Characteristics of a macrozoobenthic community in the sea adjacent to the Yangtze River estuary during the wet season

Abstract

To explore the characteristics of a macrozoobenthic community in the sea adjacent to the Yangtze River estuary during the wet season, macrozoobenthic samples were collected during June, August, and October, 2012, and data were analyzed using statistical methods including Two-Way ANOVA, Cluster analysis, Non-metric Multidimensional Scaling (NMDS), and Abundance-Biomass Comparison Curves (ABC Curves). A total of 181 macrozoobenthic species were recorded, with 82 species of Polychaeta, 46 Crustacea, 31 Mollusca, 11 Echinodermata and 11 species belonging to other groups. The abundance, biomass, Margalef’s richness index (d), Shannon-Wiener index (H'), and Pielou index (J') did not show any significant temporal or spatial differences except that J' in the offshore area was significantly higher than that found in the inshore area. Three to four macrozoobenthic assemblages were identified using the 20% similarity level and a low similarity level among stations was also observed. ABC curves revealed that the macrozoobenthic community in the offshore area was less disturbed than that in the inshore area. As a result of the continuous impact of anthropogenic activities, the macrozoobenthic community was severely disturbed and unevenly distributed in the sea adjacent to the Yangtze River estuary.