“Usually, when you go to the Arctic, you go with an icebreaker carrying maybe 50 scientists”
Arctic diatoms live in the ice, but part of their life cycle still eludes Chris Bowler, a medal-winning biologist specialising in marine diatoms. He hopes that the Tara Polar Station – a drifting polar station adapted to sea ice – will enable him to observe the ice tunnels in which these micro-organisms hibernate during the polar night.
You are working with phytoplankton, mostly with diatoms. How do such tiny creatures survive the winter in the ice, do they have any metabolic activity?
When you see the ice surface, it is white, but when it turns over, sometimes in a storm or during oceanic circulation, the ice appears kind of brown. This brown color is often due to diatoms. They do metabolism, they are alive for sure, but they are in a quiescent state, as we call it. It is like hibernation for squirrels.
When seawater freezes, the ice forms. As it is water, so H2O, all the salt is excluded from the ice network. This salt, which is expelled from the ice, becomes concentrated. Thus, there are small channels inside the ice matrix that remain liquid and are highly saline. The temperature inside is very low, and the water is extremely salty, yet the diatoms are very happy in there. We don’t know how they survive in such conditions, and that is something we really want to understand with the Tara Polar Station mission.
What is the specific role of diatoms in the Arctic?
They are a very important component of phytoplankton in the Arctic, maybe the most important group. These organisms are crucial for generating food that everything else is eating through the trophic chain. All the way up to the polar bears, the whales, and the fish, generating energy and food from photosynthesis, just like forests on land.
These diatoms can live inside the ice and use the ice as a refuge during the winter when it is dark and cold, and there is not much light for photosynthesis. Then, in the spring, when the light comes, they proliferate, make very large blooms, and activate the whole life cycle.
Is it a very productive ocean?
It is not like a desert at all. The Arctic and Antarctic are very productive regions, somewhat equivalent to the Amazon rainforest.
You said diatoms are very important for the food chain. What do they contain – vitamins, carbohydrates… ?
One very important component is lipids – they are the currency of the entire ecosystem. Lipids are very rich in energy, and all organisms are trying to acquire them. They help organisms survive the winter. Just like animals need to eat and store lipids as fat to survive, diatoms are a very important source of these molecules: lipids, vitamins, and carbohydrates.
Diatoms help to mitigate climate change. What do you think we don’t know yet in relation to this phytoplankton and climate change?
We don’t really know what will happen to phytoplankton in the future with climate change. There are some studies that suggest that abundance will decrease in the ocean as temperatures increase, but we don’t know for sure. What is crucial to understand in the Arctic is what happens if the ice disappears. What this means for phytoplankton that use the ice as a refuge during the winter, how they survive.
This is a big question we hope to answer. What is the importance of ice as an environment for life? We know a lot about life in the ocean and on land, but we don’t know much about life in the ice. This is also true for glaciers and ice on land – we are beginning to see that there is a lot of life in the ice.
Do you have a time point useful for the comparison between past and present to understand the changes ?
No. We have data from the Canadian Arctic, the Russian Arctic, and the Norwegian Arctic, but these are at lower latitudes. We don’t have much information about the central Arctic because nobody is there in the winter. So we don’t really have a baseline, and we want to establish one and then observe the evolution over time.
We expect the Tara Polar Station to have a lifespan of 25 or 30 years and to follow the changes over this period. Typically, as scientists, we consider that we need at least 15 years of continuous records before we can start determining whether things are increasing or decreasing.
It’s impressive, this timeframe.
You see, things are changing very rapidly. We scientists are surprised to see how fast climate change is happening. But still, to know the real signal and distinguish it from the noise, we need to properly establish the database.
Did you order special materials or laboratory equipment to solve this question or to be able to collect pieces of ice?
The really big novelty of the Tara Polar Station is that we are staying in the Arctic for the whole year. Normally, when you do a mission, you go for maybe one month and then come back, so you don’t know much about the continuity throughout the annual cycle. Here, we will be able to follow what is happening throughout the entire year. That is a major novelty.
We will also have access to the organisms under the ice. Inside the ship, we have a moonpool, about 1.5 meters in diameter, through which we will deploy scientific equipment directly under the ice.
This equipment will measure what is happening beneath the ice and in the water and will also allow us to collect samples, like diatoms.
Then, we bring them back to the Tara Polar Station, where we have laboratories to observe them under powerful microscopes. We also have other scientific equipment that helps us understand what is happening inside the cells, including DNA sequencing devices, allowing us to perform DNA sequencing in the Arctic and understand almost in real time what is happening inside the cells. This is a major innovation in this project.
Will you drift there during the winter?
Probably not me. I think we need a special kind of scientist on board. The scientists need to understand Arctic science, but they also need to be good engineers – “un bon bricoleur” [he adds in French, ed. note] -, because equipment will break down, and we will have to repair things quite often. We need scientists who are also good at engineering. That’s not really me.
I think it will be more for young and strong people, both physically and psychologically. This is an extreme mission; we are pushing the limits of what humans can tolerate. It is the first time that people are trying to do this – to bring science to the central Arctic for a long period.
First time at this scale, isn’t it ?
Usually, when you go to the Arctic, you go with an icebreaker carrying maybe 50 scientists. This time, in Tara Polar Station, we will have only six scientists during the winter. These scientists have to be multitaskers, very well-organized, and we have to prepare in advance a daily schedule to ensure that all necessary tasks are completed throughout the mission.
We will have an aspect of experimentation, which we will conduct spontaneously when something interesting happens, such as during the spring. But we will also have the observational aspect, monitoring what is happening in the Arctic week by week and day by day.
We need to ensure a certain set of observations that we can provide to ESA and NASA, so they can validate their satellite observations and provide additional data to oceanographers. We have already spent a lot of time organizing the schedule, the task list of each scientist, as well as time off.
Do you already know who will be part of the team, or are you still in the recruitment process?
A little bit of both. We already have well-trained people who are well suited for this mission, but we are also recruiting people in the coming months.
You have already sailed extensively on ships, what is your personal experience with isolation?
Yes, being far away from people on land and disconnected from daily news. I have good experience with that. It’s very special, we live in a little ecosystem on the boat, with very little contact with the outside world.
Now, things are changing with satellites, but I remember when France won the World Cup in 2018. We were in the middle of the Pacific Ocean and were probably the last French people to hear the news, three weeks later or something like that. It was still nice.
It’s a very special ecosystem. Life is determined by the time of day and the sea conditions, and that’s all. You don’t really have any other interruptions like in daily life on land. It’s a very simple and precious ecosystem on the boat, shared with scientists, sailors, journalists, and artists.
It’s a special environment where we respect each other. There is a very flat hierarchy. Everyone is equal except for the captain, who has a higher rank. Otherwise, everyone is equal, and I like it.
Is this an international, European, or French project?
The Tara Polar Station has significant participation from Canada, the USA, Japan, Switzerland, and other European countries. It’s really international. We are fostering an international spirit and considering it like the ISS for the North Pole.
Indigenous people live in the Arctic, do you have a way to link the study with them?
We will make contact with Inuit communities, but there is nobody living so far north in the Arctic. They tend to be at 80°N at most, but they are mostly around 70°N. But, of course, people living in the Arctic understand ice very well – they have more than ten different words for it, whereas we have only one.
Considering that ice has a memory of the past within different layers of ice cores, we hope to interact with Inuit populations to engage with them and gather ideas and personal memories of the ecosystem, their lifestyle, and their cultures.
Interviewed by Camille Lin, Polar Journal AG
Chris Bowler is an English biologist, CNRS silver medallist and member of the French Academy of Agriculture working at the École normale supérieure. His work on photosynthetic organisms focuses mainly on marine diatoms, whose reactions to environmental stresses he observes.
Antarctic, Atlantic, Pacific and Mediterranean… more than 60 scientific publications in which he is involved are directly linked to the expeditions of the Tara schooner. As Chair of the Tara Ocean Foundation’s scientific council, the biologist is currently preparing for the Arctic expeditions.
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