Geochemical analysis reveals viable methanogens and organic nutrients in thawing Arctic permafrost cliffs, suggesting rapid greenhouse gas release upon coastal erosion.
Key Points
To assess the biogeochemical effects, nutrient availability, and microbial community composition associated with the thermal abrasion of Arctic coastal permafrost cliffs.
Sampled frozen clayey aleurite sediment horizons from the Mamontovyi Khayata coastal cliff outcrop on the Bykovsky Peninsula, Northern Yakutia.
Quantified lithological properties, organic matter content, methane concentrations, and biogenic nutrients, including ammonium, nitrite, nitrate, phosphate, and acetate.
Profiled taxonomic diversity and identified viable bacterial and archaeal populations within the permafrost horizons using 16S rRNA gene profiling.
Methane was present in all permafrost horizons, with concentrations correlating positively with the organic matter content and alongside biogenic elements like ammonium and acetate.
16S rRNA gene profiling revealed diverse bacterial phyla (Chloroflexota, Actinobacteriota) and archaeal communities dominated by acetoclastic and hydrogenotrophic methanogens (Methanosarcinales, Rice Cluster II) and ANME-2d methanotrophs, while bacterial methanotrophs were absent.
Viable microbial cells were detected across all samples, indicating high capacity for rapid microbial reactivation and elevated greenhouse gas release once frozen sediments thaw.
Cite This Study
Berestovskaya et al. (2026) studied this question.