Seasonal Pattern of Planktonic Ciliates in a Subtropical Shallow Urban Lake

In order to realize the ecological specialty of man-made lake located in urban area in South China, species composition, dominant species dynamics and other parameters of ciliate community were investigated with the qualitative and quantitative observations from April of 2009 to March of 2010, in Dongshan Lake, a subtropical shallow urban lake in South China. The relationship between the parameters of ciliate community and aquatic environment was analyzed by using statistics method. The highest abundance of ciliates was 164.7×10 ind/L and the largest biomass of ciliates was 11.23 mg/L. Among the 111 species of ciliates, Urotricha spp. (U. agilis, U. armata, U. farcta, U. furcata, U. globosa, U. ovata and U. saprophila), Halteria grandinella, Cinetochilium margaritaceum, Strobilidium caudatum and Cyclidium spp (C. citrullus, C. elongatum, C. glaucoma and C. simulans) contributed more to total ciliate abundance, meanwhile Holophrya discolor, Didinium nasutum, H. grandinella, R. caudatum, Coleps hirtus and Monodinium balbianii made more contributions on biomass. ShannonWiener biodiversity index of the ciliate communities was from 2.1 to 3.2 during the investigation. The patterns of abundance temporal distribution on major planktonic ciliates could be divided into 3 groups. The first one presented typical monomodal composed by Coleps hirtus and Cinetochilium margaritaceum; the second was trimodal type, including Halteria grandinella, Urotricha spp. and Cyclidium spp.; the last type had no significant peaks during the investigation. Based upon the data from ciliate abundance and biomass and take the hydrochemical parameters into consideration the lake were hypereutrophic. The results from both parametric and non-parametric analysis showed that there was no relationship between the abundance and other biotic or abiotic factors and biomass of ciliate was no relevant with. other biotic or abiotic factors as well.