Award: OCE-1829773

The main research goal of this project was to understand the effects of disturbance and recolonization on resilience of hydrothermal vent communities and on their persistence and biodiversity at the regional scale. The results have provided new insights on ecological succession in general, and on the processes driving functional diversity at vents in particular. Over the course of three blue-water expeditions to the East Pacific Rise (EPR) in 2019-2023, we gathered and analyzed data on the trajectory of functional diversity and species succession at vents that had experienced a catastrophic eruption in 2006. We found that the species composition continues to change, and the diversity of their traits continues to increase, even 17 years after the eruption, overturning the paradigm that vent communities recover quickly (2-10 years) and are highly resilient to disturbance. This result has important implications for the impact of deep seafloor mining on seafloor communities. In addition, we developed a new approach to quantify connectivity in hydrothermal vent communities and quantified the diversity and dynamics of parasites in vent ecosystems. We developed tools and approaches for ecological analysis of animal movement, analyzing vertical swimming behaviors of vent snail larvae and horizontal motions of benthic snails on inactive vents and in coastal marsh habitat. The analysis of functional diversity at vents shows a different trajectory than in terrestrial systems, due to the symbioses established by pioneer foundation species with chemosynthetic microbes. This discovery broadens our understanding of ecological succession across different ecosystems. We found that parasites in vent communities are unexpectedly prevalent. Early studies had suggested that parasites were uncommon and unimportant at vents, but our studies targeted a wider diversity of potential hosts and showed very high parasite loads in many trophic pathways. Furthermore, numerical simulations of parasite population dynamics showed that tradeoffs between colonization potential and impact on host allow parasites to persist over a broad range of habitat disturbance frequency. Although most of our studies focused on animals at active vents, we noticed that inactive sulfide structures host an unusual and abundant guild of grazing gastropods that may be specifically adapted to that sulfide mineral habitat. Behavioral responses of these gastropods to environmental conditions likely influence their distributions and trophic interactions and are being investigated through another project. Movement ecology studies with coastal marsh species conducted as part of the present study have served as a test for future deep-sea experiments. The broader impacts of this study include training of the next generation of marine ecologists and increasing accessibility of ocean science careers to students from historically under-represented groups. The project provided training in laboratory protocols, statistical analysis, data visualization, coding and data science, as well as professional development opportunities in ethics and career options, for early career researchers. Graduate student Lauren Dykman completed her PhD thesis research on vent parasites, published two papers and has two more in preparation for publication. Graduate student Michael Meneses completed a study on megafauna at inactive vent sulfide features and had a poster accepted at the Benthic Ecology Meeting. Graduate student Bethany Fleming published a study comparing colonization of vents at the EPR with two other locations in the Pacific. All of these graduate students and postbacc technician Ayinde Best got cruise experience and dived in the submersible Alvin. Undergraduates Mon?t Murphy and Parker Mooney conducted research projects as part of summer intern programs in Woods Hole. We helped inform policy and management decisions for deep-sea hydrothermal vents through support of the InterRidge Vents Database, contributions to the Ocean Climate Platform, and participation in the Deep Ocean Stewardship Initiative. We contributed to information infrastructure through participation in national and international working groups helping to develop best practices for publishing data to the Global Biodiversity Information Facility (GBIF) and to the Ocean Biodiversity Information System (OBIS). In total, we produced 11 publications in peer reviewed journal articles, one PhD thesis, five data publications, and presented results at numerous scientific conferences, to the public, and to policy makers. Data from this project have been submitted into BCO-DMO under project 783674. Last Modified: 08/15/2023 Submitted by: Lauren S Mullineaux