Assessment the macrobenthic diversity and community structure in the Musi Estuary, South Sumatra, Indonesia

Abstract

The macrobentic community in the Musi Estuary is very diverse. However, it has been showing a declining trend recently due to an increase in waste from human activities entering the waters. This study aimed to assess the macrobenthic diversity and community structure and correlated to the water quality parameters of the Musi Estuary, South Sumatra. The method used was a survey collecting water quality parameters at eight observation stations. The salinity is measured with a refractometer, temperature is measured with a digital thermometer, pH is measured with a pH meter. The dissolved oxygen (DO), brightness and current are measured with a DO meter, Seichii disk, and current meter, respectively. The Ekman grab was used to collect the samples, and then we used a diversity index, a similarity index, and principal components analysis (PCA) for analysis. The results show that the water quality is found in a good condition for macrobenthos growths. The salinity is ranging between 0 and 15 ppt, temperature is about 29–30.8 °C, pH is about 7.6–8.1, the dissolved oxygen is found to be 3.2–12.5 mg/L, the brightness is about 4.71–31.67% and the current speed is about 0.02–0.08 m.s−1. The analysis also indicates that the microbenthic compositions consist of 18 species, which is grouped into five classes, namely Gastropods 56%, Crustacea 22%, Bivalve 11%, Actinopterygii 6%, and Polychaeta 5%, with an abundance of 0,67 to 13,33 Ind.m−2. The diversity index is generally in low categories (H′ < 1), and the dominance index is more than 0.5. Based on the PCA analysis, it was found that the water quality parameters (e.g. dissolved oxygen and temperature) show significant correlation with similarity index at all observation stations. The macrobenthic diversity and community structure in the Musi Estuary is found to be increasing offshore and decreasing towards the river.