한국 남해 동부 해역의 계절별 수괴변화에 따른 중형 동물플랑크톤 군집 특성

Abstract

The seasonal variation of zooplankton community in relation to hydrographic characteristics in the eastern South Sea of Korea was investigated in February, May, August and December 2013. The eastern South part of study area was strongly influenced by Tsushima Current of warm and high salinity in summer and autumn. The coastal upwelling occurred near Geoje island during the summer. Nutrients (NO3-N, PO4-P) was relatively higher in winter, whereas Chl-a was relatively lower in the summer and winter. A total of 93 taxa (52 species) was found. Mean zooplankton density ranged from 2,391.5 inds. m-3 in December to 5,388.5 inds. m-3 in August. Noctiluca scintillans, Paracalanus copepodite, Oikopleura spp., Corycaeus affinis, Cirripedia larvae, Pseudevadne tergestina, and Oithona similis were dominant species. Oceanic warm water copepods, belonging to the genera, Eucalanus, Euchaeta and Undinla were collected in all seasons except spring in the marginal and middle regions of study areas in autumn when the area strongly influenced by the Tsushima Current. According to non-metric multidimensional scaling(nMDS) and cluster analysis by season, zooplankton community was divided into three groups in spring and summer, four groups in autumn and winter. Our results suggest that the community of zooplankton are influenced by seasonal variation of water masses in the eastern South Sea of Korea.