Victoria Preston watched as the ChemYak, a robotic kayak rigged with sensors, navigated the shallow, ice-filled waters of Cambridge Bay in Nunavut, Canada. Preston, a doctoral student at the time, was working with a team of researchers looking into the release of greenhouse gases in the Arctic during the annual spring thaw. The ChemYak allowed the team to take thousands of in situ measurements, instead of needing to bring water samples back to the lab.
When we think about the power of putting instruments on robotic machines that can place those instruments optimally, it’s so different than the oceanography of just a few decades ago,” says Preston, who is now a postdoctoral investigator at the Woods Hole Oceanographic Institution (WHOI). “Having access to so much data is changing the game in many fields.”
Robots are a vital tool for ocean science and their role has only grown over time. The first videos of deep-sea hydrothermal vents and the unexpected plethora of life they support were taken in 1977 by Alvin, WHOI’s crewed submersible. Since then, researchers have been able to explore details of the seafloor through remotely operated vehicles (ROVs) like Jason, which are tethered to a ship, or map areas of it with autonomous underwater vehicles (AUVs) like Sentry, sent out on preprogrammed missions.
With improved longevity, battery life, processing power, and intelligence, ocean robots have grown into new roles. Some are jacks-of-all trades, with swappable sensor packages for different missions, and others are specialists designed for under-ice exploration or other harsh environments. They act as scouts, explorers, warning systems, monitors, and, increasingly, scientific partners.
“I don’t think we’ll ever stop wanting a vehicle that can take people to the deep sea to do science in a real, 3D space, but there are a lot of ways that we want to take measurements in the ocean that don’t require us to go out there,” says Anna Michel, chief scientist of WHOI’s National Deep Submergence Facility. “Because of big problems like climate change, there’s a lot of need for technology to monitor the oceans. We’re nowhere near having too many robots.”
As designs and technology continue to evolve, robots of the future will be integral parts of understanding and helping to address some of the biggest challenges facing the ocean, including the climate crisis, dying coral reefs, and other damages caused by human activity.
But the technological innovations needed to make this future a reality are not insignificant. We need ocean robots that are affordable, independent, long-lasting, networked, and loaded with sensors. We need the capacity to store, process, and transmit vast amounts of data. We need long-lasting batteries and charging stations powered by renewable energy sources. And we need all of this at an unprecedented scale.
Monitoring a changing ocean
Robotic platforms like the ChemYak provide valuable access to hard-to-reach places and are great for investigating specific events or areas. But their deployments are measured in hours, not weeks or months—researchers have to make sure they’re in the right place at the right time. To make accurate predictions for the ocean and our planet as the climate continues to change, we need to combine these local observations with consistent, long-term data sets to reveal both ongoing changes and sporadic or seasonal events.
Researchers and research vessels can’t be everywhere at once, but fleets of long-lived, inexpensive robots can fill in the gaps and, in some cases, already are. Around 4,000 Argo floats drift through the world’s oceans, recording temperature and salinity profiles through the water column, which help us predict and track extreme weather. Scientific buoys, moored and drifting, collect data on the air-sea interactions that produce El Niño events and alert us to everything from tsunami waves to endangered marine mammals. Torpedo-shaped gliders loaded with sensors coast through different layers of the ocean for months at a time, improving predictions of tropical storm and hurricane intensity, while helping us understand the ocean’s currents, which play a critical role in our climate system.
“Ocean robots are heading towards longer endurances, shore launch, and autonomous recovery capabilities.”
—WHOI senior engineer Mike Jakuba
“Ocean robots are heading towards longer endurances, shore launch, and autonomous recovery capabilities, at-sea maintenance—these trends have been going on for a long time, but some of them are finally maturing,” says Mike Jakuba, a senior engineer at WHOI. “I don’t see research ships or ship-launched AUVs ever going away, but operations are going to become more autonomous and less people-intensive at sea.”
One of the major limiting factors for today’s ocean robots is power. Engineers often have to make trade-offs between a robot’s capabilities—which sensors it uses, how quickly it travels, what information it can process on board—and how long it can operate independently.
Jakuba is collaborating with researchers at WHOI and the University of Washington on a low-power system to improve undersea navigation for ocean gliders, autonomous robots that use changes in their buoyancy to cruise slowly through the ocean.
Typically, underwater navigation systems use a lot of power. To avoid that, ocean gliders only get an accurate location when they surface and connect to satellites. Underwater, they navigate by dead reckoning—estimating their position based on where they started and the speed and direction they have traveled. This type of navigation doesn’t account for ocean currents, so a glider’s estimated location can be off by several kilometers.
“Gliders have been a very successful platform for collecting profiles of salinity, temperature, and other things in the water column,” Jakuba says. “But if we had more precision navigation, it would open up new possibilities.”
Gliders could, for example, be sent out to survey the seafloor to identify the locations of methane seeps or hydrothermal vents. Researchers are still studying how these seafloor phenomena and the unique ecosystems around them affect ocean chemistry and circulation, and understanding their quantity and locations could help improve ocean models and climate predictions.
The researchers have created an extremely low-power navigation system for ocean gliders by pairing them with an autonomous surface vessel called a wave glider. The wave glider, which is powered by wave and solar energy, broadcasts a simple acoustic signal under the water and the ocean gliders use that to determine where they are in the water column.
“If you want to move the ocean glider on the bottom, you would move the wave glider—it follows like a dog on a leash,” Jakuba says. “It speaks to this vision of longer-term robots working in parallel with one another in a scalable system, getting away from the model of needing a ship.”
Closer to shore, volunteers often lead water quality monitoring efforts, collecting samples by hand. As robotic technologies become less expensive and more commercially available, coastal communities may be able to build simple ocean robots to get a better idea of what’s going on in their own backyard. Over the past four years, Jakuba has been working with a local high school student, Patrick McGuire, to design and build an inexpensive coastal profiling float known as the TideRider that can monitor changing ocean conditions.
Climate change is warming the waters of Cape Cod Bay, shifting seasonal patterns and allowing new species of phytoplankton to bloom and decompose, potentially causing deadly low-oxygen zones along the bottom. One such event occurred in September of 2019, when fishermen in southern Cape Cod Bay started hauling up trap after trap of dead lobsters. A blob of hypoxic water—water with very little oxygen—had formed along the bottom of the bay and any animal that couldn’t escape it had suffocated. If the fishermen had known about the hypoxic water, they could have placed their traps in other areas.
The TideRider was originally designed to help aid in the public understanding of the coastal ocean and to foster a sense of stewardship, but a small fleet of them could also provide continuous data throughout the bay, forming the basis of an alert system for changing conditions. They can be programmed over cell networks to move between the seafloor and the surface, using favorable tides to drift to new locations. And, the instrument costs less than $1,000 to build and can carry sensors to detect dissolved oxygen levels or other water quality data.
“What we’re imagining is a hypoxia alert system where the TideRider would sit on the seafloor and if the oxygen dips below the level where it’s going to cause fish kills, for example, then it would come to the surface and at least warn you,” Jakuba says.
Robots as emergency responders
When the Deepwater Horizon oil rig exploded in April of 2010, millions of gallons of oil began gushing out of a damaged seafloor well in the Gulf of Mexico. In the months that followed, as cleanup workers tried to contain and disperse the spill, robots were sent down to survey the damage and help track the currents that would spread the plume of oil. Although they were the best available instruments for the job, none of them had been designed with this sort of emergency in mind. In the years that followed, government agencies and researchers started considering better tools to respond to oil spills.