Influence of bacterial density on the exchange of phosphate between sediment and overlying water

Fluxes of phosphate across the sediment-water interface have been measured using inhibitors of bacterial activity sterilization and chloramphenicol an d a control in order to quantify the influence of bacterial abundance on th em. Results show that phosphate concentration in the interstitial water dec reased when bacteria were present, in relation to treated aquaria. The meas ured (Jo) and theoretical fluxes (Jd) of phosphate also were higher when ba cterial activity was suppressed. Mass balance calculated for Carbon, Nitrog en and Phosphorus in the sediment revealed a loss of theses compounds when bacterial activity was suppressed, and a net accumulation of Carbon and Pho sphorus, and loss of Nitrogen under natural conditions.