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Astrid Hylén
Photo: Malin Arnesson

"As inhabitants of this Earth, we researchers have a responsibility to make our voices heard"


Astrid Hylén came to the West Coast of Sweden to realise a dream of becoming a marine biologist. But it was at the bottom of the Baltic Sea that she found her true passion: understanding the effects of human activity on our seas, and what we can do to save them.

Astrid Hylén lets me into her room in Botanhuset, the part of the University of Gothenburg located direct next to the Botanical Gardens. A more idyllic place to work is difficult to imagine for a scientist. But Astrid, who is studying for her doctorate in marine chemistry, would rather be out at sea. That is where she does her field studies and finds her data.
“I definitely appreciate the part of my work that I do here at the Department, in particular the lecturing, but my favourite thing to do is stand on a boat mucking about in mud all day,” she laughs.

Studying the cause of anoxic sea beds 

Astrid is part of a group of marine chemists who have been studying the seabeds of the Baltic Sea for a long time. Among other things, they measure the levels of phosphorus, nitrogen and carbon in the sediment. Large parts of the seabeds of the central Baltic are currently anoxic. It has been caused by discharges, for example via sewage and from agriculture, that have been going on for decades. These discharges have led to eutrophication and increased growth of algae which, when it is broken down by bacteria, consumes all the oxygen in the sea.
“It’s an old debt we are paying the price for now. For even if discharges are reduced, phosphorus has been settling in the seabed sediment for a long period of time. When the water is depleted of oxygen, phosphorus leaks out and keeps on contributing to the algal growth,” says Astrid.

For Astrid and her colleagues, it is clear that our seas are wrestling with enormous problems. In the past, the thinking has been roughly “what you don’t see, you don’t need to worry about”. But marine research is now revealing more and more about the impact that we humans are having on our oceans and seas, through over-fishing, plastic pollution and other pollutants. Two research tracks are particularly interesting to Astrid.

Want to learn more about the aquatic carbon cycle

One deals with climate trends and the capacity of our oceans and seas to bind carbon. By studying the aquatic carbon cycle, for example by seeing what happens to the carbon that algae binds, you can provide those scientists who are making climate models with relevant data.
“Algae can be decomposed by the bacteria in water. When that happens, the carbon goes back into circulation. Or it’s buried in the sediment. In that case, the carbon is taken out of circulation, at least in the short term. That’s why it’s important to understand what factors lead to carbon being bound in the sediment or released into the water.”

Expedition about eutrofiering in the Baltic Sea

The second area of research concerns eutrophication. Because even if researchers today understand the mechanisms behind the problem, there is no direct solution to it. To achieve that will require more research at the detailed level. However, there was a breakthrough in 2014 when unique weather conditions resulted in large quantities of oxygenated water beginning to flow into the Baltic Sea. A research team from the University of Gothenburg set out on the Baltic in order to see what effects this would have on the seabeds. Astrid Hylén got to go on one of these expeditions when she was doing her Master’s thesis.
“The whole group was very excited. We wondered what would happen to the oxygen level on the dead seabeds. And now that oxygen-rich water was flowing into the Baltic, what effects would this have on the sediment and the phosphorus bound in it?”

The researchers’ studies showed that the seabeds did in fact become oxygenated. But even more than this, the oxygen-rich water meant that the phosphorus stayed in the sediment and was converted into a form that cannot be utilised by algae. So algal growth was inhibited.

Unfortunately, the effect was relatively short-lived and today oxygenated water has again disappeared from the Baltic and its status has largely reverted to what it was before.

How was your interest in marine research first piqued?
“Curiously enough, it also had to do with the Baltic Sea. I grew up in Falun but spent many summers on Blidö, an island in the Stockholm archipelago. That was probably where my interest began, but the dream of becoming a marine biologist was really born when I was nine years and got to pat a stingray at the London Aquarium. After that, I was sure what I wanted to do.”

But you became a marine chemist instead?
“Ha ha! yes. That was partly coincidence. The University of Gothenburg has merged their marine study programmes into one programme in marine sciences, where the idea is to provide a system overview of the marine environment. This was something that I really liked. Later on when I was going to do my Bachelor’s project, there was an opening to participate in an expedition to the Bothnian Sea to help explore the nitrogen cycle there. My idea wasn’t to become a chemist then but the expedition was such a fantastic experience that I got hooked!”

How do you like being out at sea?
“It’s so much fun to be out at sea with a group of researchers. There’s an exceptionally strong camaraderie that arises. But I get terribly seasick sometimes and that is certainly a handicap for a researcher in marine sciences. But I’ve found the best remedy. Potato chips! Preferably very greasy and salty.”

Why did you choose to become a doctoral student?
“I love to learn things. Understanding why things happen, finding connections and learning more about how systems work. As a doctoral student and researcher, I get to continue doing this full-time. I also get to travel a lot, go on research adventures and meet other researchers.”

To what extent do you think that researchers ought to be involved in shaping public opinion?
“That’s a difficult question. In the first instance, as a researcher I’m supposed to be impartial. But I’m also an inhabitant of this Earth and as such have a responsibility to point out big and urgent problems. We researchers are generally scared of sticking our heads out and so we avoid black-and-white answers. That’s part of the scientific approach. But now that the problems have become so acute, we ought to become better at explaining the consequences of human behaviours that we see for our seas, for example.”

What is the future of our seas?
“Our seas will persist but we should probably expect that they are going to look different. We humans have gone so far in our interference that some species have been lost forever. Just look at the Baltic Sea for example. When my grandparents bathed there in the 1950s, the water was completely different. There were a lot more fish and different species of fish. Today, cod have almost collapsed as a species and bladder wrack and blue mussels are in decline.”

What’s in store for you in the future?
“I would like to continue working in the academic world. Because it’s so much fun! But I also know that it’s tough establishing yourself as a researcher. It takes a lot of work and the competition is fierce. An alternative is to become a teacher, because I love teaching others. Just as much as I love learning myself.”

Astrid Hylén

Age: 27
Studying: For her doctorate in marine chemistry
Lives: Grew up in Falun but currently live in Gothenburg. (“It’s a great city and I've loved living here from day one.”)
Leisure activities: “I like reading and travelling.”