MOSS LANDING, Calif. -- A multi-institutional group of scientists, working on an expedition in the waters off Antarctica, has revealed that the iron supply to the Southern Ocean may have controlled Earth's climate during past ice ages.

The group of scientists, led by Dr. Kenneth Coale, of Moss Landing Marine Laboratories, and Dr. Ken Johnson, of the Monterey Bay Aquarium Research Institute, say they fertilized two key areas of the Southern Ocean with trace amounts of iron. Their goal was to observe the growth and fate of microscopic marine plants (phytoplankton) under iron-enriched conditions, which are thought to have occurred in the Southern Ocean during past ice ages.

The results of the field experiments, known as SOFeX, for Southern Ocean Iron Enrichment Experiments, were reported in the April 16, 2004, issue of Science Magazine.

The research showed that massive "blooms" of phytoplankton were triggered when ice-age conditions were simulated. Those "blooms" consumed more than 30,000 tons of carbon dioxide (a greenhouse gas), according to the statistics.

Observations by Dr. Ken Buesseler, of Woods Hole Oceanographic Institution, and Dr. Jim Bishop, of Lawrence Berkeley National Laboratories, indicated that much of the "blooms," along with the carbon, sank to hundreds of meters below the surface. When extrapolated over large portions of the Southern Ocean, the finding suggests that iron fertilization could cause billions of tons of carbon to be removed from the atmosphere each year, according to the research. Officials say the removal of this much carbon dioxide from the atmosphere could have helped cool the Earth during ice ages.

Similarly, it has been suggested by the researchers that humans might be able to slow global warming by removing carbon dioxide from the atmosphere through a massive ocean fertilization program.

The SOFeX experiment was carried out during January and February of 2002, after a decade of planning and preparation, and was funded by the U.S. National Science Foundation and the U.S. Department of Energy. It involved two U.S. research vessels from Scripps Institution of Oceanography and one U.S. Coast Guard research icebreaker, as well as about 100 scientists from at least 18 different research institutions.

For more information on the research and pictures from the adventure, click here.