There are only 21 species of benthonic animals in the Nanhu Lake,Changchun.The dominant species in the benthos community are obvious,and the individual quantity of Limnodrilus hoffmeisteri,Branchiura sowerbyi,and Tendipus plumosus accounts for 87% of the total individual quantity of all benthonic animals.It indicates that the water in the Nanhu Lake is suffering serious organic pollution,and belongs to an eutrophic lake.The peak values of benthos biomass and energy are found in July(48 23gWW·m -2 and 241 16kJ·m -2 respectively),while the maximum individual quantity is appeared in May(401ind·m -2 ).The distribution of Oligochaeta and aquatic insects has a significant positive correlation to organic content in the sediment(α<0 05).The community structure of benthonic animals reflects adequately the feature of the Nanhu Lake as an eutrophic lake in temperate zone.
