新疆红山水库浮游动物群落结构特征

Ecological features of zooplankton community of Hongshan Reservoir in Xinjiang

红山水库位于新疆阿勒泰地区吉木乃县境内,为了解水库浮游动物群落动态特征,于2008年7月平水期、10月枯水期以及2009年5月丰水期对该水库进行了浮游动物调查,共采集鉴定浮游动物52属81种,其中原生动物22属38种,占浮游动物总物种数的46.9%;轮虫15属22种,占27.2%;桡足类9属14种,占17.3%;枝角类6属7种,占8.6%。水库浮游动物群落结构呈现以小型原生动物、轮虫为主,大型浮游甲壳动物占少数的特征。调查结果显示红山水库浮游动物不同时期优势种不尽相同,某些优势种仅在特定水文期出现。浮游动物各类群间生物密度和生物量均存在显著差异,但水库浮游动物总生物量无明显季节差异(p>0.05),生物密度则具有季节性特征(p<0.01)。库区生物密度变化趋势为:枯水期(16.23±3.01×103 ind/L)>丰水期(7.99±1.60×103 ind/L)>平水期(7.61±2.57×103 ind/L)。

Hongshan Reservoir(85°51′58″E,47°2′10″N) locates in Jeminay county of Xinjiang's Altay Prefeture.The Musidao glacier is the only water source place of this county.In recent years,the global climate becomes warming and humanity's frequent activity;the Musidao glacier's snow line has been decreased 500 meters.The zooplankton which has a significant impact on the plankton community is the major component groups of aquatic plankton and a culture of quality fishing bait.Based on the data collected from the flow period,dry period and flood period,the species composition,community structure and species diversity of the zooplankton were determined in Hongshan Reservoir.Results show that 81species of 52 genera in total was identified,of which 38 species of 22 genera were protozoa,22 species of 15 genera were rotifera,14 species of 22 genera were copepod and 7 species of 6 genera were cladocera,it was higher than that of other reservoirs in the same latitude of China.The number of species for protozoa,rotifera,copepod and cladocera accounted for 46.9%,27.2%,17.3% and 8.6% of the total species respectively,which shows that the community structure approached to miniaturization.The changing trends of species show: the dry period(54 species)'s> the flood period(42 species)'s> the flow period(36 species)'s,each hydrological period was made up by four groups,but the species number of zooplankton categories existed very significant difference(p<0.001).The dominance analysis shows that the zooplankton in Hongshan Reservoir has the characteristic that the dominant species alternate larger,it has significant difference(p<0.05) in each hydrological period.T.victnospinalis,T.prasinus and Polyarthr trigla appear and become the dominant species in three hydrological periods.The zooplankton in Hongshan Reservoir shows a larger alternation with hydro-periods,the highest density being 16.23±3.01×103 ind/L in the dry period,followed density being 7.99±1.60×103 ind/L in the flood period),and the lowest density being 7.61±2.57×103 ind/L in the flow period,it also has a very significant differences(p<0.01),the most obvious difference appears in the dry period.The protozoa accounts for the vast majority in density,reaching 96.67% of the total density.The biomass of different zooplankton has no significant differences(p>0.05),the biomass is 0.94±0.18 mg/L in the flow period,0.96±`0.22 mg/L in the dry period and 0.97±0.13 mg/L in the flood period,mainly constitutes by protozoa and rotifers,which account for 53.71% and 44.42% of the total biomass of zooplankton respectively.We analyzed the Shannon-Wiener and evenness indexes of zooplankton community during three cruises in Hongshan Reservoir.The diversity index of protozoa shows that: the flood period(2.58)'s index> the dry period(2.06)'s> the flow period(1.88)'s,which is consistent with the change of Carlson trophic state index.According to our analysis,the water quality condition of Hongshan Reservoir was determined as the light pollution-β-middle pollution.