OPENAIRE OpenAire u:cris Recolector de Ciencia Abierta, RECOLECTA Digitala Vetenskapliga Arkivet - Academic Archive On-line DIGITAL.CSIC Crossref Global Biogeochemical Cycles Open Access 2024-03-07 2023-10-03 2023-10-03 Abstract<p>Photochemical degradation of dissolved organic matter (DOM) has been the subject of numerous studies; however, its regulation along the inland water continuum is still unclear. We aimed to unravel the DOM photoreactivity and concurrent DOM compositional changes across 30 boreal aquatic ecosystems including peat waters, streams, rivers, and lakes distributed along a water residence time (WRT) gradient. Samples were subjected to a standardized exposure of simulated sunlight. We measured the apparent quantum yield (AQY), which corresponds to DOM photomineralization per photon absorbed, and the compositional change in DOM at bulk and individual compound levels in the original samples and after irradiation. AQY increased with the abundance of terrestrially derived DOM and decreased at higher WRT. Additionally, the photochemical changes in both DOM optical properties and molecular composition resembled changes along the natural boreal WRT gradient at low WRT (&lt;3ￂﾠyears). Accordingly, mass spectrometry revealed that the abundance of photolabile and photoproduced molecules decreased with WRT along the boreal aquatic continuum. Our study highlights the tight link between DOM composition and DOM photodegradation. We suggest that photodegradation is an important driver of DOM composition change in waters with low WRT, where DOM is highly photoreactive.</p 105904 Environmental research water retention time Oceanografi, hydrologi och vattenresurser 01 natural sciences aquatic continuum Oceanography, Hydrology and Water Resources Photodegradation 14. Life underwater SDG 15 – Leben an Land dissolved organic matter quality 106020 Limnology SDG 15 - Life on Land 0105 earth and related environmental sciences Ekologi Ensure availability and sustainable management of water and sanitation for all Ecology Dissolved organic matter quality Water retention time Aquatic continuum 15. Life on land Miljövetenskap 106020 Limnologie 6. Clean water Apparent quantum yield SDG 6 – Sauberes Wasser und Sanitäreinrichtungen Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation 13. Climate action apparent quantum yield photodegradation 105904 Umweltforschung SDG 6 - Clean Water and Sanitation Environmental Sciences Responsible Consumption and Production C. Grasset, K. Einarsdottir, N. Catalán, L. J. Tranvik, M. Groeneveld, J. A. Hawkes, K. Attermeyer, 2023-10-03 journalpaper Abstract<p>Photochemical degradation of dissolved organic matter (DOM) has been the subject of numerous studies; however, its regulation along the inland water continuum is still unclear. We aimed to unravel the DOM photoreactivity and concurrent DOM compositional changes across 30 boreal aquatic ecosystems including peat waters, streams, rivers, and lakes distributed along a water residence time (WRT) gradient. Samples were subjected to a standardized exposure of simulated sunlight. We measured the apparent quantum yield (AQY), which corresponds to DOM photomineralization per photon absorbed, and the compositional change in DOM at bulk and individual compound levels in the original samples and after irradiation. AQY increased with the abundance of terrestrially derived DOM and decreased at higher WRT. Additionally, the photochemical changes in both DOM optical properties and molecular composition resembled changes along the natural boreal WRT gradient at low WRT (&lt;3ￂﾠyears). Accordingly, mass spectrometry revealed that the abundance of photolabile and photoproduced molecules decreased with WRT along the boreal aquatic continuum. Our study highlights the tight link between DOM composition and DOM photodegradation. We suggest that photodegradation is an important driver of DOM composition change in waters with low WRT, where DOM is highly photoreactive.</p Decreasing Photoreactivity and Concurrent Change in Dissolved Organic Matter Composition With Increasing Inland Water Residence Time 10.1029/2023gb007989 https://doi.org/10.1029/2023gb007989 839709