caa a22 4500 605517630 CHVBK 20210128100721.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s10533-015-0139-7 doi (NATIONALLICENCE)springer-10.1007/s10533-015-0139-7 Hot spots for carbon emissions from Mediterranean fluvial networks during summer drought [Elektronische Daten] [Lluís Gómez-Gener, Biel Obrador, Daniel von Schiller, Rafael Marcé, Joan Casas-Ruiz, Lorenzo Proia, Vicenç Acuña, Núria Catalán, Isabel Muñoz, Matthias Koschorreck] During summer drought, Mediterranean fluvial networks are transformed into highly heterogeneous landscapes characterized by different environments (i.e., running and impounded waters, isolated river pools and dry beds). This hydrological setting defines novel biogeochemically active areas that could potentially increase the rates of carbon emissions from the fluvial network to the atmosphere. Using chamber methods, we aimed to identify hot spots for carbon dioxide (CO2) and methane (CH4) emissions from two typical Mediterranean fluvial networks during summer drought. The CO2 efflux from dry beds (mean±SE=209±10mmol CO2 m−2 d−1) was comparable to that from running waters (120±33mmolm−2 d−1) and significantly higher than from impounded waters (36.6±8.5mmolm−2 d−1) and isolated pools (17.2±0.9mmolm−2 d−1). In contrast, the CH4 efflux did not significantly differ among environments, although the CH4 efflux was notable in some impounded waters (13.9±10.1mmol CH4 m−2 d−1) and almost negligible in the remaining environments (mean <0.3mmolm−2 d−1). Diffusion was the only mechanism driving CO2 efflux in all environments and was most likely responsible for CH4 efflux in running waters, isolated pools and dry beds. In contrast, the CH4 efflux in impounded waters was primarily ebullition-based. Using a simple heuristic approach to simulate potential changes in carbon emissions from Mediterranean fluvial networks under future hydrological scenarios, we show that an extreme drying out (i.e., a four-fold increase of the surface area of dry beds) would double the CO2 efflux from the fluvial network. Correspondingly, an extreme transformation of running waters into impounded waters (i.e., a twofold increase of the surface area of impounded waters) would triple the CH4 efflux. Thus, carbon emissions from dry beds and impounded waters should be explicitly considered in carbon assessments of fluvial networks, particularly under predicted global change scenarios, which are expected to increase the spatial and temporal extent of these environments. Springer International Publishing Switzerland, 2015 Greenhouse gas fluxes nationallicence Carbon dioxide nationallicence Methane nationallicence Fluvial network nationallicence Temporary rivers nationallicence Summer drought nationallicence Gómez-Gener Lluís Department of Ecology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain aut Obrador Biel Department of Ecology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain aut von Schiller Daniel Department of Plant Biology and Ecology, Faculty of Science and Technology, University of the Basque Country, Apdo. 644, 48080, Bilbao, Spain aut Marcé Rafael Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut Casas-Ruiz Joan Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut Proia Lorenzo Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut Acuña Vicenç Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut Catalán Núria Limnology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, 75236, Uppsala, Sweden aut Muñoz Isabel Department of Ecology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain aut Koschorreck Matthias Department Lake Research, Helmholtz Centre for Environmental Research, Brückstrasse 3a, 39114, Magdeburg, Germany aut Biogeochemistry Springer International Publishing 125/3(2015-09-01), 409-426 0168-2563 125:3<409 2015 125 10533 https://doi.org/10.1007/s10533-015-0139-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-015-0139-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gómez-Gener Lluís Department of Ecology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain aut NATIONALLICENCE 700 1- Obrador Biel Department of Ecology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain aut NATIONALLICENCE 700 1- von Schiller Daniel Department of Plant Biology and Ecology, Faculty of Science and Technology, University of the Basque Country, Apdo. 644, 48080, Bilbao, Spain aut NATIONALLICENCE 700 1- Marcé Rafael Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Casas-Ruiz Joan Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Proia Lorenzo Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Acuña Vicenç Catalan Institute for Water Research, Scientific and Technological Park of the University of Girona, Carrer Emili Grahit 101, 17003, Girona, Spain aut NATIONALLICENCE 700 1- Catalán Núria Limnology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, 75236, Uppsala, Sweden aut NATIONALLICENCE 700 1- Muñoz Isabel Department of Ecology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain aut NATIONALLICENCE 700 1- Koschorreck Matthias Department Lake Research, Helmholtz Centre for Environmental Research, Brückstrasse 3a, 39114, Magdeburg, Germany aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 125/3(2015-09-01), 409-426 0168-2563 125:3<409 2015 125 10533