Heatwave breaks down the linearity between sun‐induced fluorescence and gross primary production

• DOI: 10.1111/nph.17920
• Publication Date: 2021-12-18T06:24:23Z
• Authors: David Martini; Karolina Sakowska; Georg Wohlfahrt; Javier Pacheco‐La...; Christiaan van de...; Albert Porcar‐Cas...; Troy S. Magney; Arnaud Carrara; Roberto Colombo; Tarek S. El‐Madany; Rosario Gonzalez‐...; María Pilar Martín; Tommaso Julitta; Gerardo Moreno; Uwe Rascher; Markus Reichstein; Micol Rossini; Mirco Migliavacca
• Keywords: Chlorophyll; extreme events; gross primary production (GPP); heatwave; nonphotochemical quenching; photosynthesis; sun-induced fluorescence; extreme events; photosynthesis; gross primary production (GPP); sun-induced fluorescence; info:eu-repo/classification/ddc/580; 0207 environmental engineering; Forestry; Heatwave; 04 agricultural and veterinary sciences; 02 engineering and technology; 15. Life on land; Fluorescence; nonphotochemical quenching; Ecology, evolutionary biology; 13. Climate action; ITC-ISI-JOURNAL-ARTICLE; 0401 agriculture, forestry, and fisheries; ddc:580; Seasons; Photosynthesis; extreme events; gross primary production (GPP); heatwave; nonphotochemical quenching; photosynthesis; sun-induced fluorescence;; Ecosystem; Environmental Monitoring

Sun-induced fluorescence in the far-red region (SIF) is increasingly used as a remote and proximal-sensing tool capable of tracking vegetation gross primary production (GPP). However, use SIF to probe changes GPP challenged during extreme climatic events, such heatwaves. Here, we examined how 2018 European heatwave (HW) affected GPP-SIF relationship evergreen broadleaved trees with relatively invariant canopy structure. To do so, combined canopy-scale measurements, estimated from an eddy covariance tower, active pulse amplitude modulation fluorescence. The HW caused inversion photosynthesis-fluorescence at both leaf scales. highly nonlinear was strongly shaped by nonphotochemical quenching (NPQ), that is, dissipation mechanism protect adverse effects high light intensity. During heat stress, plants experienced saturation NPQ, causing change allocation energy pathways towards SIF. Our results show complex NPQ-SIF-GPP level which not completely represented state-of-the-art coupled radiative transfer photosynthesis models.