SEDIMENTATION, RESUSPENSION, AND OXYGEN DEPLETION IN LAKE ERIE (1979)

Oxygen depletion in Lake Erie''s central basin hypolimnion is ultimately sustained by the respiration rate of organisms using organic matter which is produced in the trophogenic zone. Although other transformations are certainly important, they are nevertheless driven by the decomposition of organic carbon both in the water column and in the sediments. Rates of transport of particulate organic carbon to the hypolimnion and sediments were estimated using sediment traps. Corrections for sediment resuspension were necessary even during the summer period when the lake is stratified. Particulate organic carbon concentrations in the hypolimnion were partially independent of short-term variations in chlorophyll concentration. The net downflux of carbon to the hypolimnion appeared less than that required to support the observed oxygen depletion. Sediment resuspension accounted for much of the particulate material caught by the sediment traps in the central basin. It is concluded that organic material stored in the surficial sediments is made available to the water column through frequent resuspension. Of total phosphorus in the trap samples, an average of 42% was potentially bioavailable (NaOH extraction).