From the banks of control room monitors on the E/V Nautilus, scientists spotted the 75-meter-high seamount jutting out of the seafloor like a spire. It came into view after DriX, a fire-engine-red surface robot operated by the University of New Hampshire (UNH)’s Center for Coastal and Ocean Mapping, echolocated it with high-resolution sonar.
The seamount was worth a closer look, the scientists thought, particularly since there was also a dense layer of marine life swimming nearby. The team sent commands to DriX, which positioned itself above the pinnacle and began circling the sea surface like a frenzied shark. Then, as if straight out of a sci-fi film, it began delegating tasks of its own to a pair of underwater robots below.
University of New Hampshire’s DriX surface robot runs high-resolution sonar through the water column while circling the sea surface like a shark. (Photo by Marley Parker, Ocean Exploration Trust)
DriX sent its first set of commands to Mesobot, a yellow-and-black ocean robot developed collaboratively by WHOI, the Monterey Bay Aquarium Research Institute, Stanford University, and the University of Texas Rio Grande Valley. The robot investigates life in the ocean’s dimly-lit twilight zone, and uses a combination of advanced camera and lighting technologies to slowly (and quietly) follow individual animals through the water column.
Once Mesobot received the text-like commands from DriX from a few hundred meters below, it propelled over to the seamount. There, it began sampling seawater to collect environmental DNA (eDNA, or “genetic fingerprints” from marine life) and capture video of animals as they swam through the ocean’s midwater.
Then, to get a picture of what was happening down on the seafloor, DriX began dishing out a different set of text commands to a second WHOI robot, Nereid Under Ice (NUI). NUI is a hybrid robot, meaning it operates as a remotely-operated vehicle (ROV) from ships via a hair-thin fiber optic tether, or as an autonomous underwater vehicle (AUV) without a human piloting it.
NUI began its investigation of the site in ROV mode, capturing real-time video and sampling while the Nautilus was off in the distance. As the science team watched the footage from the ship, they could see a patch of water a few meters above the seafloor began to shimmer—a freshwater plume had escaped from below the seafloor and was now gushing straight up into the water column. NUI proceeded to ascend the steep inclines of the seamount, capturing additional video while passing fish, eel, tunnels, and cliff faces along the way.
Shortly after, NUI transitioned to AUV mode, taking all of its commands from DriX circling above. This allowed the science team to prompt NUI for images, bathymetric data, and other measurement data it was collecting.
Suddenly, those aboard the Nautilus realized what they were witnessing: three ocean robots were working together as a team to explore different dynamics of the ocean as the freshwater plume event was unfolding—all at the same time.
“Multi-vehicle collaboration represents a whole new paradigm for ocean robots and at-sea operations.”
—WHOI research engineer Robin Littlefield
“Multi-vehicle collaboration represents a whole new paradigm for ocean robots and at-sea operations,” said Robin Littlefield, one of the WHOI roboticists aboard the Nautilus for two weeks of ocean technology integration testing off Oahu, Hawaii in May, 2022.
The expedition was aimed at answering a central question: What’s possible when a group of robots starts exploring and working on science questions together?
During this particular dive, the science team came away with a snapshot of how something like a freshwater plume can affect things like water density and animal behavior in different layers of the ocean. But more generally, the robotic teamwork allowed for the ability to explore more things in less time.
“Autonomy is important as it takes pressure off human operators,” Littlefield said. “If robots can be communicating and working together, people will no longer have to commit all of their time to overseeing missions and can be freed up to add value in other ways.”
Ships can also be freed up, according to Eric Hayden, an engineer on the Mesobot team.
“When you have a ship that costs tens of thousands of dollars a day having to stay within the range of a robot like Mesobot, it has to babysit that operation and that limits the other things a ship can do, like deploying other vehicles and instruments at sea,” Hayden said.
