The Role of Iron Oxides in Marine Phosphorus Cycling

Abstract

Dissolved and particulate phase iron (Fe) and phosphorus (P) concentrations were characterized in Effingham Inlet, a fjord located on the west coast of Vancouver Island. The effect of redox conditions on Fe and P cycling was investigated through comparison of sediment and water samples taken above and below a water column redox boundary in the fjord. The data show that sharp increases in the concentration of dissolved P across the redox boundary cannot be explained solely by release of absorbed phosphorus associated with dissolution of iron oxide phases. These findings support new theories of P cycling in oceans, which suggest that redox sensitive cycling of polyphosphates by microorganisms may be a significant source of dissolved phosphorus in marine environments.