciting because they detect effects of biological invasions on ecosystems, not just the presence of an invader. Islands like Hawaii are vulnerable to biological invasion; new species can wreak havoc very quickly. The fact that the new techniques allowed the researchers to detect an invader before it dominated the landscape is important to future management strategies. As a result of the findings, the group has expanded to include collaborators from federal, state, and private organizations. Researchers and resource managers from Carnegie, Stanford University, the U.S. National Park Service, NASA, and.........

Posted by: Tyler      Permalink


December 26, 2005, 5:31 PM CT

Increasing Carbon Retention In Soil

Scientists from the U.S. Department of Energy's Argonne National Laboratory - with collaborators from Oak Ridge National Laboratory, Kansas State University and Texas AandM University- have shown that soils in temperate ecosystems might play a larger role in helping to offset rising atmospheric carbon dioxide (CO2 ) concentrations than earlier studies had suggested. Results of the new study are published in the current issue of Global Change Biology.

Higher CO2 concentrations often stimulate plant growth. A subsequent increase in the amount of decaying plant material might then lead to an accumulation of carbon in soil. Yet nearly all field experiments to date have failed to demonstrate changes in soil carbon against the large and variable background of existing soil organic matter.

In this new study, funded by DOE's Office of Science, researchers overcame that issue using a statistical technique called meta-analysis. This analysis of earlier published experiments showed that elevated CO2 concentrations - ranging from double pre-industrial levels to double current levels - increased carbon in soil surface layers by an average of 5.6 percent across diverse temperate ecosystems. If a response of this magnitude occurred globally for all temperate systems in a CO2 -enriched world, the authors calculated that increased soil carbon storage might remove 8 to 13 billion metric tons of carbon from the atmosphere over a period of about 10 years.........

Posted by: Jessica      Permalink


December 26, 2005, 4:29 PM CT

Recycling Automotive Plastics Is Good For The Environment

Recycling is not just good for the environment, it is good for business. Argonne scientists have developed a technology to successfully recover plastic from obsolete automobiles that may add plastic to the list of valuable materials recycled from old cars and trucks.

"About 75 percent of the weight of an obsolete car is already profitably recycled," explained Energy Systems Division Director Ed Daniels, "so we are working on the balance of that material." Developing and evaluating new process technology for industry is one of Energy Systems Division's main thrusts.

Old cars and trucks end their days at dismantling facilities where usable parts are recovered. The metal is recycled next, leaving shredder residue - polyurethane foam, polymers, and some metal oxides, glass and dirt. Between 3 and 4.5 million tons of shredder residue a year ends up in landfills.

Argonne is working with the American Plastics Council and the Vehicle Recycling Partnership of USCAR to develop and advance sustainable technologies for automotive materials recycling.

Current research at Argonne is focused on "mechanical recycling" - recovery of materials such as plastics from shredder residue for re-use in automotive and other applications. The technology being developed at Argonne consists of two major processes. The first is a bulk separation process to separate shredder residue into constituent fractions, followed by the second process, which recovers specific plastics from a polymer concentrate.

Scientists designed and installed a large-scale shredder-residue separation pilot plant at Argonne. The mechanical separation facility can process about 1 ton of shredder residue per hour. About one-third of the shredder residue - the plastic-intensive portion - is recovered as a polymer concentrate.........

Posted by: Jaison      Permalink


December 26, 2005, 3:00 PM CT

Tibetan Plateau's secrets

A University of Alberta physicist who helped solve the age-old mystery of what keeps the highest plateau on Earth afloat, has added more pieces to the Tibetan puzzle. Dr. Martyn Unsworth has uncovered new research about the Tibetan Plateau-an immense region that for years has plagued researchers studying how the area became so elevated.

Several years ago, Unsworth and a team of researchers from China and the United States used low-frequency radio waves to determine that the mid-crust of the plateau is like "a big waterbed." The hot, molten rocks supporting the plateau are less dense than cold rocks, which means they rise up slowly, similar to how a hot-air balloon works. The discovery provides an explanation for how the whole of Tibet could rise up over millions of years.

After that finding, Unsworth returned to Tibet and has since learned that this geological make-up is typical of the whole length of the Himalayas, not just a small region. "We initially thought that this layer might be a local structure, but it's not so," said Unsworth, a professor in the U of A Faculty of Science. His research results are published in the current edition of the scientific journal, Nature.

Dubbed "the roof of the world," or the "abode of the Gods," the plateau contains not only Mount Everest but also all of the world's territory higher than 4,000 metres. The area was formed when India rammed into Asia about 50 million years ago and is considered a showcase of plate tectonics. Eventhough a number of theories have been proposed to explain the unusual thickness of the plateau-its crust doubles the average 30 to 35-kilometre thickness found the world over-little concrete evidence has been offered. Tibet was closed to foreign access until the 1980s, when French and Chinese researchers collaborated to investigate the plateau. Since then, Unsworth and his international research team have made a number of significant findings, and access to data collected in India was recently negotiated.........

Posted by: Jaison      Permalink