Microbial iron cycling during palsa hillslope collapse promotes greenhouse gas emissions before complete permafrost thaw

Abstract Reductive dissolution during permafrost thaw releases iron-bound organic carbon to porewaters, rendering previously stable vulnerable microbial decomposition and subsequent release the atmosphere. How mineral iron stability processes influencing vary transitional are poorly understood, yet have important implications for cycling emissions. Here we determine reactive associated content of core extracts porewaters along gradients in a peatland Abisko, Sweden. We find that by fermentative dissimilatory iron(III) reduction aqueous Fe 2+ aliphatic compounds collapsing palsa hillslopes. Microbial community analysis emission measurements indicate this is accompanied an increase hydrogenotrophic methanogen abundance methane emissions at front. Our findings suggest minerals contributes dioxide production emission, even before complete thaw.