Collaborative Research: Analysis of a Protist Assemblage of the Coastal Ctenophore Mnemiopsis leidyi

本项目重点研究了一组与叶状栉水母相关的表生原生生物的特征、系统发育和功能影响。栉水母是从墨西哥湾沿大西洋海岸延伸到新英格兰的海洋沿海浮游生物群落的主要捕食者。来自四个机构的合作研究小组正在记录该组合的物种多样性，每个组合成员的相对物种丰度，地理范围和传染性。合作实验室拥有当地环境的具体知识和生态学、生命史、细胞生物学、显微镜学和分子生物学方面的科学专业知识，正在对表观微生物与凝胶捕食者的相互作用进行全面研究。在每个收集点，正在测定盐度、温度、溶解氧、叶绿素和浊度，以便将特定的物理因素与组合的发生联系起来。这些信息将决定环境参数对组合（或特定组件）的影响程度；反过来，确定该组合是否可以作为环境质量标志。了解微生物-宿主相互作用的范围对于更全面地了解记忆虫的生物学至关重要。记忆藻通过对浮游动物种群的贪婪捕食改变了群落结构，以至于这种资源仅限于其他捕食者物种（即鱼类）。记忆藻也是一种全球性的入侵生物，它已经证明了其破坏全球沿海社区营养结构的能力，并带来严重的经济后果。密集的原生生物组合可能改变记忆藻的繁殖能力和摄食，并可能在新的环境中转移给新的宿主。因此，了解这一组合的生物学特性、它对宿主的影响以及它侵染其他物种的能力，可以阐明记忆藻入侵新环境的机制和影响。通过分子系统发育技术、传统原生动物学鉴定方法和细胞超微结构数据的结合，获得了该组合的全面概况，以提供每个组成物种的详细信息。正在研究环境中细胞的来源（即是否来自水柱或底栖生物群落），以及个别物种是否正在转移到更高营养水平的捕食者，如较大的胶状掠食性栉水母（例如，Bero）或鱼类。本研究的结果为该群落的组成、地理范围、起源和环境参数提供了一个数据库，并为将该群落建立为未来研究的模型系统奠定了基础，这些研究领域包括细胞-细胞相互作用和水生群落结构维持机制，包括对沿海环境的潜在影响和可能的控制手段。这项研究需要本科生和研究生在每个研究者的位置。私立学院正在吸引男女非裔美国人、西班牙裔、亚裔和美洲原住民学生参加他们的课程。

Project summary This project focuses on the characterization, phylogeny, and functional impact of a specific assemblage of epicommensal protists associated with the lobate ctenophore, Mnemiopsis leidyi, a keystone predator of marine coastal planktonic communities extending from the Gulf of Mexico along the Atlantic Coast to New England. The species diversity, relative species abundance of each member of the assemblage, geographic range and infectivity of this assemblage is being documented by a team of collaborating researchers from four institutions. The collaborative laboratories have the specific knowledge of each of the local environments and the scientific expertise in ecology, life history, cell biology, microscopy and molecular biology and are making a comprehensive study of epibiotic microbial interactions with a gelatinous predator. Salinity, temperature, dissolved oxygen, chlorophyll and turbidity are being determined at each collection site in order to correlate specific physical factors with the occurrence of the assemblage. This information will determine to what degree the assemblage (or specific components) is affected by environmental parameters; and conversely, to establish whether this assemblage can be used as an environmental quality marker. Understanding the range of the microbe-host interaction is critical to a more complete understanding of the biology of Mnemiopsis. Mnemiopsis alters community structure through voracious predation on zooplankton populations to the point where this resource becomes limiting to other predator species (i.e., fish). Mnemiopsis is also a globally invasive organism that has demonstrated its capacity to disrupt the trophic structure of coastal communities worldwide, with severe economic consequences. Dense protist assemblages may alter reproductive capacity and feeding in Mnemiopsis, and could be transferred to new hosts in new environments. As such, understanding the biology of this assemblage, its impact on the host, and its capacity to infest alternate species, could illuminate the mechanisms and effects of Mnemiopsis invasion into a new environment. Comprehensive profiles of the assemblage are being obtained by a combination of molecular phylogenetic techniques, conventional protozoological identification methods and cellular ultrastructural data to provide detailed information about each component species. The source of the cells within the environment (i.e. whether derived from the water column or benthic communities) is being studied and whether individual species is being transferred to higher trophic level predators such as larger gelatinous predatory ctenophores (e.g., Bero) or fish. Results of this study are providing a database of the composition, geographic range, origin and environmental parameters of this assemblage and is forming the basis for establishing this assemblage as a model system for future studies in areas as widely diverse as cell-cell interactions and mechanisms of maintenance of aquatic community structure, including potential for effects on the coastal environment and possible means of control. This study is requiring undergraduate and graduate students at each investigator's location. The PIs are attracting female and male African-American, Hispanic, Asian and Native American students to their programs.