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Marina Nieto-Caballero, Postdoctoral Fellow, Atmospheric Science Department, Colorado State University

Arctic air temperatures are rising at more than four times the global rate. As a result, permafrost and ice wedges are rapidly thawing, releasing greenhouse gas reservoirs and microorganisms with greenhouse gas-generating metabolism. Thawed permafrost landslides are also increasing due to warming temperatures, introducing thawed soil into various water bodies (i.e., ocean, rivers, and lakes). Microorganisms from thawed permafrost and ice wedges discharged to these water bodies can ultimately be aerosolized through wind-driven and/or greenhouse gas bubble bursting in thermokarst lakes. In addition, these airborne biological particles can be a potential source of biologically-derived ice nucleating particles (INPs) at warm temperatures (≥ -10^oC), potentially altering cloud dynamics in Arctic regions.

Environmental samples were collected during Summer 2021 in Northern Alaska (Utqiaġvik region), including air, water (i.e., ocean, rivers, and thermokarst lakes), permafrost, ice wedge, and vegetation, as well as aerosol particle distribution data. Results from 16S rRNA gene sequencing were used to characterize microbial diversity, showing how permafrost, vegetation, and different water bodies are potential sources of bioaerosol composition in Northern Alaska, based on DNA source tracking (SourceTracker2). The obtained air microbiome results are additionally linked to air mass back trajectories calculated with NOAA’s HYSPLIT model. This study is part of the multidisciplinary ARCSPIN project (ARCtic Study of Permafrost Ice Nucleation), which additionally includes INP analysis, as well as aerosol and INP modeling. (meet the ARCSPIN team here)