Distribution, partitioning and mixing behavior of phosphorus species in the Jiulong River estuary

Surface and bottom water samples were collected along a salinity gradient from the Jiulong River estuary during May 2010 to examine the distribution and mixing behavior of dissolved and particulate phosphorus (P) species. Particulate P was further fractionated into five operationally defined phases through a sequential extraction method. In addition to field studies, laboratory experiments were carried out to examine key processes regulating the distribution and partitioning of P during estuarine mixing. Dissolved inorganic P (DIP) was the main species in the total dissolved P (TDP) pool, comprising up to 83 plus or minus 3% at river end-member station and 32 plus or minus 21% at coastal stations. While the concentration of dissolved organic P (DOP) changed little with salinity, DIP concentrations varied dramatically between stations, especially in the low-salinity (S