April 12, 2006, 11:50 PM CT

Volcano-like Tremors Detected Deep Within Earth's Crust

Tremors within the Earth are usually--but not always--correlation to the activity of a volcano. Now, such vibrations have been recorded nowhere near a volcano, but at a geologic observatory at the San Andreas Fault. Researchers believe the fault tremors may be correlation to activity at a subduction zone--a place where one of Earth's constantly moving tectonic plates slips beneath another.

To determine whether the San Andreas Fault is moving with the tremors, researchers with the San Andreas Fault Observatory at Depth (SAFOD) are installing instruments to measure the tremors' activity. Located near Parkfield, Calif., SAFOD is part of the EarthScope Project, an effort to study the North American continent's geology.

"Unlike the sharp jolt of an earthquake, tremors within Earth's crust emerge slowly, rumbling for longer periods of time," said Kaye Shedlock, program director for EarthScope at the National Science Foundation (NSF), which funds the project. "Eventhough not in this case, tremors are commonly produced by magma moving in cracks or other conduits beneath a volcano."

The rumblings are the first recordings of non-volcanic tremors in a deep borehole, providing researchers with data to better understand such mysterious underground movements.

The results will help geologists understand whether the deeply buried rocks of the San Andreas Fault - which are derived from an ancient subduction zone - behave in a similar way to the rocks of the Cascadia Subduction Zone, still active today.........

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April 11, 2006, 11:21 PM CT

Global Warming May Lead To Mass Species Extinctions

The Earth could see massive waves of species extinctions around the world if global warming continues unabated, as per a new study reported in the scientific journal Conservation Biology.

Given its potential to damage areas far away from human habitation, the study finds that global warming represents one of the most pervasive threats to our planet's biodiversity - in some areas rivaling and even surpassing deforestation as the main threat to biodiversity.

The study expands on a much-debated 2004 paper reported in the journal Nature that suggested a quarter of the world's species would be committed to extinction by 2050 as a result of global warming. This latest study picks up where the Nature paper left off, incorporating critiques and suggestions from other researchers while increasing the global scope of the research to include diverse hotspots around the world. The results reinforce the massive species extinction risks identified in the 2004 study.

"Climate change is rapidly becoming the most serious threats to the planet's biodiversity," said lead author Dr. Jay Malcolm, an assistant forestry professor at the University of Toronto. "This study provides even stronger scientific evidence that global warming will result in catastrophic species loss across the planet."........

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April 11, 2006, 10:49 PM CT

Arsenic-eating Plants

Environmental arsenic pollution is a serious and growing environmental problem, particularly on the Indian subcontinent. Scientists at the University of Georgia had, several years ago, used genetic techniques to create "arsenic-eating" plants that could be planted on polluted sites.

There was a problem, however. The arsenic sequestered from soil remained largely in the roots of the plant, making it difficult to harvest for safe disposal. Now, the research team, led by geneticist Richard Meagher, has discovered a way to move the arsenic from roots to shoots. The payoff could be a new and effective tool in cleaning up thousands of sites where arsenic presents serious dangers to human health.

The research was just reported in the Proceedings of the National Academy of Sciences (PNAS). Other authors of the paper include Om Parkash Dhankher and Elizabeth McKinney from the department of genetics at UGA and Barry Rosen of Wayne State University.

"High levels of arsenic in soil and drinking water have been reported around the world," said Meagher, "but the situation is worst in India and Bangladesh, where around 400 million people are at risk of arsenic poisoning. Unfortunately, the high cost of using excavation and reburial at these sites makes these technologies unacceptable for cleaning up the vast areas of the planet that need arsenic remediation. As a result, the overwhelming majority of arsenic-contaminated sites are not being cleaned up."........

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April 10, 2006, 8:17 PM CT

Nature Can Help Reduce Greenhouse Gas

Plants apparently do much less than previously thought to counteract global warming, as per a paper would be published in next week's online edition of Proceedings of the National Academy of Sciences.

The authors, including Bruce Hungate of Northern Arizona University and lead author Kees-Jan van Groenigen of UC Davis, discovered that plants are limited in their impact on global warming because of their dependence on nitrogen and other trace elements. These elements are essential to photosynthesis, whereby plants remove carbon dioxide, a greenhouse gas, from the air and transfer carbon back into the soil.

"What our paper shows is that in order for soils to lock away more carbon as carbon dioxide rises, there has to be quite a bit of extra nitrogen available--far more than what is normally available in most ecosystems," said Hungate of NAU's Merriam-Powell Center for Environmental Research.

The paper notes that various plants can pump nitrogen from the air into soils, and some scientists expected rising carbon dioxide to speed up this natural nitrogen pump, providing the nitrogen needed to store soil carbon. However, the research team found that this process, called nitrogen fixation, cannot keep up with increasing carbon dioxide unless other essential nutrients, such as potassium, phosphorus and molybdenum, are added as fertilizers.........

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April 10, 2006, 7:24 PM CT

Mysteries Of Ozone-eating Clouds

Polar stratospheric clouds have become the focus of a number of research projects in recent years due to the discovery of their role in ozone depletion, but essential aspects of these clouds remain a mystery. MIPAS, an instrument onboard ESA's Envisat, is allowing researchers to gain information about these clouds necessary for modelling ozone loss.

"The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is unique in its possibilities to detect polar stratospheric clouds (PSCs) since it is the first instrument with the ability to observe these clouds continuously over the polar regions particularly during the polar night," Michael Hopfner of Gera number of's Forschungszentrum Karlsruhe GmbH said.

Using data collected by MIPAS, a German-designed instrument that observes the atmosphere in middle infrared range, Hopfner and other researchers discovered a belt of nitric acid trihydrate (NAT) PSCs developing in the polar night over Antarctica in 2003 about one month after the first PSCs, which were composed of water crystals, were detected.

There are two classifications of PSCs - Type I clouds contain hydrated droplets of nitric acid and sulphuric acid, while Type II clouds consist of relatively pure water ice crystals.

The presence of NAT was detected because of MIPAS' ability to map the atmospheric concentrations of more than 20 trace gases, including ozone as well as the pollutants that attack it.........

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April 6, 2006, 11:00 PM CT

5-Million-Year Climate Record

Using chemical clues mined from ocean mud, Brown University scientists have generated the longest continuous record of ocean temperatures on Earth.

The 5-million-year record is a history of temperatures in the eastern equatorial Pacific, or EEP, located off the coast of South America. The area is an anomaly - a huge swath of cool water in the tropics - that plays an important role in global climate. In the EEP, trade winds pull nutrient-rich cold water to the surface, which makes for fertile fisheries off the coasts of Peru, Chile and Ecuador. The interplay of wind and water can also fuel El Niño events, a large-scale warming in the EEP that slows the upwelling of cold water and forces changes in weather, such as droughts or floods, far from the tropical Pacific.

In the EEP, the Brown geology team found that surface temperatures were 27 degree C 5 million years ago. Surface temperatures are 23 degree C today. In between, they found a pattern of steady cooling - roughly one degree Celsius every million years.

This finding, published in Science, contradicts the long-standing notion that rapid glacier growth in the high northern latitudes about 3 million years ago alone set off dramatic cooling of the global climate. The finding shows instead that glaciation was part of a long-term cooling trend.........

Posted by: Tyler      Permalink         Source

April 6, 2006, 10:53 PM CT

The Future Of Tropical Forests

Deforestation and habitat loss are expected to lead to an extinction crisis among tropical forest species. Humans in rural settings contribute most to deforestation of extant tropical forests. However, "Trends such as slowing population growth and intense urbanization give reason to hope that deforestation will slow, regeneration will accelerate, and mass extinction of tropical forest species will be avoided," report S.J. Wright, Smithsonian Tropical Research Institute and H.C. Muller-Landau, University of Minnesota, in Biotropica online.

The authors show that the proportion of potential forest cover remaining correlates with human population density among countries in both the tropics and the temperate zone. They use United Nations population projections and continent-specific relationships between both total and rural population density and forest remaining today to project future tropical forest cover.

According to their projections, deforestation rates will decrease as population growth slows, and a much larger area will continue to be forested than previous studies suggest. Tropical forests diminished during repeated Pleistocene glacial events in Africa and more recently in selected areas that supported large prehistoric human populations. "Despite many caveats, our projections for forest cover provide hope that many tropical forest species will be able to survive the current wave of deforestation and human population growth," stress Wright and Mueller-Landau.........

Posted by: Tyler      Permalink         Source

April 6, 2006, 10:47 PM CT

Wireless Sensor Networks Gives Assurance

An earthquake strikes a large city, wrecking roads and bridges, stranding rush-hour commuters, trapping office workers inside high-rise buildings.

As director of the city's transportation authority, you have minutes to make a momentous decision. What is the safest, fastest route that rescue teams can take to travel to hard-hit areas of the city? Which bridges, even if damaged, can still support traffic loads?.

Questions like these are increasingly on the minds of structural engineers and emergency personnel as the world prepares to mark the 100th anniversary of the Great San Francisco Earthquake of April 18, 1906.

The answers to the questions, says Yunfeng Zhang, can be provided by sensors - networks of tiny sensors with built-in computer chips that are attached to a bridge to monitor its safety and performance.

Sensors deployed strategically on a bridge, says Zhang, an assistant professor of civil and environmental engineering at Lehigh University, can provide a high-resolution, multi-dimensional picture of the health of a structure, giving engineers vital information about a bridge's performance and, in the aftermath of a catastrophe, its ability to carry traffic.

To be useful in the event of an earthquake or other emergency, says Zhang, sensor data must be transmitted in real time, virtually without delay, to remote processing centers for interpretation and then to decision-makers.........

Posted by: Tyler      Permalink         Source

April 5, 2006, 9:47 PM CT

Coral Bleaching At Great Barrier Reef

An international team of researchers are working at a rapid pace to study environmental conditions behind the fast-acting and widespread coral bleaching currently plaguing Australia's Great Barrier Reef. NASA's satellite data supply researchers with near-real-time sea surface temperature and ocean color data to give them faster than ever insight into the impact coral bleaching can have on global ecology.

Australia's Great Barrier Reef is a massive marine habitat system made up of 2,900 reefs spanning over 600 continental islands. Though coral reefs exist around the globe, scientists actually consider this network of reefs to be the center of the world's marine biodiversity, playing a critical role in human welfare, climate, and economics. Coral reefs are a multi-million dollar recreational destinations, and the Great Barrier Reef is an important part of Australia's economy.

Researchers use ocean temperatures and ocean "color" as indicators of what is happening with coral. Coral is very temperature sensitive. Ocean "color," or the concentration of chlorophyll in ocean plants, is important because it informs researchers about changes in the ocean's biological productivity. NASA satellites capture both temperature and color data from their space-based view of the coral reefs.........

Posted by: Tyler      Permalink         Source

April 4, 2006, 11:13 PM CT

Does tropical biodiversity increase during global warming?

"Plant diversity seems to increase when tropical forests cover large areas. Shrinking ecosystems may experience biodiversity loss lasting for millions of years." STRI's Carlos Jaramillo and colleagues Milton J. Rueda from the Colombian Petroleum Institute and Germán Mora, from Iowa State University, seek explanations for the longest Central and South America pollen record, published in today's issue of Science.

Jaramillo et al. used cores drilled through 5km of rock in eastern Colombia and western Venezuela to get at the fossil pollen record in a sequence of samples representing 10 to 82 million years before present (mybp). Then they correlated pollen diversity with global temperature estimates for the middle part of that sequence (20-65 mybp).

"We found that pollen diversity tracks global temperature through time over millions of years. Diversity increases as the planet warms and decreases as it cools. The mystery is that even when global temperatures vary enormously, average temperatures in the tropics don't change much, so why do we see global temperature patterns reflected in tropical plant diversity?" Jaramillo proposes that changes in area drive speciation and extinction in the tropics.

During global warming, tropical areas expand and diversity goes up, the opposite happens during global cooling. If this is the case, fragmentation of modern tropical forest could be equated to a global cooling period, because forested areas are shrinking dramatically, resulting in plummeting diversity in the forests that remain".........

Posted by: Tyler      Permalink         Source

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