January 10, 2007, 10:01 PM CT

Homer's Ithaca Possibly Found

Results of geologic tests released on January 9, 2007, by British businessman Robert Bittlestone, Cambridge classicist James Diggle, and University of Edinburgh geologist John Underhill suggest further evidence to support the hypothesis that Homer's Ithaca can be found on western Kefalonia as published in the January 2007 issue of Geotimes magazine, published by the American Geological Institute (AGI).

This hypothesis, fully explained in Geotimes, suggests that the western peninsula of the modern-day Greek island Kefalonia, called Paliki, was a separate island 3,000 years ago. Landslides and rockfalls from earthquakes filled in the valley between Kefalonia and Paliki, thus disguising the ancient landscape that was described by Homer in the Odyssey.

Underhill and his colleagues have conducted extensive geological and geophysical studies on the southern end of the isthmus between Kefalonia and Paliki where the team drilled a 122-meter borehole. The team never encountered bedrock but instead bored through unconsolidated rockfall and landside material even below sea level. The absence of bedrock and presence of very young marine fossils in the reworked borehole sediments confirm that rockfalls and landslides could have filled in the ancient sea channel to create the isthmus between the once separate islands. If this hypothesis holds true, Paliki likely matches Homer's description of Ithaca.........

Posted by: Tyler      Read more         Source

January 9, 2007, 9:05 PM CT

Forest Fires Release Mercury

Forest fires release more mercury into the atmosphere than previously recognized, a multidisciplinary research project at the University of Michigan suggests.

The study, which has implications for forest management and global mercury pollution, was published online today (Jan. 9) in the journal Global Biogeochemical Cycles.

Doctoral student Abir Biswas, the paper's lead author, came up with the idea for the project when he was a student at U-M's Camp Davis Rocky Mountain Field Station near Jackson Hole, Wyoming. Wildfires were burning all around the station that summer, and smoke blanketed the camp. Around that time, Biswas happened to read a new scientific paper suggesting the possible role of fires in global mercury emissions.

"There I was, watching forest fires around our field camp, and it seemed like the ideal place to study the problem," he said.

The study Biswas read investigated mercury emissions from the combustion of foliage at locations around the USA and extrapolated to estimate mercury release during forest fires. "I'm interested in earth surface geochemistry so I wanted to approach the question differently," Biswas said.

Over the next two summers, under the direction of U-M professor Joel Blum, Biswas collected core samples of forest soil from burned and unburned areas, using sections of PVC pipe sharpened at one end to obtain the cylindrical samples. He and Blum also collaborated with U-M professor Gerald Keeler and former research scientist Bjorn Klaue to take air samples at Camp Davis-measuring mercury and trace metals over two summers-which provided the researchers with a picture of the atmospheric background on which the fires were superimposed.........

Posted by: Tyler      Read more         Source

January 9, 2007, 8:42 PM CT

Diamonds From Outer Space

If indeed "a diamond is forever," the most primitive origins of Earth's so-called black diamonds were in deep, universal time, geologists have discovered. Black diamonds came from none other than interstellar space.

In a paper published online on December 20, 2006, in the journal Astrophysical Journal Letters, researchers Jozsef Garai and Stephen Haggerty of Florida International University, along with Case Western Reserve University scientists Sandeep Rekhi and Mark Chance, claim an extraterrestrial origin for the unique black diamonds, also called carbonado diamonds.

Infrared synchrotron radiation at Brookhaven National Laboratory was used to discover the diamonds' source.

"Trace elements critical to an 'ET' origin are nitrogen and hydrogen," said Haggerty. The presence of hydrogen in the carbonado diamonds indicates an origin in a hydrogen-rich interstellar space, he and his colleagues believe.

The term carbonado was coined by the Portuguese in Brazil in the mid-18th century; it's derived from its visual similarity to porous charcoal. Black diamonds are found only in Brazil and the Central African Republic.

"Conventional diamonds are mined from explosive volcanic rocks [kimberlites] that transport them from depths in excess of 100 kilometers to the Earth's surface in a very short amount of time," said Sonia Esperanca, program director in the National Science Foundation's Division of Earth Sciences, which funded the research. "This process preserves the unique crystal structure that makes diamonds the hardest natural material known".........

Posted by: Brooke      Read more         Source

January 7, 2007, 9:39 PM CT

Chemistry of Volcanic Fallout

A team of American and French researchers has developed a method to determine the influence of past volcanic eruptions on climate and the chemistry of the upper atmosphere, and significantly reduce uncertainty in models of future climate change.

In the January 5 issue of the journal Science, the scientists from the University of California, San Diego, the National Center for Scientific Research (CNRS) and the University of Grenoble in France report that the chemical fingerprint of fallout from past eruptions reveals how high the volcanic material reached, and what chemical reactions occurred while it was in the atmosphere. The work is especially relevant because the effect of atmospheric particles, or aerosols, is a large uncertainty in models of climate, as per Mark Thiemens, Dean of UCSD's Division of Physical Sciences and professor of chemistry and biochemistry.

"In predictions about global warming, the greatest amount of error is linked to atmospheric aerosols," explained Thiemens, in whose laboratory the method, which is based on the measurement of isotopes-or forms of sulfur-was developed. "Now for the first time, we can account for all of the chemistry involving sulfates, which removes uncertainties in how these particles are made and transported. That's a big deal with climate change".........

Posted by: Tyler      Read more         Source

December 28, 2006, 9:36 PM CT

Carbon Dioxide Emissions Andt Atmosphere

Carbon dioxide emissions from the burning of fossil fuels will produce a 3 percent reduction in the density of Earth's outermost atmosphere by 2017, as per a team of researchers from the National Center for Atmospheric Research (NCAR) and Pennsylvania State University (PSU).

The research appears in the latest issue of the journal Geophysical Research Letters, and will be presented today at the American Geophysical Union conference in San Francisco, Calif.

"We're seeing climate change manifest itself in the upper as well as lower atmosphere," said NCAR scientist Stan Solomon, a co-author of the study. "This shows the far-ranging impacts of greenhouse gas emissions".

Lower density inthe thermosphere, which is the highest layer of the atmosphere, would reduce the drag on satellites in low Earth orbit, allowing them to stay airborne longer. Forecasts of upper-level air density could help NASA and other agencies plan the fuel needs and timing of satellite launches more precisely, potentially saving millions of dollars.

-----Confirming a prediction-----.

Recent observations by researchers tracking satellite orbits have shown that the thermosphere, which begins about 60 miles above Earth and extends up to 400 miles, is beginning to become less dense, said Robert Kerr, program director in the National Science Foundation's (NSF) Division of Atmospheric Sciences.........

Posted by: Tyler      Read more         Source

December 27, 2006, 5:06 AM CT

Mixed Prairie Grasses Better Source Of Biofuel

Diverse mixtures of native prairie plant species have emerged as a leader in the quest to identify the best source of biomass for producing sustainable, bio-based fuel to replace petroleum.

A new study led by David Tilman, an ecologist at the University of Minnesota, shows that mixtures of native perennial grasses and other flowering plants provide more usable energy per acre than corn grain ethanol or soybean biodiesel and are far better for the environment. The research was supported by the National Science Foundation (NSF) and the University of Minnesota Initiative for Renewable Energy and the Environment.

"Biofuels made from high-diversity mixtures of prairie plants can reduce global warming by removing carbon dioxide from the atmosphere. Even when grown on infertile soils, they can provide a substantial portion of global energy needs, and leave fertile land for food production," Tilman said.

The findings appear in the Dec. 8, 2006, issue of the journal Science.

The is study based on 10 years of research at Minnesota's Cedar Creek Natural History Area, one of 26 NSF long-term ecological research (LTER) sites. It shows that degraded agricultural land planted with diverse mixtures of prairie grasses and other flowering plants produces 238 percent more bioenergy on average than the same land planted with various single prairie plant species, including switchgrass.........

Posted by: Kevin      Read more         Source

December 27, 2006, 4:53 AM CT

Links Between African And U.S. Weather Systems

When their DC-8 flew into a tropical storm off the coast of West Africa, Aaron Pratt and Tamara Battle realized their lifelong dream--to study storms and weather systems at their source. During that flight, lightning struck their plane. The resulting storm turned into a tropical depression and ultimately became known as Hurricane Helene, one of the strongest Atlantic hurricanes in 2006.

Pratt and Battle were thrilled. They, along with Stephen Chan, Amber Reynolds, Daniel Robertson and Deanne Grant, spent a month conducting weather research in Senegal and Cape Verde, West Africa. The students worked with researchers from universities and government agencies to study how land storms become ocean storms and then make their way west to U.S. and Caribbean waters.

"African dust is very critical for hurricane formation. One of our flights allowed us to see the dust kicked up in the Sahara Desert," said Pratt, who is pursuing a doctorate in atmospheric science from Howard University in Washington, D.C. "I had never done research overseas before and didn't know what to expect. Working with researchers in both Senegal and Cape Verde helped put our research in the proper perspective".

Battle is also a doctoral candidate in atmospheric science at Howard University. "When we flew over the Sahara Desert, it was serene and beautifully simple," she said. "Africa's easterly waves and Saharan dust storms not only impact the weather in the United States and the Caribbean, but they also have implications for the inhabitants of a number of African countries. By sharing what we've learned, we increase the chances of helping those countries improve forecasting and predictability. That will have a positive impact on the agriculture and economy of the region".........

Posted by: Tyler      Read more         Source

December 26, 2006, 6:12 PM CT

Western Wildfires And Atlantic Ocean Surface Temperatures

Western U.S. wildfires are likely to increase in the coming decades, as per a new tree-ring study led by the University of Comahue in Argentina and involving the University of Colorado at Boulder that links episodic fire outbreaks in the past five centuries with periods of warming sea surface temperatures in the North Atlantic.

States like Washington, Oregon, California, Colorado, New Mexico, Arizona and South Dakota all had an increased prevalence of wildfires in recent centuries when a phenomenon known as the Atlantic Multi-Decadal Oscillation -- similar but longer in duration than the better known El Nino-Southern Oscillation -- periodically shifted from a cool to a warm mode that lasted roughly 60 years each time, said the study authors.

Warmer waters in the North Atlantic correspond with episodes of drought and subsequent fires in the West as shown by fire scars in annual tree rings studied by the researchers, said Thomas Kitzberger of the University of Comahue, who led the study with scientists from CU-Boulder, the University of Arizona, the U.S. Forest Service and Rocky Mountain Tree-Ring Research Inc., a private lab in Fort Collins, Colo.

Kitzberger, who received his doctorate from CU-Boulder in 1994 under co-author and CU-Boulder geography Professor Thomas Veblen, said the North Atlantic warming trend, coupled with warming temperatures and the earlier onset of spring in the West, poses "an increased hazard for wildfires that may continue for decades." The paper was published the week of Dec. 25 in the Proceedings of the National Academy of Sciences.........

Posted by: Tyler      Read more         Source

December 25, 2006, 4:28 PM CT

Ocean Temperature And Marine Species

Ocean temperature apparently has a great effect on the spread of marine species. I was reading the following article this morning, and thought about writing this article in this column.

Researchers can predict how the distance marine larvae travel varies with ocean temperature - a key component in conservation and management of fish, shellfish and other marine species - as per a new study from the University of North Carolina at Chapel Hill.

Most marine life, including commercially important species, reproduces via larvae that drift far along ocean currents before returning to join adult populations. The distance larvae travel before maturing, called dispersal, is directly associated with ocean temperature, the scientists found. For example, larvae from the same species travel far less in warmer waters than in colder waters, said lead author Mary O'Connor, a graduate student in marine ecology in UNC's curriculum in ecology and the department of marine sciences in the College of Arts and Sciences.

"Temperature can alter the number and diversity of adult species in a certain area by changing where larvae end up," O'Connor said. "It is important to understand how a fish population is replenished if we want to attempt to manage or conserve it".

Using data from 72 marine species, including cod, herring, American lobster, horseshoe crabs and clams, O'Connor and her colleagues developed a model that predicts how far larvae travel at a certain temperature. The predictions appear to hold for virtually all marine animals with a larval life cycle.........

Posted by: Tyler      Read more         Source

December 20, 2006, 5:09 AM CT

Climate Change And Endangered Naked Carp

Forthcoming in the January/February 2007 issue of Physiological and Biochemical Zoology, a groundbreaking study reveals an unanticipated way freshwater fish may respond to water diversion and climate change. Endangered naked carp migrate annually between freshwater rivers, where they spawn, and a lake in Western China, where they feed and grow. However, Lake Qinghai is drying up and becoming increasingly more saline--leading to surprising adjustments to the carps' metabolic rate.

Naked carp take seven to ten years to reach reproductive size. Although historically abundant, overfishing and destruction of spawning habitat through dam-building caused the species to become endangered during the 1990s. Diversion of water for agriculture from the lake has been compounded by climate change, leading to a decline in water level in the lake of 1012 cm per year during the past fifty years (see accompanying image).

However, Chris M. Wood (McMaster University) and coauthors found that naked carp respond to the increased salinity of the lake water in a surprising way--by taking a "metabolic holiday." In the first forty-eight hours after transitioning from the freshwater river system to lake water, the carps' oxygen consumption falls --eventually reaching just 60 percent of that in river fish.........

Posted by: Tyler      Permalink         Source