浙江千岛湖深水区大型底栖动物时空变化格局

2007-2008年对浙江千岛湖深水区底栖动物群落进行了研究.共调查到8种底栖动物,其中寡毛类7种,线形动物门1种.群落类型不存在季节差异,优势种为霍甫水丝蚓和正颤蚓.群落年均密度和生物量分别为594.6ind./m~2和0.54g/m~2.双因素方差分析表明,密度和生物量无季节变化,但存在显著的空间差异,两者均是上游中游下游.密度和生物量与水深、透明度显著负相关,前者与水柱混合水样的TN和TP、与底部局部水样的TP显著正相关,后者与水柱混合水样的TP显著正相关.逐步回归分析表明,水深是密度和生物量的唯一最优解释因子,随水深增加密度和生物量均呈指数式下降.

Temporal and spatial distribution of profundal macrozoobenthic community in Lake Qiand-ao,Zhejiang,China

The profundal community of macrozoobenthos in Lake Qiandao,Zhejiang Province,China has been seasonally investigated from January 2007 to October2008.A total of eight taxa were collected,among which 7 taxa belonged to oligochaeta and one to nematoda.Limnodrilus hoffmeisteri and Tubifex tubifex dominated the communities of macrozoobenthos,and type of which showed no seasonal variation.Annual mean density and biomass were 594.6ind./m~2 and 0.54g/m~2,respectively,and they neither display any seasonal variation.However,both differed significandy in horizontal distribution with the maximum at the upper reaches and the minimum at the lower reaches.Density and biomass both negatively significantly correlated with water depth and secchi depth.Density positively correlated with TN and TP of mixed water samples of water column(MWSWC)and with TP of local water samples at bottom(LWSB),respectively,and biomass positively correlated with TP of MWSWC.Only water depth from eight main physical and chemical parameters of LWSB could be accepted finally by the stepwise regression models and usedt o explain the variation of density and biomass,which decreased exponentially with water depth.