Edge of Climate Change:  Scientists Detect Early Warning of Ecosystem Collapse in Wisconsin

Researchers eavesdropping on complex signals emanating from a remote Wisconsin lake have detected what they say is an unmistakable warning — a death knell — of the impending collapse of the lake's aquatic ecosystem.
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The implications of the National Science Foundation-supported study are big, says Carpenter.
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The group led by Carpenter experimentally manipulated Peter Lake during a three-year period by gradually adding predatory largemouth bass to the lake, which was previously dominated by small fish that consumed water fleas, a type of zooplankton. The purpose, Carpenter notes, was to destabilize the lake's food web to the point where it would become an ecosystem dominated by large predators.