Collaborative Research: Diversity and Biogeography of Marine Oligotrich and Choreotrich Ciliates Assessed by Morphological and Molecular Markers

海洋微型浮游动物的组合往往占主导地位的寡毛类和choretrich纤毛虫。 纤毛虫群落是多样的和动态的，在短时间尺度上的丰度和物种组成的快速变化。 了解纤毛虫群落的多样性的性质和影响是至关重要的，如果我们要外推的测量（如放牧，生长）与一个纤毛虫群落或文化中的几个物种获得区域或全球模型的食物网。 此外，在空间和时间尺度上的种间和种内遗传变异的程度是未知的这些纤毛虫。 最后，仅形态标记的分析已经产生了相当大的争论，研究人员认为，所有纤毛虫是世界性的与那些谁认为，有有限的基因流动之间的地理隔离的纤毛虫种群。 解决所有这些问题的一个关键是量化群体内和群体间分子标记和形态学之间的对应关系。 然而，目前，这些生态上重要的群体的分子数据很少。 本项目结合分子和形态学方法来阐明海洋纤毛虫的Choreotrichia和Oligotrichia（Cl：Spirotrichea）亚类的多样性。这一大群浮游食草动物包括浮游植物和细菌生产和更高的消费者之间的重要营养环节。 这项研究的主要重点是收集来自自然种群的舞毛和寡毛的DNA序列数据，并将这些序列与传统方法确定的形态种相关联。 将对从自然群落中精心挑选的细胞采用一系列技术，以评估从几米到几千公里范围内的多样性，并对新英格兰南部海岸和联合王国西部海岸的沿着纤毛虫进行密集采样。 种内遗传变异性也将被量化为短时间和空间尺度上种群内的变化。 这项研究有两个目标：1）使用形态学和分子标记对从近岸环境中取样的海洋寡毛类和舞毛类物种的一个子集内的多样性进行量化，以及2）评估寡毛类和舞毛类纤毛虫的一些丰富物种在短的空间和时间尺度上的种内变异模式。 对于这两个目标，将挑选单个细胞进行遗传分析，并保存用于种属鉴定。 对于目标一，小亚基核糖体基因序列进行比较。 对于第二个目标，将分析更多的可变标记，包括核糖体基因的内部转录间隔区（ITS1和ITS2）和组蛋白H3和H4之间的插入序列（H3H4IS）。 结合分子和形态学的方法，这项研究将产生全面的数据，种群的遗传多样性的寡毛和choreotrichs。 这些数据是将跨时间和空间采样的单个物种丰度信息与整个纤毛虫群落联系起来的重要第一步。此外，这项工作将首次利用海洋纤毛虫特有性的分子数据进行测试，并将对研究生进行相关形态学和分子技术方面的培训。 由此产生的数据将对全球原生生物多样性和生物地理学问题产生更广泛的影响，并将有必要充分探讨纤毛虫在海洋系统中的能量流动和营养循环中的作用。

Microzooplankton assemblages in the sea are often dominated by oligotrich and choretrich ciliates. Ciliate communities are diverse and dynamic, with rapid changes in abundance and species composition over short time scales. Understanding the nature and implications of diversity in ciliate communities is critical if we are to extrapolate measurements (e.g. grazing, growth) obtained with one ciliate community or a few species in culture to regional or global models of food webs. In addition, the degree of inter- and intraspecific genetic variability across spatial and temporal scales is unknown for these ciliates. Finally, analysis of morphological markers alone has generated considerable debate between researchers who argue that all ciliates are cosmopolitan versus those who believe that there is limited gene flow between geographically isolated ciliate populations. One key to addressing all of these issues is to quantify the correspondence between molecular markers and morphology within and between populations. At present, however, molecular data are sparse for these ecologically important groups. This project combines molecular and morphological methods to elucidate the diversity of marine ciliates in the subclasses Choreotrichia and Oligotrichia (Cl: Spirotrichea). This large group of planktonic grazers comprises an important trophic link between phytoplankton and bacterial production and higher consumers. The main focus of the study is to collect DNA sequence data from natural populations of choreotrichs and oligotrichs, and to relate these sequences to morphospecies determined by traditional methods. A combination of techniques will be applied to handpicked cells from natural assemblages to evaluate diversity across a range of scales from meters to thousands of kilometers, with intensive sampling of ciliates along the southern coast of New England and the western coast of the United Kingdom. Intraspecific genetic variability will also be quantified as changes within populations over short temporal and spatial scales. The study has two objectives: 1) to quantify diversity within a subset of marine oligotrich and choreotrich species sampled from nearshore environments using both morphology and molecular markers, and 2) to assess patterns of intraspecific variation on short spatial and temporal scales in a few abundant species of oligotrich and choreotrich ciliates. For both objectives, individual cells will be picked for genetic analysis and preserved for species identification. For objective one, small subunit ribosomal gene sequences will be compared. For the second objective, more variable markers will be analyzed, including the internally transcribed spacer regions (ITS1 and ITS2) of the ribosomal genes and an intervening sequence between histones H3 and H4 (H3H4IS). Combining molecular and morphological approaches, this study will produce comprehensive data on genetic diversity of populations of oligotrichs and choreotrichs. These data are an essential first step for connecting information on individual species abundances sampled across time and space to whole communities of ciliates. In addition, this work will provide the first test using molecular data on marine ciliate endemism and will train graduate students in relevant morphological and molecular techniques. The resulting data will have broader implications for questions regarding global protist diversity and biogeography and will be necessary to fully explore the role of ciliates in energy flow and nutrient cycling in marine systems.