Distribution, source and chemical speciation of phosphorus in surface sediments of the central Pacific Ocean

The abundance of five forms of phosphorus (P) in surface sediments from the central Pacific Ocean (4.5–15ºN, 154–143ºW) was determined using a sequential extraction procedure (SEDEX) to examine the distribution and source of different P species. Total P (TP) concentrations ranged from 13.2 to 119µmol-P/g with an average of 48.6±27.4µmol-P/g. Within the TP pool, total inorganic P (TIP) concentrations varied from 11.1 to 121µmol-P/g, while total organic P (TOP) concentrations ranged from undetectable to 4.8µmol-P/g. Inorganic P was generally the predominant form in surface sediments, comprising on average up to 93% of sedimentary TP, leaving 90% of total sedimentary P in the central Pacific Ocean.•High detrital and authigenic P but low exchangeable P were found.•Atmospheric input was the major P source in central Pacific Ocean sedim