SEDIMENTARY ENVIRONMENT AND MEIOFAUNA COMMUNITY STRUCTURE IN RIVER-SEA INTERACTION AREA OFF CHAOSHAN,GUANGDONG
Estuarine delta is the most intense area of human activities,with complicated land-sea interaction and highly fragile ecology.Field observation and sediment sampling were carried out in Hanjiang River estuaries off Chaoshan,Guangdong in June 2021,to analyze the sedimentary environments and meiofaunal community for the deep understanding of ecological condition.Results showed that sediment was mainly clay-silt with a mgs range of 6.66～1 301.34 μm.The salinity varied from 15.91 to 35.11,reflecting tyical characteristics of the river-sea interaction zone.Organic carbon content(TOC),chlorophyll a(chl a)and phaeophorbide(Phaeo)showed a decreasing trend from land to sea.Heavy metal Cu and Zn,Phaeo,transparency,and sand contents were the main factors leading to the differences of sedimentary environments.Thirteen major groups of meiofauna were identified,among which free-living marine nematodes were dominant species in abundance and biomass,accounting for 90％and 38％,followed by copepods and polychaetes.The mean abundance and biomass(dry weight)of meiofauna were(295±195)inds./10 cm2 and(277.8±202.8)μg/10 cm2,respectively,and the spatial distribution showed an overall increasing trend from land to sea,with significant differences among different estuarine sections.Salinity and estuary were also important factors influencing the spatial distribution of the meiofauna community.The community similarity was high in the euhaline region(salinity＞30).The abundance,biomass,and the number of meiofaunal taxon were negatively correlated with Phaeo and heavy metals(Cu,Zn,Pb,Cd);the combination of salinity and heavy metal Cd was the best explanation for the differences of meiofauna community.Environmental assessments of heavy metals,organic pollution index,and the ratio of marine nematodes to copepods generally agreed well,showing that the most polluted area was located in the river mouth.This study provided the basic data for deep insight of resource protection,ecological monitoring,and implement of ecosystem-based integrated management.
万方数据
维普
