Adsorption of Phosphorus on Sediments of the Balearic Islands (Spain) Related to Their Composition

The adsorption of phosphorus onto sediment particles has a major role in coastal areas, where continental inputs may increase levels of phosphate in the water mass. This paper reports a study of the adsorption capacity of phosphorus in two coastal areas located in the Balearic Islands: one in Majorca (The Albufera of Alcudia), and the other in Minorca (The Albufera of Es Grau). The range of adsorption capacity was 35–121 μmol Pg−1in Majorca, and 30–55 μmol Pg−1in Minorca. Considering the slope of the Langmuir equation for low or moderate phosphorus concentrations as a measure of the efficiency of sediments in taking up phosphate, sediments from Minorca were more efficient than those from Majorca (21–36 ml g−1and 14–21 ml g−1, respectively. A horizontal pattern of variation was observed in both areas, with the highest values near the sea and at the points with least marine influence. In Majorca, maximum adsorption capacities (Cmax) were positively correlated with concentrations of iron and aluminium, and efficiencies of sorption were related to carbon. In Minorca,Cmaxand efficiencies were negatively correlated with iron and aluminium, and positively correlated with carbon and calcium.