It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Young researcher makes surprising methane discovery in Yukon glaciers: "Much more widespread than we thought"
Global melting is prying the lid off methane stocks, the extent of which we do not know. A young researcher from University of Copenhagen has discovered high concentrations of the powerful greenhouse gas in meltwater from three Canadian mountain glaciers.
SARAH ELISE SAPPER DIRECTED THE HELICOPTER PILOT TO LAND CLOSE TO THE GLACIER EDGE TO MEASURE THE METHANE IN WHIRLPOOLS OF MELTWATER STREAMING OUT. PHOTO: SARAH ELISE SAPPER
Young researcher makes surprising methane discovery in Yukon glaciers: "Much more widespread than we thought"
Global melting is prying the lid off methane stocks, the extent of which we do not know. A young researcher from University of Copenhagen has discovered high concentrations of the powerful greenhouse gas in meltwater from three Canadian mountain glaciers, where it was not thought to exist - adding new unknowns to the understanding of methane emissions from Earth’s glaciated regions
The helicopter’s rotor blades spin as its skillful pilot performs aerial acrobatics between the steep Yukon mountain sides where PhD student Sarah Elise Sapper is leading her first field expedition deep into the heart of the mountains of northwestern Canada. From the helicopter windows, her eyes fall on the jagged edge of the Donjek glacier: meltwater swirls out from beneath the ice like a whirlpool.
Soon after landing, it becomes apparent that Sarah has stumbled upon an unusual find on the first attempt. Seconds after starting up her portable methane analyzer it is clear that the air is enriched with methane and the culprit is soon found. Collecting a sample of meltwater, she measures concentrations of methane that far exceed expectations.
"We expected to find low values in the meltwater because it is believed that glacial methane emissions require larger ice masses such as vast ice sheets. But the result was quite the opposite. We measured concentrations up to 250 times higher than those in our atmosphere," explains Sarah Elise Sapper of the University of Copenhagen’s Department of Geosciences and Natural Resource Management.
The field party lifted off and continued to two more mountain glaciers, Kluane and Dusty. And after measuring the methane in the meltwater of each of those two glaciers, the preliminary finding turned out to be more than an anomaly. Here too, measurements showed high methane concentrations. Somewhere beneath the ice, there are previously unknown sources of the gas.
Demonstrates possibility of widespread methane emissions
"The finding is surprising and raises several important questions within this area of research," says Associate Professor Jesper Riis Christiansen of the Department of Geosciences and Natural Resource Management.
Christiansen, the research article’s co-author, believes that the finding demonstrates the possibility of methane being present beneath many of the world’s glaciers, ones that have thus far been written off.
"When we suddenly see that even mountain glaciers, which are small in comparison with an ice sheet, are able to form and emit methane, it expands our basic understanding of carbon cycling in extreme environments on the planet. The formation and release of methane under ice is more comprehensive and much more widespread than we thought," he says.
Until now, the prevailing view has been that methane in meltwater could only be found in oxygen- free environments under large masses of ice like the Greenland Ice Sheet.
The researchers assume that the production of methane is biological and happens when an organic carbon source – e.g., deposits from prehistoric marine organisms, soils, peat or forests – is decomposed by microorganisms in the absence of oxygen, such as we know from wetlands. As such, it is surprising that the mountain glaciers emit methane.
"The meltwater from the surface of glaciers is oxygen-rich when it travels to the bottom of the ice. So we found it quite surprising that all this oxygen is used up somewhere along the way, so that oxygen-free environments form underneath these mountain glaciers. And even more surprising that it happens to such a degree, that microbes start producing methane and we can observe these high methane concentrations in the water flowing out at the glacier edges" states Sarah Elise Sapper.
"Sarah's findings change our basic understanding and send us back to the drawing board in relation to some of the key mechanisms at play," adds Jesper Riis Christiansen.
An uncertain role for the climate of the future
According to the researchers, the findings in Canada do not immediately spur an increased concern in relation to their effect on climate change. However that conclusion may be temporary.
"Methane plays a major role in warming our planet. The challenge with methane is that it is a super-potent greenhouse gas and increasing emissions will accelerate climate warming. From a global perspective, we can measure how much is emitted into the atmosphere and, roughly speaking, where the methane comes from, using the isotopes found in the atmospheric methane. And for now, the contribution of methane from ice-covered regions on our planet, including ice sheets and glaciers, isn’t increasing,” explains Jesper Riis Christiansen.
However, he emphasizes that the measurements cannot distinguish between methane from glaciated regions and methane from wetlands. Therefore, the numbers could be deceiving. And, the effect of melting remains unknown.
Jesper Riis Christiansen believes that the findings demand vigilance.
"The three sites Sarah measured were randomly selected due to the availability of a research station and helicopter, yet methane was found in all three. In itself, that is a good reason to better understand the area. There's too much that we don't know, and the melting glaciers expose unknown environments that have remained hidden for thousands of years. In reality, no one knows how emissions will behave," says Jesper Riis Christiansen.
He hopes that a better understanding of methane behaviour beneath glaciers will also help researchers better understand the mechanisms at play when wetlands release methane, and thereby contribute to the development of solutions to remove methane from the atmosphere through oxidation - e.g., through the use of certain soil types.
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Extra info: A subglacial black box
The actual sources and locations of subglacial methane production actually remain somewhat of a mystery, hidden beneath ice masses of all sizes. Indeed, this methane can only be measured as the meltwater emerges from beneath the ice. And because it originates from large areas below the ice masses, this makes it difficult to access exactly where the production happens.
It is known to not originate from the ice itself, as concentrations both in the ice and meltwater atop it are lower than what is measured at the glacier edge. As such, the researchers believe that the methane must derive from a source beneath the ice. And the best theory, as mentioned, is that it is formed by microbes in oxygen-free pockets and then carried out with meltwater.
But this indirect knowledge of the source leaves a great deal of uncertainty about how much methane is hidden beneath the ice.
"It's a big black box under the ice – and you could say that the meltwater is prying the lid off it. We do not know whether methane emissions from glacial areas will increase in the future with increased melting, or whether the 'lid' has already been opened to such a degree that the methane beneath the ice is actually being washed out with the meltwater," says Sarah Elise Sapper.
Facts: Methane and CO2 are different greenhouse gases
The half-life of methane in the atmosphere is 12 years.
CO2 has a much longer half-life, at roughly 1000 years.
On the other hand, methane is about 25 times more powerful as a greenhouse gas on a 100-year basis and a far more serious threat to global climate in the shorter term.
Due to greenhouse gas-driven climate change, researchers around the world are working to develop ways to capture or store CO2.
Similarly, solutions are being devised to limit the emission of – or increase the oxidation of – methane. Doing so requires more knowledge about how methane is formed.
Extra facts: Carbon circulation of methane and CO2
Biological traces from animal and plant material in the subsoil consist of carbon.
Within these environments, microorganisms have developed an ability to convert carbon into energy in a process where methane is created as a byproduct in the absence of oxygen (e.g. in beneath ice sheets or in wetlands).
However, if the methane is released into an oxygen-rich environment, it can effectively be oxidized and converted into CO2 by microbes. Wetlands play an important role in this process.
Once, in the atmosphere, methane reacts with other chemicals (hydroxyl radicals) which keep the concentrations down.
However, as temperatures rise, the amount of methane emitted from ecosystems around the world increases – from the Arctic to the Amazon. And the balance may be shifting if the processes that remove methane do not react to the same degree.
Extra info: An expedition of her own design
Sarah Elise Sapper’s expedition to Western Canada was the first organised on her own. The young researcher impressed her more experienced colleagues by arranging the field study completely by herself. When Sapper found out that EU funds, through the INTERACT network, were available to finance a visit to the Kluane Lake Research Station in the Yukon Territory of northwest Canada, she immediately saw the opportunity to get measurements of glacial methane emissions from places no one had thought of before.
"Together with people from the Canadian research community, she arranged for a helicopter and everything else needed for the expedition. We were really impressed by this back home. We hope that it will inspire other young researchers to embark on fieldwork on their own, when the opportunities arise," says Jesper Riis Christiansen, who in addition to being a co-author of the research article, is also Sarah's supervisor at the Department of Geosciences and Natural Resource Management.
Behind the research
In addition to Sarah Elise Sapper and Jesper Riis Christiansen from the University of Copenhagen, the following researchers have also contributed to the study:
Christian Juncher Jørgensen from Ecoscience at Aarhus University, Denmark
Moritz Schroll and Frank Keppler from the Heidelberg Center for the Environment (HCE), Heidelberg University, Germany
Over the last four decades, warming climate and ocean temperatures have rapidly altered the Greenland Ice Sheet, creating concern for marine ecosystems and weather patterns worldwide. The environment has challenged scientists in their attempts to measure how water moves around and melts the ice sheet because equipment can be destroyed by icebergs floating near the glaciers.
Collected using a novel approach, research from the University of Maine has unearthed new information to help scientists better understand circulation patterns of ocean water around glaciers. A group of pioneers in glacial research attached GPS devices to icebergs and used their mobility to understand fjord circulation, which can ultimately enhance the accuracy of climate models.
In the summers of 2014 and 2019, the GPS devices tracked hourly changes in the position of 13 icebergs as they passed through Greenland’s Ilulissat Icefjord toward the ocean. Starting as research during her time at the University of Oregon, UMaine assistant professor of geomatics Kristin Schild collected the fjord data with a colleague from UO, earth sciences professor and oceanographer David Sutherland. In 2020, an undergraduate student, Sydney Baratta, used these datasets as the focus of her senior capstone project. Continuing the research into her graduate studies, Baratta processed and analyzed her findings and recently published the results in the Journal of Geophysical Research: Oceans.
Study results showed circulation in the primary fjord is greatly affected by freshwater flow from connecting tributary fjords, which is critically important to consider in circulation models. Such models can range from studying ocean currents to predicting the speed at which sea level could rise.
“Being able to utilize the many icebergs that are in this fjord is really unique to the study,” said Baratta.
Ilulissat Icefjord is home to Sermeq Kujalleq, one of the fastest and most active glaciers in the world. This makes the fjord a good, but challenging location to understand glaciers’ interaction with the ocean and predict how the icy giants respond to ocean warming.
“Think about ice cubes in a glass of water. They float,” said Baratta. “But if it's in a fjord, under the influence of other forces like wind and the currents, the icebergs move around. What we wanted to do was put GPS trackers on those icebergs to infer what the circulation in the fjord is and see how that is influenced by the environment.”
Carlos Moffat, who researches glacier-ocean interactions and polar oceanography at the University of Delaware, said equipment stationed in fjords is commonly crushed by all the movement. How Schild collected these datasets, he said, was innovative. Instead of viewing the icebergs as an obstacle, she used them as a tool to carry and protect the equipment.
“It's a situation where the thing you're interested in is destroying your gear,” said Moffat. “So what they've done in this study is basically flip the script.”
Kristin Schild getting back in the helicopter after deploying a GPS tracker on the surface of one of the icebergs in 2019.
CREDIT
Mark Carey
Impact beyond the Arctic
Greenland, where Ilulissat Icefjord is located, and Antarctica have the largest fresh water reservoirs of ice in the world. How quickly the ice sheets melt contribute to sea level rise worldwide. In Greenland and Antarctica, glaciers “dip their toes” in ocean water, Moffat said, which can allow ocean warming to accelerate how quickly the ice melts or breaks into icebergs.
Lauren Ross, UMaine associate professor of hydraulics and water resources engineering, said Baratta, Schild and Sutherland’s findings will be useful for a range of research relating to fjord circulation, including her area of expertise — the transport of material in water.
She recently studied how freshwater flowing into a fjord negatively impacted the growth of a harmful microscopic algae. Unlike in Greenland, more freshwater helped the economy and ecosystems surrounding the fjord.
“In order to be as accurate as possible, we have to have the most accurate data to feed into the models,” said Ross. “I think it's going to become more and more important as the climate warms.”
Similar to Ross’ reflection, Schild said recognizing that changes are happening in the environment is the starting point. Scientists are now working to fill gaps in research to represent the changing environment and create better predictive models.
“Glaciers have reshaped global climate and ecosystems for millions of years,” said UMaine President Joan Ferrini-Mundy. “Novel research from our world-renowned climate scientists provides more insight into how they interact with their surrounding environments and plays a vital role in predicting our climate future.”
Data processing and analysis was supported by grants from the U.S. National Science Foundation (NSF) and NASA’s Early Career Investigator Program, which focuses on the use of space-based remote sensing and model integration to benefit humanity.
While the ever-altering Greenland Ice Sheet has dramatic local impact, it is the top of a slippery slope slanted toward changes worldwide. What happens in the frozen fjords 2,000 miles to the north of Maine affects New England's seafood cuisine and has a role in the increasingly devastating storms along the coast.
“Everything is interconnected,” said Baratta. “Changes happening in the Arctic can have trickle-down effects that impact what we see in Maine.”
Microbial life will flourish in mountain streams because of ongoing glacier shrinkage. This is what a team of scientists from EPFL and Charles University, Prague, report in a paper published in Nature Geoscience. Their observations are based on samples collected from 154 glacier-fed streams worldwide as part of the EPFL-led Vanishing Glaciers project, which is funded by the NOMIS Foundation. Glacier-fed streams are murky, raging torrents in the summer. Large quantities of glacial meltwater churn up rocks and sediment, allowing very little light to reach the streambed, while freezing temperatures and snow in other seasons provide little opportunity for a rich microbiome to develop. But, as glaciers shrink under the effects of global warming, the volume of water originating from glaciers is declining. That means the streams are becoming warmer, calmer, and clearer, giving algae and other microorganisms an opportunity to become abundant and to contribute more to local carbon and nutrient cycles. “We’re witnessing a process of profound change at the level of the microbiome in these ecosystems – nothing short of a ‘green transition’ because of the increased primary production,” says Tom Battin, a full professor at EPFL’s River Ecosystems Laboratory (RIVER). Changing composition In their paper, the scientists looked at the nutrients, such as nitrogen and phosphorus, in the stream water as well as the enzymes that microorganisms living in the streambed sediment produce in order to use these nutrients. Then, they looked at changes in both of these over a very large gradient of streams fed by glaciers that differ in size. “Glacier-fed-stream ecosystems generally have limited quantities of carbon and nutrients, particularly phosphorous,” explains Tyler Kohler, a former postdoc at RIVER and the paper’s lead author. “As glaciers shrink and the demand for phosphorus by algae and other microorganisms grows, phosphorus may become more limiting in high-mountain streams.” Hence phosphorus, a critical building block for life, will become even more rare in downstream ecosystems, including larger rivers and lakes, with yet unknown impacts for their food webs. Advanced stage in Uganda
These findings are supported by a paper published in Royal Society Open Science in August 2023 by scientists from the Vanishing Glaciers project. In this study, the authors analyzed the microbiome of a small glacier-fed stream in the Rwenzori Mountains, in Uganda, where the “green transition” was already at an advanced stage. Here, the nutrient and enzyme composition was also much different, and algae were abundant. “What’s happening with the Rwenzori glacier gives us a glimpse of what Swiss glacier-fed streams will look like 30 or 50 years from now,” says Battin. One outcome of this change is that as glacier-fed streams host more microbial life, they will play a bigger role in biogeochemical cycles such as CO2 fluxes.
The RIVER team plans to build on this research. They are conducting a census of the microbial biodiversity in glacier-fed streams and, using various lines of genomic information, are exploring how diverse microorganisms are able to dwell in one of Earth’s most extreme freshwater ecosystems.
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