Detritus in the Lake Ecosystem

Abstract
Present view of the roles of detritus are not consistent with the ecosystem concept, and result in an underestimation of the importance of C and energy pathways involving detritus. Nonpredatory losses from a plant-herbivore transfer, particularly as dissolved organic matter and egestion, may be greater than the amount of material and energy transmitted up the grazer food chain. Ecosystem efficiencies are significantly higher than Lindeman (food chain) efficiencies. Benthic anaerobic metabolism (CO2 production) is greater than benthic O2 uptake estimates indicate, and the energy-rich intermediate products which undergo deferred respiration (O2 uptake) far from their origin may create redox gradients, drive chemosynthesis and subsidize bacterial photosynthesis in the water column. Aquatic detrital material, particulate and dissolved, and its metabolism create a dynamic structure in lake sediments and water somewhat analogous to the trophic-dynamic aspect of the biota. The detrital-dynamic structure in lakes is not simply an alternative mode of support for biota, but is a major factor in the entrainment of abiotic substances which subsidize the biota.