Author : Rajuddin Syam

Summary : A study was carried out in the Jeneberang Estuary to observe the physico-chemical characteristics of sediment and the overlying water. The estuary is subject to heavy siltation due to erosion in the catchment area particularly during the wet months. The nutrients nitrogen and phosphorus along with the organic matter and clay particles were found abundant. However, because of heavy siltation which interfered with light penetration, photosyntheses in the phytoplankton could not proceed at high rates. Low transparency was the result of heavy silt load which was promoted by turbulence. The dry months (September-October and May-June) characterized by high transparency, nitrogen concentration, pH, temperature, transparency, alkalinity, salinity, total hardness, calciu, and sulfate. The wet month had reverse conditions. Between the two seasons, high productivity was exhibited by the dry months. Benthic algal communities consisted of cyanophytes, euglenophytes, chlorophytes, bacillariophytes, and pyrrophytes. A total 111 species were identified. Bacillariophytes dominated both seasons, followed by the chlorophytes. Maximum algal species populations were noted in November or at the end of the dry months. Among the macrozoobenthos, mollusca and arthropoda were dominant, attained highest density in May of the dry months. No relation was evident between the fluctuation of population of macroobenthos and benthic algae. Water transparency, turbidity and dissolved oxygen were positively correlated with the density of macroobenthic organisms, while temperature, organic matter and particulate carbon were negatively correlated. The fish species dominantly fed on algae were mullet (Mugil dussumiery) and tilapia (Tilapia mossambica). Both are euryhaline species.