Southern Ocean current faces slowdown threat

http://news.yahoo.com/s/nm/20070322/sc_nm/climate_ocean_dc;_ylt=AoUbepe1lEn6QaoMWwjO8xIDW7oF

The impact of global warming on the vast Southern Ocean around Antarctica is starting to pose a threat to ocean currents that distribute heat around the world, Australian scientists say, citing new deep-water data.

Melting ice-sheets and glaciers in Antarctica are releasing fresh water, interfering with the formation of dense "bottom water," which sinks 4-5 kilometers to the ocean floor and helps drive the world's ocean circulation system.

A slowdown in the system known as "overturning circulation" would affect the way the ocean, which absorbs 85 percent of atmospheric heat, carries heat around the globe.