纤毛虫是大洋微食物网的重要贡献者，是探讨微型生物地理分布的模式类群。由于研究不足，对深海大洋中的纤毛虫多样性和分布模式的认知仍需完善，申请人前期研究发现存在如下主要科学问题：表层海水中纤毛虫的水平分布模式是否异于其他主要原生生物类群而不存在距离-衰减关系，中深层和深层海水中纤毛虫的水平分布是否与表层类似？各个水层间纤毛虫群落的关联水平及200米环境过渡层是否为深层的物种库？本项目拟选择热带西北太平洋这一影响我国近海生态系统的深海关键区，采用第二代和第三代高通量测序技术结合形态学方法，基于形态和分子数据的相互校正，从水平和垂直二维尺度上解析纤毛虫的多样性分布特征，明晰纤毛虫在不同水层中的水平分布模式和各水层间群落的联系，阐释地理距离、水深、化学和生物参数等对其分布的影响。本项目将基于优化的研究体系，解答上述科学问题，为未来研究提供可靠的技术体系，并为深海微型生物地理分布提供新的认知。

Ciliates play a variety of critical roles in deep-sea microbial food web and have been used as model organisms for the investigation of microbial diversity and distribution. However, due to the lack of research, the knowledge on the diversity and distribution pattern of pelagic ciliates in the deep sea is scarce. Based on our previous research, we find the following scientific questions: Is that ciliate distribution in the surface water is different from other main protozoa groups in the open ocean and has no significant distance-decay relationship real or artifact? Is the distribution of pelagic ciliates from the same water layer in the aphotic zone similar to that of ciliates in surface samples? What is the relationship among ciliate communities from each water layer? Is the 200m layer an important “species bank” for deep ocean layers? To answer these questions, we will investigate the diversity of pelagic ciliates and their horizontal and vertical distribution in the tropical Northwest Pacific Ocean, by using a combination of the second and third generation high-throughput DNA sequencing and the morphological method after the procedures of calibrating and improving each other. The distribution patterns and links of ciliate communities at different water layers will be investigated. Moreover, the effects of geographic distance, water depth, and chemical and biological factors on the ciliate distribution will be estimated. The project will answer the above questions by an improved methodology, provide a reliable protocol for further study and offer insights into the mechanisms of microbial geographical distribution in the deep sea.