Rare look at animals in the ocean twilight zone

The ocean is so vast that it can be hard for scientists to find the species they want to study. That’s why two ocean robots are better than one for capturing these rarely-seen glimpses of twilight zone animals!

During an October 2023 Nautilus Live expedition to the Geologist Seamounts–about 60 miles (100 km) southwest of Hawai’i’s Big Island– researchers used the University of New Hampshire’s uncrewed surface vessel DriX to find the best place to deploy WHOI’s hybrid remotely operated vehicle (HROV) Mesobot– right into dense patches of marine life! Because these animals migrate between surface waters at night and deeper regions during the day, they captured this footage at the relatively shallow depth of 328 feet (100 meters).

 

It’s all part of a co-robotics experiment aboard the Ocean Exploration Trust’s E/V Nautilus, funded by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute (OECI) to advance the pace of ocean exploration through innovation with teams from OET, WHOI, University of New Hampshire, and the University of Rhode Island.

 

For more about Mesobot visit: https://twilightzone.whoi.edu/work-im...

We designed Mesobot, our new hybrid robot, specifically to study life in the ocean twilight zone. It can maneuver under its own power for more than 24 hours, using its cameras and lights to slowly follow individual animals while making a variety of other measurements and even taking samples. We call it a hybrid robot because it can be controlled either by human pilots through a lightweight tether or it can run autonomously with no tether. For example, we can pilot the vehicle while tethered to locate an interesting target, then we can release the tether and the vehicle can continue on its own.

 

Mesobot was carefully designed to avoid disturbing the animals it observes. It is relatively small and has a streamlined form. Large, slow-moving propellers allow it to hover and transit with minimal disturbance of the surrounding water. Mesobot carries standard white lights and red lights which many deep-sea species can’t see. Red lights allow Mesobot to observe animals without either frightening or attracting them.

 

In addition to taking high-quality images, Mesobot can also accommodate different types of auxiliary devices. As one example, Mesobot often carries a sampler that pumps seawater through filters to collect environmental DNA—or eDNA—traces of DNA that were left behind by animals recently in the area. These samples will help scientists understand what types of animals are living in the zone, even if they never actually see them.

 

Mesobot is a collaborative effort by WHOI, the Monterey Bay Aquarium Research Institute (MBARI), Stanford University, and the University of Texas Rio Grande Valley. Mesobot development and at-sea operations have been funded by the National Science Foundation and the Ocean Twilight Zone project.

 

 

© Woods Hole Oceanographic Institution