DURHAM, N.C. -- Evolving into diverse forms over billions of years, tiny one-celled marine plants and bacteria have, up to now, successfully interacted with the changeable physics and chemistry of the land and sea to stabilize to a surprising extent the relative concentrations of Earth's atmospheric gases, according to a report in the July 10 issue of the journal Science.

These varied organisms, collectively known as phytoplankton, have not only generated and sustained most of the oxygen we breathe, but they also "play a profound role in regulating atmospheric carbon dioxide," in part by sequestering vast amounts of the gas deep in the ocean when they die, wrote oceanographers from Rutgers and Duke universities and a German institution.

Because carbon dioxide traps solar heat, phytoplankton growth also helps regulate Earth's climate in an intricate interplay with ocean currents, wind-blown dust, nutrient discharges from rivers, solar radiation levels and other factors, their paper added.

Buried phytoplankton remains from past eons also created part of the fossil fuel that now drives the industrialized world. And, ironically, the extra carbon dioxide generated by burning those fuels, in turn, will almost certainly affect future activity and distribution of ocean phytoplankton in ways that are hard to forecast, the authors wrote.

For instance, the extra carbon dioxide could warm the atmosphere and seas in a way that shifts ocean currents, while changing rainfall patterns over land masses could alter the supply of vital phytoplankton nutrients. The result could be as drastic as "a net efflux of CO2 from the oceans to the atmosphere; that is, a positive feedback," the authors warned. But they also stressed "such an analysis is greatly oversimplified, perhaps even naive."

Richard Barber, a professor at Duke's Nicholas School of the Environment Marine Laboratory in coastal Beaufort, N.C., said their paper's purpos
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Contact: Monte Basgall
Monte@dukenews.duke.edu
(919) 681-8057
Duke University
9-Jul-1998