Oxygen Depletion Model for Cayuga Lake

A one-dimensional oxygen depletion model was constructed for Cayuga Lake (upstate New York) for the period of summer stratification. A primary objective was to determine the relative importance of horizontal diffusion rates to planktonic and benthic respiration in the vertical. Terms in the one-dimensional diffusion equation account for sinking rate and consumption by respiration of algae, plankton, and benthos. A separate equation computes oxygen transport. The sensitivity of the model is tested with respect to the various parameters. Practical diffusion coefficients were obtained using a combination of methods. The results indicate that in Cayuga Lake all three of the depletion agents exert a large demand in the upper 30 m, the total uptake is small in the mid 70 m, but diffusion from this region into areas of the high demand is large, and the lowest 30 m is dominated by the benthic demand.