Distribution and speciation of phosphorus in surface sediments of the intertidal zone in the Yellow River Delta

For better understanding the phosphorus (P) cycle, it is essential to distinguish the contents of different P speciation in sediments. In the study, the content of total phosphorus (TP) in the sediments ranged from 88.80 to 227.56 mu g.g(-1), with an average of 138.42 mu g.g(-1). The content of inorganic phosphorus (IP) ranged from 84.21 to 224.26 mu g.g(-1), accounting for 88.74%-98.55% of the TP content, which was the main occurrence form in the intertidal sediments of the Yellow River Delta. the contents of phosphorus fractions in surface sediments were 37.06 to 106.35 mu g.g(-1 )for detrital phosphorus (De-P), 2.99 to 34.39 mu g .g(-1) for exchangeable phosphorus (Ex-P), 5.27-106.06 mu g.g(-1) for iron bound phosphorus (Fe-P). On the whole, the existing forms of inorganic phosphorus could be ranked as follows: De-P > Fe-P > Ex-P > authigenic phosphorus (Au-P). The regression analysis between TOC content and various forms of phosphorus showed that TOC content was negatively correlated with De-P.