Phosphorus forms of the surface sediment in the Iranian coast of the Southern Caspian Sea

Sediments from the Southern Caspian Sea, located in Iranian coast were examined on the basis of P-fractionation (five forms of phosphorus) by a sequential extraction scheme. Ninety-six surface sediment samples (for each season with triplicate) were collected from eight sampling transects in ۱۰ and ۱۰۰ m depths during summer and winter in ۲۰۱۰-۲۰۱۱. The result indicated that the most abundant forms of phosphorus were calcium bound phosphorus. Relative abundance of other forms of phosphorus follow the order: organic-P>Fe-P>Al-P>Absorbed-P. The loosely absorbed phosphorus represented <۱% of the sedimentary inorganic phosphorus, while the Fe/Al phosphorus ranged ۵–۶%.The calcium bound phosphorus showed considerable contribution (۸۸%) to the sedimentary inorganic P-loads.

Keywords:

Caspian coastline , rice , Pesticides , Mineral elements