Antarctica's Supersized Icebergs Shut Down Currents

Colossal icebergs careening along the Antarctic coastline can shut down the deep, cold currents that help drive ocean circulation, a new study reports. These aren't everyday icebergs, even by Antarctica's mighty standards — these huge icebergs are the size of small European countries. Unleashed by fracturing glaciers, they interfere with the Antarctic Ocean's sea-ice factories, called polynyas, according to the study. The open-water polynyas persist year-round, allowing bitter winter winds to freeze seawater into freshwater ice, leaving behind dense, salty seawater that sinks to the ocean depths.