Adding iron to ocean spurs photosynthesis

Abstract

Experiments in the equatorial Pacific Ocean demonstrate that lack of iron is what keeps large ocean areas from being biologically productive. This makes iron great candidate as the agent that leads to the temperature changes that produce ice ages, says Kenneth S. Johnson, professor of oceanography at Moss Landing Marine Laboratories in California, one of the principal investigators. But the experiments also point out problems with a proposal first floated about six years ago: to alleviate some of the global warming effects caused by huge increases in atmospheric carbon dioxide by fertilizing the oceans with iron. The work was conducted by a team of oceanographers from nine institutions in the U.S., the U.K., and Mexico [ Nature , 383 , 495, 508, 511, and 513 (1996)]. The researchers added iron sulfate and a biologically inert tracer molecule, sulfur hexafluoride, to a patch of ocean some 800 miles west of the Galapagos Islands, then monitored the effect on ...