| A sequential extraction technique has been developed which separates and quantifies five sedimentary phosphorus reservoirs: (1) exchangeable or loosely-sorbed-P, (2) ferric iron-P, (3) authigenic apatite + biogenic apatite + CaCO;A revised global oceanic phosphorus budget shows that continental margins are important loci for phosphorus burial. Oceanic residence times for phosphorus, calculated on the basis of the revised global oceanic phosphorus budget, are considerably shorter than previous estimates which neglected the importance of continental margins as sinks for reactive phosphorus.;This method has been applied to sediments from four different marine depositional environments. Variations in solid-phase phosphorus speciation with depth in these sediments, coupled with pore water profiles, have permitted identification of mechanisms controlling the early diagenesis of phosphorus and the phases responsible for phosphorus retention by sediments. For example: (1) There is considerable diagenetic transformation of one form of phosphorus to another in continental margin sediments but not in deep sea sediments; (2) Ferric-iron phases act as a long term sink for phosphorus in rapidly-depositing deltaic sediments. (3) There is a high concentration of authigenic apatite + biogenic apatite + CaCO... |
