Growing up in Minnesota, Scott Sugden spent a lot of time in the outdoors, particularly canoeing and backpacking in the Arctic.
The Arctic became a landscape that he cared deeply about. It led to work in outdoor education, a high school biology classroom, and now as a researcher in environmental microbiology.
This perfect blend of the outdoors and science brought him to Lyle Whyte’s laboratory at McGill University in Quebec, Canada. Whyte is a professor who has spent more than two decades conducting polar microbiology research at McGill and shares a passion for the outdoors.
Sugden, a third-year PhD student, approached Whyte about pursuing research looking at deglaciated soils near the North and South Poles. Deglaciated soils are soils that have been trapped under glaciers for thousands of years, with very limited biological activity during that time. As a result of climate change, these nutrient-poor soils, or “pioneer soils,” are now exposed, and new communities of microorganisms have subsequently emerged and are evolving.
Through a project award from EMSL, the Environmental Molecular Sciences Laboratory, a Department of Energy Office of Science user facility, Sugden and Whyte are developing a long-term, predictive understanding of how microbial activity affects carbon flows and climate patterns in the Arctic—one of the most rapidly changing environments on the planet.
Deglaciated soils research
In 2022 and 2023, Sugden’s field research took him to receding glaciers near both poles. He traveled by prop plane to White Glacier on Axel Heiberg Island in Nunavut, Canada. To get to the Hurd Glacier on Livingston Island in Antarctica, Sugden flew to Chile, boarded a charter flight to Antarctica, and then took a boat to the island.
In both locations, Sugden collected samples of five- to sixty-year-old soils from the area in front of the glaciers.
“We’re collecting soils of a bunch of different exposure ages to look at this process of community development and, in particular, how microbial community development affects the flow of nutrients through that system, especially carbon,” said Sugden. “That’s of major interest for the climate. Soil can be a really important carbon repository, but it can also be a really important carbon source, so it’s important for predicting future Arctic climate budgets and carbon budgets.”
After collecting the soils, Sugden incubated a portion of the samples at projected future environmental conditions, including increased temperature and precipitation.
From there, Sugden has been examining the microbial activity within the soils as well as the carbon flux.
Advancing glacial research with EMSL instrumentation
After incubation and laboratory analysis at McGill University, soil cores were prepped for single-cell analyses at EMSL. Using EMSL’s in situ hybridization (FISH) and nanoscale secondary ion mass spectrometry (nanoSIMS) capabilities, Sugden is working to determine where microorganisms live within the soil, which carbon sources are being used, and how cellular activity may vary among cells or soils. Sugden is working to determine where microorganisms live within the soil, which carbon sources are being used, and how cellular activity may vary among cells or soils.
“One of the biggest advantages of collaborating with EMSL is that EMSL has a nanoscale secondary ion mass spectrometer, which is called a NanoSIMS, and excellent expertise in using this platform,” said Sugden. “There are only 40 or 50 of those in the world. Only about 17 to 20 are publicly accessible.”
With NanoSIMS, Sugden said that he can visually observe the process of how cell-to-cell and cell-to-mineral associations develop.
Sugden also analyzed microbial communities using metagenomic and metatranscriptomic sequencing to provide information on how single-cell processes relate to the carbon-cycling activity of the whole microbial community.
These analyses will help provide a comprehensive understanding of the molecular processes that impact carbon flow through deglaciated soils.
Sugden noted that he benefited from working with EMSL staff who are experts, particularly with using NanoSIMS. This included in house training on how to prepare the samples and how to analyze the data.
EMSL’s resources have allowed researchers like Sugden to be visionary, Whyte added, and to take their science much further than what they may have available to them at their institution.