Temporal analysis of fresh leaf spectroscopy and chemical properties in Quercus ilex trees

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Evolución del comportamiento espectral y la composición química en el dosel arbóreo de una dehesa

[EN] In the context of the BIOSPEC and FLUXPEC projects(http://www.lineas.cchs.csic.es/fluxpec/), spectral and biophysical variables measurements at leaf level have been conducted in the tree canopy of a holm oak dehesa (Quercus ilex) ecosystem during four vegetative periods. Measurements of bi-conical reflectance factor of intact leaf (ASD Fieldspec 3® spectroradiometer), specific leaf mass (SLM), leaf water content (LWC), nutrient (N, P, K, Ca, Mg, Mn, Fe, and Zn) and chlorophyll concentration were performed. The spectral measurements have been related with the biophysical variables by stepwise and partial least squares regression analyses. These analyses allowed to identify the spectral bands and regions that best explain the evolution of the biophysical variables and to estimate the nutrient contents during the leaf maturation process. Statistically significant estimates of the majority of the variables studied were obtained. Wavelengths that had the highest contributions explaining the chemical composition of the forest canopy were located in spectral regions of the red edge, the green visible region, and the shortwave infrared[ES] : En el contexto de los proyectos BIOSPEC y FLUXPEC (http://www.lineas.cchs.csic.es/fluxpec/), se han realizado mediciones espectrales y de variables biofísicas a nivel de hoja en el dosel arbóreo de una dehesa de encina (Quercus ilex) durante cuatro períodos vegetativos. Se han llevado a cabo mediciones de reflectividad bi-cónica de hoja intacta (ASD Fieldspec 3® spectroradiometer), masa foliar específica (SLM), contenido de agua (LWC), concentraciones de nutrientes (N, P, K, Ca, Mg, Mn, Fe, y Zn) y clorofilas. Las mediciones espectrales se han relacionado con las variables biofísicas mediante análisis de regresión múltiple por pasos (SWR) y regresión de mínimos cuadrados parciales (PLSR). Estos análisis han permitido identificar las bandas y regiones espectrales que explican la evolución de las variables biofísicas y estimar los contenidos de nutrientes a lo largo del proceso de maduración de las hojas en la copa. Se han obtenido modelos estadísticamente significativos para la mayoría de las variables foliares estudiadas. Las longitudes de onda que aportan mayor información sobre la composición química del dosel, se encuentran en las regiones espectrales del límite del rojo, la región verde del visible y el infrarrojo medio de onda corta (SWIR).Este trabajo ha sido financiado por los proyectos BIOSPEC (CGL2008-02301/CLI, Ministerio de Ciencia e innovación) y FLUXPEC (CGL-2012- 34383, Ministerio de Economía y Competitividad). Agradecemos a los equipos de investigación y trabajo que han participado en ambos proyectos su ayuda durante las campañas de muestreo y las mediciones de campo, así como al personal del Laboratorio de Ecología Forestal del CIFORINIA por su colaboración en los análisis foliaresPeer reviewe

Understanding the optical responses of leaf nitrogen in Mediterranean Holm oak (Quercus ilex) using field spectroscopy

The direct estimation of nitrogen (N) in fresh vegetation is challenging due to its weak influence on leaf reflectance and the overlaps with absorption features of other compounds. Different empirical models relate in this work leaf nitrogen concentration ([N]Leaf) on Holm oak to leaf reflectance as well as derived spectral indices such as normalized difference indices (NDIs), the three bands indices (TBIs) and indices previously used to predict leaf N and chlorophyll. The models were calibrated and assessed their accuracy, robustness and the strength of relationship when other biochemicals were considered. Red edge was the spectral region most strongly correlated with [N]Leaf, whereas most of the published spectral indexes did not provide accurate estimations. NDIs and TBIs based models could achieve robust and acceptable accuracies (TBI1310,1720,730: R2 = 0.76, [0.64,0.86]; RMSE (%) = 9.36, [7.04,12.83]). These models sometimes included indices with bands close to absorption features of N bonds or nitrogenous compounds, but also of other biochemicals. Models were independently and inter-annually validated using the bootstrap method, which allowed discarding those models non-robust across different years. Partial correlation analysis revealed that spectral estimators did not strongly respond to [N]Leaf but to other leaf variables such as chlorophyll and water, even if bands close to absorption features of N bonds or compounds were present in the models.This research has been funded by the BIOSPEC project “Linking spectral information at different spatial scales with biophysical parameters of Mediterranean vegetation in the context of Global Change” (http://www.lineas.cchs.csic.es/biospec) (CGL2008-02301/CLI, Ministry of Science and Innovation) and the FLUXPEC project “Monitoring changes in water and carbon fluxes from remote and proximal sensing in a Mediterranean dehesa ecosystem” (http://www.lineas.cchs.csic.es/fluxpec) (CGL2012-34383, Ministry of Economy and Competitiveness). Pacheco-Labrador, J. was sponsored by a JAE-Predoc grant (CSIC)Peer reviewe

Annual Variation of Foliar Nitrogen and Chlorophyll Contents in Mature Holm Oak Trees as a Basis for the Estimation of Canopy Nitrogen in a Mediterranean Wooded Grassland Ecosystem

Spanish Ministry of Science and Innovation in the framework of the BIOSPEC Project (CGL2008-02301/CLI). Laboratory of the Ecology and Forest Genetic of CIFOR (INIA), that conducted the foliar analysis and colleagues from CCHS-CSIC, CEAM, University of Alcalá and University of Zaragoza that contributed to the field and laboratory worksPeer reviewe

Análisis de la diversidad funcional del estrato herbáceo en un ecosistema de dehesa a partir de datos hiperespectrales "in situ"

El presente trabajo aborda la estimación de la diversidad funcional (FD) del estrato herbáceo en un ecosistema de dehesa mediante datos hiperespectrales obtenidos con un espectro-radiómetro portátil ASD FieldSpec® 3 (Analytical Spectral Devices Inc., Boulder, CO, EE. UU.). Los datos ópticos se correlacionaron con variables biofísicas (área foliar específica (SLA), biomasa aérea (AGB), índice de área foliar (LAI) y contenido de nitrógeno (N%)) e índices de diversidad tradicionales como Shannon y Evenness y otros relacionados con la diversidad funcional como el índice multidimensional de dispersión funcional (FDis) usando como variables predictoras: a) índices de vegetación (VIs) y métodos de regresión simple, y b) bandas espectrales y Partial Least Squares Regression (PLSR). Las correlaciones, especialmente de las variables biofísicas relacionadas con FDis, mejoraron sustancialmente al utilizar información hiperespectral (R2 >0.6, rRMSE <0.1) lo que confirma el interés de la dimensión espectral para estimar la diversidad funcional de un ecosistema complejo como es el caso de los pastizales semi-áridos

Improving the Performance of 3-D Radiative Transfer Model FLIGHT to Simulate Optical Properties of a Tree-Grass Ecosystem

The 3-D Radiative Transfer Model (RTM) FLIGHT can represent scattering in open forest or savannas featuring underlying bare soils. However, FLIGHT might not be suitable for multilayered tree-grass ecosystems (TGE), where a grass understory can dominate the reflectance factor (RF) dynamics due to strong seasonal variability and low tree fractional cover. To address this issue, we coupled FLIGHT with the 1-D RTM PROSAIL. The model is evaluated against spectral observations of proximal and remote sensing sensors: the ASD Fieldspec® 3 spectroradiometer, the Airborne Spectrographic Imager (CASI) and the MultiSpectral Instrument (MSI) onboard Sentinel-2. We tested the capability of both PROSAIL and PROSAIL+FLIGHT to reproduce the variability of different phenological stages determined by 16-year time series analysis of Moderate Resolution Imaging Spectroradiometer-Normalized Difference Vegetation Index (MODIS-NDVI). Then, we combined concomitant observations of biophysical variables and RF to test the capability of the models to reproduce observed RF. PROSAIL achieved a Relative Root Mean Square Error (RRMSE) between 6% to 32% at proximal sensing scale. PROSAIL+FLIGHT RRMSE ranged between 7% to 31% at remote sensing scales. RRMSE increased in periods when large fractions of standing dead material mixed with emergent green grasses —especially in autumn—; suggesting that the model cannot represent the spectral features of this material. PROSAIL+FLIGHT improves RF simulation especially in summer and at mid-high view angles.This research was funded by Ministerio de Economía y Competitividad, CGL2012-34383 and CGL2015-G9095-R and Ministerio de Educación, Cultura y Deporte, FPU15/03558.Peer reviewe

Nutrients and water availability constrain the seasonality of vegetation activity in a Mediterranean ecosystem

Anthropogenic nitrogen (N) deposition and resulting differences in ecosystem N and phosphorus (P) ratios are expected to impact photosynthetic capacity, that is, maximum gross primary productivity (GPP). However, the interplay between N and P availability with other critical resources on seasonal dynamics of ecosystem productivity remains largely unknown. In a Mediterranean tree–grass ecosystem, we established three landscape-level (24 ha) nutrient addition treatments: N addition (NT), N and P addition (NPT), and a control site (CT). We analyzed the response of ecosystem to altered nutrient stoichiometry using eddy covariance fluxes measurements, satellite observations, and digital repeat photography. A set of metrics, including phenological transition dates (PTDs; timing of green-up and dry-down), slopes during green-up and dry-down period, and seasonal amplitude, were extracted from time series of GPP and used to represent the seasonality of vegetation activity. The seasonal amplitude of GPP was higher for NT and NPT than CT, which was attributed to changes in structure and physiology induced by fertilization. PTDs were mainly driven by rainfall and exhibited no significant differences among treatments during the green-up period. Yet, both fertilized sites senesced earlier during the dry-down period (17–19 days), which was more pronounced in the NT due to larger evapotranspiration and water usage. Fertilization also resulted in a faster increase in GPP during the green-up period and a sharper decline in GPP during the dry-down period, with less prominent decline response in NPT. Overall, we demonstrated seasonality of vegetation activity was altered after fertilization and the importance of nutrient–water interaction in such water-limited ecosystems. With the projected warming-drying trend, the positive effects of N fertilization induced by N deposition on GPP may be counteracted by an earlier and faster dry-down in particular in areas where the N:P ratio increases, with potential impact on the carbon cycle of water-limited ecosystems.The authors acknowledge the Alexander von Humboldt Foundation for supporting this research with the Max-Planck Prize to Markus Reichstein. Yunpeng Luo and Mirco Migliavacca gratefully acknowledge financial support from the China Scholarship Council. Gerardo Moreno acknowledges financial support from the grant agreement IB16185 of the Regional Government of Extremadura

Occurrence and size distribution study of microplastics in household water from different cities in continental Spain and the Canary Islands

9 pages, 5 figures, 1 table, supplementary materials https://doi.org/10.1016/j.watres.2023.120044.-- Data availability: Data will be made available on requestThe purpose of this study was to investigate the occurrence of microplastics (MPs) in drinking water in Spain by comparing tap water from different locations using common sampling and identification procedures. We sampled tap water from 24 points in 8 different locations from continental Spain and the Canary Islands by means of 25 μm opening size steel filters coupled to household connections. All particles were measured and spectroscopically characterized including not only MPs but also particles consisting of natural materials with evidence of industrial processing, such as dyed natural fibres, referred insofar as artificial particles (APs). The average concentration of MPs was 12.5 ± 4.9 MPs/m3 and that of anthropogenic particles 32.2 ± 12.5 APs/m3. The main synthetic polymers detected were polyamide, polyester, and polypropylene, with lower counts of other polymers including the biopolymer poly(lactic acid). Particle size and mass distributions were parameterized by means of power law distributions, which allowed performing estimations of the concentration of smaller particles provided the same scaling parameter of the power law applies. The calculated total mass concentration of the identified MPs was 45.5 ng/L. The observed size distribution of MPs allowed an estimation for the concentration of nanoplastics (< 1 µm) well below the ng/L range; higher concentrations are not consistent with scale invariant fractal fragmentation. Our findings showed that MPs in the drinking water sampled in this work do not represent a significant way of exposure to MPs and would probably pose a negligible risk for human healthThe authors acknowledge the financial support provided by Plastics Europe and that of the Spanish Government, Ministerio de Ciencia e Innovación, grants PID2020-113769RB-C21/C22.With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

EnviroPlaNet Project: A systematic monitoring of atmospheric deposition of microplastics in Spain

SETAC EUROPE 33RD ANNUAL MEETING 30 APRIL-4 MAY 2023 | DUBLIN, IRELANDPlastic pollution is a global concern. The world's production continues to increase yearly, reaching more than 367 million tons in 2020 [1]. Part of these plastics are directly manufactured as microplastics (MPs) while another fraction becomes MPs as a result of the degradation processes of larger plastics into microsized particles. In this context, MPs have already been found in the hydrosphere, biosphere, cryosphere, lithosphere and, recently, atmosphere. However, the presence of MPs in the atmosphere has been poorly studied. The objective of this work was the systematic monitoring of the deposition of MPs in areas of Spain with different characteristics (population, economic activities, and climate) using a common method for sampling, quantification, and identification during the four seasons of a one-year sampling campaign with the purpose of clarifying the role of the atmosphere in the fate and dispersion of MPs. This was possible thanks to the collaboration of several Spanish research groups in the project Thematic Network of Micro- and Nanoplastics in the EnvironmentPeer reviewe

CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research