Soil Geochemistry Confines Microbial Abundances Across an Arctic Landscape; Implications for Net Carbon Exchange with the Atmosphere

Soil Geochemistry Confines Microbial Abundances Across an Arctic Landscape; Implications for Net Carbon Exchange with the Atmosphere

A large portion of the World’s terrestrial organic carbon is stored in Arctic permafrost soils. However, due to permafrost warming and increased in situ microbial mineralisation of released carbon, greenhouse gas releases from Arctic soils are increasing, including methane (CH4(g)). To identify environmental controls on such releases, we characterised soil geochemistry and microbial community conditions in 13 near-surface Arctic soils collected across Kongsfjorden, Svalbard. Statistically significant correlations were found between proxies for carbonate mineral content (i.e. Ca and Mg) and soil pH (Spearman rho = 0.87, p < 0.001). In turn, pH significantly inversely correlated with bacterial and Type I methanotroph gene abundances across the soils (r = −0.71, p = 0.01 and r = −0.74, p = 0.006, respectively), which also co-varied with soil phosphorous (P) level (r = 0.79, p = 0.01 and r = 0.63, p = 0.02 …

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