Experimental Evaluation of Microbial Biomass and Production in Limnetic Food Webs Dominated by Planktivorous Fish

这项研究将确定微生物生物量和 生产（细菌，直径小于5微米的藻类， 原生动物）对湖沼其余部分的变化作出反应 由食鱼性鱼类构成的食物网。 实验将 在18个大型室外水箱中进行，以比较 三种食腐鱼类（Dorosoma cepedianum，Tilapia aurea和 对微生物和其他成分的影响 湖沼食物网 因为这些鱼有不同的 对浮游动物和浮游植物的选择性， 微生物生物量的显著间接响应， 生产，以及将微生物生产转移到其他 食物网成分。 实验将在不同的 季节比较鱼类对浮游生物群落的影响 代表不同的天气状况。 在每次坦克 实验中，原生动物对细菌和藻类的摄食率， 后生浮游动物对细菌、藻类和 原生动物将通过测量摄入的 原生动物和后生动物放射性同位素标记细菌和藻类 浮游生物 摄食鱼类对原生动物的影响 将在短期喂养试验中进行测量， 每一个坦克实验。 这些实验提供了一个综合的 实验方法来确定的作用， 微生物循环在浮游食物网中。

This research will determine how microbial biomass and production (bacteria, algae less than 5 um in diameter, and protozoa) respond to changes in the remainder of the limnetic food web brought about by planktivorous fish. Experiments will be conducted in 18 large outdoor tanks to compare the effects of three planktivorous fish (Dorosoma cepedianum, Tilapia aurea and Menidia beryllina) on microbial and other components of the limnetic food web. Because these fish have different selectivities on zooplankton and phytoplankton, we expect significant indirect responses of microbial biomass and production, and in the transfer of microbial production to other food web components. Experiments will be conducted in different seasons to compare fish effects on plankton communities representative of different weather regimes. During each tank experiment, grazing rates of protozoa on bacteria and algae, and grazing rates of metazoan zooplankton on bacteria, algae, and protozoawill be determined by measuring ingestion of radioisotope-labelled bacteria and algae by protozoa and metazoan plankton. The grazing impact of planktivorous fish on protozoa will be measured in short-term feeding trials associated with each tank experiment. These experiments provide an integrated experimental approach to the determination of the role of the microbial loop in planktonic food webs.