The estimation of bioavailable phosphorus in sediments.

Abstract

Sediment has a great capacity to absorb phosphorus from overlaying water, releasing it when conditions become favourable. This can cause recurrent algal and macrophyte blooms without the need for additional nutrient inputs. Since phosphate is the limiting nutrient in many aquatic ecosystems, the accurate measurement of sediment available phosphate (SAP) is essential for effective catchment management. Past attempts to estimate bioavailable phosphorus have shown limited usefulness due to discrepancies between different chemical and biological assays used. They fail to take into account the trementdous diversity available in the natural setting and, therefore, have underestimated potentially available phosphorus. A new method has been developed that takes advantage of indigenous sediment micro-organisms to measure SÅP. The method will be described and strategies for field-testing the method will be presented.