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1. Evergreen broadleaf greenness and its relationship with leaf flushing, aging, and water fluxes

Author

China Scholarship Council, National Science Foundation (US), German Centre for Air and Space Travel, European Commission, Ministerio de Economía y Competitividad (España), Luo, Yunpeng [0000-0001-6383-8300], Pacheco-Labrador, Javier [0000-0003-3401-7081], Richardson, Andrew D. [0000-0002-0148-6714], Seyednasrollah, Bijan [0000-0002-5195-2074], Perez-Priego, Oscar [0000-0002-3138-3177], González-Cascón, Rosario [0000-0003-3468-0967], Martín, M. Pilar [0000-0002-5563-8461], Nair, Richard [0000-0002-6293-3610], Wutzler, Thomas [0000-0003-4159-5445], Bucher, Solveig F. [0000-0002-2303-4583], Carrara, Arnaud [0000-0002-9095-8807], Cremonese, Edoardo [0000-0002-6708-8532], El-Madany, Tarek S.[0000-0002-0726-7141], Filippa, Gianluca [0000-0002-4554-6045], Galvagno, Marta [0000-0002-0827-487X], Ma, Xuanlong [0000-0003-1499-8476], Martini, David [0000-0003-2180-5126], Zhang, Qihuan [0000-0002-0860-4023], Reichstein, Markus [0000-0001-5736-1112], Menzel, A. [0000-0002-7175-2512], Römermann, Christine [0000-0003-3471-0951], Migliavacca, Mirco [0000-0003-3546-8407], Luo, Yunpeng, Pacheco-Labrador, Javier, Richardson, Andrew D., Seyednasrollah, Bijan, Pérez-Priego, Óscar, González-Cascón, Rosario, Martin, M. Pilar, Moreno, Gerardo, Nair, Richard, Wutzler, Thomas, Bucher, Solveig F., Carrara, Arnaud, Cremonese, Edoardo, El-Madany, Tarek S., Filippa, Gianluca, Galvagno, Marta, Hammer, Tiana W., Ma, Xuanlong, Martini, David, Zhang, Qihuan, Reichstein, Markus, Menzel, A., Römermann, Christine, Migliavacca, Mirco, China Scholarship Council, National Science Foundation (US), German Centre for Air and Space Travel, European Commission, Ministerio de Economía y Competitividad (España), Luo, Yunpeng [0000-0001-6383-8300], Pacheco-Labrador, Javier [0000-0003-3401-7081], Richardson, Andrew D. [0000-0002-0148-6714], Seyednasrollah, Bijan [0000-0002-5195-2074], Perez-Priego, Oscar [0000-0002-3138-3177], González-Cascón, Rosario [0000-0003-3468-0967], Martín, M. Pilar [0000-0002-5563-8461], Nair, Richard [0000-0002-6293-3610], Wutzler, Thomas [0000-0003-4159-5445], Bucher, Solveig F. [0000-0002-2303-4583], Carrara, Arnaud [0000-0002-9095-8807], Cremonese, Edoardo [0000-0002-6708-8532], El-Madany, Tarek S.[0000-0002-0726-7141], Filippa, Gianluca [0000-0002-4554-6045], Galvagno, Marta [0000-0002-0827-487X], Ma, Xuanlong [0000-0003-1499-8476], Martini, David [0000-0003-2180-5126], Zhang, Qihuan [0000-0002-0860-4023], Reichstein, Markus [0000-0001-5736-1112], Menzel, A. [0000-0002-7175-2512], Römermann, Christine [0000-0003-3471-0951], Migliavacca, Mirco [0000-0003-3546-8407], Luo, Yunpeng, Pacheco-Labrador, Javier, Richardson, Andrew D., Seyednasrollah, Bijan, Pérez-Priego, Óscar, González-Cascón, Rosario, Martin, M. Pilar, Moreno, Gerardo, Nair, Richard, Wutzler, Thomas, Bucher, Solveig F., Carrara, Arnaud, Cremonese, Edoardo, El-Madany, Tarek S., Filippa, Gianluca, Galvagno, Marta, Hammer, Tiana W., Ma, Xuanlong, Martini, David, Zhang, Qihuan, Reichstein, Markus, Menzel, A., Römermann, Christine, and Migliavacca, Mirco

Abstract

Remote sensing capabilities to monitor evergreen broadleaved vegetation are limited by the low temporal variability in the greenness signal. With canopy greenness computed from digital repeat photography (PhenoCam), we investigated how canopy greenness related to seasonal changes in leaf age and traits as well as variation of trees’ water fluxes (characterized by sap flow and canopy conductance). The results showed that sprouting leaves are mainly responsible for the rapid increase in canopy green chromatic coordinate (GCC) in spring. We found statistically significantly differences in leaf traits and spectral properties among leaves of different leaf ages. Specifically, mean GCC of young leaves was 0.385 ± 0.010 (mean ± SD), while for mature and old leaves was 0.369 ± 0.003, and 0.376 ± 0.004, respectively. Thus, the temporal dynamics of canopy GCC can be explained by changes in leaf spectral properties and leaf age. Sap flow and canopy conductance are both well explained by a combination of environmental drivers and greenness (96% and 87% of the variance explained, respectively). In particular, air temperature and vapor pressure deficit (VPD) explained most of sap flow and canopy conductance variance, respectively. Besides, GCC is an important explanatory variable for variation of canopy conductance may because GCC can represent the leaf ontogeny information. We conclude that PhenoCam GCC can be used to identify the leaf flushing for evergreen broadleaved trees, which carries important information about leaf ontogeny and traits. Thus, it can be helpful for better estimating canopy conductance which constraints water fluxes.

Published
2022

2. How Nitrogen and Phosphorus Availability Change Water Use Efficiency in a Mediterranean Savanna Ecosystem

Author

Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Junta de Extremadura, El-Madany, Tarek S. [0000-0002-0726-7141], Reichstein, Markus [0000-0001-5736-1112], Carrara, Arnaud [0000-0002-9095-8807], Martín, M. Pilar [0000-0002-5563-8461], Moreno, Gerardo [0000-0001-8053-2696], González-Cascón, Rosario [0000-0003-3468-0967], Peñuelas, Josep [0000-0002-7215-0150], Ellsworth, David S.[0000-0002-9699-2272], Burchard-Levine, Vicente [0000-0003-0222-8706], Knauer, Jürgen [0000-0002-4947-7067], Kolle, Olaf [0000-0002-7373-7519], Pacheco-Labrador, Javier [0000-0003-3401-7081], Nelson, Jacob A. [0000-0002-4663-2420], Perez-Priego, Oscar [0000-0002-3138-3177], Rolo, Victor [0000-0001-5854-9512], Wutzler, Thomas [0000-0003-4159-5445], Migliavacca, Mirco [0000-0003-3546-8407], El-Madany, Tarek S., Reichstein, Markus, Carrara, Arnaud, Martin, M. Pilar, Moreno, Gerardo, González-Cascón, Rosario, Peñuelas, Josep, Ellsworth, David S., Burchard-Levine, Vicente, Hammer, Tiana W., Knauer, Jürgen, Kolle, Olaf, Luo, Yunpeng, Pacheco-Labrador, Javier, Nelson, Jacob A., Pérez-Priego, Óscar, Rolo, Victor, Wutzler, Thomas, Migliavacca, Mirco, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Junta de Extremadura, El-Madany, Tarek S. [0000-0002-0726-7141], Reichstein, Markus [0000-0001-5736-1112], Carrara, Arnaud [0000-0002-9095-8807], Martín, M. Pilar [0000-0002-5563-8461], Moreno, Gerardo [0000-0001-8053-2696], González-Cascón, Rosario [0000-0003-3468-0967], Peñuelas, Josep [0000-0002-7215-0150], Ellsworth, David S.[0000-0002-9699-2272], Burchard-Levine, Vicente [0000-0003-0222-8706], Knauer, Jürgen [0000-0002-4947-7067], Kolle, Olaf [0000-0002-7373-7519], Pacheco-Labrador, Javier [0000-0003-3401-7081], Nelson, Jacob A. [0000-0002-4663-2420], Perez-Priego, Oscar [0000-0002-3138-3177], Rolo, Victor [0000-0001-5854-9512], Wutzler, Thomas [0000-0003-4159-5445], Migliavacca, Mirco [0000-0003-3546-8407], El-Madany, Tarek S., Reichstein, Markus, Carrara, Arnaud, Martin, M. Pilar, Moreno, Gerardo, González-Cascón, Rosario, Peñuelas, Josep, Ellsworth, David S., Burchard-Levine, Vicente, Hammer, Tiana W., Knauer, Jürgen, Kolle, Olaf, Luo, Yunpeng, Pacheco-Labrador, Javier, Nelson, Jacob A., Pérez-Priego, Óscar, Rolo, Victor, Wutzler, Thomas, and Migliavacca, Mirco

Abstract

Nutrient availability, especially of nitrogen (N) and phosphorus (P), is of major importance for every organism and at a larger scale for ecosystem functioning and productivity. Changes in nutrient availability and potential stoichiometric imbalance due to anthropogenic nitrogen deposition might lead to nutrient deficiency or alter ecosystem functioning in various ways. In this study, we present 6 years (2014–2020) of flux-, plant-, and remote sensing data from a large-scale nutrient manipulation experiment conducted in a Mediterranean savanna-type ecosystem with an emphasis on the effects of N and P treatments on ecosystem-scale water-use efficiency (WUE) and related mechanisms. Two plots were fertilized with N (NT, 16.9 Ha) and N + P (NPT, 21.5 Ha), and a third unfertilized plot served as a control (CT). Fertilization had a strong impact on leaf nutrient stoichiometry only within the herbaceous layer with increased leaf N in both fertilized treatments and increased leaf P in NPT. Following fertilization, WUE in NT and NPT increased during the peak of growing season. While gross primary productivity similarly increased in NT and NPT, transpiration and surface conductance increased more in NT than in NPT. The results show that the NPT plot with higher nutrient availability, but more balanced N:P leaf stoichiometry had the highest WUE. On average, higher N availability resulted in a 40% increased leaf area index (LAI) in both fertilized treatments in the spring. Increased LAI reduced aerodynamic conductance and thus evaporation at both fertilized plots in the spring. Despite reduced evaporation, annual evapotranspiration increased by 10% (48.6 ± 28.3 kg H2O m−2), in the NT plot, while NPT remained similar to CT (−1%, −6.7 ± 12.2 kgH2O m−2). Potential causes for increased transpiration at NT could be increased root biomass and thus higher water uptake or rhizosphere priming to increase P-mobilization through microbes. The annual net ecosystem exchange shifted from a c

Published
2021

3. Multiple-constraint inversion of SCOPE. Evaluating the potential of GPP and SIF for the retrieval of plant functional traits

Author

Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), European Commission, González-Cascón, Rosario [0000-0003-3468-0967], Pacheco-Labrador, Javier [0000-0003-3401-7081], Carrara, Arnaud [0000-0002-9095-8807], Martín, M. Pilar [0000-0002-5563-8461], Pérez Priego, Oscar [0000-0002-3138-3177], Pacheco-Labrador, Javier, Pérez-Priego, Óscar, El Madany Tarek, S, Julitta, Tommaso, Rossini, Micol, Jinhong, Guan, Moreno, Gerardo, Carvalhais, Nuno, Martín, M. Pilar, González-Cascón, Rosario, Kolle,Olaf, Reichstein, Markus, Van der Tol, Christiaan, Carrara, Arnaud, Martini, David, Hammer, Tiana W., Moossen, Heiko, Migliavacca, Mirco, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), European Commission, González-Cascón, Rosario [0000-0003-3468-0967], Pacheco-Labrador, Javier [0000-0003-3401-7081], Carrara, Arnaud [0000-0002-9095-8807], Martín, M. Pilar [0000-0002-5563-8461], Pérez Priego, Oscar [0000-0002-3138-3177], Pacheco-Labrador, Javier, Pérez-Priego, Óscar, El Madany Tarek, S, Julitta, Tommaso, Rossini, Micol, Jinhong, Guan, Moreno, Gerardo, Carvalhais, Nuno, Martín, M. Pilar, González-Cascón, Rosario, Kolle,Olaf, Reichstein, Markus, Van der Tol, Christiaan, Carrara, Arnaud, Martini, David, Hammer, Tiana W., Moossen, Heiko, and Migliavacca, Mirco

Abstract

The most recent efforts to provide remote sensing (RS) estimates of plant function rely on the combination of Radiative Transfer Models (RTM) and Soil-Vegetation-Atmosphere Transfer (SVAT) models, such as the SoilCanopy Observation Photosynthesis and Energy fluxes (SCOPE) model. In this work we used ground spectroradiometric and chamber-based CO2 flux measurements in a nutrient manipulated Mediterranean grassland in order to: 1) develop a multiple-constraint inversion approach of SCOPE able to retrieve vegetation biochemical, structural as well as key functional traits, such as chlorophyll concentration (Cab), leaf area index (LAI), maximum carboxylation rate (Vcmax) and the Ball-Berry sensitivity parameter (m); and 2) compare the potential of the of gross primary production (GPP) and sun-induced fluorescence (SIF), together with up-welling Thermal Infrared (TIR) radiance and optical reflectance factors (RF), to estimate such parameters. The performance of the proposed inversion method as well as of the different sets of constraints was assessed with contemporary measurements of water and heat fluxes and leaf nitrogen content, using pattern-oriented model evaluation. The multiple-constraint inversion approach proposed together with the combination of optical RF and diel GPP and TIR data provided reliable estimates of parameters, and improved predicted water and heat fluxes. The addition of SIF to this scheme slightly improved the estimation of m. Parameter estimates were coherent with the variability imposed by the fertilization and the seasonality of the grassland. Results revealed that fertilization had an impact on Vcmax, while no significant differences were found for m. The combination of RF, SIF and diel TIR data weakly constrained functional traits. Approaches not including GPP failed to estimate LAI; however GPP overestimated Cab in the dry period. These problems might be related to the presence of high fractions of senescent leaves in the grassland. The pro

Published
2019

4. Correction: Luo, Y.P. et al., Using Near-Infrared Enabled Digital Repeat Photography to Track Structural and Physiological Phenology in Mediterranean Tree-Grass Ecosystems. Remote Sens. 2018, 10, 1293.

Author

Martín, M. Pilar [0000-0002-5563-8461], González-Cascón, Rosario [0000-0003-3468-0967], Pacheco-Labrador, Javier [0000-0003-3401-7081], Luo, Yunpeng, El-Madany, Tarek S., Filippa, Gianluca, Ma, Xuanlong, Ahrens, Bernhard, Carrara, Arnaud, González-Cascón, Rosario, Cremonese, Edoardo, Galvagno, Marta, Hammer, Tiana W., Pacheco-Labrador, Javier, Martín, M. Pilar, Moreno, Gerardo, Pérez-Priego, Óscar, Reichstein, Markus, Richardson, Andrew D., Römermann, Christine, Migliavacca, Mirco, Martín, M. Pilar [0000-0002-5563-8461], González-Cascón, Rosario [0000-0003-3468-0967], Pacheco-Labrador, Javier [0000-0003-3401-7081], Luo, Yunpeng, El-Madany, Tarek S., Filippa, Gianluca, Ma, Xuanlong, Ahrens, Bernhard, Carrara, Arnaud, González-Cascón, Rosario, Cremonese, Edoardo, Galvagno, Marta, Hammer, Tiana W., Pacheco-Labrador, Javier, Martín, M. Pilar, Moreno, Gerardo, Pérez-Priego, Óscar, Reichstein, Markus, Richardson, Andrew D., Römermann, Christine, and Migliavacca, Mirco

Abstract

Tree–grass ecosystems are widely distributed. However, their phenology has not yet been fully characterized. The technique of repeated digital photographs for plant phenology monitoring (hereafter referred as PhenoCam) provide opportunities for long-term monitoring of plant phenology, and extracting phenological transition dates (PTDs, e.g., start of the growing season). Here, we aim to evaluate the utility of near-infrared-enabled PhenoCam for monitoring the phenology of structure (i.e., greenness) and physiology (i.e., gross primary productivity—GPP) at four tree–grass Mediterranean sites. We computed four vegetation indexes (VIs) from PhenoCams: (1) green chromatic coordinates (GCC), (2) normalized difference vegetation index (CamNDVI), (3) near-infrared reflectance of vegetation index (CamNIRv), and (4) ratio vegetation index (CamRVI). GPP is derived from eddy covariance flux tower measurement. Then, we extracted PTDs and their uncertainty from different VIs and GPP. The consistency between structural (VIs) and physiological (GPP) phenology was then evaluated. CamNIRv is best at representing the PTDs of GPP during the Green-up period, while CamNDVI is best during the Dry-down period. Moreover, CamNIRv outperforms the other VIs in tracking growing season length of GPP. In summary, the results show it is promising to track structural and physiology phenology of seasonally dry Mediterranean ecosystem using near-infrared-enabled PhenoCam. We suggest using multiple VIs to better represent the variation of GPP.

Published
2019

5. Desorption of Trace Inorganic Contaminants from Solids in Drinking Water Distribution Systems

Author

Hammer, Tiana W.

Subjects
Civil and Environmental Engineering, Environmental Engineering, water, desorption, drinking, contaminants
Abstract

In order to maintain high quality safe drinking water, we need to understand what happens after the water has been cleaned at the drinking water plant and before it gets to the consumer���s house. Even if low concentrations of toxic contaminants enter the drinking water distribution system (DWDS) there is potential for contaminants to accumulate and be released by changes in flow or water conditions in high concentrations at the tap. For this study, we collected solid material from Park City, Utah that accumulated within the DWDS, along with a year of monthly monitoring of the DWDS. These solids were tested under five chemical and physical changes to see what contaminants can be released into the drinking water, with focus on eight elements: antimony (Sb), arsenic (As), chromium (Cr), copper (Cu), lead (PBS), and thallium (Tl) termed inorganic contaminants (TICs), also pipe elements iron (Fe) and manganese (Mn). From this study it was found that high concentrations of Sb, As, and Tl could be released under some conditions. Fortunately, we saw that the release of Cr, Cu, and Pb was either unmeasurable or so low that the amount never approached drinking water standards. The factors that were the most influential in producing high concentrations were both high and low pH, high temperature, low Cl2, and CaSO4. The most surprising observation was the very high concentrations of Tl released, reaching up to 90 ��g/L, where the safe limit in drinking water is 2 ��g/L. This study showed the importance of monitoring changes within the DWDS and that small changes can cause harmful levels of some contaminants to be released into the drinking water. However, monthly monitoring showed under normal conditions no harmful levels were detected.

Published
2018
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6. Using near-infrared-enabled digital repeat photography to track structural and physiological phenology in mediterranean tree–grass ecosystems

Author

China Scholarship Council, Ministerio de Economía y Competitividad (España), Department of Agriculture (US), National Science Foundation (US), Department of Energy (US), National Park Service (US), U.S. Geological Survey, González-Cascón, Rosario [0000-0003-3468-0967], Pacheco-Labrador, Javier [0000-0003-3401-7081], Martín, M. Pilar [0000-0002-5563-8461], Carrara, Arnaud [0000-0002-9095-8807], Pérez-Priego, Óscar [0000-0002-3138-3177], Luo, Yunpeng, El-Madany, Tarek S., Filippa, Gianluca, Ma, Xuanlong, Ahrens, Bernhard, Carrara, Arnaud, González-Cascón, Rosario, Cremonese, Edoardo, Galvagno, Marta, Hammer, Tiana W., Pacheco-Labrador, Javier, Martín, M. Pilar, Moreno, Gerardo, Pérez-Priego, Óscar, Reichstein, Markus, Richardson, Andrew D., Römermann, Christine, Migliavacca, Mirco, China Scholarship Council, Ministerio de Economía y Competitividad (España), Department of Agriculture (US), National Science Foundation (US), Department of Energy (US), National Park Service (US), U.S. Geological Survey, González-Cascón, Rosario [0000-0003-3468-0967], Pacheco-Labrador, Javier [0000-0003-3401-7081], Martín, M. Pilar [0000-0002-5563-8461], Carrara, Arnaud [0000-0002-9095-8807], Pérez-Priego, Óscar [0000-0002-3138-3177], Luo, Yunpeng, El-Madany, Tarek S., Filippa, Gianluca, Ma, Xuanlong, Ahrens, Bernhard, Carrara, Arnaud, González-Cascón, Rosario, Cremonese, Edoardo, Galvagno, Marta, Hammer, Tiana W., Pacheco-Labrador, Javier, Martín, M. Pilar, Moreno, Gerardo, Pérez-Priego, Óscar, Reichstein, Markus, Richardson, Andrew D., Römermann, Christine, and Migliavacca, Mirco

Abstract

Tree–grass ecosystems are widely distributed. However, their phenology has not yet been fully characterized. The technique of repeated digital photographs for plant phenology monitoring (hereafter referred as PhenoCam) provide opportunities for long-term monitoring of plant phenology, and extracting phenological transition dates (PTDs, e.g., start of the growing season). Here, we aim to evaluate the utility of near-infrared-enabled PhenoCam for monitoring the phenology of structure (i.e., greenness) and physiology (i.e., gross primary productivity—GPP) at four tree–grass Mediterranean sites. We computed four vegetation indexes (VIs) from PhenoCams: (1) green chromatic coordinates (GCC), (2) normalized difference vegetation index (CamNDVI), (3) near-infrared reflectance of vegetation index (CamNIRv), and (4) ratio vegetation index (CamRVI). GPP is derived from eddy covariance flux tower measurement. Then, we extracted PTDs and their uncertainty from different VIs and GPP. The consistency between structural (VIs) and physiological (GPP) phenology was then evaluated. CamNIRv is best at representing the PTDs of GPP during the Green-up period, while CamNDVI is best during the Dry-down period. Moreover, CamNIRv outperforms the other VIs in tracking growing season length of GPP. In summary, the results show it is promising to track structural and physiology phenology of seasonally dry Mediterranean ecosystem using near-infrared-enabled PhenoCam. We suggest using multiple VIs to better represent the variation of GPP.

Published
2018

7. Using Near-Infrared-Enabled Digital Repeat Photography to Track Structural and Physiological Phenology in Mediterranean Tree–Grass Ecosystems

Author

Luo, Yunpeng, primary, El-Madany, Tarek S., additional, Filippa, Gianluca, additional, Ma, Xuanlong, additional, Ahrens, Bernhard, additional, Carrara, Arnaud, additional, Gonzalez-Cascon, Rosario, additional, Cremonese, Edoardo, additional, Galvagno, Marta, additional, Hammer, Tiana W., additional, Pacheco-Labrador, Javier, additional, Martín, M. Pilar, additional, Moreno, Gerardo, additional, Perez-Priego, Oscar, additional, Reichstein, Markus, additional, Richardson, Andrew D., additional, Römermann, Christine, additional, and Migliavacca, Mirco, additional

Published
2018
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8. Plant functional traits and canopy structure control the relationship between photosynthetic CO2 uptake and far-red sun-induced fluorescence in a Mediterranean grassland under different nutrient availability

Author

European Commission, Martín, M. Pilar [0000-0002-5563-8461], Pérez Prieto, Oscar [0000-0002-3138-3177], Carrara, Arnaud [0000-0002-9095-8807], Pacheco-Labrador, Javier [0000-0003-3401-7081], Migliavacca, Mirco, Pérez-Priego, Óscar, Rossini, Micol, El Madany Tarek, S, Moreno, Gerardo, Van der Tol, Christiaan, Rascher, Uwe, Berninger Anna, Bessenbacher Verena, Burkart, Andreas, Carrara, Arnaud, Fava, Francesco, Hong Juan, Jin, Hammer, Tiana W., Henkel Kathrin, Juarez Alcalde, Enrique, Julitta, Tommaso, Kolle,Olaf, Martín, M. Pilar, Musavi, Talie, Pacheco-Labrador, Javier, Perez Burgueño, Andrea, Wutzler, Thomas, Zaehle, Sonke, Reichstein, Markus, European Commission, Martín, M. Pilar [0000-0002-5563-8461], Pérez Prieto, Oscar [0000-0002-3138-3177], Carrara, Arnaud [0000-0002-9095-8807], Pacheco-Labrador, Javier [0000-0003-3401-7081], Migliavacca, Mirco, Pérez-Priego, Óscar, Rossini, Micol, El Madany Tarek, S, Moreno, Gerardo, Van der Tol, Christiaan, Rascher, Uwe, Berninger Anna, Bessenbacher Verena, Burkart, Andreas, Carrara, Arnaud, Fava, Francesco, Hong Juan, Jin, Hammer, Tiana W., Henkel Kathrin, Juarez Alcalde, Enrique, Julitta, Tommaso, Kolle,Olaf, Martín, M. Pilar, Musavi, Talie, Pacheco-Labrador, Javier, Perez Burgueño, Andrea, Wutzler, Thomas, Zaehle, Sonke, and Reichstein, Markus

Abstract

Sun-induced fluorescence (SIF) in the far-red region provides a new noninvasive measurement approach that has the potential to quantify dynamic changes in light-use efficiency and gross primary production (GPP). However, the mechanistic link between GPP and SIF is not completely understood. We analyzed the structural and functional factors controlling the emission of SIF at 760 nm (F760) in a Mediterranean grassland manipulated with nutrient addition of nitrogen (N), phosphorous (P) or nitrogen¿phosphorous (NP). Using the soil¿canopy observation of photosynthesis and energy (SCOPE) model, we investigated how nutrient-induced changes in canopy structure (i.e. changes in plant forms abundance that influence leaf inclination distribution function, LIDF) and functional traits (e.g. N content in dry mass of leaves, N%, Chlorophyll a+b concentration (Cab) and maximum carboxylation capacity (Vcmax)) affected the observed linear relationship between F760 and GPP. We conclude that the addition of nutrients imposed a change in the abundance of different plant forms and biochemistry of the canopy that controls F760. Changes in canopy structure mainly control the GPP¿F760 relationship, with a secondary effect of Cab and Vcmax. In order to exploit F760 data to model GPP at the global/regional scale, canopy structural variability, biodiversity and functional traits are important factors that have to be considered.

Published
2017

9. Plant functional traits and canopy structure control the relationship between photosynthetic CO2 uptake and far‐red sun‐induced fluorescence in a Mediterranean grassland under different nutrient availability

Author

Migliavacca, Mirco, primary, Perez‐Priego, Oscar, additional, Rossini, Micol, additional, El‐Madany, Tarek S., additional, Moreno, Gerardo, additional, van der Tol, Christiaan, additional, Rascher, Uwe, additional, Berninger, Anna, additional, Bessenbacher, Verena, additional, Burkart, Andreas, additional, Carrara, Arnaud, additional, Fava, Francesco, additional, Guan, Jin‐Hong, additional, Hammer, Tiana W., additional, Henkel, Kathrin, additional, Juarez‐Alcalde, Enrique, additional, Julitta, Tommaso, additional, Kolle, Olaf, additional, Martín, M. Pilar, additional, Musavi, Talie, additional, Pacheco‐Labrador, Javier, additional, Pérez‐Burgueño, Andrea, additional, Wutzler, Thomas, additional, Zaehle, Sönke, additional, and Reichstein, Markus, additional

Published
2017
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10. Plant functional traits and canopy structure control the relationship between photosynthetic CO2 uptake and far-red sun-induced fluorescence in a Mediterranean grassland under different nutrient availability.

Author

Migliavacca, Mirco, Perez‐Priego, Oscar, Rossini, Micol, El‐Madany, Tarek S., Moreno, Gerardo, van der Tol, Christiaan, Rascher, Uwe, Berninger, Anna, Bessenbacher, Verena, Burkart, Andreas, Carrara, Arnaud, Fava, Francesco, Guan, Jin‐Hong, Hammer, Tiana W., Henkel, Kathrin, Juarez‐Alcalde, Enrique, Julitta, Tommaso, Kolle, Olaf, Martín, M. Pilar, and Musavi, Talie

Subjects
ECOLOGY, GRASSLANDS, PLANT canopies, CHLOROPHYLL, CARBOXYLATION, BIOCHEMISTRY
Abstract

Sun-induced fluorescence ( SIF) in the far-red region provides a new noninvasive measurement approach that has the potential to quantify dynamic changes in light-use efficiency and gross primary production ( GPP). However, the mechanistic link between GPP and SIF is not completely understood., We analyzed the structural and functional factors controlling the emission of SIF at 760 nm (F760) in a Mediterranean grassland manipulated with nutrient addition of nitrogen (N), phosphorous (P) or nitrogen-phosphorous ( NP). Using the soil-canopy observation of photosynthesis and energy (SCOPE) model, we investigated how nutrient-induced changes in canopy structure (i.e. changes in plant forms abundance that influence leaf inclination distribution function, LIDF) and functional traits (e.g. N content in dry mass of leaves, N%, Chlorophyll a+b concentration ( Cab) and maximum carboxylation capacity ( Vcmax)) affected the observed linear relationship between F760 and GPP., We conclude that the addition of nutrients imposed a change in the abundance of different plant forms and biochemistry of the canopy that controls F760. Changes in canopy structure mainly control the GPP-F760 relationship, with a secondary effect of Cab and Vcmax., In order to exploit F760 data to model GPP at the global/regional scale, canopy structural variability, biodiversity and functional traits are important factors that have to be considered. [ABSTRACT FROM AUTHOR]

Published
2017
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11. Correction: Luo, Y.P. et al., Using Near-Infrared Enabled Digital Repeat Photography to Track Structural and Physiological Phenology in Mediterranean Tree-Grass Ecosystems. Remote Sens. 2018, 10, 1293.

Author

Luo, Yunpeng, El-Madany, Tarek S., Filippa, Gianluca, Ma, Xuanlong, Ahrens, Bernhard, Carrara, Arnaud, Gonzalez-Cascon, Rosario, Cremonese, Edoardo, Galvagno, Marta, Hammer, Tiana W., Pacheco-Labrador, Javier, Martín, M. Pilar, Moreno, Gerardo, Perez-Priego, Oscar, Reichstein, Markus, Richardson, Andrew D., Römermann, Christine, and Migliavacca, Mirco

Subjects
PHENOLOGY, DIGITAL photography
Abstract

A correction is presented to the article "Luo, Y.P. et al., Using Near-Infrared Enabled Digital Repeat Photography to Track Structural and Physiological Phenology in Mediterranean Tree-Grass Ecosystems. Remote Sens. 2018, 10, 1293" which appeared on March 15, 2019 in this issue.

Published
2019
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12. How Nitrogen and Phosphorus Availability Change Water Use Efficiency in a Mediterranean Savanna Ecosystem

Author

Yunpeng Luo, Gerardo Moreno, Josep Peñuelas, Thomas Wutzler, Oscar Perez-Priego, M. Pilar Martín, David S. Ellsworth, Victor Rolo, Olaf Kolle, Rosario Gonzalez-Cascon, Arnaud Carrara, Vicente Burchard-Levine, Tarek S. El-Madany, Mirco Migliavacca, Tiana W. Hammer, Jürgen Knauer, Javier Pacheco-Labrador, Markus Reichstein, Jacob A. Nelson, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Junta de Extremadura, El-Madany, Tarek S., Reichstein, Markus, Carrara, Arnaud, Martín, M. Pilar, Moreno, Gerardo, Gonzalez-Cascon, Rosario, Peñuelas, Josep, Ellsworth, David S., Burchard-Levine, Vicente, Knauer, Jürgen, Kolle, Olaf, Pacheco-Labrador, Javier, Nelson, Jacob A., Perez-Priego, Oscar, Rolo, Victor, Wutzler, Thomas, Migliavacca, Mirco, 1 Max Planck Institute for Biogeochemistry Department Biogeochemical Integration Jena Germany, 2 Centro de Estudios Ambientales del Mediterráneo (CEAM), Charles R. Darwin 14 Spain, 3 Environmental Remote Sensing and Spectroscopy Laboratory (SpecLab) Spanish National Research Council Madrid Spain, 4 Forest Research Group INDEHESA University of Extremadura Plasencia Spain, Gonzalez‐Cascon, Rosario, 5 Department of Environment National Institute for Agriculture and Food Research and Technology (INIA‐CSIC) Madrid Spain, 6 Global Ecology Unit CREAF‐CSIC‐UAB Campus de Bellaterra (UAB) Edifici C Catalonia Spain, 8 Hawkesbury Institute for the Environment Western Sydney University Penrith Australia, Burchard‐Levine, Vicente, Hammer, Tiana W., Luo, Yunpeng, Pacheco‐Labrador, Javier, and Perez‐Priego, Oscar

Subjects
Hydrology, Mediterranean climate, Atmospheric Science, 577.2, Ecology, Phosphorus, Eddy covariance, Water use efficiency, Paleontology, Soil Science, chemistry.chemical_element, Forestry, Stoichiometric imbalance, Aquatic Science, Nitrogen, Transpiration, MANIP, chemistry, Nutrient availability, Environmental science, Ecosystem, Water-use efficiency, Water Science and Technology
Abstract

Nutrient availability, especially of nitrogen (N) and phosphorus (P), is of major importance for every organism and at a larger scale for ecosystem functioning and productivity. Changes in nutrient availability and potential stoichiometric imbalance due to anthropogenic nitrogen deposition might lead to nutrient deficiency or alter ecosystem functioning in various ways. In this study, we present 6 years (2014–2020) of flux‐, plant‐, and remote sensing data from a large‐scale nutrient manipulation experiment conducted in a Mediterranean savanna‐type ecosystem with an emphasis on the effects of N and P treatments on ecosystem‐scale water‐use efficiency (WUE) and related mechanisms. Two plots were fertilized with N (NT, 16.9 Ha) and N + P (NPT, 21.5 Ha), and a third unfertilized plot served as a control (CT). Fertilization had a strong impact on leaf nutrient stoichiometry only within the herbaceous layer with increased leaf N in both fertilized treatments and increased leaf P in NPT. Following fertilization, WUE in NT and NPT increased during the peak of growing season. While gross primary productivity similarly increased in NT and NPT, transpiration and surface conductance increased more in NT than in NPT. The results show that the NPT plot with higher nutrient availability, but more balanced N:P leaf stoichiometry had the highest WUE. On average, higher N availability resulted in a 40% increased leaf area index (LAI) in both fertilized treatments in the spring. Increased LAI reduced aerodynamic conductance and thus evaporation at both fertilized plots in the spring. Despite reduced evaporation, annual evapotranspiration increased by 10% (48.6 ± 28.3 kg H2O m−2), in the NT plot, while NPT remained similar to CT (−1%, −6.7 ± 12.2 kgH2O m−2). Potential causes for increased transpiration at NT could be increased root biomass and thus higher water uptake or rhizosphere priming to increase P‐mobilization through microbes. The annual net ecosystem exchange shifted from a carbon source in CT (75.0 ± 20.6 gC m−2) to carbon‐neutral in both fertilized treatments [−7.0 ± 18.5 gC m−2 (NT) 0.4 ± 22.6 gC m−2 (NPT)]. Our results show, that the N:P stoichiometric imbalance, resulting from N addition (without P), increases the WUE less than the addition of N + P, due to the strong increase in transpiration at NT, which indicates the importance of a balanced N and P content for WUE., Plain Language Summary: The availability of nutrients like nitrogen (N) and phosphorus (P) is important for every living organism on Earth. Due to human activities, especially combustion processes large amounts of N are transported into the atmosphere and ecosystems. Therefore, ecosystems receive additional N but no other nutrients. We are investigating if the addition of N alone will lead to deficits in other nutrients and thus impact the functioning of ecosystems. Hence, we set up a large‐scale ecosystem experiment in a Mediterranean tree‐grass ecosystem where we fertilized two plots with N (16.9 ha) and N + P (21.5 ha). A third plot served as the control treatment. While the N‐only treatment created an imbalance between the available N and P, this imbalance was relieved in the N + P treatment where both N and P were provided. Our measurements showed that both fertilized treatments increased their carbon uptake and turned the ecosystem from a carbon source to carbon neutral. One of the main differences between the fertilized treatments which is associated with the imbalance of available N and P is the loss of water through the vegetation (transpiration). This increase in transpiration was only observed in the N‐only but not in the N + P treatment. Our results show, that the N:P stoichiometric imbalance, resulting from N‐only addition, increases the water‐use efficiency (i.e., the carbon gain per water loss) less than the addition of N + P, due to the strong increase in transpiration at the N‐only treatment., Key Points: Stoichiometric N:P‐ratio imbalance increases ecosystem transpiration. High nitrogen availability increases carbon uptake and changed the ecosystem from a carbon source to carbon neutral. Ecosystem scale functional relationships are altered through nutrient availability and imbalance., Ministerio de Economía y Competitividad http://dx.doi.org/10.13039/501100003329, Deutsches Zentrum für Luft‐ und Raumfahrt http://dx.doi.org/10.13039/501100002946

Published
2021

13. Plant functional traits and canopy structure control the relationship between photosynthetic CO 2 uptake and far-red sun-induced fluorescence in a Mediterranean grassland under different nutrient availability.

Author

Migliavacca M, Perez-Priego O, Rossini M, El-Madany TS, Moreno G, van der Tol C, Rascher U, Berninger A, Bessenbacher V, Burkart A, Carrara A, Fava F, Guan JH, Hammer TW, Henkel K, Juarez-Alcalde E, Julitta T, Kolle O, Martín MP, Musavi T, Pacheco-Labrador J, Pérez-Burgueño A, Wutzler T, Zaehle S, and Reichstein M

Subjects
Computer Simulation, Mediterranean Region, Plant Leaves drug effects, Plant Leaves physiology, Seasons, Spectrometry, Fluorescence, Carbon Dioxide metabolism, Grassland, Nitrogen pharmacology, Phosphorus pharmacology, Photosynthesis drug effects, Plant Leaves anatomy & histology, Quantitative Trait, Heritable, Sunlight
Abstract

Sun-induced fluorescence (SIF) in the far-red region provides a new noninvasive measurement approach that has the potential to quantify dynamic changes in light-use efficiency and gross primary production (GPP). However, the mechanistic link between GPP and SIF is not completely understood. We analyzed the structural and functional factors controlling the emission of SIF at 760 nm (F 760 ) in a Mediterranean grassland manipulated with nutrient addition of nitrogen (N), phosphorous (P) or nitrogen-phosphorous (NP). Using the soil-canopy observation of photosynthesis and energy (SCOPE) model, we investigated how nutrient-induced changes in canopy structure (i.e. changes in plant forms abundance that influence leaf inclination distribution function, LIDF) and functional traits (e.g. N content in dry mass of leaves, N%, Chlorophyll a+b concentration (Cab) and maximum carboxylation capacity (V cmax )) affected the observed linear relationship between F 760 and GPP. We conclude that the addition of nutrients imposed a change in the abundance of different plant forms and biochemistry of the canopy that controls F 760 . Changes in canopy structure mainly control the GPP-F 760 relationship, with a secondary effect of Cab and V cmax . In order to exploit F 760 data to model GPP at the global/regional scale, canopy structural variability, biodiversity and functional traits are important factors that have to be considered., (© 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.)

Published
2017
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