Actualités
Thématiques
Projets de recherche
Plateformes techniques
Productions scientifiques
CollaborationsThèses et stages
Personnes
Global Change Biology, 25 (5), pp. 1591-1611
Shumilova, O., Zak, D., Datry, T., Von schiller, D., Corti, R., Foulquier, A., Obrador, B., Tockner, K., Altermatt, F., Isabel arce, M., Arnon, S., Banas, D., Banegas-medina, A., Beller, E., Blanchette, M., Blanco-libreros, J.F., Blessing, J., Gonçalves boëchat, I., Boersma, K., Bogan, M.T., Bonada, N., Bond, N., Brintrup, K., Bruder, A., Burrows, R., Cancellario, T., Carlson, S.M., Cauvy-fraunié, S., Cid, N., Danger, M., De freitas terra, B., De girolamo, A.M., Del campo, R., Dyer, F., Elosegi, A., Emile, F., Febria, C., Figueroa, R., Four, B., Gessner, M.O., Gnohossou, P., Gómez cerezo, R., Gómez-gener, L., Graça, M.A.S., Guareschi, S., Gücker, B., Hwan, J.L., Kubheka, S., Langhans, S.D., Leigh, C., Little, C., Lorenz, S., Marshall, J., Mcintosh, A., Mendoza-lera, C., Meyer, E.I., Miliša, M., Mlambo, M.C., Moleón, M., Negus, P., Niyogi, D., Papatheodoulou, A., Pardo, I., Paril, P., Peši?, V., Rodríguez-lozano, P., Rolls, R.R., Sánchez-montoya, M.M., Savi?, A., Steward, A., Stubbington, R., Taleb, A., Vander vorste, R., Waltham, N., Zoppini, A., Zarfl, C.
2019
Global climate change and human pressures are changing the distribution and extent of intermittent rivers and ephemeral streams (IRES), which are estimated to comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and are subject to physico-chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted. Rewetting events cause pulsed releases of dissolved nutrients and organic matter (OM) from channel substrates. Yet, there are no estimates of amounts and quality of leached substances nor information on constraining environmental variables at the global-scale. We experimentally simulated, under controlled 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 1 m2 riverbeds. In addition, we evaluated the variance in leachate characteristics explained by selected environmental variables and substrates characteristics. We found that sediments, due to their dominance within riverbeds, act as main contributors to the overall flux of dissolved substances during rewetting events (56-98%), and that fluxes are climate-specific. Dissolved organic carbon, phenolics, and nitrate were the main contributors to the amounts of areal fluxes. The largest amounts of leached substances, but with the lowest potential bioavailability of OM, were found in the continental climate zone opposite to the arid zone. Environmental variables expected to be modified under climate change (namely, potential evapotranspiration, aridity, dry period duration, land-use) were correlated with amounts of leached substances with variance best explained for sediments. The results of our study show that the role of IRES should be accounted for in global biogeochemical cycles, especially because their role will increase due to an increasing severity of drying events.