High-amplitude midge fluctuations and the ecosystem dynamics of Lake Myvatn, Iceland

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Understanding populations that undergo fluctuations in abundance from one year to the next continues to challenge ecologists. This study will investigate midges in Lake Mývatn, Iceland, to determine why their abundance fluctuates over 5 orders of magnitude in irregular cycles lasting 4-7 years. Juvenile midges feed on algae at the bottom of the lake, and experiments that encompass a full peak-to-peak midge cycle will be initiated to test the hypothesis that the extreme midge fluctuations are caused when the larvae consume all the algae. The research will also investigate the consequences of the midge cycles. During high midge years, over 300 metric tons of midges are deposited in the surrounding heathland, providing food for predators and nutrients for plants. This provides a natural experiment to test hypotheses about how the lake and shoreline ecosystems interact by observing how the pulses of midges ramify through the ecosystem networks. The research will strengthen international collaborations with scientists in Iceland. It will train US graduate and undergraduate students doing work at Mývatn, providing them exposure to challenging scientific questions whose answers require expertise from several disciplines. Students will work in both aquatic and terrestrial habitats under the tutelage of an interdisciplinary and international research group.