Benthification of freshwater lakes: Exotic mussels turning ecosystems upside down

Abstract

Many north-temperate lakes are experiencing a shift in energy production from the open pelagic to the benthic region. This process termed “benthification” is occurring across lakes due to increased water clarity. Benthification alters habitats within aquatic ecosystems by augmenting benthic production and escalating the flow of energy and materials between the pelagic and benthic subsystems. Two anthropogenically driven factors, reduced phosphorus inputs and filter feeding by nonindigenous species (i.e., zebra and quagga mussels, Dreissena polymorpha and Dreissena rostriformis bugensis, respectively), can both enhance water clarity. However, long-term data from seven lakes in North America and Europe indicate that dreissenids are driving benthification more than nutrient reductions. Therefore, ecosystem engineering by these two nonindigenous species is changing the fundamental, physical nature of an entire category of ecosystems.