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Phytoplanton Changed Color 250 mya


NEW BRUNSWICK/PISCATAWAY, N.J. - Green was the dominant color for plants
both on land and in the ocean until about 250 million years ago when
changes in the ocean's oxygen content - possibly sparked by a cataclysmic
event - helped bring basic ocean plants with a red color to prominence - a
status they retain today. That's the view of a group led by marine
scientists from Rutgers, The State University of New Jersey, in a paper,
"The Evolutionary Inheritance of Elemental Stoichiometry in Marine
Phytoplankton" in the journal Nature, published Thursday (Sept. 18).

Studying ancient fossils plus current species of microscopic ocean plants
called phytoplankton, the scientists found evidence that a "phytoplankton
schism" took place after a global ocean oxygen depletion killed 85 percent
of the organisms living in the ocean about 250 million years ago at the
end of the Permian era. "This paved the way for the evolution of red
phytoplankton," said one of the paper's authors, Paul G. Falkowski,
professor in the Environmental Biophysics and Molecular Ecology Program at
Rutgers' Institute of Marine and Coastal Sciences (IMCS). Falkowski has a
joint appointment with Rutgers' Department of Geological Sciences.

The Permian era, prior to the advent of the dinosaurs, ended in a global
extinction scientists believe may have been linked to extraterrestrial
collisions or earthly eruptions or explosions.

"Plants on land are green, and they inherited the cell components that
gave them a green color about 400 million years ago," Falkowski said. "But
most of plants or phytoplankton in the ocean are red - they inherited
their pigments about 250 million years ago. Our paper suggests that a
global ocean oxygen depletion changed the chemistry of the ocean and
selected for red phytoplankton. The ocean has been dominated by the red
line ever since."