Optical properties (absorbance and fluorescence) of dissolved organic matter in the active layer and permafrost in Canada

We use absorbance and fluorescence indices to characterize dissolved organic matter aromaticity and molecular weight.We performed PARAFAC modeling to identify the main chemical components explaining the fluorescent DOM pool. By characterizing DOM in permafrost soils from a wide range of formation histories, ages, surficial geology, and climate conditions, we are able to highlight the distinct signature of DOM in permafrost layers compare to the active layer and to investigate the controls of DOM character.