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Unexplained hydrogen isotope offsets complicate the identification and quantification of tree water sources in a riparian forest

hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorBARBETA, Adrià
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorJONES, Sam P.
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorCLAVÉ, Laura
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorWINGATE, Lisa
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
hal.structure.identifierBasque Centre for Climate Change [BC3]
hal.structure.identifierIkerbasque - Basque Foundation for Science
dc.contributor.authorGIMENO, Teresa E.
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorFRÉJAVILLE, Bastien
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorWOHL, Steven
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorOGÉE, Jérôme
dc.date.accessioned2024-04-08T12:04:38Z
dc.date.available2024-04-08T12:04:38Z
dc.date.issued2019
dc.identifier.issn1027-5606
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/196316
dc.description.abstractEnWe investigated plant water sources of an emblematic refugial population of Fagus sylvatica (L.) in the Ciron river gorges in south-western France using stable water isotopes. It is generally assumed that no isotopic fractionation occurs during root water uptake, so that the isotopic composition of xylem water effectively reflects that of source water. However, this assumption has been called into question by recent studies that found that, at least at some dates during the growing season, plant water did not reflect any mixture of the potential water sources. In this context, highly resolved datasets covering a range of environmental conditions could shed light on possible plant–soil fractionation processes responsible for this phenomenon. In this study, the hydrogen (δ2H) and oxygen (δ18O) isotope compositions of all potential tree water sources and xylem water were measured fortnightly over an entire growing season. Using a Bayesian isotope mixing model (MixSIAR), we then quantified the relative contribution of water sources for F. sylvatica and Quercus robur (L.) trees. Based on δ18O data alone, both species used a mix of top and deep soil water over the season, with Q. robur using deeper soil water than F. sylvatica. The contribution of stream water appeared to be marginal despite the proximity of the trees to the stream, as already reported for other riparian forests. Xylem water δ18O could always be interpreted as a mixture of deep and shallow soil waters, but the δ2H of xylem water was often more depleted than the considered water sources. We argue that an isotopic fractionation in the unsaturated zone and/or within the plant tissues could underlie this unexpected relatively depleted δ2H of xylem water, as already observed in halophytic and xerophytic species. By means of a sensitivity analysis, we found that the estimation of plant water sources using mixing models was strongly affected by this δ2H depletion. A better understanding of what causes this isotopic separation between xylem and source water is urgently needed.
dc.language.isoen
dc.publisherEuropean Geosciences Union
dc.rights.urihttp://creativecommons.org/licenses/by/
dc.title.enUnexplained hydrogen isotope offsets complicate the identification and quantification of tree water sources in a riparian forest
dc.typeArticle de revue
dc.identifier.doi10.5194/hess-23-2129-2019
dc.subject.halSciences du Vivant [q-bio]
dc.subject.halSciences de l'environnement
dc.description.sponsorshipEuropeCarbonic anhydrase: where the CO2, COS and H2O cycles meet
bordeaux.journalHydrology and Earth System Sciences
bordeaux.page2129-2146
bordeaux.volume23
bordeaux.hal.laboratoriesInteractions Soil Plant Atmosphere (ISPA) - UMR 1391*
bordeaux.issue4
bordeaux.institutionBordeaux Sciences Agro
bordeaux.institutionINRAE
bordeaux.peerReviewedoui
hal.identifierhal-02625636
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02625636v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Hydrology%20and%20Earth%20System%20Sciences&rft.date=2019&rft.volume=23&rft.issue=4&rft.spage=2129-2146&rft.epage=2129-2146&rft.eissn=1027-5606&rft.issn=1027-5606&rft.au=BARBETA,%20Adri%C3%A0&JONES,%20Sam%20P.&CLAV%C3%89,%20Laura&WINGATE,%20Lisa&GIMENO,%20Teresa%20E.&rft.genre=article


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