Scientists have discovered a vast plume of iron and other micronutrients more than 1,000 km long billowing from hydrothermal vents in the South Atlantic Ocean. The finding, soon to be published in the journal Nature Geoscience, calls past estimates of iron abundances into question, and may challenge researchers' assumptions about iron sources in the world's seas.
"This study and other studies like it are going to force the scientific community to reevaluate how much iron is really being contributed by hydrothermal vents and to increase those estimates, and that has implications for not only iron geochemistry but a number of other disciplines as well," says Mak Saito, a WHOI associate scientist and lead author of the study.
Saito and his team of collaboratorswhich includes WHOI researchers and a colleague affiliated with the University of Liverpool (U.K.)didn't set out to find iron plumes in the South Atlantic. They set sail aboard the R/V Knorr in 2007 as part of the Cobalt, Iron and Micro-organisms from the Upwelling zone to the Gyre (or CoFeMUG, pronounced "coffee mug") expedition, which intended to map chemical composition and microbial life along the ship's route between Brazil and Namibia. As the scientists traveled the route, they sampled the seawater at frequent intervals and multiple depths along the way, and then stored the samples for in-depth analysis back on land.
Their route passed over the Mid-Atlantic Ridge, a band of mountains and valleys running along the Atlantic Ocean floor from the Arctic to the Antarctic where several of the Earth's major tectonic plates are slowly spreading apart. Hydrothermal vents, or fissures in the Earth's crust, are found along the ridge, but they haven't been extensively studied because slow-spreading ridges are thought to be less active than fast-spreading ones. Past studies using helium, which is released from the Earth's mantle through hydrothermal vents and is routinely used as a
|Contact: Media Relations Office|
Woods Hole Oceanographic Institution