Decreasing Photoreactivity and Concurrent Change in Dissolved Organic Matter Composition With Increasing Inland Water Residence Time

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 (<3 years). 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.

Bibliographic Details

Main Authors:	Grasset, C., Einarsdottir, K., Catalán, N., Tranvik, L. J., Groeneveld, M., Hawkes, J. A., Attermeyer, K.
Other Authors:	European Commission
Format:	artículo biblioteca
Language:	English
Published:	Wiley-Blackwell 2024-03-01
Subjects:	Water retention time, Apparent quantum yield, Aquatic continuum, Dissolved organic matter quality, Photodegradation, Ensure availability and sustainable management of water and sanitation for all, Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation, Responsible Consumption and Production,
Online Access:	http://hdl.handle.net/10261/350658 http://dx.doi.org/10.13039/501100000780 https://api.elsevier.com/content/abstract/scopus_id/85187117080
Tags:	Add Tag No Tags, Be the first to tag this record!