Response of Plankton Biomass Across Gradients of Fish Density and Lake Trophic State: Experimental Test of the Fish X Lake Trophic State Interaction Hypothesis

生态学家假设，浮游生物对浮游生物群落的调节随着湖泊营养状态的不同而不同，这表明鱼类效应和湖泊营养状态对浮游生物群落的影响之间存在交互作用。鱼与湖泊营养状态的相互作用效应是不能通过独立于湖泊营养状态影响来考虑鱼的影响来预测的。到目前为止，还没有对这种鱼类与湖泊营养状态相互作用的假说进行测试。在拟议的研究中，主要包括两个部分：(1)利用室外水箱实验检验鱼类与湖泊营养状态相互作用假说，以考察五种不同密度的浮游动物--蓝鳃对微浮游生物、微型浮游生物、微型浮游生物、中游浮游生物的生物量和物种组成的影响。主要研究内容包括：(1)从代表西南水库营养状态范围的六个湖泊群落中提取浮游生物和大型浮游生物；(2)建立预测不同鱼类密度和湖泊营养状态梯度的微浮游生物、微型浮游生物、微型浮游生物、中大型浮游生物生物量的回归模型。这项研究将提供第一个观点，即不同密度的鱼对浮游生物生物量的影响如何随着湖泊营养状态的变化而变化。

Ecologists have hypothesized that regulation of plankton communities by planktivores varies with lake trophic state, suggesting that an interaction effect exists between fish effects and lake trophic state effects on plankton communities. A fish x lake trophic state interaction effect is one that cannot be predicted by considering fish effects independently of lake trophic state effects. To date, there have been no tests of this fish x lake trophic state interaction hypothesis. In the proposed study, there are two principle parts: (1) a test of the fish x lake trophic state interaction hypothesis using outdoor tank experiments to examine the effects of five different densities of a planktivore, bluegill (Lepomis macrochirus), on the biomass and species composition of picoplankton, nanoplankton, microplankton, mesoplankton, and macroplankton from six lake communities representing the range of trophic states of southwestern reservoirs, and (2) the development of regression models for predicting biomass of picoplankton, nanoplankton, microplankton, mesoplankton, and macroplankton across gradients of fish density and lake trophic state. The study will provide the first view of how the impacts of different densities of fish on plankton biomass change with lake trophic state.