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oai:docta.ucm.es:20.500.14352/1016992025-03-18T13:22:02Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Butturini, Andrea author Herzsprung, Peter author Lechtenfeld, Oliver author Alcorlo, Paloma author Benaiges-Fernández, Robert author Berlanga, Mercedes author Boadella, Jesús author Freixinos Campillo, Zeus author Gómez, Rosa author Sánchez Montoya, María Del Mar author Urmeneta, Jordi author Romaní, Ana Maria author 2022 Hypersaline endorheic aquatic systems (H-SEAS) are lakes/shallow playas in arid and semiarid regions that undergo extreme oscillations in salinity and severe drought episodes. Although their geochemical uniqueness and microbiome have been deeply studied, very little is known about the availability and quality of dissolved organic matter (DOM) in the water column.. A H-SEAS from the Monegros Desert (Zaragoza, NE Spain) was studied during a hydrological wetting-drying-rewetting cycle. DOM analysis included: (i) a dissolved organic carbon (DOC) mass balance; (ii) spectroscopy (absorbance and fluorescence) and (iii) a molecular characterization with Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The studied system stored a large amount of DOC and under the highest salinity conditions, salt-saturated waters (i.e., brines with salinity > 30%) accumulated a disproportionate quantity of DOC, indicating a significant in-situ net DOM production. Simultaneously, during the hydrological transition from wet to dry, the DOM pool showed strong alterations of it molecular composition. Spectroscopic methods indicated that aromatic and degraded DOM was rapidly replaced by fresher, relatively small, microbial-derived moieties with a large C/N ratio. FT-ICR-MS highlighted the accumulation of small, saturated and oxidized molecules (molecular O/C > 0.5), with a remarkable increase in the relative contribution of highly oxygenated (molecular O/C>0.9) compounds and a decrease of aliphatic and carboxyl-rich alicyclic moleculesThese results indicated that H-SEAS are extremely active in accumulating and processing DOM, with the notable release of organic solutes probably originated from decaying microplankton under large osmotic stress at extremely high salinities. Butturini, A., et al. «Origin, Accumulation and Fate of Dissolved Organic Matter in an Extreme Hypersaline Shallow Lake». Water Research, vol. 221, agosto de 2022, p. 118727. https://doi.org/10.1016/j.watres.2022.118727. 0043-1354 10.1016/j.watres.2022.118727 https://hdl.handle.net/20.500.14352/101699 https://doi.org/10.1016/j.watres.2022.118727 Origin, accumulation and fate of dissolved organic matter in an extreme hypersaline shallow lake