A blessing in disguise

Bettina Meyer is head of the Working Group “Ecophysiology of Pelagic Key Species” at the Alfred Wegener Institute in Bremerhaven. Roughly two weeks ago she returned from an expedition to the Southern Ocean. In the following interview she explains what she worked on there, and how the coronavirus pandemic initially put her planned return on ice.

Over the past several weeks, the majority of research expeditions had to be discontinued, or had to be cancelled before they could even begin, thanks to the coronavirus pandemic. You were in the Southern Ocean region at the time, which means you were one of the few experts who was still able to actively pursue research in the field. How did that come about, and how long was your journey originally meant to last?

When we began our journey, on 20 February, no-one could have predicted how radically the situation was about to change. The expedition on the ship was scheduled through 27 March, the official end date. Our return flight was planned for 6 April.

During the journey, when did you first hear about the coronavirus pandemic, and how did the global developments in connection with COVID-19 affect you?

We first heard about it in March, when it was all over the media. We had Internet access on board, and were of course in contact with our friends and families.

The images and stories that we saw and read seemed totally surreal. We saw it, but couldn’t really absorb it; sometimes we felt like observers from another planet.

You were ultimately on board an entire month longer than planned. Were you able to make the most of the situation?

For us, the whole affair was a major advantage, because the two crates of equipment that flew with us to Santiago de Chile somehow got lost on the way to the Falklands, so when we boarded the ship on 22 February, we had very little to work with. Thankfully we had the bare essentials in our carry-on luggage, like tools for dissecting krill and sample tubes for freezing the specimens. When the crates finally arrived in mid-March, we put the additional time to good use testing the prototype of a newly developed measuring device.

What exactly are you researching now?

Our goal is to find out how krill’s internal clock works – or more precisely, how it works in different seasons, and which daily and seasonal life functions it governs. For instance, we’re interested in identifying the factors that determine when krill are sexually mature. Or why krill sometimes grow more slowly, sometimes more quickly. Is their growth chiefly dependent on environmental factors, or is it the internal clock?

Could you describe the nature of your work?

We’re investigating the ‘clock gene’ in order to find out what drives the internal clock in different seasons. In order to conduct our studies on krill’s internal clock, we need to gather samples at different times. In other words, in a given region we collect samples every 3 to 4 hours over a 48-hour period. This allows us to analyse the daily changes in the ‘clock gene’. To do so, we dissect the krill, and later they undergo molecular biological testing in the lab back in Bremerhaven.

At the same time we need live krill from the same region, so that we can conduct experiments with them in various phases of light and darkness over the course of a week. We do this type of work directly on board. We analyse the krill’s behaviour using a device that combines a range of light settings and sensors. Normally, krill move to deeper water layers during the day, so as to hide from predators, and come to the surface at night to feed. We can use the device to simulate just the opposite light phases, so that we can find out whether the krill maintain their daily migration or adapt to the new lighting conditions. This can offer us insights into whether their migratory behaviour is dictated by their internal clock – or by external factors.

In addition, we plan to compare the results of our clock gene analyses and activity experiments with the animals’ behavioural patterns in the wild. On board we can use acoustic monitoring methods to explore the krill’s swarming behaviour on a large scale.

What makes krill so interesting to you?

Especially in the Southern Ocean, the krill is an important key species. It plays a central part in the food web, because many animals, like penguins, fish and seabirds, eat it. But it’s also the primary food source for larger animals like seals and whales. That’s why it’s important for us to understand whether, and if so, how the krill population is being altered by climate change.

What climate change impacts do you expect to see?

Because of climate change, the interplay between organisms’ key life functions and their environment, which developed over millions of years, and which in many organisms is controlled by an internal clock, could become imbalanced. One example would be phytoplankton blooms in the spring. After the long winter break, the phytoplankton blooms are an essential food source for the krill, helping them reach sexual maturity. We know that this interaction is governed by an internal clock. At a specific time in the Antarctic spring, the krill need energy and fatty acids from the blooms in order to become sexually mature. If the blooms came too early or too late, it could have a major impact on when the krill reach sexual maturity. And this in turn would have a negative impact on the development of the entire krill population.

For this cruise, you weren't traveling by research ship as usual; you were on a Norwegian krill fishing ship. How does day-to-day life on board a research vessel like Polarstern differ from life on board a commercial ship?

Everything on board is focused on commercial krill fishing. If the ship is fishing in a given area and the yield isn’t as good as expected, it moves on to another area. There’s no consideration given to important research questions or our sample-gathering plans. On the Polarstern, when the findings we make on board raise interesting new questions, we have a certain degree of freedom to explore them. But that’s not the case on a fishing ship: for instance, if I wanted to investigate the size structure of the krill in a swarm, and asked the captain to fish more in the upper or lower margin of the swarm, it would be virtually impossible, since the ship’s goal is always to catch as many as possible.

That being said, one major advantage is that we could easily get fresh krill samples direct from the sea, virtually whenever we wanted. Those are optimal conditions that you’d otherwise only find in a laboratory – for the first time, we were able to conduct our tests on the internal clock using wild krill. Moreover, the krill are pumped onto the ship quite gently, which means the samples we got were outstanding in terms of both their quality and quantity. Plus we didn’t have to coordinate with any other researchers to divide up the time on board the ship.

What’s the next step in your research? What will happen to the samples?

This was intended as a test phase, to see what’s possible on board from a scientific perspective, and to field-test devices currently under development for the AWI’s activity studies. The project is planned to cover two years, so that we have enough time to conduct our research in all seasons. The campaign’s official start is slated for this December. The frozen krill samples gathered on this cruise will be shipped to the AWI for analysis.  

Have you already made any important findings?

First of all, the many conversations we had with the crew and officers on board confirmed that the krill fishing industry, after years of operating in the same regions and seasons, has a tremendous amount of knowhow regarding krill behaviour and the seasonal geographic distribution of swarms. If we can successfully ‘translate’ these observations and hands-on experience into scientific findings, it could offer us far more detailed insights into the complex processes at work in the Southern Ocean.

Another important finding: using the ship’s acoustic monitoring system, we discovered that, in some regions, the krill don’t exhibit a daily vertical migration, as generally assumed; instead, they remain at the surface all day in huge swarms. Though we still don’t know why they behave this way in certain regions, we do know that it has a significant influence on the carbon flow.

You and your team have managed to put the extra time on board, due to the coronavirus pandemic, to excellent use for your krill research. But when and how did you get back to Germany? Thanks to the pandemic, your return was also a bit different than planned …

Yes, it was. First, on 30 April we returned to the Falkland Islands. The British Antarctic Survey, a close partner of the AWI and also stationed on the Falklands, did a brilliant job of helping us. They had to plan a major retrieval mission of their own, to bring their researchers in the Antarctic back home. The Royal Air Force flew us to a military base near London. Then we took a commercial flight from Heathrow to Germany, and finally, a train trip that brought us home.  

What was the best part about coming home?

That’s easy: the spring, the green, the blooming flowers and warm temperatures. For me it was an incredibly long winter, with plenty of snow, ice and fog.

Professor Meyer was interviewed by Laura Niemeyer, Communications Dept.