Squat Lobsters and Tubeworms of Toto Caldera

During our first ROV dive of NA171 (and the 2025 season!), the Corps of Exploration took ROV Hercules down to the Toto Caldera. Located about 75 nm southwest from Guam and inside the Mariana Trench Marine National Monument, this seamount wowed us with active hydrothermal vents last visited in 2003. Meet some of the plethora of life adapted to live around these underwater hot springs! 

On our descent, squat lobsters (Munidopsis spp.) blanketed the seafloor and showed off their unique swimming capabilities in front of the camera. Tubeworms (Lamellibrachia juni) remind us of the chemosynthetic adaptations of vent life; these large polychaete worms rely entirely on internal symbionts to create their food. We also get cameos from Ectagena nautilei clams and large white snails waving their siphons used to sense chemicals in the water to find prey. 

The Mattingan: Mariana Arc Volcanic Exploration (NA171) expedition is exploring deep-sea areas identified by the local management and science community, including sites with signatures of active volcanism, abyssal plain habitats, and areas in and around the Monument where new data can support resource management priorities. This expedition is supported by NOAA Ocean Exploration, the Bureau of Ocean Energy Management, and the US Geological Survey via the Ocean Exploration Cooperative Institute.