Parasitic Dinoflagellates of Marine Ciliates: Their Significance in Microbial Food Webs

纤毛虫是浮游生物群落的重要组成部分，在海洋微生物食物网中起着举足轻重的作用。纤毛虫作为浮游植物和浮游细菌的消费者的重要性已经得到了很好的研究，现在已经被普遍接受。大型浮游动物通常被视为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影响。最近对切萨皮克湾寄生的杜氏杜氏鞭毛虫及其寄主果胶原虫的研究表明，在果胶原虫密度足够高的沿海环境中，寄生对寄主丰度有显著影响。寄生是否对其他河口物种或寄主密度低得多的开阔海域的纤毛虫有很大影响尚不确定。将通过结合实地研究来评估寄生对切萨皮克湾纤毛虫原生浮游动物命运的重要性，以确定宿主-寄生虫的丰度、物种组成、寄生虫生活史和世代时间。

Ciliated protozoa are widely recognized as an important component of planktonic communities and are believed to play a pivotal role in marine microbial food webs. The importance of ciliates as consumers of phytoplankton and, to a lesser extent, bacterioplankton has been well studied and is now generally accepted. Larger zooplankton are usually viewed as the predominant consumers of ciliates, yet there is little evidence that grazing by metazoa has a substantial impact on ciliate populations. Recent studies of the parastiic dinoflagellate Duboscquella cachoni and its tintinnine host Eutintinnus pectinis in Chesapeake Bay indicate that parasitism can have a significant impact on host abundance in coastal environments where E. pectinis densities are sufficiently high to support epizootic infections. Whether parasitism has a strong influence on other estuarine species or on ciliates in the open ocean where host densities are considerably lower is uncertain. The importance of parasitism to the fate of the ciliate protozooplankton in Chesapeake Bay will be evaluated through a combination of field studies to determine host-parasite abundance, species composition, parasite life histories and generation times.