In May and June of 2022, a team of researchers from the U.S Geological Survey, the Bureau of Ocean Energy Management, and partners have explored Escanaba Trough, a seafloor spreading area 200 nautical miles off the coast of northern California.

Studying the seafloor more than 3,000 meters beneath the surface without ever leaving the deck of the research vessel Thomas G. Thompson requires specific tools and state-of-the-art technology.

Using the submersible robots Jason and Sentry from Woods Hole Oceanographic Institution (WHOI), the research team conducts exploratory dives to study seafloor features at Escanaba Trough as often as conditions allow. In between dives, the team sinks gravity-driven cores to obtain sediment samples and deploys instruments to measure water conductivity, temperature, and depth, among other parameters.

Researchers are enthusiastic about the data collected so far. In addition to gathering samples from locations not previously sampled, the joint deployment of Sentry and Jason is allowing researchers to plan each dive with greater precision.

Researchers work with WHOI staff to map the route of each robot’s dive. Working from detailed bathymetric maps created by Sentry’s autonomous transects of the seafloor, researchers can fine-tune Jason’s dive plans to make the best use of the ROV’s time on the bottom. Jason can collect a variety of seafloor samples as well as photos and videos but only travels at less than half a kilometer per hour; using Sentry’s high-resolution maps helps the team place Jason as close to specific seafloor features as possible for each dive.