Contribution of Phytoplankton Photosynthesis to a Mangrove Ecosystem

Abstract

Primary production in a fringing mangrove ecosystem was measured using two techniques. The first estimated gross oxygen production and community metabolism based on the diel difference in dissolved oxygen concentrations. The second estimated carbon assimilation in the water column. The difference between the two results has been taken as the contribution of benthic microalgae and bacterial chemo- and photosynthesis to primary production in the environment. There is no apparent causal relationship between phytoplankton biomass and either benthic animal populations or edible fish catch in the area. Phytoplankton activity appears to be of marginal importance in this environment. Detritus contribution of mangrove leaves to the water column and sediment of this region is considerable. If smaller tidal estuaries such as the Galjibag are bunded, they will prove very useful for the aquaculture of deposit feeders