The SEDEX method, a sequential extraction scheme for sedimentary phosphorus phases, was tested for use on eastern Mediterranean sediments using two in-house reference sediments. In addition a 2 M NH&l and a 0.1 M NaOH extraction were tested to extract CaCO,-associated and iron-bound P respectively. These methods were then applied to samples of a sediment core from the eastern Mediterranean (ABC26). The sum of extracted P phases of the reference sediments (and core ABC26) was not significantly different from total P and precision of each extraction was better then 17% (Is), except for detrital P and iron-bound P (extracted by CDB). The NaOH extraction dissolved only iron-oxides associated with the surface of minerals, while the CDB extraction dissolved a much larger fraction.
In core ABC26, P produced in the sapropel layer (Sl ) appeared to have diffused both upwards and downwards. This P is now found as exchangeable+loosely bound P and as iron oxide bound P in the adjacent oxic sediments. There was evidence that P was released from CaCO,-P in the "burn-down" zone which was affected by sulfide oxidation. The organic C/P molar ratio was -4OO:l in the sapropel while it was indeterminate for the oxic layers.