Short-term photodegradation of autochthonous and allochthonous dissolved organic matter in Lake Taihu, China

Abstract Photochemistry is one of the key processes that shape the quality of dissolved organic matter (DOM) in aquatic systems, yet the photoreactivity of DOM from different sources remains largely unclear. In this study, DOM from 10 typical autochthonous and allochthonous sources in Lake Taihu bas...
Ausführliche Beschreibung

Abstract Photochemistry is one of the key processes that shape the quality of dissolved organic matter (DOM) in aquatic systems, yet the photoreactivity of DOM from different sources remains largely unclear. In this study, DOM from 10 typical autochthonous and allochthonous sources in Lake Taihu basin were exposed to simulated sunlight, and quantitative and compositional changes of the DOM were explored by measuring its UV–Visable absorption and fluorescence spectroscopy. Photochemical release of nutrients was also explored during the incubations. Results showed that, although DOM from most sources experienced photobleaching effects with decreased absorption coefficients at 254 nm (a(254)) and fluorescence component intensities after light exposure, photochemical alterations of DOM linked to their original composition. Macrophyte-derived (Potamogeton malaianus) DOM, with the largest molecular size, showed increased a(254), humic- and protein-like fluorescence component (C1 and C2) abundances, and inorganic nutrient concentrations relative to dark controls, indicating photo-release of labile components. However, DOM with relatively higher aromaticity, e.g., from agricultural water and the lake, showed photobleaching effects and increased humification degree, probably due to the loss of aromatic components. Allochthonous anthropogenic DOM, e.g., from sewage, showed stronger photo-ammonification, likely relating to the fresh labile N-containing compositions. The form of inorganic nutrient releases during the DOM photolysis also varied with the original DOM sources. Macrophyte-derived DOM incubations showed larger photo-releases of $ NO_{3} $− and $ PO_{4} $3−, while $ NO_{2} $− dominated inorganic nutrient releases during groundwater DOM light incubations. Thus, this study concludes that the photoreactivity of DOM closely relates to its original composition and sources. Ausführliche Beschreibung

Autor*in:	Liu, Yanan [verfasserIn] Xue, Jingya Gui, Zhifan Zhang, Lu Yao, Xiaolong

Format:	E-Artikel
Sprache:	Englisch

Erschienen:	2023

Schlagwörter:	Photodegradation Dissolved organic matter (DOM) Sources Nutrients

Anmerkung:

© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Übergeordnetes Werk:	Enthalten in: Environmental science and pollution research - Berlin : Springer, 1994, 30(2023), 52 vom: 12. Okt., Seite 111982-111994
Übergeordnetes Werk:	volume:30 ; year:2023 ; number:52 ; day:12 ; month:10 ; pages:111982-111994

Links:	Volltext

DOI / URN:	10.1007/s11356-023-30107-5

Katalog-ID:	SPR053720342