The Community Structure Of Zooplankton In The Enteromorpha Prolifera Outbreak Area Of The South Yellow Sea In Summer And Spring

The study was carried out on two surveys of the South Yellow Sea in August2008(summer) and March2009(spring). The aim was to examine the speciescomposition, abundance, biomass and biodiversity of the zooplankton community.Moreover, the correlations between zooplankton community and environmentalparameters were also analyzed by multivariate analysis method. This research canprovide important fundamental information for the long-term monitoring ofzooplankton ecology in the South Yellow Sea.A total of87zooplankton taxa and29pelagic larvae were identified during twosurveys, and they belonged to Cnidaria, Ctenophora, Annelida, Mollusca, Arthropoda,Chaetognatha and Urochordata, respectively. The pelagic crustacean and cnidariawere the most dominant zooplankton in surveyed waters. They were accounted for57.5%and24.1%of total species richness.In surveyed area in2008, the mean abundance value of zooplankton was1080.0ind/m3, the high abundance was in the middle of the South Yellow Sea, and they werehigher than that in the inshore area of the surveyed waters. In2009, the meanabundance of zooplankton was428.6ind/m3, The abundance in the middle part of thesouth yellow sea were higher than that in the inshore of Shandong and Subei water.In2008, four assemblages or communities of zooplankton were differentiated byusing the method of cluster analysis.1) Group Ⅰ lay in the inshore of the southyellow sea, dominated with Sagitta crassa, Evadne tergestina, Paracalanus parvusand Calanus sinicus;2) Group Ⅱ belonged to the central water of the south YellowSea community, dominated with Calanus sinicus, Oithona plumifera, Peniliaavirostris and Sagitta crassa;3) Group Ⅲ lay in the neighborhood of the ChangjiangRiver mouth, dominated with Centropages dorsispinatus, Paracalanus parvus and Acartia pacifica.;4) Group Ⅳ located in G7station was dominated by Nannocalanusminor, Sapphirina opalina, Euchaeta wolfendeni and Hydroida larva. Sea bottomSalinity and sea bottom temperature and depth were the most important abiotic factorsfor the zooplankton distribution and community classification in spring, while insummer, sea bottom temperature and the water depth were the primary factors whichinfluenced the zooplankton distribution and abundance in the surveyed waters. In2009, three groups were distinguished by the cluster analysis method, based on thespecies composition and abundance of zooplankton.1) Group Ⅰ located in theinshore of Shandong, Calanus sinicus, Paracalanus parvus and Echinopluteus larvawere the dominate species;2) Group Ⅱ located in the middle of the south yellow sea,was dominated by Calanus sinicus, Paracalanus parvus, Oithona plumifera andSagitta crassa;3) Group Ⅲ located in the inshore of Subei, the dominate speciesincluded Calanus sinicus, Paracalanus parvus and Sagitta crassa, Paracalanusparvus was the most important specie.In2008, the values were1.89,0.56and0.46, respectively. The species numberand Margalef richness had the same trend, the Pielou’s evenness and Shannon-Weanerindex had the same trend, too. In2009, the mean Shannon-Weaner Diversity, Pielou′sevenness and Margalef species richness were1.36,0.46and2.75, respectively. whichwere lower than in2008.