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The world's oceans participate in a global network of circulating ocean currents which have a definite effect on the earth's climate. A research team led by Assistant Prof. Yasushi Fukamachi of the Institute of Low Temperature Science revealed the export of a massive cold current near the sea floor off the Kerguelen Plateau in the Indian Ocean sector, and recognized that it is an important pathway from Antarctica to oceans around the world as well as playing an important role in global ocean circulation. In this joint research with Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), Fukamachi and his colleagues conducted field monitoring off the Kerguelen Plateau - a major export pathway for Antarctic Bottom Water (AABW) - over a two-year period starting in February 2003. By utilizing a variety of instruments such as current meters and temperature-salinity recorders moored in the deep ocean to obtain time-series data, they were able to detect an equatorward flow of a very strong, deep ocean current with an average velocity of over 20 cm per second. It was also revealed for the first time that the volume of water carried by this current toward the equator has significant temporal variations. Their research clarified that conventional ship-based observations, which were carried out previously, are unable to obtain the mean strength of the flow because it varies significantly over time off the Kerguelen Plateau. This finding strongly suggests the importance of continuous monitoring for the oceanic general circulation such as that currently under way in the North Atlantic in the outflow areas of AABW. The results of this study were first reported in Nature Geoscience (Advance online publication) on April 25, 2010. 
Water temperature distribution near the sea floor at depths deeper than 4,000 m. The purple and green arrows show Antarctic Bottom Water and North Atlantic Deep Water pathways from polar waters (  show areas where Antarctic Bottom Water is formed). The brown area indicates the Kerguelen Plateau, and the orange circle shows the area where data was obtained in this study. The map shows cold currents spreading worldwide from the Antarctic.Contact information:
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