ocean life support dwindling

The Scientist | 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.

"It is troubling," said marine scientist 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 photosynthetic activities, phytoplankton reduce atmospheric carbon dioxide. Satellite data from the last few decades has suggested that phytoplankton might be on the decline.