MEASUREMENT AND VERIFICATION OF RATES OF SEDIMENT PHOSPHORUS RELEASE FOR A HYPEREUTROPHIC URBAN LAKE

The contribution of sediment release to the phosphorus budget of hyper eutrophic Onondaga Lake was determined through laboratory measurements made on intact cores. Rates ranged from 9-21 mg P m-2 d-1 with a mean of 13 mg P m-2 d-1, values similar to those observed in other lakes o f comparable trophic state. There was no statistically significant tre nd in rates in time (July versus September) or in space (location alon g the major N/S axis of the lake). Rates of sediment phosphorus releas e measured in the laboratory compared favorably with the observed rate of soluble reactive phosphorus accumulation in the lake's hypolimnion . The sediments are the second largest source of phosphorus for Ononda ga Lake, contributing 24% of the overall phosphorus load to the system .