Credit: P. TOWNSEND/ASTER

This false-colour infrared image, taken in September 2006 with the ASTER sensor on NASA’s Terra satellite, shows Mývatn, a shallow lake in Iceland from which emerge huge numbers of mating midges in summer.

Bright red indicates vigorous vegetation; the thin border of hot pink around the lake has been fertilized by the bodies of dead midges. In late July and early August, 135 kilograms of biomass was deposited there per hectare per day, according to Phil Townsend, a remote sensing specialist at the Department of Forest and Wildlife Ecology at the University of Wisconsin in Madison.

Townsend, who presented his results last week at the Ecological Society of America meeting in Milwaukee, Wisconsin, is using satellite imagery to identify more ‘midge lakes’.