Ocean Mixing Encouraged by Underwater Mountains Affect Climate Change

Researchers have discovered how ocean water of deep and medium depth mix with each other, a mystery that has long stumped scientists, according to a press release.

The team of scientists found that waters mix substantially as they rush over undersea mountains in a channel between South America's southern tip and Antarctica, known as the Drake Passage.

The mixing of these waters affects and regulates Earth's ocean currents and climate change. The research provides scientists with much needed information on the mixing of ocean waters, vital for developing climate models.

The study was published in the journal Nature and included researchers from the University of Exeter, the University of East Anglia, the University of Southampton, the Woods Hole Oceanographic Institution, the British Antarctic Survey and the Scottish Association for Marine Science.

The researchers tracked a chemical tracer in the Southern Ocean for years to measure mixing in the Southeast Pacific. The scientists followed the tracker in the waters as it flowed through the Drake Passage to determine how quickly the waters would mix.

"A thorough understanding of the process of ocean mixing is crucial to our understanding of the overall climate system," Exeter's professor Andrew Watson said.

The team of scientists discovered little to no vertical mixing, but that the waters mixed most significantly as they passed over underwater mountains in the Drake Passage. Oceans store carbon dioxide from the Earth's atmosphere at its deepest depths and mixing controls the rate at which oceans absorb that carbon dioxide. As ocean mixing increases, more heat will be transferred to the Earth's poles.

Our study will provide climate scientists with the detailed information about the oceans that they currently lack," Watson said.

Scientists believe ocean mixing played a role in the ice ages by slowing down the rate at which the deep-sea waters blended with the medium and surface waters. This theory is not quite substantiated, but it would further tie ocean mixing to climate change.