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

NSF Award Abstract:

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.