SIGNIFICANCE TO EUTROPHICATION OF SPATIAL DIFFERENCES IN NUTRIENTS AND DIATOMS IN LAKE MICHIGAN1

Abstract

Sampling was conducted from a railroad ferry between Milwaukee, Wisconsin, and Ludington, Michigan, 27 May 1970–6 January 1971, to determine inshore—offshore differences in species and abundance of diatoms, and concentrations of phosphorus, silica, nitrate, and pigments. Inshore waters, especially off Milwaukee, had greater populations of diatoms, different species composition of the diatom communities, and different concentrations of major nutrients and pigments than offshore waters. It appears, therefore, that data from water intakes, which have been used in the past to document changes in the lake, may have represented only local conditions.