Rates of Accumulation of Phosphorus Forms in Lake Erie Sediments

Six Lake Erie sediment cores from locations of widely different sedimentation rates show that rate of input and sedimentation of apatite phosphorus at a given locality has been approximately constant during the last few hundred years relative to total sedimentation rate at the same locality. Apatite is not a significant source of soluble phosphorus for Lake Erie. By contrast, rate of sedimentation of nonapatite inorganic phosphorus (NAIP) and organic phosphorus has steadily increased in accordance with increased loadings in recent years of the source material, namely phosphorus of anthropogenic origin. The rate of sedimentation of these two forms of phosphorus at a given locality varied greatly within the lake, and was greatest where the most fine-grained sediments were accumulating. It was concluded that the sediments of Lake Erie contain sufficient orthophosphate-retaining sites to prevent major regeneration of phosphate under any conceivable condition provided the overlying water remains oxic.