Nonapatite phosphorus of fresh-water bottom sediments

The paper presents a theory to understand the mechanism governing the contribution of sediments to the phosphorus exchange with the water column, and to plan methods of evaluating the danger of the sediments acting as a secondary source of 'phosphorus pollution.' In addition to published data, additional data on the breakdown of organic matter in oozes, the density of the phosphorus flux (Ip) from the bottom sediments, the concentration of organic matter and forms of phosphorus in the sediments of Lake Naroch' and in Uchinsk and Mozhaysk Reservoirs. Since authigenic nonapatitie phosphorus constitutes between 1/3 and over 9/10 of total nonapatite phosphorus in bottom oozes, the vertical distribution of the concentration of nonapatite phosphorus in the top 30-cm layer of the sediments can be used to analyze the conversion paths of phosphorus compounds. Study results are discussed. The potential of sediments as a source of phosphorus increases with the relative concentration of authigenic nonapatite phosphorus in them. In this respect, the detrital oozes of Lake Naroch' would present a considerably greater danger than do the clayey oozes of Lake Erie or the Uchinsk Reservoir.