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

深海温泉被称为热液喷口，在原本食物有限的深海中，动物主要依靠细菌共生体获取营养。这些动物在它们的组织内或组织上培养细菌，这些组织利用排气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，但大多数共生的喷口动物在发育过程中的某个时候会从环境池中获得共生体。特别是对于长期分散的海洋动物，它们在定居时可能会遇到新的栖息地条件，长期以来一直认为，在定居后获得局部最优的共生菌菌株可能具有生态和进化优势。为了测试这一想法，PI将评估与基础蜗牛属Alviniccha有关的细菌共生体在西太平洋深海热液喷口的局部适应性。利用种群基因组学方法和高压生理实验，该项目将评估特定于栖息地的共生菌是否在适应不同的栖息地条件方面有所不同。该项目调查了关于深海喷口适应的一个基本假设，并为我们理解阿尔维尼奥查属的生态提供了关键信息，这是一种重要的基础物种，由于深海采矿活动迫在眉睫，已在IUCN红色名单上被评估为“濒危物种”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本开放的、专家撰写的和同行评议的深海生物学数字教科书，该教科书整合了深海媒体，为公众提供了一个重要的资源，并将PI培训为一种资源和开放教育资源的倡导者。尽管它对了解热液喷口生态系统中优势动物的生态具有重要意义，但化学合成共生体的本地适应问题仍然没有得到很好的解决。该项目将使用种群基因组学和类似普通花园的实验来评估与基础蜗牛属Alviniccha有关的细菌共生体在西太平洋深海热液喷口的局部适应性。首先，阿尔维尼康查的高分辨率地球化学调查将与共生体种群基因组学相结合，以调查局部适应的基因组证据。这将允许识别可能在适应当地地球化学方面发挥作用的基因座。其次，将进行高压、普通花园般的实验，以直接评估局部适应的潜力，并调查与观察到的表型相关的潜在共生体基因组特征。最后，西太平洋的Alviniccha共生体种群将以种群基因组学为特征，以确定可能有助于跨多个地理尺度、宿主种群连接性水平和站点间栖息地差异强度的本地共生体适应的基因组特征。该项目由生物海洋学计划、既定的激励竞争研究计划(EPSCoR)、进化过程计划和海洋教育计划联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.