Distribution and diagenesis of organic and inorganic phosphorus in sediments of the Baltic proper

Measurements of the distribution of organic and inorganic phosphorus in the sediment have been performed at 10 sites, in the central-northern Baltic p roper. Variations in deposition environment and environmental properties, s uch as redox chemistry and bottom water dynamics, apparently affect the dis tribution by altering the supply and diagenesis of organic and inorganic ph osphorus constituents. The CIP and the N/P ratios of the sediment are highl y divergent (higher) from the average Redfield ratio for marine living orga nisms at all examined sites. This indicates preferential autolytic organic phosphorus degradation and/or (deeper down in the sediment) altered input o f terrestrial organic matter. The redox condition seems to affect the degra dation efficiency of the organic matter since higher concentrations of C-or g occur at anoxic conditions than at oxic. At two sites significant amounts of Ci,g have been detected indicating authigenic precipitation of carbonat es. Further, authigenic precipitation of phosphate minerals also seems to o ccur at certain environmental conditions. (C) 2001 Published by Elsevier Sc ience Ltd.