Some aspects of the fauna and flora components of polluted estuarine sediment

Abstract

The abundance, community structure and diversity of benthic diatom and macrofauna in two polluted sites in an estuarine system were investigated by quantitative sample collection and analyses. Range of values of physicochemical parameters investigated were; 28.7– 30.4 oC for air temperature, 3– 3.7 mg/L for dissolved oxygen, 1.17 - 1.57 mg/L for biological oxygen demand, 0.01 - 0.08 m for transparency, 0.8 – 6.9 mg/L for sulphate and 24.3 – 72.9 mg/L for nitrate. A total of 136 diatomic cells comprising 11 genera and two orders of benthic forms were collected in the polluted stations. The most frequently recorded species were Aulacoseira granulata and Cyclotella striata making the order centrales the dominant group. A total of 70 individuals of benthic macrofauna comprising three Phyla, four classes, seven families, seven genera and seven species were recorded in this study. The phylum mollusca was the most dominant and constituted 73% of the total macrofaunal population. The trend in patterns of abundance and diversity of diatom and macrofauna in the study locations were not different. The generally low species abundance and diversity of flora and fauna observed in the area is likely the overall impact of the degraded environmental conditions.