The lead author is C. Fred T. Andrus, a postdoctoral associate at UGA. Co-authors include Douglas E. Crowe, Elizabeth J. Reitz and Christopher S. Romanek of UGA and Daniel H. Sandweiss of UMaine. Romanek also works at the Savannah River Ecology Laboratory in Aiken, S. C. The paper presents the results of chemical analyses of fish bones known as otoliths from a species of sea catfish (Galeichthys peruvianus) living along the Peruvian coast.
"Our data strengthen the argument that El Nio, as we know it, began relatively recently - since 5000 years ago," said Andrus. (El Nio is, in large part, warming of the ocean waters off Peru at irregular intervals.) "This is more evidence that climate change is the norm, and climate stability is the exception in the earth's history, even in relatively recent times. Given the enormous global impact of El Nio, it's important to understand that climate is a naturally variable system, and that just six thousand years ago El Nio was less frequent."
Andrus said that otoliths from sea catfish are a good candidate for such analysis because the fish do not migrate. They tend to stay near shore in relatively small areas away from river mouths where fresh water can complicate the oxygen results.
"Otoliths act like miniature temperature recording devices," said Crowe. "Throughout the life of a fish, they grow concentrically larger, and the ratio of oxygen isotopes in each individual growth band allows us to determine the temperature of the water at that time. By looking at the entire otolith, we can reconstruct the water temperatu
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Contact: Phil Williams
phil@franklin.uga.edu
706-542-8501
University of Georgia
21-Feb-2002