Is the ice at the South Pole melting?

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Ice-at-the-South

Ice-at-the-South

The change in the ice mass covering Antarctica is a critical factor in global climate events. Scientists at the GFZ German Research Centre for Geosciences have now found that the year by year mass variations in the western Antarctic are mainly attributable to fluctuations in precipitation, which are controlled significantly by the climate phenomenon El Nino. They examined the GFZ data of the German-American satellite mission GRACE (Gravity Recovery and Climate Experiment). The investigation showed significant regional differences in the western coastal area of the South Pole area. Two areas in Antarctica are of particular interest because of their potential sensitivity to global climate change: the Antarctic Peninsula, which is currently experiencing a warming exceeding the global mean and the disappearance of large ice shelf areas, and the Amundsen Sector of West Antarctica, where currently the largest flow rates and mass loss of the Antarctic Ice Sheet is occurring. For some glaciers the ice thickness is decreasing rapidly, and glaciers and ice streams are notably retreating back into the interior. With 0.3 millimeters per year, both regions are currently contributing considerably to the global sea level change of about three millimeters per year.

n the study, the mass balance of both regions is reevaluated from gravity data of the satellite mission GRACE. As a result, the estimates were lower than those of conventional mass balance methods. “With the GRACE time series, it was for the first time possible to observe how the large-scale ice mass varies in the two areas due to fluctuations in rainfall from year to year,” said the GFZ scientists Ingo Sasgen. It has long been known that the Pacific El Niño climate phenomenon and the snowfall in Antarctica are linked. The complementary piece to the warm phase El Nino, the cold phase known as La Nina, also affects the Antarctic climate: “The cooler La Nina years lead to a strong low pressure area over the Amundsen Sea, which favors heavy rainfall along the Antarctic Peninsula – the ice mass is increasing there. In contrast, the Amundsen area is dominated by dry air from the interior during this time. El Nino years with their warm phase lead to precisely the opposite pattern: reduced rainfall and mass loss in the Antarctic Peninsula, and an increase in the Amundsen Sectorfield, respectively” explains Professor Maik Thomas, head of the section “Earth System Modelling” at the German Research Centre for Geosciences (Helmholtz Association).

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Troubled islands: Hurricanes, oil spill and sea level rise

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Hurricanes

Hurricanes

The islands flanking the outlet of the Mississippi River are not only facing losses due to sea level rise and local subsidence, according to one study, but new unknown impacts from oil recovery operations, say researchers working on another project. Both will be presenting their work on Nov. 1 and 2 at the meeting of the Geological Society of American in Denver. Some islands could disappear entirely in coming decades, exposing huge swaths of marshland to the waves of the open sea. On one side of the Mississippi River outlet, to the east of the river outlet, is the Chandeleur Islands-Biloxi Marsh system which is on it’s last legs, say researchers studying the recent geological history of the area via peat layers beneath in the marshes. On the other side, to the west, is Grand Isle which is the focus of a study that helps document what conditions BP needs to restore oil-damaged beaches to return to some kind of normal state – at a time when the island itself is undergoing massive and rapid changes due to hurricanes and repeated beach nourishment efforts.

Islands’ Last Gasps

The Chandeleur Islands, are remote, tenuous strips of sand that have served as surf breaks for the steadily sinking Biloxi Marsh. The marshes used to be farmland and are still fishing grounds, though no one lives in the area today, say researchers who now say these islands’ are on track for oblivion.

“Hurricanes have done a number on them,” said Mary Ellison of the University of New Orleans. Ellison and her colleagues have been putting the present storm batterings and bleak future of the islands and marsh into perspective by studying the past via sediments beneath the marsh. Ellison is scheduled to present their work on Nov. 2.

The sediments show that a thousand years ago the disappearing marshes were part of the delta with the Mississippi river debouching in an eastern direction, loading the area with sediments. Then the river abandoned the east channel and drained further west. Waves from the Gulf took over and started chipping away at the delta, eventually winnowing out the finer grained silts and leaving the larger-grained sand. That piled up along long strips to create the Chandeleur Islands.

Today, the thousand-year trend is being accelerated by the lack of any sand from the Mississippi River to feed the islands. The islands are now cannibalizing themselves in order to maintain their shorelines. Unfortunately, unlike what was once supplied by the river, the supply of cannibalized sediment is finite The result is that the islands are on course to become little more than shoals in 50 years or so, Ellison explains.

“These islands are beyond the point of recovery,” said Ellison. If the past is any measure of the future, the loss of the islands will allow more waves to attack the marsh directly, which will lead to more winnowing of fines and coarse material, and perhaps the creation of another long strip of islands closer to the mainland, she said.

“It’s kind of at warp speed” compared to such changes at other barrier island systems along other coasts, said Ellison. And that’s exactly why the Chandeleur Islands are so important to study for the sake of barrier islands everywhere.

Animal evolution springs from ‘Snowball Earth’

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UC-Riverside

UC-Riverside

Biogeochemists have found new evidence linking “Snowball Earth” glacial events to the rise of early animals. The research was funded by the National Science Foundation (NSF). Study results appear in this week’s issue of the journal Nature.

The controversial Snowball Earth hypothesis posits that, on several occasions, the Earth was covered from pole to pole by a thick sheet of ice lasting for millions of years.

These glaciations, the most severe in Earth history, occurred from 750 to 580 million years ago.

In the aftermath, the researchers discovered, the oceans were rich in phosphorus, a nutrient that controls the abundance of life in the oceans.

The team, led by scientists at the University of California Riverside, tracked phosphorus concentrations through Earth’s history by analyzing the composition of iron-rich chemical precipitates. These precipitates accumulated on the seafloor and “scavenged” phosphorus from seawater.

The analyses revealed that there was a pronounced spike in marine phosphorus levels in the mid-Neoproterozoic (from ~750 to ~635 million years ago).

Safety Concerns Over Healthful Plant-Based Antioxidants

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Antioxidants

Antioxidants

Concerns about the safety of ‘healthful‘ plant-based antioxidants’, including those renowned for their apparent ability to prevent cancer have been raised by scientists.

They are calling for more research on the possibility that some antioxidants may actually aggravate or even cause cancer in some individuals.

Their recommendation follows a study in which two such antioxidants – quercetin and ferulic acid – appeared to aggravate kidney cancer in severely diabetic laboratory rats.

Kuan-Chou Chen, Robert Peng, and colleagues note that vegetables, fruits, and other plant-based foods are rich in antioxidants that appear to fight cancer, diabetes, heart disease, and other disorders.

Among those antioxidants is quercetin, especially abundant in onions and black tea, and ferulic acid, found in corn, tomatoes, and rice bran.

Both also are ingredients in certain herbal remedies and dietary supplements. But questions remain about the safety and effectiveness of some antioxidants, with research suggesting that quercetin could contribute to the development of cancer, the scientists note.

The Great Chemical Unknown: A Graphical View of Limited Lab Testing

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Graphscicolors

Graphscicolors

Experts guesstimate that about 50,000 chemicals are used in U.S. consumer products and industrial processes. Why the uncertainty? The 1976 Toxic Substances Control Act does not require chemicals to be registered or proven safe before use. Because the Environmental Protection Agency must show, after the fact, that a substance is dangerous, it has managed to require testing of only about 300 substances that have been in circulation for decades. It has restricted applications of five.

The House Toxic Chemicals Safety Act of 2010 and the Senate Safe Chemicals Act of 2010 would require manufacturers to prove that existing and new chemicals meet specific safety criteria. Stricter scrutiny in Europe and Canada suggests that “10 to 30 percent of U.S. chemicals would need some additional level of control,” says Richard Denison, a molecular biochemist at the Environmental Defense Fund. That would be 5,000 to 15,000 chemicals, not five.

New colorectal cancer test could eliminate need for colonoscopy for many people

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Colorectal-cancer

Colorectal-cancer

Colonoscopies might beat out root canals as the most reviled commonplace medical procedure that many of us might expect to undergo. Nevertheless, the uncomfortable undertaking is currently one of the best ways to detect early signs of colorectal cancer, a disease that more than 142,000 Americans are diagnosed with each year—and one that kills more than 51,000.

But adults between the ages of 50 and 74 might soon be able to put the dread days of recommended decadal colonoscopies behind them. Researchers announced Thursday early results that indicate their noninvasive test has excellent accuracy in detecting the cancer—as well as more than half of substantial precancerous polyps.

“This test exceeded our expectations,” David Ahlquist, a professor of medicine at the Mayo Clinic and study collaborator, said in a press briefing at the American Association for Cancer Research’s Colorectal Cancer conference in Philadelphia. The test, which is being developed by Madison, Wisc.–based company Exact Sciences, looks for telltale signs of cancerous DNA methylation in stool samples

TED MED 2010: The Astronaut, the Author and the Prince of Darkness

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The-Astronaut

The-Astronaut

SAN DIEGO—The last sessions of TED MED today offered some unusual windows into health and the individual from astronaut Scott Parazynski, author AJ Jacobs, and Ozzy and Sharon Osbourne.

Parazynski, a NASA astronaut, physician and Everest summiteer, offered: “I feel a little bit like Forrest Gump.” He’s seen the planet from above, at its highest peak and below the ocean’s surface. “But today, I’m the opening freaking act for Ozzy Osbourne.” In 2009, he was climbing Mount Everest when crippling back pain forced him to halt his ascent before the top. “On the bright side, I had an unlimited amount of ice,” said Parazynski, so he could lie down and ease his back pain on the way back down. Surgery later corrected the nerve impingement, and he reached the summit a year later.

A.J. Jacobs, author, described three years each spent with a different focus, and resulting in a book. To develop his mind, he read the encyclopedia from A to Z: “my intellectual Everest.” Next, he worked on his spirit, following the rules of the Bible. The third year, he wanted to work on his body. He said that i t takes a lot of time to be healthy. You need to spend time exercising, even chewing more thoroughly. “I am pro-chewing,” he said. He tried different workouts and diets, including calorie restriction. “ You’ll live a lot longer, even if you don’t want to.” He still has five months to go, but already has gained some lessons, including: eat less, move more, relax. “Be kind to your future self, like you would anyone,” he adds. He hung up a digitally aged picture of himself for inspiration.

Ozzy also proved to have some Neandertal DNA on chromosome 10, but Harvard University professor “George Church has about three times as much,” said Pearson. “I’d like to meet him,” said Sharon.

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