1. Heatwave breaks down the linearity between sun-induced fluorescence and gross primary production
- Author
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David Martini, Karolina Sakowska, Georg Wohlfahrt, Javier Pacheco‐Labrador, Christiaan van der Tol, Albert Porcar‐Castell, Troy S. Magney, Arnaud Carrara, Roberto Colombo, Tarek S. El‐Madany, Rosario Gonzalez‐Cascon, María Pilar Martín, Tommaso Julitta, Gerardo Moreno, Uwe Rascher, Markus Reichstein, Micol Rossini, Mirco Migliavacca, Department of Water Resources, Faculty of Geo-Information Science and Earth Observation, UT-I-ITC-WCC, Martini, D, Sakowska, K, Wohlfahrt, G, Pacheco-Labrador, J, van der Tol, C, Porcar-Castell, A, Magney, T, Carrara, A, Colombo, R, El-Madany, T, Gonzalez-Cascon, R, Martin, M, Julitta, T, Moreno, G, Rascher, U, Reichstein, M, Rossini, M, Migliavacca, M, Viikki Plant Science Centre (ViPS), Department of Forest Sciences, Ecosystem processes (INAR Forest Sciences), Forest Ecology and Management, and Institute for Atmospheric and Earth System Research (INAR)
- Subjects
0106 biological sciences ,Chlorophyll ,extreme events ,010504 meteorology & atmospheric sciences ,Physiology ,sun-induced fluorescence ,Plant Science ,01 natural sciences ,Fluorescence ,photosynthesi ,heatwave ,Photosynthesis ,extreme event ,Ecosystem ,0105 earth and related environmental sciences ,4112 Forestry ,gross primary production (GPP) ,15. Life on land ,nonphotochemical quenching ,ddc:580 ,13. Climate action ,ITC-ISI-JOURNAL-ARTICLE ,1181 Ecology, evolutionary biology ,Seasons ,010606 plant biology & botany ,Environmental Monitoring - Abstract
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, the use of SIF to probe changes in GPP is challenged during extreme climatic events, such as heatwaves. Here, we examined how the 2018 European heatwave (HW) affected the GPP-SIF relationship in evergreen broadleaved trees with a relatively invariant canopy structure. To do so, we combined canopy-scale SIF measurements, GPP estimated from an eddy covariance tower, and active pulse amplitude modulation fluorescence. The HW caused an inversion of the photosynthesis-fluorescence relationship at both the canopy and leaf scales. The highly nonlinear relationship was strongly shaped by nonphotochemical quenching (NPQ), that is, a dissipation mechanism to protect from the adverse effects of high light intensity. During the extreme heat stress, plants experienced a saturation of NPQ, causing a change in the allocation of energy dissipation pathways towards SIF. Our results show the complex modulation of the NPQ-SIF-GPP relationship at an extreme level of heat stress, which is not completely represented in state-of-the-art coupled radiative transfer and photosynthesis models.
- Published
- 2021
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