Pickled Protists or Community Uniquely Adapted to Hypersalinity

原生生物是微生物食物网的重要组成部分，在全球生物地球化学循环中发挥着核心作用，因此是维持任何生态系统健康运作的关键参与者。在过去的几年里，在一系列极端环境中发现了丰富多样的原生生物，这表明真核生物的前沿仍在探索中。直到最近，在地中海东部约3500米深处发现了科学上已知的最极端的海洋环境之一，即深超盐缺氧盆地（DHAB）。这些盆地的特点是盐浓度极高（达到饱和），被认为是生命的诅咒。相反，在这些盆地的沃茨中存在着高度多样化的细菌群落。除了一个初步的研究，这一建议，表明在水柱中的原生生物的多样性和活跃的组合沿着盐跃层和盐跃层以下，这些DHAB仍然在很大程度上未被探索的真核生命形式。DHAB的沉积物中根本没有发现原生生物。调查人员将在两个具有不同盐水化学成分的盆地进行短途航行，收集水柱和沉积物样本。一个令人兴奋的组合分子，培养独立和文化为基础的方法将被用来研究班诺克和发现盆地的微生物群落，以及确定海洋原生生物群落的适应战略，高盐，缺氧环境和程度的潜在影响生态地球化学循环作为其捕食活动的结果，在何种程度上占主导地位的原生生物保持细菌或古菌共生体，以及这些共生体的身份采用的方法包括基于18 S rDNA基因的多样性RNA序列分析，群落组成和群落类型丰富度的统计分析，使用经典和微电极方法的水柱和沉积物的地球化学记录，使用mRNA的3 '-UTR片段的表达谱，似乎赋予对高盐度适应的蛋白质的完整基因转录物的测序，蛋白质组签名的分析，FISH-扫描电子显微镜表征新的极端微生物，CARD-FISH识别真核生物的猎物和假定的共生体，TEM评估形态和内生生物在常见的底栖形态类型中的存在。更广泛的影响。高盐环境在极端系统的列表中排名很高，吸引了越来越多的科学界和公众的注意。例如，考虑到我们星球某些地区气温上升和干旱的预测，高盐栖息地的数量可能会急剧增加，导致这个生态系统在全球范围内变得重要。因此，了解这些栖息地的生态系统将有助于预测未来的生态系统功能，由于全球变化。从不同的角度来看，揭示适应高盐度的机制已成为生物科学和与这些适应相关的天然产品的潜在商业开发的主要目标。此外，该项目有各种教育组成部分，从中学到研究生学习，并为中学科学教师和普通公众提供外联机会。例如，该项目将部分资助一名研究生，他们将参加研究航行，以获得第一手海洋学经验，并增加他们对海洋微生物生态学和生理学的知识。该项目的方法和成果将在为世界各地的初中和高中科学教师举办的一个长期举办的年度讲习班上介绍。

Protists are an essential component of microbial food webs and play a central role in global biogeochemical cycles, and thus are key players in sustaining the healthy functioning of any ecosystem. Over the past few years a rich diversity of protists has been revealed in a range of extreme environments, indicating that the frontiers of eukaryotic life are still being explored. Only recently, one of the most extreme marine environments known to science was discovered in the eastern Mediterranean Sea at a depth of ~3500m, namely deep hypersaline anoxic basins (DHABs). These basins are characterized by extremely high salt concentrations (up to saturation) that have been considered anathema to life. Instead, highly diverse communities of bacteria exist in the waters of these basins. With the exception of a preliminary study to this proposal that indicated a diverse and active assemblage of protists in the water column along the halocline and below the halocline, these DHABs remain largely unexplored regarding eukaryotic life forms. The sediments of the DHABs have not been explored for protists at all. The investigators will collect water column and sediment samples on a short cruise to two basins with different brine chemistries. An exciting combination of molecular, cultivation-independent and culture-based approaches will be used to study the microbial communities of Bannock and Discovery Basins as well as determine adaptive strategies of marine protist communities to hypersaline, anoxic environments and the degree of their potential impact on biogeochemical cycling as a result of their predation activities, the degree to which the dominant protists maintain bacterial or archaeal symbionts, and the identity of those symbionts. Methods to be employed include RNA-based sequence analysis of diversity based on 18S rDNA genes, statistical analyses of community composition and phylotype richness, geochemical documentation of the water column and sediments using classical and microelectrode approaches, expression profiling using 3'-UTR fragments of mRNAs, sequencing of complete gene transcripts for proteins appearing to confer adaptation to hypersalinity, analysis of the proteome signatures, FISH-SEM to characterize novel extremophiles, CARD-FISH to identify eukaryote prey and putative symbionts, and TEM to assess morphology and endobiont presence in common benthic morphotypes.Broader Impacts.Hypersaline environments rank highly in the list of extreme systems that have attracted increasing notice in science as well as by the lay public. For example, considering predictions of increasing temperatures and drought in certain regions of our planet, the number of hypersaline habitats may increase dramatically causing this ecosystem to gain importance on a global scale. Thus, an understanding of the ecosystem in these habitats will help predict future ecosystem functioning due to global change. From a different perspective, revealing the mechanisms of adaptation to high salinity has become a major objective, both for biological science and for potential commercial exploitation of natural products associated with those adaptations. Additionally, this project has varied educational components, ranging from middle school to graduate studies, and outreach opportunities for secondary school science teachers and the lay public. For example, this project will partially support one graduate student, who will join the research cruise to gain first-hand oceanographic experience and augment their knowledge of marine microbial ecology and physiology. The methodologies and results of this project will be presented at a well-established annual workshop for middle and secondary science teachers from around the world.