Wednesday, May 29, 2013

Antarctica's Ecosystem Is 33 Million Years Old

The Antarctic drilling vessel JOIDES Resolution was used in the Integrated Ocean Drilling Program to dig deep into Antarctic sediments.


The modern ecosystem of icy Antarctica is some 33.6 million years old, new research finds, with a system dating back to the formation of the polar ice caps.

The date is revealed by fossilized remnants of plankton found in Antarctic sediments, which show how plankton diversity plummeted when a big chill came along at the end of the Eocene Epoch and the beginning of the Oligocene Epoch. Before the transition, Earth was a toastier place, and a wide array of plankton survived even at the poles.

The study, published in the journal Science in April, focused on single-celled plankton called dinoflagellates, which contain materials that fossilize. Before the Eocene-Oligocene transition about 34 million years ago, Antarctic dinoflagellates were extremely diverse. When the ice pack formed, however, only plankton that could survive cold temperatures and a seasonal freeze-melt cycle remained.

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