Food web structure and littoral zone coupling to pelagic trophic cascades

Lake productivity ultimately depends on phosphorus (P) supply rates (Schindler, 1977). Community interactions, especially size-selective predation by fishes and size-dependent rates of grazing and nutrient recycling by zooplankton, determine the efficiency and rate with which P inputs are translated to ecosystem productivity (Carpenter and Kitchell, 1993). Limnologists are now trying to determine how trophic cascades interact with the P cycle to influence lake productivity (McQueen et al., 1986; Elser and Goldman, 1991; Carpenter et al., 1991). One informative approach analyzes food web interactions in P currency, thereby integrating the direct and indirect effects of fishes on lake P cycles.