3. Sulfur Cycling in Coastal Upwelling Systems and
Its Potential Effects on Climate
S. Mary P. Benbow
Climatic variability and change occur as a result of interaction between
the atmosphere and the other components comprising the earth's system
(i.e., hydrosphere, lithosphere , biosphere , and cryosphere) . The complex
relationship between the oceans and the atmosphere is only beginning to
be understood, and many of the factors implicated in their interaction
include the biogeochemical cycles. Sulfur may not have the same media
attention as, for example, carbon dioxide, but it is nevertheless an
influential element, not only because of its role in anthropogenic emissions
as sulfur dioxide but also in its many forms and consequent roles in the
environment. Of particular interest is the role of the marine biosphere,
notably marine phytoplankton, in the production of dimethylsulfide and
its potential effects on climate.
Upwelling regions are characterized by large primary productivities and
may therefore demonstrate the role of DMS not only upon climate but
also upon the transfer of-sulfur from oceans to land surfaces. The DMS
feedback may be envisioned as a subsystem of near-coastal ecosystems,
and the resultant input of DMS may be of considerable benefit to resident
terrestrial primary producers. The model presented illustrates the relationship between DMS production and resultant cloud cover and also
endeavors to illustrate the relationship between terrestrial ecosystems and
the production of DMS.
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