万峰湖枯、丰水期浮游动物群落结构特征及水环境评价OA

To investigate the temporal and spatial patterns of the zooplankton community structure in Wanfeng Lake and its relationship with environmental factors,ecological surveys were conducted during the dry season(September)and the wet season(May).Non-metric multidimensional scaling(NMDS)and redundancy analysis(RDA)were employed to study the zooplankton community structure.A total of 84 species belonging to 34 genera across 3 phyla were identified,with the main groups being rotifers and protozoa,which accounted for 61.29%of the total abundance.The dominant species during both hydrological periods included Keratella cochlearis and Keratella valga,with a turnover rate of dominant species at 63.4%,indicating significant variations in dominant species between the two periods.The average density and biomass of zooplankton in Wanfeng Lake during the dry and wet seasons were 1856.3 ind·L-1 and 13.94 mg·L-1,respectively.Both density and biomass exhibited significant horizontal and temporal variations(P<0.05),while vertical differences were not significant(P>0.05).NMDS ordination results revealed varying degrees of spatial dispersion among sampling sites,indicating different levels of temporal and spatial differences in community structure.The functional groups of zooplankton during both hydrological periods were predominantly represented by particulate feeders(PF)and rotifer feeders(RF),with considerable differences in functional group composition between the two periods.RDA results indicated that ammonia nitrogen,dissolved oxygen,and salinity were significant influencing factors(P<0.05).Based on the annual data from both hydrological periods,the zooplankton community in Wanfeng Lake could support a fish productivity of 11001.1098 tons,with a maximum environmental carrying capacity for filter-feeding fish of 833 ind·hm-2.Except for the richness index,all other diversity indices of the zooplankton community exhibited temporal and spatial variations.The overall water quality status was classified as mildly to moderately polluted,with a mesotrophic nutritional condition.The findings of this study provide baseline data for the ecological protection and scientific management of the aquatic environment in the region.