The waters of the Southern Ocean have absorbed much of the excess heat and carbon generated by humanity.
Joellen Russell wasn’t prepared for the 10-metre waves that pounded her research vessel船只 during an expedition远征 south of New Zealand. “It felt like the ship would be crushed each time we rolled into a mountain of water,” recalls Russell, an ocean modeller at the University of Arizona in Tucson. At one point, she was nearly carried overboard by a rogue wave.
But what really startled震惊 her was the stream of >倾斜的 and groaned因压力而发出声响, she realized that the ocean surface was low in oxygen, high in carbon and extremely acidic酸性 — surprising signs that nutrient-rich water typically found in the deep sea had reached the surface. As it turned out, Russell was riding waves of ancient water that had not been exposed to the atmosphere for centuries.
Although controversial争议 when she encountered it back in 1994, this powerful upwelling上升流 is now recognized as a hallmark标志 of the Southern Ocean, a mysterious beast that swirls around Antarctica, driven by the world’s strongest sustained winds. The Southern Ocean absorbs copious amounts of carbon dioxide and heat from the atmosphere, which has slowed the rate of global warming. And its powerful currents drive much of the global ocean circulation环流.
The hostile不利的 conditions have kept oceanographers海洋学家 at bay for decades, but a new era时代 of science is now under way. Researchers from around the world are converging接近 on the region with floats浮标, moorings系泊, ships, gliders滑翔机, satellites, computer models and even seals fitted with sensors. The goal is to plug enormous data gaps and bolster understanding of how the Southern Ocean — and the global climate — functions. Doing so could be key to improving predictions预测 of how quickly the world will warm, how long the Antarctic ice sheet冰盖 will survive and how fast sea levels will rise.
“It’s been amazing to see this explosion of information,” says Arnold Gordon, an oceanographer at Lamont-Doherty Earth Observatory地球观测站 in Palisades, New York, who led some of the early Southern Ocean surveys in the 1960s. “New technologies are allowing us access to these remote areas偏远地区, and we are far less dependent on driving a ship through the sea ice.”
Already, initial data from an array of ocean floats suggest that upwelling waters could be limiting how much CO2 the Southern Ocean absorbs each year. This raises new questions about how effective these waters will be as a brake制动 on global warming in decades to come.
“The Southern Ocean is doing us a big climate favour at the moment, but it’s not necessarily the case that it will continue doing so in the future,” says Michael Meredith, an oceanographer with the British Antarctic Survey in Cambridge, UK. Meredith is heading a series of expeditions over the next five years to help document the uptake of heat and carbon. “It really is the key place for studying these things.”
南极洲环流为全球洋流系统的最强劲的洋流，也叫为西风漂流，为一个环绕南极洲由西向东的洋流。它是南冰洋的主要循环系统特征。洋流成为抵制全球变暖的重要武器，科学家采用多种设备探测该区域以预测洋流对热和二氧化碳的吸收。
