The Importance of Inter-species Predation among Marine Ciliate Protozooplankton

点击翻译按钮获取中文摘要

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.