A green ocean is a productive ocean; the light from the sun fuels the bloom of phytoplankton, tiny ocean plants that turn the seas surface a light green each spring. This production in turn drives ocean food webs. New research, published in the journal Science on April 26, assesses the color of the ocean and finds that it may yield clues about the relation between marine ecosystems and the climate system. The research was funded by the National Science Foundation (NSF).

David Siegel, a scientist at the University of California, Santa Barbara, and colleagues analyzed ocean color data from the satellite Sea-viewing Wide Field of view Sensor (called Sea WiFS) to address the factors regulating the spring bloom of phytoplankton in the north Atlantic Ocean. The productivity of the ocean [from blooms] is well established, said Siegel. What we dont know is how it gets recycled. Were trying to get at how the oceans biological pump works. The biological pump is the mechanism by which carbon dioxide is exported from the surface ocean into the deep ocean via sinking particles, like the remains of phytoplankton as they die off after blooms. It is a critical factor in understanding global climate change.

From the satellite is information Siegel and colleagues were able to deduce the conditions required to start a spring bloom: appropriate amounts of light reaching down into the water column, a condition that occurs when ocean waters turn over or mix, in spring.

When viewed from space, the north Atlantic spring bloom is among the largest mass greenings observed on the Earths surface, said Siegel. The blooming progresses at speeds of 20 kilometers per day, leaving a green wake in its path.

Jim Yoder, a co-author of the paper, on leave from the University of Rhode Island Graduate School of Oceanography and currently division director
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Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-8070
National Science Foundation
25-Apr-2002