安宁河浮游动物资源现状及其与环境因子的关系

为了解安宁河浮游动物资源现状,于2015年7月至2016年6月进行了安宁河支流的周年调查,并分别于雨季和旱季增加了安宁河干支流的两次调查。通过调查分析共检出浮游动物3门33属47种,其中以原生动物和轮虫居多,桡足类较少。全年优势种为普通表壳虫(Arcella vulgaris)、无棘匣壳虫(Centropyxis ecornis)、球形砂壳虫(Difflugia globulosa)和长圆砂壳虫(D.oblonga)。安宁河支流浮游动物平均密度和生物量分别为4.704 ind./L和0.002 4 mg/L。浮游动物密度以3月和5月最高,8月最低;生物量以5月最高,1月最低。干流雨季和旱季浮游动物的密度和生物量都显著低于支流。大多数环境因子在不同月份间呈现出显著性差异。本研究表明,安宁河支流浮游动物的丰度呈现明显的周年变化,主要与水深和p H等环境因子相关;雨季和旱季安宁河浮游动物丰度支流明显高于干流,主要与溶氧和水深等环境因子相关。

Zooplankton resource and its relation to the environmental conditions in the Anning River

Zooplankton was collected monthly from July 2015 to June 2016 in the tributaries of Anning River,and complementary surveys of zooplankton in wet and dry seasons were conducted in the main stream and tributaries.Total 47 species of zooplankton were identified,which belonged to 33 genera of 3 phyla.The prevalent organisms were protozoans and rotifers,while copepods were very rare.The dominant species were Arcella vulgaris,Centropyxis ecornis,Difflugia globulosa and Difflugia oblonga all the year.The mean density and biomass of zooplankton in the tributaries of Anning River were 4.704 ind./L and 0.0024 mg/L,respectively.Temporal variability of zooplankton showed that the densities were highest in March and May,lowest in August;while the biomasses were highest in May,lowest in January.Most environmental parameters had significant differences among months.Our results indicated that monthly variations of zooplankton abundance in the tributaries of Anning River were relative to the ecological factors such as water depth and pH.In addition,the zooplankton abundance in the tributaries was significantly higher than those in the main stream both in the wet and dry seasons,which may be relative to the ecological factors such as dissolved oxygen and water depth.