Mesobot: A New Class of Robot for Investigating the Ocean’s Interior

Dana Yoerger1, Annette Govindarajan1, Joel Llopiz2, Peter H Wiebe1, Jonathan Howland1, Christopher R German1, Bruce H Robison3, Kakani Katija4 and Stephen Rock5,6, (1)Woods Hole Oceanographic Institution, Woods Hole, MA, United States, (2)Woods Hole Oceanographic Institution, Biology Department, Woods Hole, MA, United States, (3)Monterey Bay Aquarium Research Institute, Moss Landing, CA, United States, (4)Monterey Bay Aquarium Research Institute, Watsonville, CA, United States, (5)Stanford University, Stanford, CA, United States, (6)Stanford University, Aeronautics and Astronautics, Stanford, CA, United States
The midwater realm is the next frontier for marine robotics. The mesopelagic, or “twilight”, zone extends for approximately 1 kilometer beneath the base of the photic zone and hosts abundant but poorly documented life and biogeochemical transformations critical to the global carbon cycle.

Autonomous platforms that can reveal the behavior of midwater animals over extended periods or document the transformation of particles continuously as they sink do not presently exist. Here we present a new class of robot, the Mesobot, that addresses those issues directly. The Mesobot provides a new and unique capability that can fill critical gaps in our understanding of midwater ecosystems, the biological pump, and their collective influence on the global carbon cycle. This new robot uniquely complements existing midwater assets such as sampling nets, hydroacoustic systems, and other towed, tethered, and untethered vehicles that carry specialized imaging and sampling systems.

The Mesobot will be a small (75 kg) maneuverable untethered robot designed specifically to observe midwater phenomena unobtrusively for extended periods. It will use a stereo camera, a gimbaled monocular camera, and a set of lights to non-invasively follow slow-moving mesopelagic animals and to track the fate of descending particles, enabling scientists to characterize their behavior in their natural setting over extended periods for the first time. The lights will be specifically chosen to minimize avoidance. A complement of small thrusters will enable fine maneuvering without disturbing the targets. A specific example of a unique Mesobot task will be to follow animals as they undertake diel vertical migrations.

The Mesobot is a collaboration between the Woods Hole Oceanographic Institution (WHOI), Stanford University, and the Monterey Bay Aquarium Research Institute (MBARI). The Mesobot is based on AUV developments at WHOI, MBARI, and Stanford, including the ability to track animals autonomously. That capability is being extended to enable reliable, long-term tracking for a wide range of targets.