Mariana Arc Volcanic Exploration

Sailing onboard E/V Nautilus for the first time during this NA171 expedition is the Orpheus AUV, built and operated by Orpheus Ocean. The Orpheus AUV will allow the team to explore the abyssal seafloor at depths up to 6,000 meters, which has to date been virtually unexplored around the Mariana Islands. During missions, Orpheus AUVs operate near or on the seafloor, performing high-resolution camera surveys as well as water and seafloor sampling tasks.
 

The Orpheus AUV is in the water for its first dive of the expedition!

Our first expedition of 2025 sees us exploring the ocean of the #MarianaIslands. This region is largely shaped by the forces of plate tectonics, with some of the oldest #seafloor on the planet being driven into the Mariana Trench (the deepest ocean trench) and then remelted to bubble up as magma, forming a chain of volcanic islands and subsea volcanoes. The volcanic arc in the Mariana region has more than 60 underwater volcanoes: 20 of which are hydrothermally active. These seafloor hot springs are hotspots of biodiversity supporting a broad range of organisms, including gastropods, mussels, tubeworms, galatheid crabs, and shrimps. To the west of the volcanic arc lies the “back-arc”, another setting of seafloor volcanism where seafloor spreading occurs, along with hydrothermal vents, but in much deeper water. Stay tuned as we explore some of these amazing and unique features!