Nutrient and oxygen redistribution during destratification in the Elefsis Bay,an anoxic basin

Destratification in Elefsis Bay due to winter cooling, heavy water formation and mechanical mixing produces homogenous water column that is moderately stratified during the summer as a result of surface heating and reduced mechanical mixing. In the Elefsis Bay, this destratification redistributes ammonia, phosphate and silicate regenerated by the organic matter as well as oxygen from the surface. This redistribution has significant implications for nutrient cycles and organism distribution in the Bay. Reasons for the increase of the phosphate concentrations through release of P from the sediments and the conversion of nitrate to nitrogen gas in oxygen-deficient water have been confirmed. The relation between the accumulation of phosphate, silicate and ammonia are discussed.