Brutal field trip provided new insights into Arctic winter
It was the hardest field trip they had ever been on, but the result was both surprising and exciting.
After hiking nine kilometres with a 400‑meter elevation gain and carrying heavy backpacks through very rocky terrain, the researchers spent more than 24 hours in the field and returned with sediment samples from Lake Stuptjørna.
Stuptjørna lived up to its name: the terrain was steep and at times almost impassable.
“We completely underestimated the trip, especially with the amount of equipment we had to carry. Sleep was also in short supply and people were exhausted,” says research professor Willem van der Bilt of the University of Bergen and the Bjerknes Centre, reflecting on the demanding field trip in the summer of 2022.
What is that white spot?
Alexandra Rouillard from Umeå University was also part of the crew. She was a postdoc at the time, and it was her first trip to Svalbard. What began as a scenic hike turned into a demanding expedition across steep terrain, unstable boulder fields, and long ascents carrying heavy equipment — all under the constant awareness that polar bears roam the area.
“I seriously began questioning my priorities in life. Indeed, living itself emerges as a strong contender versus science at that point,” she says.
After more than 24 hours, they returned to the shore of Wijdefjorden with their sediment cores and wet gear.
“We all took a (much needed) cleansing swim and finally made it back to the sailboat, ferrying our equipment and people back and forth until the last of the team were on board. Pure joy. Minutes later, we noticed a white spot on the beach we just left behind,” Rouillard says. In the picture below you can see what that was.
Surprising layers
The lake was chosen because of its high elevation. The goal was to gain a better understanding of past Arctic winter climate, along with the natural mechanisms that control it, by using this lake as an archive of winter conditions.
“The higher the lake, the longer winter lasts,” van der Bilt explains.
They collected a sediment core from the lake containing 7,000 years of climate history, and during laboratory analyses they discovered something surprising. The paper is published in Geophysical Research Letters.
“We found out that these little layers we saw during fieldwork were minerals that form in the lake under very specific conditions, when there is no oxygen in the water. The longer the lake is covered by ice, the less oxygen is found in the water, which is directly linked to winter climate,” van der Bilt explains.
Combining methods
Methodologically, the study married established laboratory methods with new scanning techniques. For example, medical CT scans were used to identify the (often invisible) anoxic mineral concretions, while their chemical composition was confirmed using microscopic analysis.
In addition, they relied on hyperspectral imaging, a method that identifies the characteristic visible and invisible light spectra of specific materials. In this case, they used the light spectra of pigments produced by bacteria that lived in the lake when there was little oxygen.
They found that variations in winter climate track a well-known 1500-year climate cycle.
“You can think of it as the heartbeat of natural climate in this area. But we are the first to report that it also has an impact on winter climate on land,” van der Bilt says.
“So, depending on where you are in that cycle in a future also shaped by human climate warming, that cycle could either make the impacts of human climate change worse, or dampen it a little bit.”
Volcanic eruptions
The second big thing is that almost every extreme winter they found in this lake appeared to happen after multiple volcanic eruptions that had occurred closely spaced in time.
Volcanic eruptions inject large clouds of particles and gases into the atmosphere, which can block incoming sunlight for years or even decades.
“By combining all kinds of fancy scanning and microscope techniques, we find that these extreme volcanic winters happened throughout the past 8,000 years, regardless of the background state of climate. That means that extremely cold volcanic winters also can happen in the warmer future that the region faces.”
Alexandra Rouillard’s full account of the hike up to Stuptjørna
That morning, semi-rested, we got ready for the big ascent (200-plus meters above sea level) to Stuptjørna. For months (if not years), we had been staring from a distance at this round gem of a lake, which has one of the highest elevations in the entire archipelago. We pack the gear we need for data collection, safety equipment, firearms, changes of clothes and food into the small boat ferrying us to land, then awkwardly into or onto our backpacks.
I have been training and building my body back for this hike. Will my injured lower back (a result of being pregnancy with two Scandinavian-sized boys) allow me to hike 20 to 30 kilograms of gear up to this lake? Twice? Then also get the work done? The stakes are high, which makes me nervous. We start walking.
We start on a nice beach of pebbles and cobbles. I am so excited to be there, even to the point of forgetting not to yell at people about how beautiful and amazing everything is, which nearly give our PI A. Schomacker a series of heart attacks. A loud voice should only ever be used in the Arctic in the case of polar bear sightings, which are (still) very common on Svalbard.
I calm down some as we start ferrying gear on an inflatable zodiac across the Røyetjørna, while some of us walk along the shore. A bit of uphill walking to a nice viewpoint onto the large lake Røyesjøen (“this is great, we can do this!”) and then some well deserved fika.
That leads to a perilous passage along a steep mountain hill, with giant, sharp boulders we need to hop to and from that look like they have only recently fallen off the cliff. The geologists among us know the timescales of this “recent” fall are way beyond that of a human life, and that from previous experience they are the best way to cross over.
But it is my very own human life I feel I am risking with every step I take to cross this much too inclined field of boulders, unbalanced by my giant backpack, and I must ask multiple times whether this was indeed the best way for some reassurance. Finally in safer terrain for a few minutes, there begins a wild ascent that gives me an impression of how it must be on the final legs of an Iron Man contest.
I’m at the tail of the group sweating, while some of us simply trot along like mountain goats. With our prize in sight, we happily walk down again towards it, trying our luck on the presumably smoother little leftover snow patch still melting into the lake, only to decide against it after sinking with every step we took.
We leave much of the gear in place for sampling the next day, hoping that polar bears do not decide to use our materials as entertainment.
The return to the boat on day one is attempted via a “short cut”, which turns out to be much too close for comfort to the “precipice of doom” (towering over a near-200 meter vertical cliff to Røyesjøen). Note to self: Next time, return via the other route.
The (too) inclined boulder field exhibits the same traits as on the way over, and I begin to seriously question my priorities in life. Indeed living itself emerges as a strong contender versus science at that point. Somehow, the souvenir of the exciting and nice “walk on the beach” is suddenly very distant in the last few 100 meters back to the sailboat.
Thinking about the hike to the lake and back is really daunting, but sleep and the promise of a unique climate record from Stuptjørna gives us strength. This time, our sampling stretches across the day, and we return more than 24 hours later to the shore of Wijdefjorden with our precious cores and wet gear sticking out from every angle of our silhouettes.
We all take a (much needed) swim and finally make it back to the sailboat, ferrying our equipment and people back and forth until the final team members are back on board. Pure joy. Minutes later, we notice a white spot on the beach we just left behind.
Tori Pedersen is a communication adviser at the Bjerknes Centre for Climate Research. She is an experienced journalist with more than 10 years at the Norwegian broadcaster TV2.
