Collaborative Research: The influence of mesoscale eddies on deep-sea dynamics and implications for larval connectivity along mid-ocean ridges

This project will examine the impact of mesoscale eddies on deep ocean dynamics and larval dispersal among deep-sea vent communities and its consequences for population connectivity and resilience at the East Pacific Rise. This will be done using a multiscale numerical ocean model in comparison with observational data of larval supply and colonization. Hydrothermal vent communities on mid-ocean ridges are characterized by temporary habitats and dynamic populations. In these habitats, dispersal in the planktonic larval stage strongly influences resilience of metacommunities to both natural and human-made disturbance. At vents on actively spreading ridges, this process is particularly critical because catastrophic eruptions occur frequently. The research approach employs a multi-scale hydrodynamic model that incorporates a Lagrangian particle-tracking algorithm using available data on larval behaviors and ocean currents. The model will be used to simulate hydrodynamically mediated larval dispersal, which is not directly observable, for comparison with an analysis of observed larval supply and colonization. Multi-scale simulations will focus on oceanic and dispersal processes at the East Pacific Rise segments under the influence of passing mesoscale eddies during the 30-year period from 1993 to 2022. The investigators will examine the impact of eddies in the main thermocline on deep ocean dynamics and transport at different spatial scales and will compute statistics over many incidents of eddy-ridge interaction. Biological analyses will provide observational constraints on the model’s representation of larval behaviors through analysis of video footage of larval swimming. This project was funded by the Physical Oceanography and Biological Oceanography Programs. 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.