Tag Archives: Southern Ocean

Stronger winds explain puzzling growth of sea ice in Antarctica

Much attention is paid to melting sea ice in the Arctic. But less clear is the situation on the other side of the planet. Despite warmer air and oceans, there’s more sea ice in Antarctica now than in the 1970s – a fact often pounced on by global warming skeptics. The latest numbers suggest the Antarctic sea ice may be heading toward a record high this year.

While changes in weather may play a big role in short-term changes in sea ice seen in the past couple of months, changes in winds have apparently led to the more general upward sea ice trend during the past few decades, according to University of Washington research. A new modeling study to be published in the Journal of Climate shows that stronger polar winds lead to an increase in Antarctic sea ice, even in a warming climate. (more…)

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Earth orbit changes were key to Antarctic warming that ended last ice age

For more than a century scientists have known that Earth’s ice ages are caused by the wobbling of the planet’s orbit, which changes its orientation to the sun and affects the amount of sunlight reaching higher latitudes, particularly the polar regions.

The Northern Hemisphere’s last ice age ended about 20,000 years ago, and most evidence has indicated that the ice age in the Southern Hemisphere ended about 2,000 years later, suggesting that the south was responding to warming in the north.

But new research published online Aug. 14 in Nature shows that Antarctic warming began at least two, and perhaps four, millennia earlier than previously thought. (more…)

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First global atlas of marine plankton reveals remarkable underwater world

Under the microscope, they look like they could be from another planet, but these microscopic organisms inhabit the depths of our oceans in nearly infinite numbers.

To begin to identify where, when, and how much oceanic plankton can be found around the globe, a group of international researchers have compiled the first ever global atlas cataloguing marine plankton ranging in size from bacteria to jellyfish. The atlas was published on July 19, 2013, in a special issue of the journal Earth System Science Data. (more…)

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Remote Clouds Responsible for Climate Models’ Glitch in Tropical Rainfall

It seems counterintuitive that clouds over the Southern Ocean, which circles Antarctica, would cause rain in Zambia or the tropical island of Java. But new research finds that one of the most persistent biases in global climate models – a phantom band of rainfall just south of the equator that does not occur in reality – is caused by poor simulation of the cloud cover thousands of miles farther to the south.

University of Washington atmospheric scientists hope their results help explain why global climate models mistakenly duplicate the inter-tropical convergence zone, a band of heavy rainfall in the northern tropics, on the other side of the equator. The study appears this week in the Proceedings of the National Academy of Sciences. (more…)

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Changing Climate, Not Tourism, Seems to Be Driving Decline in Chinstrap-Penguin Populations

High-resolution satellite imagery aids in study

The breeding population of chinstrap penguins has declined significantly as temperatures have rapidly warmed on the Antarctic Peninsula, according to researchers funded in part by the National Science Foundation (NSF).

The study indicates that changing climatic conditions, rather than the impact of tourism, have had the greatest effect on the chinstrap population.

Ron Naveen, founder of a nonprofit science and conservation organization, Oceanites, Inc., of Chevy Chase, Md., documented the decline in a paper published in the journal Polar Biology. Naveen and coauthor Heather Lynch, of Stony Brook University, are researchers with the Antarctic Site Inventory (ASI). (more…)

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A ‘B-12 Shot’ for Marine Algae?

Scientists find key protein for algae growth in the ocean

Scientists have revealed a key cog in the biochemical machinery that allows marine algae at the base of the oceanic food chain to thrive. They have discovered a previously unknown protein in algae that grabs an essential but scarce nutrient out of seawater, vitamin B12.

Many algae, as well as land-dwelling animals, including humans, require B12, but they cannot make it and must either acquire it from the environment or eat food that contains B12. Only certain single-celled bacteria and archaea have the ability to synthesize B12, which is also known as cobalamin. (more…)

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Fish of Antarctica Threatened By Climate Change

A Yale-led study of the evolutionary history of Antarctic fish and their “anti-freeze” proteins illustrates how tens of millions of years ago a lineage of fish adapted to newly formed polar conditions – and how today they are endangered by a rapid rise in ocean temperatures.

“A rise of 2 degrees centigrade of water temperature will likely have a devastating impact on this Antarctic fish lineage, which is so well adapted to water at freezing temperatures,” said Thomas Near, associate professor of ecology and evolutionary biology and lead author of the study published online the week of Feb. 13 in the Proceedings of the National Academy of Sciences. (more…)

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NSF’s Nathaniel B. Palmer Sails with Sweden’s Oden to Study Antarctic Peninsula Ecosystem

*Amundsen Sea Polynya International Research Expedition (ASPIRE) Combines Research and Education*

In a unique and complex example of “science diplomacy,” teams of U.S. and Swedish scientists are sailing this month aboard two research vessels to study the ecology of the Amundsen Sea, one of the least-explored and most productive bodies in Antarctic waters, and to gauge the potential effects of a changing climate on the Southern Ocean.

The joint American and Swedish expedition, involving the U.S. icebreaking research vessel Nathaniel B. Palmer and the Swedish icebreaker Oden, was cooperatively planned and is being carried out by the National Science Foundation’s Office of Polar Programs and the Swedish Polar Research Secretariat (SPRS). (more…)

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