Scientists using an autonomous underwater vehicle (AUV) to study previously unexplored ultra-deep waters near the Mariana Trench have collected the first-ever images of polymetallic nodules and other features of this remote seafloor abyss.
Led by the Ocean Exploration Cooperative Institute (OECI), based at the University of Rhode Island’s Graduate School of Oceanography, with support from the National Oceanic and Atmospheric Administration (NOAA), the Bureau of Ocean Energy Management (BOEM), and the U.S. Geological Survey (USGS), the pioneering effort aimed to reinforce the scientific value of AUVs when exploring hard to reach areas of the planet.
Located in the western Pacific Ocean, the Mariana Trench is the deepest ocean trench on Earth. Exploring these ultra-deep waters has proven challenging, with some sections reaching over 36,00 feet below the surface. The trench’s remote location, freezing cold temperatures, and extreme pressures, which can reach eight tons per square inch, also add to the difficulty. As a result, much of the trench and the area surrounding it remain unmapped and unexplored.
To study these ultra-deep waters up close, scientists from the Woods Hole Oceanographic Institution (WHOI) and NASA’s Jet Propulsion Laboratory joined forces with NOAA to develop an AUV capable of operating in the Mariana Trench’s ultra-deep, high-pressure environment. Those prototypes evolved into the newly designed model from Orpheus Ocean, which was officially founded in 2024.
After joining a larger expedition aboard the Ocean Exploration Trust’s (OET) expedition platform Exploration Vessel Nautilus, which has played a key role in mapping and exploring the U.S. Outer Continental Shelf in the Central and West Pacific Ocean, Orpheus and OECI were able to field test the vehicle in the plains just east of the Marian Trench.
According to a statement, the AUV successfully completed “several dives” up to depths exceeding 5,600 meters (3.5 miles). The company said the AUV, which completed the expeditions without incident, can explore ocean depths “up to 11,000 meters (6.8 miles).”
During the dives, the team says their custom-built AUV captured the “first direct observations” of these ultra-deep waters. The AUV also captured images of polymetallic nodules resting on the sea floor.
The team stated that finding polymetallic nodules is crucial for marine biologists and resource managers, “due to their unique geochemical properties.” Although USGS experts preselected this particular Mariana Trench-adjacent site due to the increased odds of spotting the nodules, the team says that imaging these previously unexplored areas helps their supporting organizations, such as NOAA, to “refine their understanding of the resources that they are tasked with characterizing and managing.”
“The abyssal plain visited on this mission is one of the least-known areas on Earth,” explained Amy Gartman, lead of the USGS Global Seabed Mineral Resources Project. “The data and images compiled help us to refine our seafloor prospectivity maps.”
“In order to responsibly manage the deep sea and its resources, we must leverage public-private partnerships and emerging technologies to gather critical baseline information about the seafloor,” added Aurora Elmore, NOAA Ocean Exploration program manager.
Team member Adam Soule, a University of Rhode Island Graduate School of Oceanography professor of oceanography and OECI executive director said collecting data in areas around the Mariana Trench “is critical” for determining the location and distribution of deep-sea mineral deposits like the polymetallic nodules The professor also notes that because of the unexplored nature of much of these ultra-deep waters the greatest need is “baseline” data that can only be gathered by “very specialized tools” like the Orpheus Ocean AUV.
Gartman agreed, noting that “Mission by mission, we are filling in the details of the map and building knowledge of where seafloor minerals may be found and their geologic and oceanographic setting.”
Jake Russell, CEO and co-founder of Orpheus Ocean, hailed the effort as a prime example of how his company’s priority of working with government, research institutions, and “other groups dedicated to advancing science, conservation, and understanding of the deep ocean, can generate significant results.
“This expedition is a great example of that,” Russell added.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.