The release of reactive phosphate by a Posidonia Australis seagrass community

Abstract

Reactive phosphate was released into the water over a bed of the seagrass Posidonia australis Hook. f., both day and night. No release occurred over a similar unvegetated area nearby. Estimates of release rate were between 0.055 and 0.17 μg-at. P h −1 g −1 leaf dry wt. It was shown that the plants themselves were not responsible for releasing this reactive phosphate into the water column. It is postulated, instead, that the seagrass bed released reactive phosphate through microbiological remineralization of destritus accumulated from the water column, seagrass leaves and epibiota. The reactive phosphate thus produced entered the water column either by diffusion or by tidal flow mechanisms.