Microbial Food Webs of Marine Intertidal Communities: Trophic Interactions and Grazing Rates

这项研究项目将研究底栖微生物食物网中的营养关系。其目的是：(1)估计潮间带群落中底栖纳米鞭毛虫、纤毛虫、线虫、肋足类和其他生物的活动性和食草性；(2)比较几种不同类型的潮间带微生物群落在裸露沙质、受保护的沙质和泥质海滩上的营养结构；(3)研究底栖微生物群落营养结构在季节演替过程中的变化。这些目标将通过田间放牧实验进行，使用荧光标记的细菌和硅藻作为食物示踪剂。这种方法以前曾被用来研究浮游原生动物的放牧，这里将适用于研究底栖后生动物。这一新颖的实验设计的一部分已经在现场进行了测试。这种实验设计的优点是它允许同时测量微型底栖动物的活动和小型底栖动物的草食性。需要这些数据来分析底栖动物群落中的能量流动，评估放牧在控制细菌和藻类生产方面的作用，并检查原生动物和小型动物之间的食物竞争。这项研究将描述一个独特的数据集，这是目前任何海底群落都无法获得的。

This research project will study trophic relations in benthic microbial food webs. The objectives are: (1) to estimate the rates of bactivory and herbivory of benthic nanoflagellates, ciliates, nematodes, copepods, and other organisms in tidal-flat communities; (2) to compare the trophic structures of several distinct types of intertidal microbial communities inhabiting exposed sandy, protected sandy and muddy beaches; and (3) to examine changes in the trophic structure of the benthic microbial community in course of seasonal succession. These objectives will be conducted through field grazing experiments using fluorescent-labeled bacteria and diatoms as food tracers. This approach has been used previously to study planktonic protozoan grazing and it will be adapted here for studying benthic metazoans. A part of this novel experimental design has been already tested in the field. The advantage of this experimental design is that it allows simultaneous measurements of microbenthic bactivory and meiobenthic herbivory. These data are needed to analyze the energy flow through benthic communities, to evaluate the role of grazing in controlling bacterial and algal production and to examine food competition among protozoans and meiofauna. This research will describe a unique data set that is currently unavailable for any benthic community.