Organic matter produced by terrestrial plants enters lakes via streams, groundwater, and surface deposition. These inputs strongly structure lake ecosystems, altering heat and light budgets, fueling carbon cycles, and becoming incorporated into the tissues of aquatic organisms like invertebrates and fishes.
Because of this incorporation into the food web, terrestrial organic matter has generally been viewed as a resource subsidy to lakes. Yet there is little empirical support for this view, and there are reasons to think that the net effect of terrestrial inputs might actually be a sort of anti-subsidy - so that lakes with greater terrestrial inputs produce less fish biomass, for instance. We are testing these ideas using whole-lake experiments on a curtain-divided lake (see picture), multi-lake surveys, models, and other methods.