Phosphorus fractions and cycling in the sediment of a shallow eutrophic pond

Abstract

The aim of this study was to quantitatively determine the phosphorus fractional composition of the eutrophicated West Pond sediment using vertical and seasonal changes (positive-upwards and/or negative-downwards) in the phosphorus cycling across the sediment-water, and to examine the most effective potential fraction or fractions on phosphorus release and the pond’s eutrophication process. In this study, mean release values of phosphorus in depths and months representing the seasons (April, July, October, January) varied between 9.19 (January, 0-5 cm) and 119.08 μg m-2 d-1 (October, 0-5 cm) in West Pond sediment which supplies water to the Sakaryabasi Fish Culture and Research Station. The mean negative phosphorus release dependent on months and depths were estimated as 1.25 μg m-2 d-1 (July, 5-10 cm) and 46.45 μg m-2 d-1 (October, 10-15 cm). The distribution of phosphorus fractions in the pond sediment: total organically bound phosphorus fraction (Org≈P) > calcium bound phosphorus fraction (Ca≈P)> carbonate bound phosphorus fraction (CO3≈P) > iron + aluminum bound phosphorus fraction (Fe+Al≈P). In line with research findings the negative phosphorus release dependent on months and depths have revealed quantitatively that West Pond sediment is a sink not a source in terms of phosphorus. In the light of this, conservation of the aquatic macrophytes, role in preventing/suppressing the dissolved inorganic phosphorus release from sediment to overlying water, suggested as the best management technique of West Pond.