Distributional Patterns of the Molluscan Assemblages in the Yellow Sea

초록

An investigation was carried out on the distribution patterns of molluscan assemblages in the Yellow Sea in September, 1992. Previous works of the adjacent countries (China, Japan and Korea) have suggested a necessity for proving whether the distribution patterns of macrobenthos community in the central part of the Yellow Sea are governed by the Yellow Sea Bottom Cold Water Mass or not. A set of environmental factors including depth, bottom water salinity and temperature, dissolved oxygen and suspended solid concentration, chemical oxygen demand, mean grain size of surface sediment, sorting coefficient, and ignition loss was measured and interrelated with the distribution pattern of molluscan assemblages. Based on the ordination and cluster analysis, central part and its circum-ambient benthic communities were established and the differences were mostly explained by bottom water temperature and secondly by chemical oxygen demand and dissolved oxygen concentration. Also, the boundary of the molluscan community in the central part of the Yellow Sea was exactly coincided with that of the Yellow Sea Bottom Cold Water Mass and it showed relatively higher homogeneity in terms of the community structure and other quantitative variables within community. The results are consistent with the hypothesis that the bottom cold water mass may govern the distribution and community structures of benthic faunal assemblages of the Yellow Sea.