The Importance of Inter-species Predation among Marine Ciliate Protozooplankton

纤毛虫捕食其他纤毛虫在原生浮游动物成员中是常见的，并且可能是次要生产转移的重要途径。本研究将结合实验室实验、野外种群操作、原生浮游动物纤毛虫丰度、物种组成和饮食习惯调查等方法，研究物种间纤毛虫捕食对切萨皮克湾的影响。认为：1)跨栖捕食者是海洋原生浮游动物群落中具有一致性和局域丰富性的组成部分；2)大量的细菌和草食纤毛虫次生产物被纤毛虫捕食所消耗；3)种间纤毛虫捕食者的放牧和生长速度足以利用和潜在地控制局部密集的猎物种群。纤毛原生动物在海洋原生浮游动物中的丰富和广泛存在表明它们在海洋浮游食物网中起着关键作用。纤毛虫作为浮游植物的消耗者，以及在较小程度上作为浮游细菌的消耗者，其重要性已经得到了充分的研究，并且现在已被普遍接受。虽然大型浮游动物被认为是纤毛虫的主要消费者，但几乎没有证据表明后生动物的放牧对纤毛虫种群有实质性的影响。因此，纤毛虫二次生产的命运仍然存在不确定性。科茨设计了一系列的猎物转换实验，以检验某些种类的纤毛虫自己消耗了大部分这种二次生产的假设。近年来，海洋中许多植物-动物的相互作用都是由这些微生物的活动主导的，这一新颖的工作将阐明海洋食物网中跨种群捕食的作用。

Ciliate predation on other ciliates is common among members of the protozooplankton and may be a significant pathway through which secondary production is transferred. The impact of inter- species ciliate predation in Chesapeake Bay will be studied through a combination of laboratory experiments, manipulations of field populations, and surveys of ciliate protozooplankton abundance, species composition, and dietary habits. It is proposed that: 1) inter-ciliate predators are a consistent and locally abundant component of the marine protozooplankton community; 2) a significant amount of secondary production by bacterivorous and herbivorous ciliates is consumed by ciliate predation; 3) grazing and growth rates of inter-species ciliate predators are sufficient to exploit and potentially control locally dense prey populations. The abundance and widespread occurrence of ciliated protozoa among the marine protozooplankton suggest that they play a pivotal role in the planktonic food web of the ocean. The importance of ciliates as consumers of phytoplankton and, to a lesser extent, bacterioplankton has been well studied and is now generally accepted. While large zooplankton have been viewed as the predominant consumers of ciliates, there is little evidence indicating that grazing by metazoa has a substantial impact on ciliate populations. Therefore, uncertainty still exists as to the fate of secondary production by ciliates. Coats has designed a series of prey switching experiments to examine the hypothesis that certain species of the ciliates themselves consume much of this secondary production. It has recently become apparent that much of the plant - animal interactions in the sea are dominated by the activities of such microbial organisms and this novel work will clarify the role of inter - ciliate predation in marine food webs.