Revealing the startling decline of diporeia in Lake Michigan, the above maps show the concentration of diporeia in thousands of animals per square meter across the bottomlands. The deepest blue indicates concentrations of 15,000 per square meter, white indicates 0 per square meter — an animal that has populated the lakes for more than 11,000 years nearly gone in the course of a decade.

Jeff Smith is editor of Traverse, Northern Michigan’s

Note: This article was first published in August 2006 and was updated for the web February 2008.