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February 5, 2002 BOISE STATE SCIENTIST LEADS OCEANOGRAPHIC EXPEDITION 
Boise State paleocoeanographer Mitch Lyle, center, discusses research findings with an international group of scientists aboard the scientific drillship the Joides Resolution during a recent voyage. Lyle served as co-chief scientist on the expedition. Download photo: 720 KB A Boise State University researcher who recently led a two-month expedition aboard a scientific drillship in the Pacific Ocean has returned to his campus laboratory with some intriguing data about what the Earth’s climate was like some 50 million years ago. Mitch Lyle, a paleoceanographer with the university’s Center for Geophysical Investigation of the Shallow Subsurface, served as co-chief scientist aboard the Joides Resolution on a research voyage to an area of the Pacific about halfway between Mexico and Hawaii. The purpose of the expedition, part of the international Ocean Drilling Program, was to learn more about tropical oceans in the warmest period on Earth in the past 65 million years — the Eocene period of 34 to 55 million years ago. 
A close-up view of radiolarians, a tiny zooplankton that was the dominant organism in the tropical Pacific some 50 million years ago. Download photo: 217 KB Working with 27 researchers from eight different countries, Lyle oversaw round-the clock shifts to collect sediment cores from deep beneath the ocean floor and analyze them. The cores, which contain fossilized remains of plankton and other organisms, are giving scientists the first-ever continuous record of the climatic conditions in the tropical Pacific during the Eocene, a time period when the first recognizable mammals appeared in North America, palm trees thrived in the Rocky Mountain region, and alligators roamed as far north as the Arctic. “I was really struck with how different oceanographic conditions were in the Eocene than I had pictured,” said Lyle. “There’s still a lot we have to learn.” The research has practical applications, Lyle added, including helping scientists develop climatic models that can be used to understand and predict future climate changes. The Eocene time period appears to have begun very quickly, with a warming on the scale and rate of modern global warming, and it ended almost as abruptly, Lyle explained. Ocean circulation at the equator was sluggish. The ecology of the area was dominated by radiolarians, a small zooplankton that builds its shell of silica. After the end of the Eocene, these organisms never attained their earlier dominance, indicating that something in the ocean ecology had fundamentally changed. Lyle and other scientists are looking for clues to the changes that signaled the end of the Eocene by analyzing the data collected from sediment cores. For example, scientists don’t know what the radiolarians were feeding on, or why they attained such dominance. “These are the fun parts,” Lyle said. “They’re the solvable problems.” The cores will also be used to calibrate different “yardsticks” for measuring geologic time, a fundamental earth science problem. By identifying the location of certain “marker” fossils, scientists can establish how old the sediment layer is to a much greater accuracy level than has ever before been accomplished. Lyle said he enjoys both the challenges of spending months at sea on scientific expeditions and analyzing the data back in the relative comfort of his lab at Boise State University. He’s led 12 oceanographic expeditions and participated in 29, and is planning an expedition in a few years to the south Pacific to survey drill sites for a study of the Eocene Antarctic. Among his duties as co-chief scientist were overseeing the drilling logistics and organizing the scientific investigation onboard ship. “It was a rewarding experience,” Lyle said of his last expedition, which included scientists from Japan, Germany, Sweden, Great Britain, France and Italy. “We had an outstanding group of people, and we accomplished a great deal.” The Ocean Drilling Program, which operates the Joides Resolution, is an international partnership of scientists and research institutions organized to explore the evolution and structure of the Earth. Funded in part by the U.S. National Science Foundation, the ODP provides researchers around the world access to a vast repository of geological and environmental information recorded far below the ocean surface in seafloor sediments and rocks. For more information on the ODP and a virtual tour of the Joides Resolution, go to www.oceandrilling.org/ODP/ODP.html. Contact: Media contact:
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