Simulating rewetting events in intermittent rivers and ephemeral streams: a global analysis of leached nutrients and organic matter

Shumilova Oleksandra, Zak Dominik, Datry Thibault, von Schiller Daniel, Corti Roland, Foulquier Arnaud, Obrador Biel, Tockner Klement, Altermatt Florian, Arce María Isabel, Arnon Shai, Banas Damien, Banegas-Medina Andy, Beller Erin, Blanchette Melanie L., Blanco-Libreros Juan F., Blessing Joanna J., Gonçalves Boëchat Iola, Boersma Kate S., Bogan Michael T., Bonada Núria, Bond Nick R., Brintrup Barría Kate C., Bruder Andreas, Burrows Ryan M., Cancellario Tommaso, Carlson Stephanie M., Cauvy-Fraunié Sophie, Cid Núria, Danger Michael, de Freitas Terra Bianca, De Girolamo Anna Maria, del Campo Ruben, Dyer Fiona, Elosegi Arturo, Faye Emile, et al.. 2019. Simulating rewetting events in intermittent rivers and ephemeral streams: a global analysis of leached nutrients and organic matter. Global Change Biology, 25 (5) : 1591-1611.

Quartile : Outlier, Sujet : BIODIVERSITY CONSERVATION / Quartile : Outlier, Sujet : ENVIRONMENTAL SCIENCES / Quartile : Outlier, Sujet : ECOLOGY

Résumé : Climate change and human pressures are changing the global distribution and extent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experimentally simulated, under standard laboratory conditions, rewetting of leaves, riverbed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative characteristics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dissolved substances during rewetting events (56‐98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contributed most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached organic matter. The opposite pattern was found in the arid zone. Environmental variables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached substances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying events.

Mots-clés Agrovoc : lessivage du sol, rivière, sécheresse, matière organique, substance nutritive, sédiment, litière végétale, changement climatique

Mots-clés complémentaires : bilan carbone

Mots-clés libres : Temporary rivers, Sediments, Leaf litter, Leaching, Rewetting

Classification Agris : P35 - Fertilité du sol
P10 - Ressources en eau et leur gestion
P40 - Météorologie et climatologie

Champ stratégique Cirad : CTS 6 (2019-) - Changement climatique

Auteurs et affiliations

• Shumilova Oleksandra, Freie Universitaet Berlin (DEU) - auteur correspondant
• Zak Dominik, University of Rostock (DEU)
• Datry Thibault, IRSTEA (FRA)
• von Schiller Daniel, University of the Basque Country (ESP)
• Corti Roland, IRSTEA (FRA)
• Foulquier Arnaud, Université Grenoble Alpes (FRA)
• Obrador Biel, UAB (ESP)
• Tockner Klement, Austrian Science Fund (AUT)
• Altermatt Florian, UZH (CHE)
• Arce María Isabel, Institute of Freshwater Ecology and Inland Fisheries (DEU)
• Arnon Shai, Ben-Gurion University of the Negev (ISR)
• Banas Damien, Université de Lorraine (FRA)
• Banegas-Medina Andy, Universidad de Concepción (CHL)
• Beller Erin, California State University (USA)
• Blanchette Melanie L., Edith Cowan University (AUS)
• Blanco-Libreros Juan F., Universidad de Antioquia (COL)
• Blessing Joanna J., Queensland Government (AUS)
• Gonçalves Boëchat Iola, Federal University of São João Del-Rei (BRA)
• Boersma Kate S., San Diego State University (USA)
• Bogan Michael T., University of Arizona (USA)
• Bonada Núria, UAB (ESP)
• Bond Nick R., La Trobe University (AUS)
• Brintrup Barría Kate C., Universidad de Concepción (CHL)
• Bruder Andreas, University of Applied Sciences and Arts of Southern Switzerland (CHE)
• Burrows Ryan M., Griffith University (AUS)
• Cancellario Tommaso, Universidad Pública de Navarra (ESP)
• Carlson Stephanie M., California State University (USA)
• Cauvy-Fraunié Sophie, IRSTEA (FRA)
• Cid Núria, UAB (ESP)
• Danger Michael, Université de Lorraine (FRA)
• de Freitas Terra Bianca, Universidade Estadual Vale do Acaraú (BRA)
• De Girolamo Anna Maria, National Research Council (ITA)
• del Campo Ruben, University of Murcia (ESP)
• Dyer Fiona, University of Canberra (AUS)
• Elosegi Arturo, University of the Basque Country (ESP)
• Faye Emile, CIRAD-PERSYST-UPR HortSys (SEN) ORCID: 0000-0001-7764-3256
• et al.

Source : Cirad-Agritrop (https://agritrop.cirad.fr/590782/)

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