Complete and Partial Photo-oxidation of Dissolved Organic Matter Draining Permafrost Soils

• DOI: 10.1021/acs.est.5b05354
• Publication Date: 2016-02-24T21:01:33Z
• Authors: Collin P. Ward; Rose M. Cory
• Keywords: Photodegradation

Photochemical degradation of dissolved organic matter (DOM) to carbon dioxide (CO2) and partially oxidized compounds is an important component the cycle in Arctic. Thawing permafrost soils will change chemical composition DOM exported arctic surface waters, but molecular controls on photodegradation remain poorly understood, making it difficult predict how inputs thawing may alter its photodegradation. To address this knowledge gap, we quantified susceptibility draining shallow mat deeper layer complete partial photo-oxidation investigated changes each source following sunlight exposure. Permafrost had similar lability photomineralization despite substantial differences initial composition. Concurrent losses carboxyl moieties shifts during indicated that photodecarboxylation could account for 40–90% photomineralized CO2. a higher compared DOM, potentially due lower abundance phenolic with antioxidant properties. These results suggest likely continue be control fate freshwaters as climate warms thaw.