Zooplankton distribution and community structure in Tianwan Offshore Area

Zooplankton spatial distributions and additional environmental features of Tianwan Offshore Area were studied in August 2009 at 14 stations. The abundance, distribution, and diversity of zooplankton were analyzed. copepods, larval stages, and hydromedusae dominated the zooplankton community. At total 72 species of zooplankton with 13 groups were identified. With 20 Zooplankton larvae, 19 Jellyfish, 11 Copepods, 32 other taxa recorded in the investigated area. Zooplankton abundance range was 182-3842 ind/m³, mean 1314 ind/m³. Mean Shannon diversity index (H') was 3.321, mean Evenness index was 0.682, mean abundance index was 2.881. The main dominant species are Obelia spp., Acartia pacifica, Centropages dorsispinatus, Penilia avirostris, Echinopluteus larva, Pseudopolydora sp., Calanopia thompsoni, Evadne tergestina. Investigation mainly by the low salinity waters inshore zooplankton composition of ecological groups, small groups of brackish estuaries and wide temperature euryhaline ecological groups, species more abundant. The analysis of correlations showed that there were significant negative correlations between water temperature and zooplankton abundance(r = -0.705) and Number of species of zooplankton (r = -0.664) and no correlation between Water temperature and Diversity index, evenness, richness index. The fluctuations in the zooplankton abundance and community structure were determined by the interactive effects of water temperature. Significant spatial variability in the distribution of zooplankton species, abundance can be ascribed to the virtual presence of a horizontal gradient in water temperature.