Temporal And Spatial Variation Characteristics Of Macrobenthos In The Pearl River Estuary

At present,under the background of climate change and human activities,the macrobenthos community in the the Pearl River Estuary has been disturbed to varying degrees.Detailed investigation and research on macrobenthos have been carried out to find out the current situation of the spatial and temporal distribution characteristics of macrobenthos community in the sea area,and analyze the environmental factors affecting the structure of macrobenthos community;It has significant scientific value for maintaining and managing biological resources and maintaining the balance of marine ecosystems.Therefore,this study carried out macrobenthos sampling surveys in the Pearl River Estuary waters in four seasons from 2019 to 2021,respectively,to explore the spatial and temporal change pattern of macrobenthos communities.Perform statistical analysis on the collected data,calculate the dominant species using the relative importance index(IRI),and calculate the diversity of macrobenthic animals in each sea area using the species richness index(D),diversity index(H’),and evenness index(J’);Pearson correlation analysis was used to analyze the correlation between the community structure of macrobenthic animals and environmental factors in each season.The main conclusions are as follows:(1)The results of species composition and seasonal distribution of macrobenthos in the the Pearl River Estuary waters show that 138 macrobenthos were collected from four large-scale sampling in August 2020,December 2019,March 2021 and October 2021 in the the Pearl River Estuary waters,with molluscs and annelids as the main groups;The largest number of benthic animal species were obtained in spring.The number of species on the spring voyage in 2021 was higher than that on the autumn voyage,and the species composition of different groups showed a trend of miniaturization and simplification.(2)The results of seasonal variation and spatial distribution of dominant macrobenthos species showed that there were significant differences in dominant species among the four large-scale sampling seasons in the the Pearl River Estuary,with the largest number of dominant species in summer and the smallest in winter.In spring and autumn,the survey of macrobenthos during the large area and gill net voyages(March,May,September and October 2021)found that the species richness of dominant species in the southwest waters of the the Pearl River Estuary was higher than that in the inner waters and southeast waters of the the Pearl River Estuary.(3)The seasonal variation and spatial distribution of habitat density and biomass in the the Pearl River Estuary showed that the highest habitat density was in spring and the lowest in summer;The biomass is the highest in winter and the lowest in autumn.In terms of spatial distribution,the high value areas of macrobenthos biomass and habitat density in spring and autumn are located in the southeast waters of the the Pearl River Estuary,followed by the southwest waters,and the waters inside the the Pearl River Estuary are the lowest.(4)The seasonal and spatial variation results of the diversity index show that the maximum values of the diversity index H ’and the evenness index J’ of macrobenthos occur in winter.In spring,the waters from Humen Island and Near East Australia Island to Guishan Island are higher,while the waters from Sanmen Island to Wailingding Island are lower.In autumn,the diversity index H ’shows the highest in the southwest waters and the lowest in the southeast waters.(5)The correlation analysis between macrobenthos indices and seasonal environmental factors shows that water temperature,suspended solids and phosphate affect the benthic community structure in the the Pearl River Estuary.Due to human interference factors,the benthic community in the coastal waters has been seriously disturbed,and the habitat environment of benthic animals is in a fragile state.