In the summers of 2018 and 2019, an all-female team of scientists ventured to the glaciers of Iceland to research the complex interactions between glacial systems, climate change and methane emissions.
Their findings were recently published in Scientific Reports. The study, one of only a handful of its kind, examined how melting glaciers release trapped methane – a potent greenhouse gas that contributes to global warming – and how microbes in glacial streams and lakes prevent that methane from reaching the atmosphere.
The team was led by 2019 National Geographic Explorer Kristin Strock, associate professor of environmental studies at Dickinson College.
She was joined by UW-Stout biology and environmental science Assistant Professor Nicole Hayes; Bridget Deemer, a research ecologist with the U.S. Geological Survey; and Dickinson student Rachel Krewson.
“Studies that span the land, ice, water, and air are rare because it requires an interdisciplinary and full ecosystem kind of perspective,” said Strock, who noted the critical work was possible because of the team’s interdisciplinary fields.
Clues to mitigating climate change in polar regions
Hayes’ research is on the effects of climate change on aquatic ecosystems, such as lakes and reservoirs.
She met Strock and Deemer when the three were PhD graduates, and together, they applied for a National Geographic Explorer grant to research the “Thermal controls on methane dynamics in Icelandic lakes: In-situ incubations across a geothermal temperature gradient.”
Polar ecosystems are being affected by climate change at a higher rate, including sea ice thinning, permafrost melting and accelerated glacial melt, with rapid loss of ice volume reported in 260 small glaciers across the globe.
“These ecosystems are really interesting because as they start to warm, they release greenhouse gases that have been trapped under the ice,” Hayes said.
“We know that under glaciers is the right environment for methane-producing microbes to live. These microbes create methane as part of their metabolism. As glaciers melt, they release large amounts of methane – a potent greenhouse gas.”
In their journey across Iceland, the team collected samples at four locations from three glaciers: Langjökull, Snæfellsjökull, and Sólheimajökull. At Sólheimajökull, they sampled water from a paraglacial lake and river.
To reach these locations, they rented a four-wheel pickup truck from an outfitter, drove down long gravel roads and parked on the side of the road to begin their trek to each site.
With no lab base, they carried in all their equipment, including inflatable rafts, oars and an electric trolling motor, as no gas motors were allowed.
“There were constant 20 miles-per-hour winds. It was very challenging to do fieldwork,” Hayes said. “But Iceland is very cool. At Thingvellir National Park, it is one of the few places where the Mid-Atlantic Rift is above sea-level. You can stand in the middle of two tectonic plates. Iceland is also famous for its midges – non-biting mosquitoes that emerge in mass every spring. They were everywhere.”
The team tested glacial meltwater samples onsite using the headspace equilibrium method – or shaky bottle method, Hayes said.
“By filling bottles with meltwater, measuring the amount of methane at the start, incubating them for 24 hours and agitating the bottles, we could then measure the methane in the shaken gas bubbles to tell us how much methane the aquatic microbes in the ecosystem used up.
“Methane is an important molecule for some microbes, which use the gas in their metabolism and turn it into carbon dioxide,” Hayes said.
The team found that when glacial meltwater enters lakes and streams, the microbes in the tributaries can consume large amounts of methane via a natural biological process called microbial methane oxidation, which may reduce atmospheric methane emissions from glaciers by up to 53%, significantly mitigating the impact of the greenhouse gas.
By incorporating methane oxidation into estimates of glacial methane emissions, scientists can more accurately assess the impact of melting glaciers on the global climate.
This expedition led Hayes to think more about under-ice research. Locally, she has studied how climate change may be affecting Lake Menomin, just blocks away from UW-Stout.
“Climate change is affecting our winter conditions here in Wisconsin, too,” she said. “Often, we think of lakes being inactive in the winter, because light tends to be limited under the snow and ice. But with warmer winters and thinner ice, we’ve been looking at how much algae is growing under the ice. We can ask questions like, ‘Does a greener winter lake affect the summer algal blooms?’”
Hayes thinks the best way to protect polar regions, glaciers, lakes and reservoirs, and the best to combat climate change is through government policies and individual actions.
“In Wisconsin, we all experience the effects of climate change firsthand. Warmer winters with less snow and less ice mean less ice fishing, skiing and snowmobiling,” Hayes said. “The data collected by scientists across the globe is just as clear. Humans are changing Earth’s climate. The real question is, how are we solving climate change.”
UW-Stout environmental science Program Director Mandy Little believes that “We are lucky that our faculty are highly engaged in globally important research and bring that cutting-edge experience to our students’ courses and research in environmental science and biology.”
The study was originally proposed by Krewson as part of her senior research thesis in environmental science as a student at Dickinson.
The team’s research was funded by a grant from the National Geographic Society, with additional support from the U.S. Geological Survey, the Churchill Exploration Fund and the Dickinson College Research and Development Fund.
UW-Stout’s biology department offers undergraduate degrees in applied biochemistry and molecular biology; applied science; biology; and environmental science, as well as a P.S.M. conservation biology. UW-Stout also offers degrees in chemistry and physics.
