Award: OCE-1851199

As part of this project, PI Xu developed two sets of numerical simulations of hydrothermal plume dispersion at the Endeavour Segment of the Juan de Fuca Ridge using the Regional Ocean Modeling System (ROMS). The initial simulations employed a nested ROMS configuration comprising three embedded model grids, with spatial resolution progressively increasing from a coarse outer grid to a fine intermediate grid and finally to an ultra-fine inner grid focused on the Endeavour Segment and its surrounding region. The results from these simulations were published in a peer-reviewed journal article (Xu and German, 2023). This process-oriented numerical study provides valuable insights into regional ocean circulation near the Endeavour Segment, including the role of seafloor venting in modulating the dynamics both surrounding the ridge segment and within its axial valley. The simulations further illuminate the dispersion of hydrothermal plumes originating from along-axis vent sites and the interannual variability of plume transport, driven by the interaction of large-scale abyssal flows with ridge topography.  

PI Xu conducted a second set of ROMS-based plume dispersion simulations using only the ultra-fine grid from the previous configuration to support at-sea operations during the 2023 research expedition to the Endeavour Segment. During the cruise, the model provided forecasts of plume distribution and trajectories, which were used to guide mission planning for a series of plume surveys conducted with the autonomous underwater vehicle (AUV) Sentry, operated by the Woods Hole Oceanographic Institution (WHOI). Following the cruise, the model was refined and rerun to generate plume age estimates, providing important constraints on plume dispersion timescales. These results facilitated interpretation of geochemical measurements from fluid samples collected during CTD casts and AUV surveys, allowing estimation of the rates of downstream evolution of hydrothermally sourced Fe and Mn within the dispersing plume. Findings from these post-cruise refined simulations were presented at the 2024 AGU conference (Xu and German 2024).

The findings from these simulations and their integration with geochemical field observations from the 2023 expedtion to Endeavour provide valuable insights into the physical and biogeochemical processes that regulate the transport and evolution of hydrothemrally source Fe and Mn within the dispersing plume. These results have important implications for advancing our understanding of the role of seafloor venting in global ocean biogeochemistry.

 

 

Last Modified: 02/02/2026
Modified by: Guangyu Xu