Report shows growing impacts of ocean acidification

CU-Boulder scientists study document decline of calcification rates in marine organisms around Antarctica

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The Southern Ocean may lose its ability to function as a carbon sink. bberwyn photo.

Staff Report

*More Summit Voice stories on ocean acidification

FRISCO — The steady increase of atmospheric carbon dioxide is already causing large-scale shifts in the ocean carbon cycle, according to University of Colorado, Boulder scientists, who calculated the calcification rate of marine organisms in the Southern Ocean.

According to the scientists there has been a 24 percent decline in the amount of calcium carbonate produced in large areas of the Southern Ocean over the past 17 years. Continue reading

Study tracks blue whales across Southern Ocean

New data will help shape conservation efforts in the waters around Antarctica

Naval training exercises off the coast of California could pose a threat to endangered marine mammals.

Australian and New Zealand researchers have tracked blue whales across thousands of miles in the Southern Ocean to help inform conservation efforts. Photo courtesy NOAA.

Staff Report

FRISCO — As a keystone species in marine ecosystems, blue whales have a significant impact in the ocean around Antarctica, but the population dynamics of the species in the region are still a mystery as the marine mammals recover from the decimation of the whaling era.

That may change following the recent six-week Australia-New Zealand Antarctic Ecosystem Voyage voyage, as researchers tracked the world’s largest creatures across thousands of miles of ocean, detecting their songs from as far as 750 kilometers away. Continue reading

Shifting Southern Ocean winds regulate pace of global warming

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Southern Ocean winds and currents are key regulators of global temperature and carbon cycles.

Strengthening eddies drive heat deep into the sea

Staff Report

FRISCO — Shifting wind patterns across the Southern Ocean around Antarctica are having a big effect on the carbon cycle and on the heat transfer between the ocean and the atmosphere.

The changes are so profound that they are actually delaying the effects of global warming, according to a new study published in the Journal of Physical Research.

“Considering the Southern Ocean absorbs something like 60 percent of heat and anthropogenic CO2 that enters the ocean, this wind has a noticeable effect on global warming,” said lead author Dr Andy Hogg from the Australian National University Hub of the ARC Centre of Excellence for Climate System Science. Continue reading

Southern Ocean carbon cycle may be key climate driver

‘Changes in ocean carbon storage are important drivers of natural atmospheric CO2 variations …’

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Melting icebergs along the shore of Dundee Island, near the tip of the Antarctic Peninsula. bberwyn photo.

Staff Report

FRISCO — The Southern Ocean’s carbon cycle may be a huge driver of climatic shifts between ice ages and interglacial periods, according to new research published last week in Nature.

The study shows that carbon stored in an isolated reservoir deep in the Southern Ocean re-connected with the atmosphere, driving a rise in atmospheric CO2 and an increase in global temperatures that may have helped end the global ice ages. Continue reading

Sonar study finds blue whale ‘hotspots’ in Southern Ocean

Whale populations around Antarctica still rebounding from industrial whaling era

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New sonar techniques could help pinpoint blue whale numbers in the Southern Ocean and identify important habitat. Photo courtesy NOAA.

Staff Report

FRISCO — After a century of relentless industrial whaling, blue whales were nearly extirpated from the Southern Ocean around Antarctica, The giant marine mammal is now making a comeback, and resurgent whale numbers could affect other parts of the ecosystem.

Other recent research has shown blue whale numbers rebounding off the coast of California, and biologists with the British Antarctic Survey recently reported that satellite technology could also help count whales.

But for the Southern Ocean, scientists don’t have a good grasp of population numbers. Between 1978 and 2010 blue whale surveys recorded only 216 visual encounters, so new research by Australian scientists may help identify important habitat areas and pinpoint numbers, which helps inform conservation strategies, with several large marine protected areas in the works for Antarctica. Continue reading

Climate: Robotic gliders probe secrets of Southern Ocean

Detailed measurements to help pinpoint rate of ice shelf melt

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Melting Antarctica ice shelves are raising global sea level. bberwyn photo.

Staff Report

FRISCO — The Southern Ocean, surrounding Antarctica, is mostly separated from the rest of the world’s oceans by a sharp temperature boundary and swift currents. But the border between the different masses of water is regularly blurred by giant swirls of water that may be transporting warmer water to the edge of the frozen continent.

Knowing how that process works could help scientists understand how fast Antarctic ice shelves will melt and raise global sea level, according to Caltech scientists who used robotic gliders to track the movement of water in the region. Continue reading

Climate: Southern Ocean layering could lead to big Antarctica meltdown along with surge in sea level rise

‘The big question is whether the ice sheet will react to these changing ocean conditions as rapidly as it did 14,000 years ago’

The ice fields of Antarctica

The ice fields of Antarctica. bberwyn photo.

Staff Report

FRISCO — A stratification of the ocean around Antarctica could lead to more rapid melting of ice sheets, triggering a sudden surge in sea level rise. That last time that happened was well before the global warming era, about 14,000 years ago, but scientists are now seeing signs of a similar pattern.

A new study found that in the past, when ocean temperatures around Antarctica became more layered, with a warm layer of water below a cold surface layer,  ice sheets and glaciers melted much faster than when the cool and warm layers mixed more easily. This defined layering of temperatures is exactly what is happening now around the Antarctic.

“The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface,” said ARC Centre of Excellence for Climate System Science researcher Prof Matthew England, an author of the paper, published in Nature Communications.

Continue reading

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