These scientists are using underwater drones to reveal the ‘weirdly complicated’ world of ocean carbon

It’s that rarest of rare conditions along coastal Newfoundland: a dead calm day.

By 7 a.m., the crew aboard the fishing boat Belle of the Bay are taking full advantage of it, steaming out of the harbour in Heart’s Content under dazzling July sunshine, with their sights set on a prized catch in the middle of Trinity Bay.

It’s not fish they’re after. The object awaiting them looks like a mashup between a torpedo, a banana, and a Dash 8 — a type of underwater drone, called a glider.

“This isn’t the regular kind of job that I would recommend for people that don’t like to be challenged. It’s a mission,” said Nicolai von Oppeln-Bronikowski, the head of Memorial University’s glider operations.

“I think everybody that works with gliders sees themselves, in one way or the other, on a mission.”

Today’s mission to retrieve that glider — nicknamed Migaloo, after a humpback whale — is a team effort. It combines the scientific lens of von Oppeln-Bronikowski and research assistant Sarik Shaikh-Upadhye, with the fishing father-son duo of Doug and Kyle Piercey, who have loaned their boat and expertise to Memorial University glider research for nearly a decade.

“It’s not light,” Doug Piercey says as he and von Oppeln-Bronikowski heave the 1.5 metre-long Migaloo out of the bay. The two check it over, paying particular attention to a prototype sensor attached to it like a little scientific backpack.

“This is the pH sensor right there, that the whole fuss is about,” said von Oppeln-Bronikowski.

At first glance, Migaloo and its sensor are intact, marking the first milestone in a year-long effort everyone on the boat simply refers to as ACOP: the Atlantic Carbon Observatory Pilot Program.

“ACOP is sort of a small stepping stone in terms of advancing our ability to make more measurements of CO2 [in the ocean],” said von Oppeln-Bronikowski.

‘Where is most of the carbon on our planet?’

Those measurements are badly needed as carbon dioxide emissions in the atmosphere continue to climb.

“If you ask the question, where is most of the carbon on our planet? The answer is, it’s in the ocean,” said Brad deYoung, a physical oceanographer at Memorial University and lead researcher with ACOP.

The world’s oceans are a vast carbon sink — absorbing anywhere from a quarter to a third of the carbon dioxide we pump into the atmosphere.

A lot of the carbon dioxide pumped into the atmosphere ends up in our oceans, particularly the North Atlantic. We head out on a Newfoundland expedition using underwater drones try to answer pressing scientific questions, like: why is the North Atlantic so good at absorbing carbon, and how much more can it hold?

“What that means for us, in a planetary sense is, that the rise that we see of the CO2 in the atmosphere is a lot less than it would otherwise be if there were no ocean. So the ocean plays a big role in mitigating and slowing down the pace of climate change,” said deYoung.

But exactly how much carbon the ocean has absorbed — and where its limit to do so may lie — are some of the many unknowns in this area of oceanography,

“Carbon in the ocean is weirdly complicated,” said deYoung.

Unlike things like temperature, deYoung said, “sensors to measure various aspects of [ocean] carbon are not so easy to build, not so reliable, and just not as well developed. So, the carbon observatory is basically a platform where we can test and and actually use the instruments.”

Migaloo’s pH sensor, taking stock of acidity, is one such ACOP instrument. Carbon makes the ocean more acidic, and checking pH is one way to try and pinpoint carbon uptake.

The Labrador Sea lung

There’s an international scientific effort looking into these carbon questions, and ACOP — which involves an array of partners, including Dalhousie University and the Department of Fisheries and Oceans — is, for now, focusing its attention on the coastal waters off Newfoundland and Labrador.

Because as it turns out, one thing science has pinpointed is that some areas of the world’s oceans are better at absorbing carbon than others. The North Atlantic is one such spot, with the Labrador Sea — that remote stretch of water between Labrador and Greenland — a particular star, thanks in part to its often stormy surface acting as a sort of lung.

“Think of the ocean as kind of reaching up to the atmosphere in the Labrador Sea, and breathing and extracting carbon dioxide and oxygen out of the atmosphere,” said deYoung.

DeYoung and his team would like to fly their gliders into the Labrador Sea to collect valuable ocean carbon data. While that can be collected by scientists aboard ships, there are big drawbacks to that work.

Research ships are in short supply in Canada, and getting a spot on a mission that does go out is extremely costly. Plus, such missions in the Labrador Sea happen mostly in the summer, and ACOP wants to know what’s happening in the winter, when temperatures plunge, winds rage and waves average 15 metres high — and the carbon uptake is thought to be higher.

“It’s a very challenging place to make measurements … and at the same time, it’s absolutely critical that we make measurements there. It’s a catch-22,” said von Oppeln-Bronikowski.

DeYoung recalled one infamous ship-based winter mission to the Labrador Sea, where “in 65 days at sea they got one day of useful work. That’s not a very good way to get work done.”

This is where autonomous vehicle technology, like gliders, comes in handy. 

“[They’ve] definitely changed the game,” said Uta Passow, a biological oceanographer at MUN and another member of the ACOP team.

Gliders do need to surface to transmit information back to waiting researchers, but they spend the majority of their time underwater and are able to dodge a lot of rough waters in a way ships simply can’t. Plus, they can roam around the ocean, whereas ship-based measurements are confined to one spot, at one point in time.

“These autonomous vehicles like … gliders or observatories, they will increase our data input by orders of magnitude and will hopefully allow us to make predictions,” said Passow.

“If we want to make predictions that are reliable, we really need to understand how the ocean will respond to climate change, and if it will continue to take up carbon, or take up more carbon in the future, or less carbon. So we really need to understand the carbon cycle and we don’t at the time.”

In an era of climate anxiety and uncertainty, it’s scary to consider that lack of knowledge at the highest level of expertise. But for deYoung, hope lies in projects like ACOP.

“The question now is, should we throw up our hands and say, ‘oh, my gosh, this is just such a big problem,'” said deYoung.

“And that’s not a reasonable response. I think part of what we argue is, let’s document what’s happening, so we understand where the the critical spaces are and how we can perhaps adapt.”

The Atlantic Carbon Observatory Pilot Program runs until mid-2023; its team hopes that a permanent carbon observatory can arise out of it — one that would include international teamwork — to continue to chip away at its ocean carbon questions.

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