[Macrozoobenthos community structure and water quality evaluation of Tian'e Zhou Oxbows].

ABSTRACT

A quarterly investigation of the macrozoobenthos community in Tian'e Zhou Yangtze Oxbows was conducted during January 2011 to October 2011. And water quality was assessed based on the benthic macroinvertebrate community structure. It shows that, a total of 30 macrozoobenthos species were found, among which, Insecta (14 species) , Mollusca (6 species), Oligochaeta (8 species) and others (2 species) accounted for 46.67%, 20.00%, 26.67%, and 6.67% of the total, respectively. The dominant species were Clinotanypus, Cryptochironomus digitatus, Limnodrilus claparedeianus, and Limnodrilus hoffmeisteri. The average annual density and biomass of macrozoobenthos were 558.37 ind · m(-2), and 14.03 g · m(-2), respectively. The density of macrozoobenthos was highest in the winter and lowest in the spring, the biomass was highest in the autumn and lowest in the spring. In ten sampling points, No. 8 had the highest density, 1986.00 ind · m(-2), No. 7 had the highest biomass, 50.22 g · m(-2), and No. 6 had the lowest density and biomass, 98.00 ind · m(-2) and 0.85 g · m(-2). The evaluation with Shannon-Wiener diversity index (H'), Margalef richness index (d), Family-level biotic index (FBI), and integrated pollution index (BI) indicated that the overall water quality of the Tian'e Zhou Oxbow was moderate-heavy pollution (III-IV). As compared to that in 2003-2004 (II), the water quality of Tian'e Zhou Oxbow was somewhat decreased.