| Summary: | With permafrost (i.e., perennially frozen ground) degradation due to the increase in air temperature in high latitudes, previously frozen soil organic carbon (OC) becomes vulnerable to mineralization which reinforces the global warming through the release of greenhouse gases. However, it is not considered that between 30 and 80% of permafrost OC are stabilized by interacting with metals. These interactions are modified by changes in redox conditions induced by changes in hydrological conditions resulting from permafrost thaw. Crucially, it is not accounted for that (i) permafrost thaw generates soil subsidence which involves changes in soil hydrology, that (ii) changing soil hydrological connectivity impacts mineral-OC interactions. Moreover, fluctuations in redox conditions directly affect soil nutrient solubility thus potentially becoming no longer available for plant uptake. Shedding light on the link between changing soil hydrological connectivity upon permafrost thaw and the release of nutrients and OC interacting with minerals bears direct relevance for predicting future permafrost C emissions. Tackling this gap in knowledge comes with the identification of three objectives: understand how permafrost thaw affects soil hydrology spatially along a natural permafrost degradation gradient and temporally throughout the late shoulder season; assess OC and nutrient fluxes spatially and temporally; scale up at the site scale DOC and nutrient fluxes found at the profile scale - using high-resolution remote sensing techniques. A multidisciplinary approach such as the LandSense project is imperative to take on the challenge of addressing this urgent concern in a warming Arctic.
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