Objective As the Arctic permafrost region warms, its large organic carbon (OC) pool becomes vulnerable to decomposition. This generates greenhouse gases (GHG) that in turn fuel increased surface warming: the permafrost carbon feedback. Higher temperatures will jump-start the coupling between the carbon and hydrological cycle, allowing for the introduction of previously frozen OC pools in aquatic systems. This lateral, or horizontal, aquatic flux remains largely unknown in contrast to the relatively well-studied vertical flux, GHG emission on land. Horizontal OC release either occurs via gradual thaw, slowly leaching OC into aquatic systems, or abrupt thaw, where ground-ice melt causes destructive surface collapse and slumping of OC into aquatic systems. Both types of thaw facilitate decomposition of OC (generating GHG) but also re-bury OC into sediments (sequestering OC). The relative importance of decomposition versus burial is unknown. For THAWSOME, I have developed a multi-scale approach combining detailed process-based field studies with up-scaling techniques on multiple levels: (i) observational, using large Arctic rivers as natural integrators, (ii) numerical, using a coupled hydrological-biogeochemical model, and (iii) spatial, using GIS-based analysis. For the first time, decomposition of particulate OC from permafrost will be quantified with a recently developed incubation method. Burial rates of permafrost OC will be assessed through molecular isotope analyses of both sources (river OC) and sinks (sediment OC) across the land-to-shelf route. THAWSOME will generate critically needed quantitative data on the amount of decomposition versus burial of permafrost OC, as well as qualitative insights into the processes that control this. This will allow a true coupling of the carbon and hydrological cycle into the 'boundless Arctic carbon cycle', and integration of horizontal OC release into estimates of the impact of the permafrost carbon feedback on global climate. Fields of science engineering and technologyenvironmental engineeringenergy and fuels Keywords THAWSOME Programme(s) H2020-EU.1.1. - EXCELLENT SCIENCE - European Research Council (ERC) Main Programme Topic(s) ERC-StG-2015 - ERC Starting Grant Call for proposal ERC-2015-STG See other projects for this call Funding Scheme ERC-STG - Starting Grant Host institution STICHTING VU Net EU contribution € 1 500 000,00 Address DE BOELELAAN 1105 1081 HV Amsterdam Netherlands See on map Region West-Nederland Noord-Holland Groot-Amsterdam Activity type Higher or Secondary Education Establishments Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Total cost € 1 500 000,00 Beneficiaries (1) Sort alphabetically Sort by Net EU contribution Expand all Collapse all STICHTING VU Netherlands Net EU contribution € 1 500 000,00 Address DE BOELELAAN 1105 1081 HV Amsterdam See on map Region West-Nederland Noord-Holland Groot-Amsterdam Activity type Higher or Secondary Education Establishments Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Total cost € 1 500 000,00