CAREER: Assessing local adaptation in the chemosynthetic symbionts of hydrothermal vent animals

深海温泉被称为热液喷口，在食物有限的深海中，由专门依赖细菌共生体获取营养的动物主导。这些动物在其组织内或组织上饲养细菌，这些细菌利用排出液体中的化学能作为能量来制造糖，这一过程被称为化学合成。虽然它们需要共生体才能生存，但大多数共生喷口动物在其发育的某个阶段从环境池中获得共生体。特别是对于长期分散的海洋动物，在定居时可能会遇到新的栖息地条件，长期以来人们一直假设在定居后获得局部最优的共生体菌株可能具有生态和进化优势。为了验证这一想法，PI将评估与西太平洋深海热液喷口的基础蜗牛属Alviniconcha相关的细菌共生体的局部适应性。本项目将利用种群基因组学方法和高压生理实验，评估生境特异性共生体菌株对不同生境条件的适应是否存在差异。该项目调查了一个关于深海喷口适应的基本假设，并为我们了解Alviniconcha的生态提供了关键信息。Alviniconcha是一种重要的基础物种，由于迫在眉睫的深海采矿活动，已被国际自然保护联盟（IUCN）列为“濒危”或“脆弱”物种。除了支持本科生和研究生参与研究外，该项目还包括创建一个开放的，专家撰写和同行评审的深海生物学数字教科书，该教科书整合了深海媒体，为公众提供重要的资源，以及培训PI作为开放教育资源的资源和倡导者。尽管这对了解热液喷口生态系统优势动物群的生态学具有重要意义，但对化学合成共生体的局部适应仍然知之甚少。该项目将使用种群基因组学和普通花园式实验来评估与西太平洋深海热液喷口的基础蜗牛属Alviniconcha相关的细菌共生体的局部适应性。首先，Alviniconcha的高分辨率地球化学调查将与共生种群基因组学相结合，以调查当地适应的基因组证据。这将使鉴定可能在适应当地地球化学方面发挥作用的位点成为可能。其次，将进行高压、普通花园式的实验，直接评估当地适应的潜力，并研究与观察到的表型相关的潜在共生基因组特征。最后，将利用种群基因组学对西太平洋地区的Alviniconcha共生体种群进行表征，以确定可能有助于当地共生体适应多个地理尺度、宿主种群连通性水平和点对点栖息地差异强度的基因组特征。该项目由生物海洋学计划、促进竞争性研究的既定计划（EPSCoR）、进化过程计划和海洋教育计划共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Deep-sea hot springs, called hydrothermal vents, are dominated by animals that obligately rely on bacterial symbionts for nutrition in the otherwise food-limited deep-sea. These animals farm bacteria in or on their tissues that use the chemical energy in venting fluid as energy to make sugar, in a process known as chemosynthesis. Though they require their symbionts for survival, most symbiotic vent animals acquire their symbionts from an environmental pool at some point in their development. Especially for long-dispersing marine animals that are likely to encounter new habitat conditions when they settle, it has long been hypothesized that acquisition of a locally optimal symbiont strain after settlement may have ecological and evolutionary advantages. To test this idea, the PI will evaluate local adaptation in the bacterial symbionts associated with a foundation snail genus, Alviniconcha, at deep-sea hydrothermal vents in the western Pacific. Using population genomics methods and high-pressure physiological experiments, this project will assess whether habitat-specific symbiont strains differ in their adaptation to different habitat conditions. The project investigates a fundamental hypothesis regarding adaptation at deep-sea vents, as well as provides key information in our understanding of the ecology of Alviniconcha, a genus of important foundation species that has been assessed as “Endangered” or “Vulnerable” on the IUCN Red List due to looming deep-sea mining activity. In addition to supporting undergraduates and graduate students to participate in research, this project includes the creation of an open, expert-authored and peer-reviewed Deep-Sea Biology digital textbook that integrates deep-sea media, providing a vital resource for public use, as well as training the PI as a resource and advocate for open educational resources.Despite its significance for understanding the ecology of the dominant fauna at hydrothermal vent ecosystems, local adaptation in chemosynthetic symbionts is still poorly addressed. This project will use population genomics and common-garden-like experiments to assess local adaptation in the bacterial symbionts associated with a foundation snail genus, Alviniconcha, at deep-sea hydrothermal vents in the western Pacific. First, high-resolution geochemical surveys of Alviniconcha will be coupled with symbiont population genomics to investigate genomic evidence for local adaptation. This will allow for the identification of loci that may play a role in adaptation to local geochemistry. Second, high-pressure, common-garden-like experiments will be performed to directly assess the potential for local adaptation and investigate underlying symbiont genomic traits associated with observed phenotypes. Finally, Alviniconcha symbiont populations across the western Pacific will be characterized with population genomics to identify the genomic traits potentially contributing to local symbiont adaptation across multiple geographical scales, levels of host population connectivity, and intensities of site-to-site habitat differences.This project is jointly funded by the Biological Oceanography Program, the Established Program to Stimulate Competitive Research (EPSCoR), the Evolutionary Processes Program, and the Ocean Education Program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.