Effects of climate change on surface-water photochemistry: a review

• Published in: Environmental science and pollution research international Vol. 21; no. 20; pp. 11770 - 11780
• Main Authors: De Laurentiis, Elisa, Minella, Marco, Maurino, Valter, Minero, Claudio, Vione, Davide
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.10.2014; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: 14th EuCheMS International Conference on Chemistry and the Environment (ICCE 2013; 2013; Alkalinity; Anions; Aquatic Pollution; Atmospheric chemistry; Atmospheric Protection/Air Quality Control/Air Pollution; Barcelona; Biodegradation; Biological Oxygen Demand Analysis; Biological warfare; Carbonates; Cations; Chemistry; Climate; Climate Change; Climate effects; Dissolved organic carbon; Dissolved organic matter; Dry season; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Epilimnion; Fluctuation; Fluctuations; Free radicals; Hypolimnion; June 25 - 28; Lakes; Leaching; Links; Oxidation; Photochemical Processes; Photochemical reactions; Photochemicals; Photochemistry; Pollutants; sediments; singlet oxygen; Solutes; Sulfates; sulfides; summer; Surface Properties; Surface water; Variables; Waste Water Technology; Water; Water - chemistry; Water column; Water Management; Water Pollution Control; Water scarcity; Water stratification; watersheds; Climate change; Environmental photochemistry; Photoinduced transformation; Environmental modelling; Direct and indirect photolysis; Surface-water photochemistry
• ISSN: 0944-1344; 1614-7499; 1614-7499
• DOI: 10.1007/s11356-013-2343-0

Information concerning the link between surface-water photochemistry and climate is presently very scarce as only a few studies have been dedicated to the subject. On the basis of the limited knowledge that is currently available, the present inferences can be made as follows: (1) Warming can cause enhanced leaching of ionic solutes from the catchments to surface waters, including cations and more biologically labile anions such as sulphate. Preferential sulphate biodegradation followed by removal as organic sulphides in sediment could increase alkalinity, favouring the generation of the carbonate radical, CO₃ ·⁻. However, this phenomenon would be easily offset by fluctuations of the dissolved organic carbon (DOC), which is strongly anticorrelated with CO₃ ·⁻. Therefore, obtaining insight into DOC evolution is a key issue in understanding the link between photochemistry and climate. (2) Climate change could exacerbate water scarcity in the dry season in some regions. Fluctuations in the water column could deeply alter photochemistry that is usually favoured in shallower waters. However, the way water is lost would strongly affect the prevailing photoinduced processes. Water outflow without important changes in solute concentration would mostly favour reactions induced by the hydroxyl and carbonate radicals (·OH and CO₃ ·⁻). In contrast, evaporative concentration would enhance reactions mediated by singlet oxygen (¹O₂) and by the triplet states of chromophoric dissolved organic matter (³CDOM*). (3) In a warmer climate, the summer stratification period of lakes would last longer, thereby enhancing photochemical reactions in the epilimnion but at the same time keeping the hypolimnion water in the dark for longer periods.