WIKIMEDIA, BUTTERFLY VOYAGESWith a little help from sensor-toting Antarctic elephant seals, researchers have pinpointed a fourth known source of the deep-ocean streams of cold water that circulate around the globe and thus help to regulate the Earth’s climate, according to a study published this week (February 24) in Nature Geoscience.
Until now, scientists knew of only three sources of Antarctic bottom water, which sinks to the depths because it’s denser than typical seawater and gradually moves off in slow-moving currents—all of them off the coast of Antarctica. But they had long suspected the existence of more sources, and some had hypothesized that undiscovered sources may be found in polynya—areas of open water near sea ice. These areas do not freeze because strong winds and currents keep freshly formed ice moving.
To test the idea, oceanographers at Hokkaido University in Sapporo, Japan, used satellite imagery to find polynya where ice formed particularly quickly. This led them to Cape Darnley, off the east coast of Antarctica, where they dropped sensing instruments to the seafloor in an attempt ...
