Study On The Zooplankton Community Near Hongdao In Jiaozhou Bay

This article is based on the surveys in April, July, November in2011andFebruary in2012near Hongdao in Jiaozhou Bay. The research is mainly done on thezooplankton from shallow water plankton Ⅱ net. Environmental factors, distributionof phytoplankton, composition, abundance and biodiversity of zooplankton,distribution of dominant species in four seasons are studied here. Correlationsbetween zooplankton, phytoplankton and environmental factors are also discussed aswell. Experiment about differences between two sampling nets is executed. Thepurpose of this article is to know the structure and changes of zooplankton communityin survey area, and provide data for zooplankton investigation in this area. Meanwhile,it can provide information for environmental protection in Jiaozhou Bay, and forsustainable development of marine aquaculture.Results are as follows.1. During four seasons, a total of59zooplankton taxa belonging to6categorieswere identified, in which copepods were the most important component. Dominantspecies in the survey waters included Noctilucidae scientillans, Paracalanus parvus, P.crassirostris, Acartia bipinnata, A.pacifica, Oithona similis, Nauplius larva (Cope-poda), Sagitta crassa and Oikopleura dioica. And there were differences amongdominant species in four seasons. Species used to living in offshore and low salinitywaters was the main ecological colony. The numbers of species in four seasonsshowed that more species presented in summer, then in autumn, spring, and winter.2. The average abundance of zooplankton in the whole year was8544.93ind/m3，and the results showed a trend of winter> summer> spring>autumn. The averagebiomass was1481.87mg/m3, and the trend was spring>winter>autumn>summer.What’s more, summer showed higher biodiversity, and the average of biodiversitywas2.892.3. Comparisons were done on the distribution of zooplankton among different stations. In spring, stations close to cultured areas showed larger abundance and bio-mass than those far from cultured areas, but lower biodiversity as well. In summer,station in non-cultured areas showed larger abundance, but lower biomass andbiodiversity as well. In autumn, station in non-cultured areas showed lowerabundance and biomass, and there was no difference in biodiversity among stations.There were no obvious rules about distribution of zooplankton in winter. Analysis oncommunity structure showed obvious difference between stations from two areas inspring, summer and autumn.4. The correlations analysis showed that, the distribution of zooplankton inHongdao area was mainly correlated with two factors, which were temperature anddensity of phytoplankton. In spring, summer and autumn, temperature did more todistribution of zooplankton, while in winter, the key factor was distribution ofphytoplankton.5. The results of experiment on the differences between two sampling netsshowed that, the composition of zooplankton from two types of nets was different.Animals from shallow waterⅠnet were larger than those from shallow water Ⅱ net insize. The total number of animals was also larger in shallow waterⅠnet. For largerindividuals, there was no obvious difference in abundance, but for small ones, thedifference was very significant. Animals from Ⅱ net were hundreds, even thousandstimes of those fromⅠnet in abundance. Animals fromⅠnet were mainly>1.5mm insize, while in Ⅱ net, they were usually <1mm. In a word, two types of sampling netsare both important in zooplankton investigations. Especially for evaluation on thestructure and function of community, shallow water Ⅱ net is indispensable.