大型浅水湖泊太湖中微型浮游动物的摄食生态研究

Grazing Ecology of Microzooplankton in the Large-scale Shallow Lake of Taihu

探讨大型浅水湖泊太湖中草型与藻型两种生态系统中微型浮游动物的摄食差异,对东太湖与西太湖6个站位进行现场试验和调查,运用稀释-流式细胞仪法研究了微型浮游动物对细菌的摄食压力。结果表明,太湖水体20μm以下的微型浮游动物对细菌日摄食量为0.61~3.05μg（L.d）-1,对细菌生产力的摄食压力为79.62%~100.48%,平均90.99%。微型浮游动物对细菌的摄食率基本呈现一个由藻型湖到草型湖逐渐递减的趋势,细菌增长率在藻型湖焦山区域最大,进一步分析发现,细菌增长率与总N有显著正相关（r=0.864,P〈0.05）,由此可见,细菌的生长繁殖和微型浮游动物对细菌的摄食与湖泊营养负荷有一定的相关性。

Ship - board dilution incubation experiments were carried out at 6 stations in surface waters of TaihuLake, to investigate the impact of microzooplankton grazing upon heterotrophic bacteria production. The resultsshowed that microzooplankton grazing rate upon heterotrophie bacteria with its size less than 20/xm was 0.61 -3.051xg（L. d） -1, and the microzooplankton grazing pressure on bacterial productivity was 79.62% x 100.48%.Microplankton feeding rate on heterotrophie bacteria has a trend descending gradually from the algae -type zoneto the grass - type zone. Bacterial growth rate reached the maximum in the algae - type zone of Jiaoshan. Furtheranalysis demonstrated that bacterial growth rate was positively correlated with the total N （ r = 0. 864, P 〈 0.05 ）. These results indicated that small - celled microzooplankton was ubiquitous and played more important rolein energy transmission and nutrients regeneration in Taihu Lake.