Robots make research on remote oceans possible
The Southern Ocean is thought to play a key role in the world’s climate. For many years, little was known about this body of water which is 14,000 kilometres away from Gothenburg. However, South African Sebastiaan Swart has chosen to carry out his research from here.
“THERE ARE MUCH BETTER resources in Europe, and modern technology makes up for the distance,” he explains.
As our climate changes, ever greater demands are placed on the models that predict what will happen in the future. Many of the answers can be found in the world’s oceans, which is why oceanography is such an important field of research.
“Oceans can absorb large quantities of carbon dioxide from the atmosphere, thereby acting as carbon sinks,” explains Professor of Oceanography Sebastiaan Swart. “The colder the water, the more carbon dioxide it can dissolve. This is one reason why we are interested in the Southern Ocean. It’s also relatively weakly stratified, meaning that the captured carbon can sink down into the depths and stay there for thousands of years.”
LOCATED BETWEEN THE southern tip of Africa and Antarctica, the Southern Ocean is like a busy intersection. Strong currents from the Atlantic, Pacific and Indian oceans converge here, bringing water masses with different temperatures and salinity levels. Sometimes they collide and mix, but the water often retains its properties in different ‘packets’ which travel onwards.
What happens in the South Atlantic can be linked to the climate we experience in Northern Europe.
“The warm, salty waters that flow around the southern tip of Africa then travel north, and can act as an engine for the Gulf Stream, for example. This is a crucial part of the global ocean circulation that regulates our climate.”
THE LAST TEN TO FIFTEEN years have seen a technological revolution within oceanography. Remote-controlled underwater robots can carry out measurements in inaccessible waters over the course of several months. This has had a significant impact on Sebastiaan’s research in the Southern Ocean.
“In the past, researchers had to go on expeditions and take measurements at a few selected sites. This provided a snapshot, but it was hard to interpret trends over time. Thanks to our robots, we now get a much larger volume of measurement data at a finer scale. For example, we can now see that the stratification varies over the seasons. This is important knowledge to feed into climate models so we can see how warm it might be in Sweden in the future.”
IT WAS DURING ONE OF THESE traditional expeditions that Sebastiaan first got into oceanography. South Africans are constantly aware of the Southern Ocean, since it determines what their weather is like. And as Sebastiaan was a keen gardener during his childhood, the weather was something he was extremely interested in. His dream was to become a forest ranger.
“That’s why I studied environmental science at university. However, I also took elective courses in archaeology and oceanography as part of my bachelor’s degree. And then I had the opportunity to go on a research vessel to the Southern Ocean. Then I was hooked, thanks in large part to my supervisors Isabelle Ansorge and Sabrina Speich during my master’s course, who also guided me during my doctoral studies. Now we’re actually working together as partners in an ERC project on the Agulhas Current, the world’s strongest ocean current which runs along the east coast of South Africa. We’ve come full circle!”
Since 2016, Gothenburg has been Sebastiaan’s research base. He came here on a Wallenberg Fellowship career scholarship for young researchers, eagerly encouraged by his colleague Anna Wåhlin, whom he had met on an international research panel. Since then, oceanography has been strengthened at the University of Gothenburg. Many researchers work with autonomous robots in the ocean, some of them under the Antarctic ice cap.
THESE ROBOTS HAVE MADE it possible to become an expert in a field located on the other side of the world.
“Our family had longed talked about wanting to spend a few years living somewhere more central than South Africa. And there are much greater resources for research in Europe, including the Wallenberg Foundation and various EU initiatives that provide research funding. But the network of researchers in South Africa is extremely important, and we have close ties. In fact, several other South African researchers have also come here.
“The southern hemisphere sometimes is used as a place where research is helicoptered in from the north, and the researchers then return home without involving the people who live there and sharing their knowledge. It’s like a modern form of colonisation. I’m keen to ensure that those of us doing oceanography in the Southern Ocean should see our colleagues in Africa as equal partners.”
Text: Olof Lönnehed
Photo: Johan Wingborg, Sebastiaan Swart
Sebastiaan Swart
Work: Professor of Oceanography, Wallenberg Academy Fellow.
Age: 41.
Family: Wife Kate and children Josh (9) and Zoe (4).
Leisure interests: I like to run in Bohuslän. I also do yoga, and I’m working on my table tennis skills so that I can beat my son!
THEN: Taking samples from vessels on individual expeditions. Data points could be 50 km apart, and the harsh climate meant that measurements could not be taken in the Southern Ocean during the winter.
NOW: Programmed, unmanned, underwater robots (‘gliders’) take continuous measurements over long periods of time in the water. This high-resolution data reveals new processes in the ocean and facts about water circulation. A dedicated satellite – SWOT – measures the Earth’s ocean currents from space.
IN THE FUTURE: We are taking series of measurement that will stretch over 50 years. This is needed to see long-term trends without forecasts being affected by individual events, such as El Niño. Our measurement robots use adaptive collection. In other words, they take measurements in those areas where this is most useful, and the evaluation is carried out using AI. It is very difficult to measure everywhere all the time, due to the size of the oceans.
