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

纤毛虫是海洋微生物群落的重要组成部分，在海洋微生物食物网中发挥着重要作用。纤毛虫作为浮游植物的消费者，以及在较小程度上作为浮游细菌的消费者的重要性已经得到了很好的研究，并且现在被普遍接受。大型浮游动物通常被视为纤毛虫的主要消费者，但很少有证据表明，后生动物的放牧对纤毛虫种群有实质性的影响。最近对切萨皮克湾的寄生甲藻Duboscquella cachoni及其锡盐寄主Eutintinnus pectinis的研究表明，在沿海环境中，寄生可以对寄主丰度产生重大影响，其中E.果胶密度足够高以支持动物流行病感染。寄生是否有一个强大的影响，其他河口物种或纤毛虫在开放的海洋，主机密度相当低是不确定的。寄生的命运的纤毛虫原生浮游动物在切萨皮克湾的重要性将通过结合实地研究，以确定主机寄生虫丰度，物种组成，寄生虫的生活史和世代时间进行评估。

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.