Phytoplankton, which are responsible for half of the world's primary production and are the basis of all marine ecosystems, have been declining for more than 100 years, perhaps the result of rising sea temperatures, according to a study published in this week's Nature -- a cause for concern about the health of the Earth's oceans.
A number of marine diatom cells, an
important group of phytoplankton in the oceans.

Image: Harry Taylor,
courtesy of Nikon Small world
"It is troubling," said marine scientist linkurl:David Siegel; of the University of California, Santa Barbara, who was not involved in the research. With data dating back to the late 1800s, "this paper finds a long-term trend that's huge," he said. "The phytoplankton community has undoubtedly been changing." Phytoplankton productivity lies at the base of the marine food web, supporting all ocean life and contributing to global geochemical processes, including the carbon cycle. Through...
Harry Taylor, Nikon Small World, National Library of Australia, NASA Earth Observatory Collection, Jack Polanen, Oceans Below underwater production & training.
NatureD.G. Boyce, et al., "Global phytoplankton decline over the past century," Nature, 466:591-5, 2010. D.P. Tittensor, et al., "Global patterns and predictors of marine biodiversity across taxa," Nature, DOI:10.1038, 2010.Editor's note: The video was added to this article on July 29, 2010.

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