A survey was performed to assess organic pollution, water properties and the marine benthic community. The need to assess the environmental status of marine and coastal waters encouraged the design of specific biotic indices to evaluate the response of benthic communities to human-induced changes in water quality. In this study of the benthic community structure in Ghanam Creek surrounding an industrial sewage discharge, water and sediment samples were collected at eight sites in the warm season and cold season. Environmental data on physical and chemical variables were also collected from each site and a multivariate analysis was carried out to determine the effect of environmental factors on the biodiversity distribution. The results indicated that the station furthest from the petrochemical industries (station located in Ghanam Creek) had higher species diversity and consequently a higher value for the Shannon-Weaver diversity index. The present study also showed that polychaetes were more abundant. Although polychaetes were also recorded at all the other stations, these stations had greater biodiversity with different numerically dominant species such as: Isopoda, Decapoda, Gastropoda, Copepoda, Bivalvia, Pennatulacea and Crustacea. Consequently, it was established that macrobenthic biodiversity was related to dissolved oxygen and the percentage of organic matter in the sediment.
Keywords: benthic community, biotic indices, human activity, macrobenthos, pollution