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Decoupling between ecosystem photosynthesis and transpiration: a last resort against overheating

Krich, Christopher und Mahecha, Miguel und Migliavacca, Mirco und De Kauwe, Martin G und Griebel, Anne und Runge, Jakob und Miralles, Diego G (2022) Decoupling between ecosystem photosynthesis and transpiration: a last resort against overheating. Environmental Research Letters. Institute of Physics (IOP) Publishing. doi: 10.1088/1748-9326/ac583e. ISSN 1748-9326.

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Offizielle URL: https://iopscience.iop.org/article/10.1088/1748-9326/ac583e

Kurzfassung

Ecosystems are projected to face extreme high temperatures more frequently in the near future. Various biotic coping strategies exist to prevent heat stress. Controlled experiments have recently provided evidence for continued transpiration in woody plants during high air temperatures, even when photosynthesis is inhibited. Such a decoupling of photosynthesis and transpiration would represent an effective strategy (‘known as leaf or canopy cooling’) to prevent lethal leaf temperatures. At the ecosystem scale, continued transpiration might dampen the development and propagation of heat extremes despite further desiccating soils. However, at the ecosystem scale, evidence for the occurrence of this decoupling is still limited. Here, we aim to investigate this mechanism using eddy-covariance data of thirteen woody ecosystems located in Australia and a causal graph discovery algorithm. Working at half-hourly time resolution, we find evidence for a decoupling of photosynthesis and transpiration in four ecosystems which can be classified as Mediterranean woodlands. The decoupling occurred at air temperatures above 35 °C. At the nine other investigated woody sites, we found that vegetation CO2 exchange remained coupled to transpiration at the observed high air temperatures. Ecosystem characteristics suggest that the canopy energy balance plays a crucial role in determining the occurrence of a decoupling. Our results highlight the value of causal-inference approaches for the analysis of complex physiological processes. With regard to projected increasing temperatures and especially extreme events in future climates, further vegetation types might be pushed to threatening canopy temperatures. Our findings suggest that the coupling of leaf-level photosynthesis and stomatal conductance, common in land surface schemes, may need be re-examined when applied to high-temperature events.

elib-URL des Eintrags:https://elib.dlr.de/191580/
Dokumentart:Zeitschriftenbeitrag
Titel:Decoupling between ecosystem photosynthesis and transpiration: a last resort against overheating
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Krich, ChristopherMax-Planck-Institute for Biogeochemistry, Jena, GermanyNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Mahecha, MiguelRemote Sensing Center for Earth System Research, Leipzig University, Leipzig, GermanyNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Migliavacca, MircoMax-Planck-Institute for Biogeochemistry, Jena, GermanyNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
De Kauwe, Martin GSchool of Biological Sciences, University of Bristol, BristolNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Griebel, AnneHawkesbury Institute for the Environment, Western Sydney University,NICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Runge, JakobJakob.Runge (at) dlr.dehttps://orcid.org/0000-0002-0629-1772NICHT SPEZIFIZIERT
Miralles, Diego GHydro-Climate Extremes Lab (H-CEL), Faculty of Bioscience Engineering, Ghent University, Ghent, BelgiumNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:März 2022
Erschienen in:Environmental Research Letters
Referierte Publikation:Ja
Open Access:Ja
Gold Open Access:Ja
In SCOPUS:Ja
In ISI Web of Science:Ja
DOI:10.1088/1748-9326/ac583e
Verlag:Institute of Physics (IOP) Publishing
ISSN:1748-9326
Status:veröffentlicht
Stichwörter:photosynthesis, transpiration, heat wave, ecosystem functioning
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Raumfahrt
HGF - Programmthema:keine Zuordnung
DLR - Schwerpunkt:Raumfahrt
DLR - Forschungsgebiet:R - keine Zuordnung
DLR - Teilgebiet (Projekt, Vorhaben):R - keine Zuordnung
Standort: Jena
Institute & Einrichtungen:Institut für Datenwissenschaften > Datenanalyse und -intelligenz
Hinterlegt von: Gerhardus, Andreas
Hinterlegt am:19 Dez 2022 11:14
Letzte Änderung:17 Jan 2023 08:46

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