Award: OCE-1819530

This award supported a series of interlinked studies that significantly increased our understanding of the ecological processes structuring hydrothermal vent ecosystems in general, and those of the Western Pacific in particular. State-of-the-art equipment and analyses were used to characterize the physico-chemical environment and conduct shipboard high-pressure physiological experiments with live organisms. Together, these experiments provide constraints on the extent to which hydrothermal vent symbioses affect geochemical flux from diffuse flows. Coupled genetic and gene expression analyses have elucidated how vent geochemistry can structure the distribution of vent taxa, as well as how environmental conditions impact the physiology of vent symbioses. In particular, we demonstrated that the predominant animal-bacterial symbioses at western Pacific hydrothermal vents, a complex of closely related snail species, can utilize both sulfur and hydrogen as an energy source. In addition, these experiments have provided critical information about how animal hosts interact with their bacterial symbionts. Given that undustrial mining of polymetallic sulfide deposits at active hydrothermal vents is imminent in the Western Pacific, this work provided crucial information on the fauna and communities endemic to this region that is critical for predicting and mitigating the effects of mining activities on these ecosystems, and for informing plans for monitoring and recovery. During our expedition, we conducted a number of presentations about these ecosystems and our research to students and the general public, both to South Pacific islanders and to a global audience via telepresence technology. Ultimately, this effort provided critical and robust data on the dynamics of vent fields and communities in the western Pacific biogeographic province, as well as on the underlying physiological and ecological factors governing these patterns. Last Modified: 12/07/2018 Submitted by: Roxanne Beinart