Adding iron to the diet of marine plant life has been shown in shipboard experiments to boost the amount of carbon-absorbing phytoplankton in certain parts of the worlds oceans.
A new study promises to give scientists their first global picture of the extent of these unique iron-limited ocean regions, an important step in understanding how the oceans biology controls the flow of carbon between the atmosphere and the ocean.
The study by researchers at NASAs Goddard Space Flight Center (Greenbelt, Md.) and the Department of Energys Oak Ridge National Laboratory, will be presented at the American Geophysical Unions annual meeting in San Francisco on December 15.
Oceanic phytoplankton remove nearly as much carbon from the atmosphere each year as all land-based plants. Identifying the location and size of nutrient-limited areas in the open ocean has challenged oceanographers for nearly a century.
We know where the major iron-limited areas are, but we cant draw a line around the precise geographic extent of these areas, says Goddards Michael J. Behrenfeld, a co-author of the new study. This new result may help us do that.
The study pinpointed iron-limited regions by seeing which phytoplankton-rich areas of the worlds oceans were also areas that received iron from wind-blown dust. Iron is one of the essential nutrients needed for microscopic marine plant life to flourish, along with nitrogen, phosphorus, and silicate. Where dust from arid regions around the world falls into the ocean depends on the location of the dust source and the rapidly shifting patterns of wind and weather.
The biologically productive ocean regions were identified by images from the SeaWiFS (Sea-viewing Wide Field-of-view Sensor) instrument on the OrbView-2 satellite, which maps global ocean biological activity. Because no similar satellite observations existed for dust-borne iron falling into the ocean, the researchers estimated the location of oceanic dust depositi
Contact: Lynn Chandler
NASA/Goddard Space Flight Center