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Carbon dynamics driven by seawater recirculation and groundwater discharge along a forest-dune-beach continuum of a high-energy meso-macro-tidal sandy coast

dc.rights.licenseopenen_US
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorCHARBONNIER, Celine
IDREF: 176318933
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorANSCHUTZ, Pierre
ORCID: 0000-0001-5331-7974
IDREF: 076300331
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorABRIL, Gwenaël
hal.structure.identifierDepartment of Earth and Planetary Sciences [Montréal] [EPS]
hal.structure.identifierMcGill University = Université McGill [Montréal, Canada]
hal.structure.identifierCentre de recherche sur la dynamique du système Terre [GEOTOP]
dc.contributor.authorMUCCI, Alfonso
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorDEIRMENDJIAN, Loris
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorPOIRIER, Dominique
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorBUJAN, Stéphane
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorLECROART, Pascal
dc.date.accessioned2023-01-10T09:02:37Z
dc.date.available2023-01-10T09:02:37Z
dc.date.issued2022-01-01
dc.identifier.issn0016-7037en_US
dc.identifier.urihttps://pub.orcid.org/v2.1/0000-0002-5720-9951/work/103962775
dc.identifier.urioai:crossref.org:10.1016/j.gca.2021.10.021
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/171639
dc.description.abstractEnHigh-energy tidal beaches are exposed to strong physical forcings. The submarine groundwater discharge (SGD) that occurs in intertidal sandy sediments includes both terrestrial, fresh groundwater flow and seawater recirculation, and plays a significant role in regulating biogeochemical cycles in some coastal zones. In this transition zone between land and sea, complex biogeochemical reactions alter the chemical composition of pore waters that discharge to the coastal ocean. Recent studies highlight that SGD can be a significant source of carbon to the coastal ocean but very few have investigated SGD in high-energy environments. We have characterized the dissolved carbon dynamics in such a high-energy environment (Truc Vert Beach, SW France) through pore-water sampling in key compartments of the SGD system. Dissolved organic carbon (DOC), pH, total alkalinity (TA), and the isotopic composition of dissolved inorganic carbon (δ13C-DIC) were measured in pore waters sampled at regular intervals between 2011 and 2014 in the intertidal zone of the beach, the mixing zone of the subterranean estuary (STE), and the freshwater aquifer upstream from the beach. Results reveal that SGD exports dissolved carbon mostly as DIC to the Aquitaine coast, some of which originates from the aerobic respiration of marine organic matter within the beach aquifer. This is highlighted by the reverse spatial trend of DOC, which is consumed, and DIC, which is produced. Saline pore waters expelled from the beach through tidally-driven recirculation of seawater provide about 4400 tons of carbon per year to the coastal zone of the 240-km long Aquitaine sandy coast. Terrestrial groundwater, characterized by high pCO2 values, is also a significant contributor to the DIC flux to the coastal ocean (16,200 tons per year). This flux is abated by CO2 evasion in the upper beach, at the onset of the salinity gradient in the STE, and within the surficial freshwater aquifer along the forest-beach transect below the coastal foredune. Accordingly, the DIC:TA ratio evolves to below 1, suggesting that this SGD increases the buffer capacity of coastal seawater against acidification. This study demonstrates that high-energy beaches are active vectors of DIC from the land to the coastal ocean as well as significant sources of CO2 to the atmosphere, and must therefore be taken into consideration in SGD carbon budgets.
dc.language.isoENen_US
dc.sourceorcid
dc.sourcecrossref
dc.subject.enTidal beach
dc.subject.enSubmarine groundwater discharge
dc.subject.enSubterranean estuary
dc.subject.enAerobic benthic respiration
dc.subject.enCO2 degassing
dc.subject.enAquitaine coast
dc.title.enCarbon dynamics driven by seawater recirculation and groundwater discharge along a forest-dune-beach continuum of a high-energy meso-macro-tidal sandy coast
dc.typeArticle de revueen_US
dc.identifier.doi10.1016/j.gca.2021.10.021en_US
dc.subject.halSciences de l'environnementen_US
bordeaux.journalGeochimica et Cosmochimica Actaen_US
bordeaux.page18-38en_US
bordeaux.volume317en_US
bordeaux.hal.laboratoriesEPOC : Environnements et Paléoenvironnements Océaniques et Continentaux - UMR 5805en_US
bordeaux.institutionUniversité de Bordeauxen_US
bordeaux.institutionCNRSen_US
bordeaux.peerReviewedouien_US
bordeaux.inpressnonen_US
bordeaux.import.sourcedissemin
hal.exportfalse
workflow.import.sourcedissemin
dc.rights.ccPas de Licence CCen_US
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Geochimica%20et%20Cosmochimica%20Acta&rft.date=2022-01-01&rft.volume=317&rft.spage=18-38&rft.epage=18-38&rft.eissn=0016-7037&rft.issn=0016-7037&rft.au=CHARBONNIER,%20Celine&ANSCHUTZ,%20Pierre&ABRIL,%20Gwena%C3%ABl&MUCCI,%20Alfonso&DEIRMENDJIAN,%20Loris&rft.genre=article


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