Monday, December 17, 2007
Algae Bleaching Key to Past Global Warming Event
New research documents bleaching of foraminifera 55 million years ago
Scripps Institution of Oceanography / University of California, San Diego
American Geophysical Union, Fall Meeting 2007
What triggered the extreme global warming event during the Paleocene-Eocene Thermal Maximum (PETM) 55 million years ago? Multiple theories have emerged on the cause, including asteroids, massive volcanic eruptions and even suggestions of a giant methane belch. Richard Norris, professor of paleobiology at Scripps Institution of Oceanography at UC San Diego provides new evidence that environmental stress existed prior to the extreme warming event; therefore, a one-time catastrophic event is not likely to have occurred.
Norris will discuss details of his research, titled "Bleaching of Symbiotic Foraminifera During Extreme Global Warming at the Paleocene-Eocene Boundary," during the 2007 American Geophysical Union Fall Meeting.
A scanned electron micrograph image of the planktonic foraminifera, Acarinina soldadoensis, a species known to bleach during past extreme warming periods.
Norris' study is the first to document bleaching of foraminifera, single-celled organisms in the kingdom Protista that paleontologists study to reconstruct Earth's climate history.
Like reef corals, many types of foraminifera play host to symbiotic algae, but this symbiosis broke down during the extreme warmth of the PETM.
By measuring the isotopic carbon soaked up by the symbiotic algae contained within the foraminifera, Norris demonstrates that the symbiotic algae disappeared for a period of time during the warming event, resulting in a large-scale bleaching event.
Scripps professor of paleobiology Richard Norris
"Clearly things were going wrong prior to the event," said Norris.
Geochemical studies on fossilized foraminifera can help scientists to better understand what was happening on Earth during the extreme global warming event 55 million years ago that produced tropical temperatures 4-5 degrees warmer than today.
Reconstruction of past global warming events has enormous implications for life now and what will happen on Earth in the future. This research can provide insight into what is happening on earth now from a climatic and geochemical perspective, notes Norris.
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Scripps Institution of Oceanography, at University of California, San Diego, is one of the oldest, largest and most important centers for global science research and education in the world. The National Research Council has ranked Scripps first in faculty quality among oceanography programs nationwide Now in its second century of discovery, the scientific scope of the institution has grown to include biological, physical, chemical, geological, geophysical and atmospheric studies of the earth as a system. Hundreds of research programs covering a wide range of scientific areas are under way today in 65 countries. The institution has a staff of about 1,300, and annual expenditures of approximately $155 million from federal, state and private sources. Scripps operates one of the largest U.S. academic fleets with four oceanographic research ships and one research platform for worldwide exploration.
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