Scientists uncover deep ocean current near Antarctica

SINGAPORE (Reuters) – Scientists have discovered  a fast-moving deep ocean current with the volume of 40 Amazon  Rivers near Antarctica that will help researchers monitor the  impacts of climate change on the world’s oceans.

A team of Australian and Japanese scientists, in a study  published in yesterday’s issue of the journal Nature Geoscience,  found that the current is a key part of a global ocean  circulation pattern that helps control the planet’s climate.

Scientists had previously detected evidence of the current  but had no data on it.

“We didn’t know if it was a significant part of the  circulation or not and this shows clearly that it is,” one of  the authors, Steve Rintoul, told Reuters.

Rintoul, of the Antarctic Climate and Ecosystems  Cooperative Research Centre in Hobart, said it proved to be the  fastest deep ocean current yet found, with an average speed of  20 cm (7.9 inches) a second. It was also found to carry more  than 12 million cubic metres a second of very cold, salty water  from Antarctica.

“At these depths, below three kilometres (two miles) from  the surface, these are the strongest recorded speeds we’ve seen  so far, which was really a surprise to us.”

He said the current carries dense, oxygen-rich water that  sinks near Antarctica to the deep ocean basins further north  around the Kerguelen Plateau in the southern Indian Ocean and  then branches out.

The current forms part of a much larger network that spans  the world’s oceans, acting like a giant conveyor belt to  distribute heat around the globe.

Oceans are also a major store of carbon dioxide, the main  greenhouse gas that is emitted naturally and by mankind, mainly  from burning fossil fuels.

For example, the Gulf Stream brings warm water to the North  Atlantic, giving northern Europe a relatively mild climate.  Failure of the current, which has occurred in the past, would  plunge parts of Europe into a deep freeze, scientists say.

“The deep current along the Kerguelen Plateau is part of a  global system of ocean currents called the overturning  circulation, which determines how much heat and carbon the  ocean can soak up,” Rintoul said.

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