新疆博斯腾湖轮虫群落季节动态及其影响因子

Rotifer Seasonal Dynamics and Driving Factors in Bosten Lake,Xinjiang

为探索内陆干旱区湖泊轮虫群落的季节变化与环境因子的关系,对博斯腾湖17个站位的轮虫及其主要环境因子进行了4次采样调查,探究其群落结构特征及其演替规律,并利用典范对应分析研究了博斯腾湖轮虫物种和多样性对环境变量的响应,为博斯腾湖水环境评价与保护、渔业资源合理利用及可持续发展提供背景资料。结果表明:(1)调查期间共鉴定轮虫41种(属),各季节优势种类共8种。夏季优势种类主要为胶鞘轮虫(Collotheca sp.)和针簇多肢轮虫(Polyarthra trigla),低温期的优势种群为矩形龟甲轮虫(Keratella cochlearis);(2)博斯腾湖轮虫密度为0.2~174.0个/L,总平均密度为25.5个/L,生长繁盛期主要出现在春、夏季且受工农业等人为影响较多的浅水区,秋、冬季密度显著降低;(3)水体综合营养指数(TLI)的波动(31.15~46.28)对博斯腾湖轮虫密度的影响不大;(4)水温是影响轮虫群落最重要的环境因子,水温升高、轮虫多样性增加。轮虫种类分布对p H变量的响应较敏感,p H较高时,壶状臂尾轮虫(Brachionus urceus)形成优势,p H较低时,裂痕龟纹轮虫(Anuraeopsis fissa)和长三肢轮虫(Filinia longiseta)形成优势。随着总有机碳预测值的增加,轮虫群落多样性呈增加趋势。

Bosten Lake is the largest lake in the arid and semiarid region of China and plays a crucial role in the e- cosystem of southern Xinjiang. Rotifers and environmental factors in Bosten Lake were investigated to explore the relationship between seasonal variation of the rotifer community and determinants from the inland arid zone. Rotifer community structure and succession dynamics were characterized and the effects of environmental variables on roti- fer distribution and diversity index were explored using canonical correlation analysis. The objectives were to pro- vide a reference for water quality evaluation and protection, and support the sustainable development of fishery re- sources in Bosten Lake. In May, August and October, 2010 and January, 2011, a field investigation was carried out across a network of 17 sampling stations that covered the lake. Water samples collected from the different water layers of each sampling station were collected for quantitative analysis of rotifers, phytoplankton, protozoa, cladoc- erans and copepoda. Rotifer samples were collected using a No. 25 plankton net with mesh size of 64 m. Physio- chemical parameters of the water body were measured in situ and samples were collected for laboratory analysis. A total of 41 rotifer species from 25 genera, representing 15 families were identified with eight dominant species ob- served through the four seasons. The most dominant species were found in summer, including Collotheca sp. , Filinia longiseta, Pedalia mira and Polyarthra trigla, but only one dominant species （Keratella quadrata） occurred at low temperature in winter, while the dominant species was observed at all the sampling stations, displaying no spatial difference with season. Rotifer densities in Bosten Lake varied from 0.2 ind/L to 174.0 ind/L, with the av- erage value of 25.5 ind/L, displaying significant temporal-spatial variations. The thriving stages of rotifers were in spring and summer and in shallow water area where the influence of anthropogenic activities is great. Rotifer densi- ties decreased sharply during autumn and winter. The study indicates that the fluctuation of nutrition levels （31.15 -46.28） had little effects on rotifer densities. Water temperature was the most important ecological factor influen- cing rotifer community, and the rotifer diversity index increased with the increase of water temperature. Rotifer spe- cies were sensitive to pH. Brachionus urceus dominated the community at higher pH condition, and Anuraeopsis fis- sa and Filinia lingiseta were the dominant species at lower pH condition. Additionally, the species richness of roti- fers was also significantly related to the total organic carbon（ P 〈 0.05 ）, and the diversity index increased as the to- tal organic carbon increased.