Research vessels from five nations in the Joint Global Ocean Flux Study are roaming the North Atlantic in an ambitious program to quantify the phenomenon. The technique could later be used from satellites. If increased atmospheric carbon dioxide should raise global temperatures, the circulation of the oceans would also change, oceanographers suggest, possibly in ways that might counteract the greenhouse effect. More plants would grow and more carbon would thus rain out into the sediments. Phytoplankton may play a major role in another important regulator of climate, clouds.
Clouds form when water vapor condenses around tiny particles floating in the air.
A new and still controversial theory suggests that phytoplankton, by excreting the chemical dimethylsulfide into the air, is a major source of these crucial particles. If the oceans should warm slightly, some researchers suggest, evaporation would increase, phytoplankton would grow faster and more particles would be produced. This, in turn, would lead to more clouds. With a heavier cloud cover, more of the sun's energy would be reflected back into space, and global temperatures would start back down. As researchers discover the increasing importance of the oceans in long-term climate change, they are also finding new evidence that oceans drive natural cycles of climate that come and go every few years.