A sequential extraction to determine the distribution of phosphorus in the seawater and marine surface sediment

Abstract

The distribution of phosphorus species among environmental compartments (e.g., between water and sediment), significantly affects the bioavailability of these species to organisms. The eastern Mediterranean Sea is one of the most extreme oligotrophic oceanic regions on earth in terms of nutrient concentrations and primary productivity. The paper presents the results of inorganic and organic forms in surface sediment and seawater from NE Mediterranean Sea (Burclar Bay, Erdemli, South Anatolia of Turkey) in May 2007. Speciation of phosphorus in seawater and surface sediment using inductively coupled plasma-atomic emission spectrometer (ICP-AES) has been reported here. The method is based on sequential extractions of the seawater and sediment each releasing four forms of inorganic phosphorus: loosely sorbed phosphorus, phosphorus bound to aluminium (P–Al), phosphorus bound to iron (P–Fe) and phosphorus bound to calcium (P–Ca). The most abundant form of inorganic phosphorus in the seawater and surface sediment is calcium-bound phosphorus. Relative abundances of the remaining phosphorus forms in sediment follow the order: P–Al > P–Fe > loosely bound-P and in seawater follow the order P–Fe > P–Al > loosely bound-P.