SPATIAL VARIATION IN THE DISTRIBUTION OF PHOSPHORUS SPECIES IN THE SURFICIAL SEDIMENTS OF CANADOHTA LAKE, PENNSYLVANIA - IMPLICATIONS FOR INTERNAL PHOSPHORUS LOADING ESTIMATES

The concentrations of total, loosely sorbed, metal-bound, calcium-bound, and organic phosphorus, iron, and organic matter (loss on ignition) were determined for 71 surface sediment samples from Canadohta Lake, Pennsylvania. The results indicate that lake sediments can be highly variable with respect to these parameters. Most of these parameters were highly intercorrelated, and some general patterns appear to exist based on these and previously published data. Given the highly variable nature of sediment quality, particularly among these parameters which have been shown to be good predictors of sediment phosphorus release rates, estimates of internal phosphorus loading based on a few incubated cores taken from the deepest area of a lake may contain serious errors. We recommend that sediment heterogeneity be assessed in order to determine an appropriate number and distribution of cores to be incubated for internal loading estimates.