A lake ecosystem is made up of living and nonliving parts that all interact with each other to form a stable system. These interactions assure the lake ecosystem’s health and sustainability. It is a fine balance of production and decomposition, made possible by the biodiversity that occurs in a healthy lake ecosystem. Researchers eavesdropping on complex signals 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. The finding, reported in the journal Science by a team of researchers led by Stephen Carpenter, an ecologist at the University of Wisconsin-Madison (UW-Madison), is the first experimental evidence that radical change in an ecosystem can be detected in advance, possibly in time to prevent ecological catastrophe.