Tag Archives: ocean current

Scientists Cast Doubt on Theory of What Triggered Antarctic Glaciation

AUSTIN, Texas — A team of U.S. and U.K. scientists has found geologic evidence that casts doubt on one of the conventional explanations for how Antarctica’s ice sheet began forming. Ian Dalziel, research professor at The University of Texas at Austin’s Institute for Geophysics and professor in the Jackson School of Geosciences, and his colleagues report the findings today in an online edition of the journal Geology.

The Antarctic Circumpolar Current (ACC), an ocean current flowing clockwise around the entire continent, insulates Antarctica from warmer ocean water to the north, helping maintain the ice sheet. For several decades, scientists have surmised that the onset of a complete ACC played a critical role in the initial glaciation of the continent about 34 million years ago. (more…)

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Scientists Uncover Diversion of Gulf Stream Path in Late 2011

Warmer waters flowed to shelfbreak south of New England

At a meeting with New England commercial fishermen last December, physical oceanographers Glen Gawarkiewicz and Al Plueddemann from the Woods Hole Oceanographic Institution (WHOI) were alerted by three fishermen about unusually high surface water temperatures and strong currents on the outer continental shelf south of New England.

“I promised them I would look into why that was happening,” Gawarkiewicz says. (more…)

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UA Climate Scientists Put Predictions to the Test

A new study has found that climate-prediction models are good at predicting long-term climate patterns on a global scale but lose their edge when applied to time frames shorter than three decades and on sub-continental scales.

Climate-prediction models show skills in forecasting climate trends over time spans of greater than 30 years and at the geographical scale of continents, but they deteriorate when applied to shorter time frames and smaller geographical regions, a new study has found.

Published in the Journal of Geophysical Research-Atmospheres, the study is one of the first to systematically address a longstanding, fundamental question asked not only by climate scientists and weather forecasters, but the public as well: How good are Earth system models at predicting the surface air temperature trend at different geographical and time scales? (more…)

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Surviving Without Ice

Arctic crustaceans use currents, deep-water migration to survive sea ice melts

With sea ice in the Arctic melting to record lows in summer months, marine animals living there face dramatic changes to their environment. Yet some crustaceans, previously thought to spend their entire lives on the underside of sea ice, were recently discovered to migrate deep underwater and follow ocean currents back to colder areas when ice disappears.

“Our findings provide a basic new understanding of the adaptations and biology of the ice-associated organisms within the Arctic Ocean,” said Mark Moline, director of the University of Delaware’s School of Marine Science and Policy in the College of Earth, Ocean, and Environment. “They also may ultimately change the perception of ice fauna as imminently threatened by the predicted disappearance of perennial sea ice.” (more…)

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Going with the Flow

Scientists studying ocean currents and oil spills with large-scale experiment

Scientists are releasing hundreds of floating GPS devices into the Gulf of Mexico this week near the Deepwater Horizon site to study the role of ocean currents in oil spills. The experiment is the largest in scale of its kind, deploying 300 satellite-tracked, untethered buoys, called drifters, over the course of two and a half weeks.

“We’re trying to use the drifters as a simulation of an oil spill,” said Dennis Kirwan, Mary A.S. Lighthipe Professor of Marine Studies in the University of Delaware’s College of Earth, Ocean, and Environment. “This is a big event in oceanography.” (more…)

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Sampling the Pacific for Signs of Fukushima

An international research team is reporting the results of a research cruise they organized to study the amount, spread, and impacts of radiation released into the ocean from the tsunami-crippled reactors in Fukushima, Japan. The group of 17 researchers and technicians from eight institutions spent 15 days at sea in June 2011 studying ocean currents, and sampling water and marine organisms up to the edge of the exclusion zone around the reactors.

Led by Ken Buesseler, a senior scientist and marine chemist at the Woods Hole Oceanographic Institution (WHOI), the team found that the concentration of several key radioactive substances, or radionuclides, were elevated but varied widely across the study area, reflecting the complex nature of the marine environment. In addition, although levels of radioactivity in marine life sampled during the cruise were well below levels of concern for humans and the organisms themselves, the researchers leave open the question of whether radioactive materials are accumulating on the seafloor sediments and, if so, whether these might pose a long-term threat to the marine ecosystem. The results appear in the April 2 online edition of the journal Proceedings of the National Academy of Sciences (PNAS). (more…)

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Woods Hole Oceanographic Institution to Lead Expedition to Measure Radioactive Contaminants in the Pacific Ocean

The Woods Hole Oceanographic Institution (WHOI) will lead the first international, multidisciplinary assessment of the levels and dispersion of radioactive substances in the Pacific Ocean off the Fukushima nuclear power plant—a research effort funded by the Gordon and Betty Moore Foundation.

“This project will address fundamental questions about the impact of this release of radiation to the ocean, and in the process enhance international collaboration and sharing of scientific data,” said Vicki Chandler, Chief Program Officer, Science at the Gordon and Betty Moore Foundation. “It is our hope that through this adverse event, we can increase our current knowledge about various natural and man-made sources of radioactivity in the ocean, and how they might ultimately impact ocean life and health around the world.” (more…)

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