Collaborative Research: Protistan Abundance, Diversity and Activity in the Deep-Sea and at Hydrothermal Vents

原生生物组合是迄今为止研究过的绝大多数水生生态系统中食物网的重要组成部分。尽管这些生物在海洋生态系统的碳固定、能量利用和元素循环中发挥着关键作用，但关于这些物种在深海，特别是热液喷口及其周围的存在、丰度和活动的信息很少。后一种环境应该特别有利于深海中吞噬原生生物的生长，因为这些地点的生物量大大增加，这些地区的有机碳有效性主要由古细菌和细菌组合介导。本研究项目将研究包括深海热液喷口区在内的深海原生生物的物种多样性、特定分类群的丰度和营养活动等基本问题。具体而言，pi将确定深海群落是否拥有原生生物的特有组合，确定与这些营养活跃环境相关的原生生物的身份，并记录在这些组合中占主导地位的原生生物分类群。他们将研究远离喷口的深海、上盖水柱、热液喷口内及其周围的微环境以及与喷口主要大型动物相关的原生生物组合的多样性。传统的（显微镜）和分子生物学（18S rDNA）方法将用于表征丰度和多样性。观察被荧光标记的猎物的摄食情况将用于原位建立具有营养活性的原生生物。他们还将利用18S rDNA克隆文库、培养和基于显微镜的观察来针对特定的分类群，用于荧光原位杂交（FISH），将形态学特征与常见的（和营养活跃的）种型联系起来。将建立深海原生生物的培养收集，以进一步表征原生生物的多样性，并为实验室的基线生理测量提供标本。生长速度将在实验室中通过在具有深海环境代表性的温度、压力和水化学成分下培养的原生生物来检验。热液喷口研究是一个极好的工具，纳入各级教育，从小学到研究生水平。从这项研究中得到的信息将被纳入pi的本科和研究生课程，并将在Caron实验室主页上展示。该项目支持的pi和博士后研究员将直接参与正在进行的教师教育计划（海洋科学教育卓越中心；coee - west），该计划将面向初高中学生，其中大多数是西班牙裔，非裔美国人或其他少数民族，其中大多数是经济上处于不利地位的学生。这将通过现有的教师增强和学生丰富活动来实现，这些活动将把这项研究纳入学习经验，从而提高学生对环境科学、微生物学和自然世界的认识。这项工作将成为国际知名的“极端2000”中学外展项目的中心特色，在过去的5年里，该项目直接吸引了美国和其他9个国家的18万多名学生。这个项目的贡献将教育各个层次的公众关于深海，以及微生物在形成和维持生物圈中的重要性。

Protistan assemblages are essential components of food webs in the vast majority of aquatic ecosystems that have been examined to date. Despite the pivotal roles that these organisms play in carbon fixation, energy utilization and elemental cycling in marine ecosystems, little information exists on the presence, abundance and activities of these species in the deep ocean in general, and in particular at and around hydrothermal vents. The latter environments should be particularly conducive to the growth of phagotrophic protists in the deep ocean because biomass is greatly elevated at these sites and organic carbon availability in these regions is largely mediated by archaeal and bacterial assemblages. This research project will address fundamental questions regarding the species diversity, abundances of specific taxa, and trophic activities of protists within the deep ocean including hydrothermal vent areas. Specifically, the PIs will determine whether deep-sea communities harbor endemic assemblages of protists, establish the identity of the protists associated with these environments that are trophically active, and document the protistan taxa that dominate these assemblages in situ. They will examine the diversity of the protistan assemblages in the deep-sea away from the vents and in the overlying water column, and in microenvironments in and around hydrothermal vents and associated with dominant macrofauna of vents. Traditional (microscopy) and molecular biological (18S rDNA) approaches will be used to characterize abundance and diversity. Observations of the ingestion of fluorescently labeled prey will be used to establish trophically active protists in situ. They will also employ 18S rDNA clone libraries, cultures and microscopy-based observations to target specific taxa for the application of fluorescent in situ hybridization (FISH) to link morphological identity to commonly occurring (and trophically active) phylotypes. A culture collection of deep-sea protists will be established to further characterize protistan diversity and also to provide specimens for baseline physiological measurements in the laboratory. Growth rates will be examined in the laboratory using cultured protists grown under temperatures, pressures and water chemistries representative of deep-sea environments. Hydrothermal vent research is an excellent vehicle for incorporation into education at all levels ranging from elementary through graduate level. The information resulting from this research will be incorporated into undergraduate and graduate courses by the PIs, and will be featured on the Caron Lab Homepage. The PIs and the postdoctoral investigator supported by this project will participate directly in an ongoing teacher education program (Centers for Ocean Science Education Excellence; COSEE-West) that will reach middle and high school students, most of whom are Hispanic, African-American or other ethnic minorities and most of whom are economically disadvantaged. This will be accomplished through existing teacher enhancement and student enrichment activities that will incorporate this research into a learning experience that will enhance student awareness of environmental science, microbiology and the natural world. This work will be the center feature for the internationally acclaimed Extreme 2000 outreach program for secondary schools which has, over the last 5 years, directly engaged over 180,000 students throughout the US and 9 foreign countries. Contributions from this project will educate the public at every level about the deepsea, and the importance of microbes in forming and maintaining the biosphere.