| Summary: | Increased land-water interactions facilitated by permafrost thaw are mobilizing terrestrial materials to aquatic networks and changing carbon and nutrient availability for microorganisms. A portion of this carbon is readily available for biological decomposition, resulting in carbon dioxide and methane emissions as by-products. However, other pathways for permafrost carbon have the potential to protect carbon from conversion into greenhouse gases. In non-permafrost soils, mineral-organic interactions are an established mechanism of sequestering carbon by reducing the bioavailability of organic matter via physico-chemical processes (McDowell and Wood 1984, Kaiser et al. 1996). In northern ecosystems, where changing climate conditions are causing active layer deepening and thermokarst formation, interactions between organic-rich surface waters and newly exposed, mineral-rich permafrost may be facilitating similar effects. […]
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