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Water-stress-induced breakdown of carbon-water relations

dc.contributor.authorNelson, Jacob A.
dc.contributor.authorCarvalhais, Nuno
dc.contributor.authorMigliavacca, Mirco
dc.contributor.authorReichstein, Markus
dc.contributor.authorJung, Martin
dc.contributor.institutionFaculdade de Ciências e Tecnologia (FCT)
dc.contributor.pblCopernicus Publications
dc.date.accessioned2023-09-22T22:15:22Z
dc.date.available2023-09-22T22:15:22Z
dc.date.issued2018-04-20
dc.descriptionFunding Information: Acknowledgements. This work used eddy covariance data acquired by the FLUXNET community and in particular by the following networks: AmeriFlux (US Department of Energy, Biological and Environmental Research, Terrestrial Carbon Program (DE-FG02-04ER63917 and DE-FG02-04ER63911)), AfriFlux, AsiaFlux, CarboAfrica, CarboEuropeIP, CarboItaly, CarboMont, ChinaFlux, FluxnetCanada (supported by CFCAS, NSERC, BIOCAP, Environment Canada, and NRCan), GreenGrass, KoFlux, LBA, NECC, OzFlux, TCOS-Siberia, and USCCC. We acknowledge the financial support to the eddy covariance data harmonization provided by CarboEuropeIP, FAO-GTOS-TCO, iLEAPS, the Max Planck Institute for Biogeochemistry, the National Science Foundation, the University of Tuscia, Université Laval and Environment Canada, and the US Department of Energy and the database development and technical support from Berkeley Water Center, Lawrence Berkeley National Laboratory, Microsoft Research eScience, Oak Ridge National Laboratory, the University of California-Berkeley, and the University of Virginia. Publisher Copyright: © Author(s) 2018.
dc.description.abstractUnderstanding of terrestrial carbon and water cycles is currently hampered by an uncertainty in how to capture the large variety of plant responses to drought. In FLUXNET, the global network of CO2 and H2O flux observations, many sites do not uniformly report the ancillary variables needed to study drought response physiology. To this end, we outline two data-driven indicators based on diurnal energy, water, and carbon flux patterns derived directly from the eddy covariance data and based on theorized physiological responses to hydraulic and non-stomatal limitations. Hydraulic limitations (i.e. intra-plant limitations on water movement) are proxied using the relative diurnal centroid (CET∗), which measures the degree to which the flux of evapotranspiration (ET) is shifted toward the morning. Non-stomatal limitations (e.g. inhibitions of biochemical reactions, RuBisCO activity, and/or mesophyll conductance) are characterized by the Diurnal Water-Carbon Index (DWCI), which measures the degree of coupling between ET and gross primary productivity (GPP) within each day. As a proof of concept we show the response of the metrics at six European sites during the 2003 heat wave event, showing a varied response of morning shifts and decoupling. Globally, we found indications of hydraulic limitations in the form of significantly high frequencies of morning-shifted days in dry/Mediterranean climates and savanna/evergreen plant functional types (PFTs), whereas high frequencies of decoupling were dominated by dry climates and grassland/savanna PFTs indicating a prevalence of non-stomatal limitations in these ecosystems. Overall, both the diurnal centroid and DWCI were associated with high net radiation and low latent energy typical of drought. Using three water use efficiency (WUE) models, we found the mean differences between expected and observed WUE to be -0.09 to 0.44 μmol mmol-1 and -0.29 to -0.40 μmol mmol-1 for decoupled and morning-shifted days, respectively, compared to mean differences -1.41 to -1.42 μmol mmol-1 in dry conditions, suggesting that morning shifts/hydraulic responses are associated with an increase in WUE, whereas decoupling/non-stomatal limitations are not.en
dc.description.versionpublishersversion
dc.description.versionpublished
dc.format.extent15
dc.format.extent2719202
dc.identifier.doi10.5194/bg-15-2433-2018
dc.identifier.issn1726-4170
dc.identifier.otherPURE: 70885082
dc.identifier.otherPURE UUID: b7bf557e-bda3-49f8-b528-68725881e7cb
dc.identifier.otherScopus: 85045889248
dc.identifier.otherWOS: 000430510700003
dc.identifier.urihttp://hdl.handle.net/10362/158148
dc.identifier.urlhttps://www.scopus.com/pages/publications/85045889248
dc.language.isoeng
dc.peerreviewedyes
dc.subjectEcology, Evolution, Behavior and Systematics
dc.subjectEarth-Surface Processes
dc.subjectSDG 13 - Climate Action
dc.subjectSDG 15 - Life on Land
dc.titleWater-stress-induced breakdown of carbon-water relationsen
dc.title.subtitleIndicators from diurnal FLUXNET patternsen
dc.typejournal article
degois.publication.firstPage2433
degois.publication.issue8
degois.publication.lastPage2447
degois.publication.titleBiogeosciences
degois.publication.volume15
dspace.entity.typePublication
rcaap.rightsopenAccess

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