1. Overland flow during a storm event strongly affects stream water chemistry and bacterial community structure
- Author
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Huong T. Le, Thomas Pommier, Olivier Ribolzi, Bounsamay Soulileuth, Sylvain Huon, Norbert Silvera, Emma Rochelle-Newall, Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Vietnam Academy of Science and Technology (VAST), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Geosciences Environment Toulouse, Centre National de la Recherche Scientifique (CNRS), Representation du Laos (IRD), Institute of Research for sustainable Development (IRD), ANR-13-AGRO-0007,TecItEasy,Effets conjugués de l'expansion des plantations d'arbres et du changement climatique sur le fonctionnement hydro-sédimentaire des bassins versants tropicaux de montagne: la diversité microbienne aquatique comme un proxy de la conversion d'usage des terres(2013), and Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
- Subjects
[SDV.EE]Life Sciences [q-bio]/Ecology, environment ,2. Zero hunger ,0303 health sciences ,010504 meteorology & atmospheric sciences ,Ecology ,Lao PDR (Laos) ,DOC ,15. Life on land ,Aquatic Science ,Southeast Asia ,01 natural sciences ,6. Clean water ,03 medical and health sciences ,Sustainability ,13. Climate action ,[SDE]Environmental Sciences ,CDOM ,Land degradation ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
International audience; As flood events are expected to become more frequent due to climate change, investigating how overland flow exports terrestrial nutrients, carbon and living organisms into aquatic systems is essential for understanding both soil and stream ecosystem status. Here we assessed how dissolved organic carbon (DOC), total suspended sediments (TSS), and stream bacterial diversity responded to stream discharge and overland flow during stormflow in a tropical catchment. A higher humification index and a decreasing ratio of allochthonous to autochthonous DOC indicated that DOC from soils was exported to stream during the flood. The delta C-13 and delta N-15 of particulate matter was indicative of a source in the cultivated areas of the upper catchment and of subsurface soils (stream banks and gullies) in the downstream section. Bacterial richness of particle-attached (PA) and the free-living (FL) fractions increased with the flood progression in the upstream section. Moreover, the community structure of the PA fraction in the stream was more similar to that of overland flow than was the FL fraction. This suggests that the soil PA bacterial community was washed-out with overland flow during the flood recession. The relative contribution of sources and the composition of TSS, rather than hydrological regime, significantly drove the composition of bacterial community. In conclusion, our results emphasize that overland flow during a flood event strongly influences the structure of stream bacterial communities further underlining the biological connectivity between terrestrial runoff and stream flow.
- Published
- 2021
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