From Vienna to Canada: Permafrost and hot springs

This summer, we – two doctoral candidates, a postdoctoral researcher and a professor – went to Canada, a vast country with pristine ecosystems that are now (increasingly) rare in Central Europe. They include roughly three million square kilometres of boreal forest and a little over 1.1 million square kilometres of peatlands – about a quarter of the world’s total peatland area. 

We are especially interested in these peat bogs because they mostly lie in the permafrost zone, which has been warming for decades and is starting to thaw at its southern edge. Organic carbon from thawing peat bogs (some 150 billion tonnes in Canada alone) can potentially be broken down by microorganisms. Yet surprisingly little is known about how global warming and thawing permafrost actually affect greenhouse gas emissions, especially methane. As part of the Cluster of Excellence 'Microbiomes Drive Planetary Health', we study how active archaea and bacteria in permafrost peat bogs respond to global warming and what that means for climate change. For that, we need peat soils – in this case, those from Canada.

Nature's climate change laboratory

Canada has even more to offer. The boreal forest zone of western Canada boasts hot springs that have become an important focus of our research. The soils around these springs have been warming for centuries and provide a unique opportunity to study the long-term adaptation of microorganisms to global warming. These 'warming experiments' fill a critical experimental gap, as climate change experiments have only been conducted since the 1980s. However, most of these experiments are no longer being carried out. As a result, we cannot validate the long-term projections of climate models.

Globally, there are only two sites where hot springs are used as natural experimental platforms: one in Iceland, which we have been studying for ten years, and one in north-western Canada. Together with a team from the Thünen Institute, we use a method developed in Vienna (vapor-qSIP) to identify the active microbial populations in this unique hot spring, which has existed for hundreds of years and has been documented since 1907.

Research location Whitehorse, Yukon: Report by PhD candidates Cornelia Rottensteiner and Anne Peter

Even getting to our research location was an adventure. A refuelling stop in Winnipeg, an unplanned overnight stay in Vancouver. But arriving in that vast, quiet landscape made it all worthwhile.

Our research site is located at the Takhini Hot Springs, where soils have been naturally heated for over a hundred years. The perfect place to investigate how a forest ecosystem adapts to long-term warming. How does microbial activity in the soil change under warming? We are now analysing our soil samples using molecular and biogeochemical methods. Our goal is to better understand important processes like future carbon storage and greenhouse gas emissions.
 

Finally back in the field

To be finally back in the field is the best feeling – digging, measuring, discussing together. That is where the best ideas are born. And sometimes stopgap solutions too, like using tea bags made from nylon curtains to determine degradation in the field. Lipton tea bags, which have been used until now, are now biodegradable.

We had a plan. But even before we started, it was clear that not everything could be planned. And, indeed, not everything was. Tools like spades and sieves had to be organised on site. This made the support provided by the local Yukon University and the Yukon Geological Survey all the more valuable.

We spent two intense weeks at the site. We were recording vegetation, measuring trees, collecting plant litter, digging soil profiles, reading water and temperature sensors, drying and weighing samples, and entering data late into the night. In fieldwork, no one sticks to official working hours. And although it stays light until 23:00 in Whitehorse in summer, we still had to switch on the lamps twice.

Science, culture and society

A free day in Kluane National Park with a visit to the Da Kų Cultural Centre taught us much about the Champagne and Aishihik First Nations. Another highlight was a local Pride drag show – colourful, warm, loud. Both reminded us how closely science, culture and society are connected. On our very last night, we were rewarded with northern lights.

Back in Vienna, however, we were shocked to find out that the airline had lost our samples – a NIGHTMARE! Luckily, our PhD supervisor, Andreas Richter, who was still working on another project in Canada, was able to replan quickly and return to Whitehorse to recollect at least the most important samples.

What did we bring home? New insights into microorganisms and climate change, fresh ideas, strong teamwork as well as the reminder that science rarely runs smoothly. But that is what makes it even richer and exciting.

Research location Yellowknife, Northwest Territories: Report by postdoctoral candidate Dennis Metze

Fieldwork as an ecologist means standing knee-deep in a peat bog, pulling samples from unstable ground. It also means waking up at 4:25, sitting 31 hours on planes, or driving more than 2,400 kilometres in a single week. Fieldwork is a special, intense time, with its own rhythm and rules. Rarely are we closer to the natural processes we try to understand. 

This summer took us from Yellowknife, on Great Slave Lake in the Northwest Territories, all the way to the far north of Alberta. You can imagine the landscape as an endless boreal forest that seems to go on endlessly as you drive straight for hours. Occasionally a track branches off, or a bison crosses the highway. Often the view is obscured by smoke from nearby wildfires. It is no surprise, then, that our only accommodation near the site was a remote fire station, from where firefighters track wildfires by helicopter and try to contain them. Our mission, however, was different.  

The microorganisms of permafrost peatlands

Despite the forest fires, there are permafrost soils here that remain permanently frozen beneath the thawing surface. On top of them are peatlands. These permafrost peatlands are a special ecosystem and cover several hundred thousand square kilometres. In them, water often stands just a few centimetres below a layer of peat moss. For the microorganisms living there, this means that there is no oxygen. But for methanogenic archaea, a special group of microorganisms, these are ideal conditions: they thrive here, producing methane, a greenhouse gas 28 times more powerful than CO₂ (calculated over 100 years). A few centimetres higher, oxygen is again available, and other microorganisms become active. Some of them are able to consume the methane produced below and use it for their metabolism. 

With the samples we collected, we aim to understand which microorganisms are active on different oxygen levels and how their interactions shift as temperatures rise and permafrost thaws. 

Beyond the data

Back in Vienna, it takes a little while to settle back into everyday life. There is not much time for adjustment. Samples must be weighed and extracted, and experiments must be started. But beyond the data and scientific insights, fieldwork leaves us with lasting memories and photos. For me, this includes a soot-covered firefighter joining us after a mission and asking about our work, or a lone wolf quietly watching us from the roadside as we drove past.

The research team