1994 Arctic Ocean Section
Contribution of Planktonic and Ice Algae to Dimethylsulfide
Production across the Arctic Ocean in Summer
Michel Gosselin, Maurice Levasseur, Nathalie Simard, Sonia Michaud,
Sangeeta Sharma, Peter Brickell and Timothy Bates
Algae produce a sulfur compound that seems not only to be a key link in
the global sulfur cycles but that also influences the formation of clouds and
therefore the Earth's temperature. Understanding how these algae affect cloud
formation in the remote oceans could be crucial to predicting how the Earth
will respond to global warming. The link between marine microscopic algae
and climate involves dimethylsulfide, or DMS, the gas that gives air its brac-
ing smell. It forms from the enzymatic breakdown of a salt, dimethylsulfonio-
propionate (DMSP). Marine algae produce DMSP to keep their osmotic balance
with seawater, without which water would leave the cells of the algae, killing
them. DMSP may also play a role as a cryoprotectant for microalgae living in
very-low-temperature marine environments, such as polar waters and ice. The
processes by which DMSP is released into the sea are not well understood, but
most researchers think it occurs when algae die or are grazed by zooplankton.
In the sea DMSP breaks down to form DMS. A fraction of this DMS, perhaps
Marine biogeo-
chemical cycle of
DMS: production,
transformation and
utilization pathways
that may ultimately
influence the quan-
tity of DMS lost to
the atmosphere.
Michel Gosselin is with the Dpartement d'ocanographie of the Universite du Qubec Rimouski, Rimouski,
Quebec, Canada. Maurice Levasseur, Nathalie Simard and Sonia Michaud are with the Institut Maurice-Lamon-
tagne, Ministre des Pches et des Ocans, Mont-Joli, Quebec, Canada. Sangeeta Sharma and Peter Brickell are
with Atmospheric Environment Service, Downsview, Ontario, Canada. Timothy Bates is with the National Ocean-
ic and Atmospheric Administration's Pacific Marine Environmental Laboratory, Seattle, Washington, U.S.A.
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