Forms of phosphorus and its accumulation in coastal sediments of Kieler Bucht

Abstract

Abstract To study the fate of natural and anthropogenic phosphorus input to a coastal system, the removal of P by accumulation in fine-grained sediments of Kieler Bucht (Western Baltic) was investigated. A phosphorus fractionation scheme was applied to 12 cores from mud, sandy mud and muddy sand sediments. Most phosphorus is contained in the moderately reducible and organic fractions. Almost all excess P in the top enrichment zone is chemisorbed or bound to iron. Evaluation of dated cores from the different sediment types yielded a natural background accumulation of 702 × 106 g P · yr−1 for the whole Kieler Bucht from erosion of till and fluvial input. There is an additional accumulation of up to 538 × 106 g P · yr−1 in recent years which is partly due to diagenetic mobilization and redistribution. In any case, the accumulation of P in fine-grained sediments of Kieler Bucht is far less than published input rates from streams and sewage plants. Thus, in addition to sediment accumulation, a substantial part...