SUSTAIN

Warming intensifies soil organic matter mineralization more than vegetation productivity, causing significant carbon (C) losses in northern soils. Initial findings from our research team suggest varying vulnerability to warming between high latitude mineral and organic soils, possibly linked to substantial nitrogen (N) losses in mineral soils during early warming stages. This crucial mechanism is currently overlooked by ecosystem models, contributing to observed vs. predicted C loss disparities. SUSTAIN will make use of the expertise of a multidisciplinary group of world-leading researchers and of unique research sites in Icelandic geothermal systems (ForHot sites, Hveragerdi) and Swedish peatlands (Abisko area) to uncover the initial biogeochemical destabilization processes triggering C losses in high latitudes soils under warming.

By comparing key metabolic and physiological processes of soil microbes (CUE, gross N transformation rates) and community shifts along a permafrost thaw gradient in organic soils and a in mineral soil translocation experiment using geothermal gradients, we aim to address three fundamental knowledge gaps: (1) the occurrence of progressive shifts in activities and stoichiometric needs of soil microbes; (2) the arise of asynchronies between the rates of microbial N mineralization and plant N uptake; (3) the effect warming on soil food web assembly and biogeochemical cycling. SUSTAIN promises groundbreaking insights into climate warming-induced alterations.