Undersea Mountains Churn Ocean Water Near Antarctica, Affect Climate

Researchers have solved a long-held mystery regarding how deep and mid-depth ocean waters mix in the part of the ocean located near Antarctica.

According to the study published in the journal Nature, water mixes in a dramatic fashion as it rushes over undersea mountains located in Drake Passage, the channel located between the southern tip of South America and the Antarctic continent.

"A thorough understanding of the process of ocean mixing is crucial to our understanding of the overall climate system," Andrew Watson, a researcher from the University of Exeter, said in a statement. "Our study indicates that virtually all the mixing in the Southern Ocean occurs in Drake Passage and at a few other undersea mountain locations."

In order to carry out their research, the international team of scientists released tiny amounts of an inert chemical tracer into the Southeast Pacific and then tracked it for several years as it made its way through Drake Passage.

The results, Watson says, "will provide climate scientists with the detailed information about the oceans that they currently lack."

Ocean mixing is responsible for transferring carbon dioxide from the atmosphere to the deep sea where it is then stored; in all, the ocean is estimated to remove as much as a third of the total carbon dioxide emitted through human activity.

Ocean mixing also affects climate by influencing the amount of heat transferred toward the poles.

Current theory holds that lower concentrations of atmospheric carbon dioxide throughout the ice ages could have been caused by slower mixing between the surface and deep sea, although the reasons for this are not clear.

The Woods Hole Oceanographic Institute, the British Antarctic Survey, the Scottish Association for Marine Science and the University of East Anglia were all involved in the study. Funding was provided by the UK Natural Environment Research Council and the US National Science Foundation.