Award: OCE-1851208

Deep-sea hydrothermal plumes are one of the ocean's most complex mixing environments. They involve many different physical and chemical processes and influence the dispersion of metals in and around vent sources and to the ocean. They occur near the seafloor from fluids discharging along tectonic plate boundaries, so they are difficult to locate, track, and study. Consequently, our knowledge of them is still very limited, even though they occur globally, and our knowledge is especially limited in the water-column zone extending out to several 100s of kilometers from vent sources. In this zone, the plume transport path meanders as a result of the influence of currents, tidal reversals, and geostrophic circulation. During transport, dissolved metals transform into particles that can sink out of the plumes. Completing our understanding of the processes involved in this transport is essential if we are to predict how these fluxes influence the distribution of nutrients like iron to the rest of the ocean.

To study these processes, we used a combination of (i) robotic observing technology (AUV Sentry), (ii) methods for autonomous sampling for particulate and dissolved metals, and (iii) high-fidelity predictive physical modeling of plume transport. We applied these tools and techniques to observe the process of plume transport as it occurs in the 100 km zone around the Main Endeavor hydrothermal field on the Juan de Fuca Ridge, off of the Pacific Northwest coast of the United States. We successfully applied a new robotic approach to observing these plumes that combines robotic vehicles and predictive transport modeling enabled by pre-deployed current sensors in the region; this combination of techniques worked well and allowed us to track the plume from this field as it dispersed many 10s of kilometers from the vents. The results of this study are allowing us to study metal dispersion from these vents at scales not previously possible, and the robotic developments of this project are expanding our capacity to study ocean processes and ocean resources more broadly.

In addition, this project supported classroom-based research activities associated with classes in marine geology and environmental sensors. It also supported the training of a graduate student in marine science and technology.

 

Last Modified: 02/24/2025
Modified by: John A Breier