Kate Schuler, PhD 
Application Scientist at Picarro

 

Picarro Spotlight is a blog series showcasing important scientific work from our customers around the world. Each blog is selected and summarized by our team. Enjoy!

Arctic glaciers are retreating rapidly, and research published in Nature Geoscience (Groundwater Springs Formed During Glacial Retreat Are a Large Source of Methane in the High Arctic, Kleber et al. 2023) reveals that this retreat is unlocking a surprisingly large and previously overlooked source of methane. Methane-rich groundwater springs with methane concentrations more than 600,000 times higher than atmospheric equilibrium, previously trapped beneath the glacier, can now flow freely to the surface and vent directly to the atmosphere.

To understand where this methane comes from, the researchers combined spatial data indicating the bedrock geology, with carbon‑isotopic measurements, which provide a chemical fingerprint of methane’s origin. The spatial data showed that the higher methane concentrations were generally associated with shale-dominated Jurassic and Triassic outcropping geology, suggesting a geologic or thermogenic source of the gas. Using a Picarro G2201‑i isotopic carbon analyzer, they measured the stable carbon isotopic ratio in methane samples (δ¹³C‑CH₄) from dozens of springs. These isotopic signatures showed that much of the methane is thermogenic, i.e. formed deep underground under high temperature and pressure conditions from ancient organic matter as opposed to biogenic methane, which is produced by microbial life, and has a relatively higher proportion of the lighter carbon isotope: ¹²C-CH₄.

This distinction is crucial, as thermogenic methane on Svalbard is sourced from deep geological reservoirs, and is brought to the surface via groundwater springs as glaciers retreat, a far larger and more persistent methane source than if it were produced by microbial life in sediments at the base of the glacier.

The study’s extensive field sampling allowed the team to estimate that Svalbard’s proglacial springs may emit up to 2.31 kilotons of methane per year. As more marine‑terminating glaciers retreat onto land, the researchers warn that similar methane‑rich springs could appear across the Arctic. Their findings highlight an additional positive feedback loop of warming driving glacial retreat, retreat driving methane release via groundwater springs, and methane release accelerating warming even further.

Meet the researchers:

Gabrielle E. Kleber, Department of Earth Sciences, University of Cambridge & University Centre in Svalbard (UNIS), Longyearbyen, Norway.

Andrew J. Hodson, University Centre in Svalbard (UNIS), Longyearbyen, Norway & Department of Environmental Sciences, Western Norway University of Applied Sciences, Sogndal, Norway.

Leonard Magerl, Department of Geology, UiT the Arctic University of Norway, Tromsø, Norway.

Erik Schytt Mannerfelt, Arctic Geology, University Centre in Svalbard (UNIS), Longyearbyen, Norway & Department of Geosciences, University of Oslo, Oslo, Norway.

Harold J. Bradbury, Department of Earth Sciences, University of Cambridge, Cambridge, UK & Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada.

Yizhu Zhu, School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK.

Mark Trimmer, School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK.

Alexandra V. Turchyn, Department of Earth Sciences, University of Cambridge, Cambridge, UK.

For more information:

Read the Paper

Explore Picarro Research Center

Learn more about the G2201-i