Spatial characteristics of the macrobenthos community near the Nakdong River estuary, on the southeast coast of Korea

Abstract

Macrobenthic fauna were collected using a van Veen grab (0.1 m2) to investigate the spatial characteristics of the macrobenthos community at 28 stations near the Nakdong River estuary, Southeast Korea, in September 2001. A total of 203 species were sampled with a mean density of 1,554 ind./m2 and a biomass of 252.3 gWWt/m2. Annelids were the dominant faunal group in terms of species and density, with 68 species and a mean density of 1,031 ind./m2, which comprised 33.5% and 66.3% of the total benthic animals, respectively. Based on density, three polychaetes were dominant Tharyx sp. (420 ind./m2), Lumbrineris longifolia (143 ind./m2), and Sternaspis scutata (118 ind./m2), along with a bivalve Theora fragilis (129 ind./m2). On cluster analysis, the benthic community was classified into four groups based on the species composition: Group-I occurred in disturbed areas, Group-II in coastal regions, Group-III in central mariculture grounds, and Group-IV offshore. Environmental factors (mean grain size, organic carbon, and depth) were primarily correlated with the macrobenthos community structure. A benthic pollution assessment based on the macrobenthos community structure showed that Group-I and Group-II were located in a coastal area that had been severely disturbed by construction of Busan new port and various pollutants, Group-III was gradually polluted, while offshore Group-IV was the most stable.