June 19, 2006, 11:43 PM CT

Poison + Water = Hydrogen

Take a pot of scalding water, remove all the oxygen, mix in a bit of poisonous carbon monoxide, and add a pinch of hydrogen gas. It sounds like a recipe for a witch's brew. It may be, but it is also the preferred environment for a microbe known as Carboxydothermus hydrogenoformans.

In a paper reported in the November 27 th issue of PLoS Genetics, a research team led by researchers at The Institute for Genomic Research (TIGR) report the determination and analysis of the complete genome sequence of this organism. Isolated from a hot spring on the Russian volcanic island of Kunashir , this microbe lives almost entirely on carbon monoxide. While consuming this normally poisonous gas, the microbe mixes it with water, producing hydrogen gas as waste.

As the world increasingly considers hydrogen as a potential biofuel, technology could benefit from having the genomes of such microbes. " C. hydrogenoformans is one of the fastest-growing microbes that can convert water and carbon monoxide to hydrogen," remarks TIGR evolutionary biologist Jonathan Eisen, senior author of the PLoS Genetics study. "So if you're interested in making clean fuels, this microbe makes an excellent starting point."

In sequencing the microbe's genome, Eisen and his collaborators discovered why C. hydrogenoformans grows more rapidly on carbon monoxide than other species: The bug boasts at least five different forms of a protein machine, dubbed carbon monoxide deyhydrogenase, that is able to manipulate the poisonous gas. Each form of the machine appears to allow the organism to use carbon monoxide in a different way. Most other organisms that live on carbon monoxide have only one form of this machine. In other words, while other organisms may have the equivalent of a modest mixing bowl to process their supper of carbon monoxide, this species has a veritable food processor, letting it gorge on a hot spring buffet all day.........

Posted by: Ashley      Permalink         Source

June 19, 2006, 11:36 PM CT

Interfering With Rainfall And Water Cycle

In the past half-century, cities have begun to expand in some of the Earth's most arid areas. While researchers have known for some time that the so-called "heat-island" effect of large cities such as Atlanta and Houston can affect their weather, they knew less about this effect and other processes in arid cities, such as Phoenix, which have experienced explosive population growth.

Now, a study by a climatologist in the department of geography at the University of Georgia has shown, using a unique 108-year-old data record and NASA's Tropical Rainfall Measuring Mission (TRMM) satellite, that arid cities such as Riyadh in Saudi Arabia and Phoenix have an effect on rainfall patterns around them. As important, it appears that human activities such as land use, aerosols and irrigation in these arid urban environments affect the entire water cycle as well.

"A number of of the fastest-growing urban areas are in arid regimes," said Marshall Shepherd, author of the report just reported in the online edition of the Journal of Arid Environments. "Because their total rainfall is low, these areas have been largely ignored in studies on how human activities affect the water cycle. But these cities are especially sensitive to such changes, since the water supply is so critical."........

Posted by: Tyler      Permalink         Source

June 19, 2006, 11:31 PM CT

Hurricanes and the US Gulf Coast

Science and sustainable rebuilding

The American Geophysical Union today published the report of a Conference of Experts, intended to guide policy makers charged with rebuilding areas affected by Hurricanes Katrina and Rita. The 20 researchers who participated in the conference looked at seven major areas: hurricanes, storm surge and flooding, subsidence, climate change, hydrology, infrastructure, and disaster preparedness and response. For each topic, they assessed current understanding of the phenomenon, near-term scientific needs, and longer-term directions.

Following is the text of the Executive Summary of the report. The full 30-page report may be seen at http://www.agu.org/report/hurricanes/.

Summary of Report

The knowledge available among AGU members provides scientific expertise on nearly all of the physical environment of the dynamic Gulf Coast ecosystem complex. Intelligently rebuilding features such as fisheries, oil fields, seaports, farms, and wetlands after hurricanes Katrina and Rita will require "a well-constructed collaborative effort to maximize the role of science in decisions made about the rebuilding," wrote Charles Groat, former director of the U.S. Geological Survey, in a news article published in Eos that stimulated an AGU meeting of experts.........

Posted by: Tyler      Permalink         Source

June 18, 2006, 11:02 AM CT

From Aerosol Particles To Cloud Droplets

In spite of diverse origins and composition of aerosol particles in central Europe, their ability to grow into cloud droplets is controlled predominantly by their size.

Clouds play a central role in the Earth's climate system and water cycle. A cloud's behavior depends to a great extent on the number and size of the droplets it is made of. Since each of these droplets requires a seed aerosol particle to grow upon (called cloud condensation nucleus, CCN), it is essential to understand what properties of an aerosol particle allow it to grow into a cloud drop. Basic physical chemistry shows that, to a first approximation, this depends on the number of soluble molecules it contains, which is a function of its size and composition. Given the very diverse origin of atmospheric particles (e.g., sea salt, dust, smoke, and industrial emissions), the complexity of their composition has long been seen as a major obstacle to modeling and predicting aerosol effects on cloud properties and climate.

To separate the effects of size and composition, the researchers of the Max Planck Institute for Chemistry and the University of Mainz divided ambient aerosols into narrow size classes and then determined their chemical composition and ability to grow into cloud drops. They made the measurements in summer 2004, on top of the Kleiner Feldberg in the Taunus Mountains of Germany. During the 3-week measurement period, diverse air masses were encountered at the mountaintop station: aged continental air that had accumulated industrial and traffic pollution, marine air masses that had moved in rapidly from the North Atlantic, and fresh pollution from the densely populated and industrialized Rhine-Main area. The aerosol composition was dominated by organic material in all air mass types, followed by ammonium, sulfate and nitrate. Interestingly, in spite of the different histories of the air, the soluble fraction of the particles did not appear to vary all that much.........

Posted by: Tyler      Permalink         Source

June 16, 2006, 0:13 AM CT

Arctic Expedition Will Investigate Alien-like Glacier

A scientific expedition to a remote glacier field in Canada's High Arctic may help scientists unlock the secrets about the beginning of life and provide insights for future exploration of our solar system.

A team assembled by the University of Calgary's Arctic Institute of North America plans to spend two weeks studying a sulfur-spewing spring on the surface of an ice field not far from the North Pole this summer, after it was discovered by Institute Executive Director Dr. Benoit Beauchamp during his travels in the area. Beauchamp, U of C adjunct professor Dr. Steve Grasby from the Geological Survey of Canada, and two graduate students will conduct the first extensive study of the spring after initial tests showed the geological oddity is home to a unique form of bacteria that has adapted to thrive in a cold and sulfur-rich environment.

"We really want to try and understand the plumbing system for this spring and where all this sulfur is coming from," Beauchamp said. "This is a very unusual feature on the earth's surface and it's an extreme ecosystem that could be a good model for how life first begins in a harsh environment".

The spring has also attracted the attention of the Canadian Space Agency and NASA, which are helping to fund the expedition, because it likely provides the best example on Earth for the conditions believed to exist on the surface of Jupiter's moon Europa. Ice-covered Europa is considered one of the best candidates for finding evidence of life on other planets within our solar system. Sending a probe to the planet is high on NASA's list of possible projects. Graduate student Damhnait Gleeson from the University Colorado, on a project sponsored by NASA's Jet Propulsion Laboratory, will be taking part in the study to determine if it will be worthwhile testing spacecraft and remote-control rover equipment on the glacier in the future.........

Posted by: Tyler      Permalink         Source

June 15, 2006, 10:57 PM CT

Thawing Permafrost

Permafrost, permanently frozen soil, isn't staying frozen and a type of soil called loess contained deep within thawing permafrost may be releasing significant, and previously unaccounted for, amounts of carbon into the atmosphere, as per authors of a paper published this week in the journal Science.

Preliminary assessments by researchers from Russia, the University of Florida, and the University of Alaska Fairbanks indicate that loess permafrost, which covers more than a million square kilometers in Siberia and Alaska, is a large carbon reservoir with the potential to be a significant contributor of atmospheric carbon, yet it is seldom incorporated into analyses of changes in global carbon reservoirs.

"The unique aspect of the Siberian loess permafrost is that it is quite deep - 20 to 40 meters - and has a surprisingly high carbon concentration at depth for a mineral soil," said Terry Chapin, co-author from the Institute of Arctic Biology at UAF. "This paper explains the processes that led to the accumulation of large amounts of soil carbon and the processes that could lead to its return to the atmosphere".

The largest carbon reservoir on Earth is the ocean, which researchers estimate holds about 40,000 gigatons; soils contain about 2,500 Gt and vegetation about 650 Gt. As per the authors, about 500 Gt of carbon are contained in the thaw-threatened loess, also called yedoma, of Siberia and Alaska.........

Posted by: Tyler      Permalink         Source

June 14, 2006, 11:35 PM CT

New Approaches To Ecosystem Restoration

Ecosystems behave in unpredictable ways and, because of this, restoration ecologists are often faced with unforeseen challenges. Researchers, in a recent article published in Restoration Ecology, argue that restoration methods of the past may not always be applicable in the future They see the largest potential challenge ahead is restoring environments undergoing the most rapid rate of change in the earth's history. This global climate change is likely to have important regional consequences for biota and ecosystems.

Ecological restoration, including reafforestation and rehabilitation of degraded land, may be a common response to the effects of climate change, but the implications of this changing environment must be considered. Using past ecosystem conditions as targets and references may be ineffective under new conditions. In addition, there may be less support in the future for longer-term, traditional restoration projects. The authors suggest that, "more consideration and debate needs to be directed at the implications of climate change for restoration practice."........

Posted by: Tyler      Permalink         Source

June 13, 2006, 11:43 PM CT

Chlorine May Contribute To Ozone Formation

Standard methods of predicting air pollution don't take atmospheric chlorine into account, but the chemical could be responsible for 10 percent or more of daily ozone production in local air, research at UC Irvine has found.

Air measurements taken nearly nonstop in the Irvine area over a two-month period showed that daytime chlorine gas levels typically measured five parts per trillion or less, but occasionally reached as high as 15 parts per trillion. Observation of daytime chlorine is surprising because chlorine molecules break apart just minutes after entering the atmosphere and being exposed to sunlight.

With these measurements, researchers estimate that chlorine photochemistry creates five to eight parts per billion of the maximum daily ozone level, which in California typically ranges between 40 and 80 parts per billion.

"Chlorine chemistry can have a direct impact on surface ozone even at parts per trillion levels," said Eric Saltzman, professor of Earth system science in the School of Physical Sciences at UCI. "Because of the strong link between ozone and human health, we need to fully understand the role chlorine may play in ozone chemistry in coastal urban environments."

Saltzman and Brandon Finley, a graduate student researcher in the Department of Earth System Science, published their findings in the current issue of Geophysical Research Letters.........

Posted by: Tyler      Permalink         Source

June 13, 2006, 11:33 PM CT

Excavation Of Home Of UNC Founder

Artifacts suggest that the South Carolina site that archaeology students and faculty from the University of North Carolina at Chapel Hill have been excavating was indeed the home of UNC founder William R. Davie, but contradict the local lore that Union troops burned the house in 1865.

The excavation uncovered parts of the foundation, which the scientists used to determine the dimensions of the house. "It was 40 feet wide, and from chimney to chimney, about 45 feet long. For the early 1800s, that's a pretty big house," said Dr. R.P. Stephen Davis, associate director of the university's Research Labs of Archaeology and an adjunct professor of anthropology in UNC's College of Arts and Sciences.

"Those house dimensions, in combination with the artifacts that we found there - some very expensive table wares, for instance - lead us to confidently assert that it is William R. Davie's home," said Dr. Brett Riggs, staff archaeologist in the Research Labs of Archaeology, also in the College of Arts and Sciences. Remnants of table wares found at the site include Chinese export porcelain and English porcelain with painted decorations.

But the scientists and their undergraduate collaborators did not find the key evidence that would suggest a fire. "We would expect masses of charcoal and burned window glass, and we just didn't encounter that," Riggs said. "It's possible that such evidence was obliterated, but we really doubt it".........

Posted by: William      Permalink         Source

June 13, 2006, 0:17 AM CT

Bacteria And Algae Destroy Coral

Researchers have discovered an indirect microbial mechanism whereby bacteria kill coral with the help of algae. Human activities are contributing to the growth of algae on coral reefs, setting the stage for the long-term continued decline of coral.

Reporting in the June 5 on-line version of the scientific journal Ecology Letters, researchers described laboratory experiments on coral and algae.

First author Jennifer Smith, a postdoctoral fellow at the National Center for Ecological Analysis and Synthesis (NCEAS) at the University of California, Santa Barbara, explained that the team of scientists, as part of a research expedition to the Line Islands, put algae and coral in chambers of seawater with filters between them. All of the corals with neighboring algae died, while coral without neighboring algae did not die. However, with the addition of an antibiotic, coral death even in the presence of algae was prevented, showing that bacteria fed by the algae are the agents of coral death. "We are the first to link these processes together," said Smith.

"This study tightly links the fields of microbiology with coral reef ecology to help guide reef conservation efforts," said senior author Forest Rohwer, assistant professor of microbiology at San Diego State University.........

Posted by: Tyler      Permalink         Source

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