The Ecological Study Of Macrobenthos In Yangtze River Estuary

In April of2009to March of2010, September of2010to September of2011,Surf zone waters, north edge of Yangtze River estuary inertidal waters and subtidalwaters sampling sections were set up. This study discuss about species composition,dominant species, habitat density, biomass and biodiversity at three different waters inYangtze River estuary. Investigate the interaction between macrobenthos communitystructural characteristics and environmental factors. Macrobenthos community is animportant part of the Yangtze River estuarine ecosystem, which plays a key role inecosystem strcture and function. This article conclusion could provide powerfulreference and help to environmental remediation, protection of Sturgeon, fisheriesdevelopment and estuarye functional areas development.Major results of this study are:1. In2009April to2010March，a list of species of macrobenthos in surf zonewater of Yangtze River estuary is achieved, which includes41species:5Polychaete,4Oligochaeta,9Gastropoda,8Lamellibrach,5Crustacea,6Incecta and4other. In2010September to2011September, there is86species of macrobenhtos lived in thenorth branch of Yangtze River estuary tidal zone: the species number of Mullsca andCrustacea is the same32. Fish species number is17, the other species includeAnnelida number is5. Collected and identified68species of4groups in Yangzte riveresruary subtidal waters:23species of Mullsca,24Crustacea,18species of Fish and3species of other kinds.2. Throughout the year of2009March to2010March, there are8dominantspecies in surf zone waters; the best dominance species is Corophium volutator. In2010September to2011September, Acanthomysis longirstrisis is the annual dominantspecies in north edge of Yangtze River estuary intertiedal waters. In September2010,Exopalaemon annandalei is the dominant species in Yangtze River estuary subtidalwaters.3.In Yangtze River estuary subtidal waters, average of the sampling sitesdensity number is1.87ind./㎡; the north edge is higher than the south branch. Thedensity average of benthic macro-invertebrates in Yangtze River estuary surf zonewaters is83.29ind./㎡, highest in sumer;lowest in spring. And the annul averagenumber is83.29ind./㎡. The annual average of macrobenthos density in north edge ofYangtze River estuary is7.32ind./㎡, highest in midstream, lowest in downstream.Thedensity of macrobenthos communities of north edge growth and reached a peak period in late spring and sumer.4. In Yangtze river estuary subtidal waters, average of the sampling sitesbiomass number is0.55g/㎡, the north edge is higher than the south branch. Thebiomass of fish is highest. The biomass trends of north edge of Yangtze River estuaryremain the same with desity trends. The sampling sites average is3.04g/㎡, and theannual average is1.27g/㎡, biomass peak in summer. The annual average ofmacrobenthos biomass in surf zone of Yangtze river estuary is5.65g/㎡, the samplingsites average is5.64g/㎡, the highest bimass in stie S2. The range of biomass is1.19g/㎡(September)-12.86g/㎡(June).5. In in surf zone of Yangtze River estuary, Shannon-Wiener diversity indexaverage is1.81, Margalef diversity index average is2.31, and Pielou diversity indexaverage is0.65. In Yangtze River estuary subtidal waters, average of Shannon-Wiener,Margalef, Pielou diversity index are1.90,5.03and0.71. In north edge of Yangtze Riverestuary intertidal waters, the highest value of Shannon-Wiener diversity index at site S3,the lowest at site S1. The range of Pielou diversity index is0.48-0.62. The highest valueof Shannon-Wiener diversity index is2.52, the lowest is1.92.6. Through the communities cluster analysis, the Yangtze River estuarysubtidal waters macrobenthos communities could be divided into6groups, and the surfzone would be divided into5groups. The communities in north edge of Yangtze Riverestuary could be divided into3groups, which had little difference.