Atmospheric deposition, CO2, and change in the land carbon sink

Fernández-Martínez M., Vicca S., Janssens I.A., Ciais P., Obersteiner M., Bartrons M., Sardans J., Verger A., Canadell J.G., Chevallier F., Wang X., Bernhofer C., Curtis P.S., Gianelle D., Grünwald T., Heinesch B., Ibrom A., Knohl A., Laurila T., Law B.E., Limousin J.M., Longdoz B., Loustau D., Mammarella I., Matteucci G., Monson R.K., Montagnani L., Moors E.J., Munger J.W., Papale D., Piao S.L., Peñuelas J. (2017) Atmospheric deposition, CO2, and change in the land carbon sink. Scientific Reports. 7: 0-0.
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Doi: 10.1038/s41598-017-08755-8

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Concentrations of atmospheric carbon dioxide (CO2) have continued to increase whereas atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades. Using time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models, we found that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011. Statistical models indicated that increasing atmospheric CO2 was the most important factor driving the increasing strength of carbon sinks in these forests. We also found that the reduction of sulphur deposition in Europe and the USA lead to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. Our findings support the hypothesis of a general CO2-fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions. Our results show the need to include the effects of changing atmospheric composition, beyond CO2, to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling. © 2017 The Author(s).

Llegeix més

Nature beyond linearity: Meteorological variability and Jensen's Inequality can explain mast seeding behavior

Fernández-Martínez, M., Bogdziewicz, M., Espelta, J.M., Peñuelas, J. (2017) Nature beyond linearity: Meteorological variability and Jensen's Inequality can explain mast seeding behavior. Frontiers in Ecology and Evolution. 5: 0-0.
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Doi: 10.3389/fevo.2017.00134

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Long-term fertilization determines different metabolomic profiles and responses in saplings of three rainforest tree species with different adult canopy position

Gargallo-Garriga A., Wright S.J., Sardans J., Pérez-Trujillo M., Oravec M., Večeřová K., Urban O., Fernández-Martónez M., Parella T., Penuelas J. (2017) Long-term fertilization determines different metabolomic profiles and responses in saplings of three rainforest tree species with different adult canopy position. PLoS ONE. 12: 0-0.
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Doi: 10.1371/journal.pone.0177030

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Background Tropical rainforests are frequently limited by soil nutrient availability. However, the response of the metabolic phenotypic plasticity of trees to an increase of soil nutrient availabilities is poorly understood. We expected that increases in the ability of a nutrient that limits some plant processes should be detected by corresponding changes in plant metabolome profile related to such processes. Methodology/Principal findings We studied the foliar metabolome of saplings of three abundant tree species in a 15 year field NPK fertilization experiment in a Panamanian rainforest. The largest differences were among species and explained 75% of overall metabolome variation. The saplings of the large canopy species, Tetragastris panamensis, had the lowest concentrations of all identified amino acids and the highest concentrations of most identified secondary compounds. The saplings of the amid canopyo species, Alseis blackiana, had the highest concentrations of amino acids coming from the biosynthesis pathways of glycerate-3P, oxaloacetate and - ketoglutarate, and the saplings of the low canopy species, Heisteria concinna, had the highest concentrations of amino acids coming from the pyruvate synthesis pathways. Conclusions/Significance The changes in metabolome provided strong evidence that different nutrients limit different species in different ways. With increasing P availability, the two canopy species shifted their metabolome towards larger investment in protection mechanisms, whereas with increasing N availability, the sub-canopy species increased its primary metabolism. The results highlighted the proportional distinct use of different nutrients by different species and the resulting different metabolome profiles in this high diversity community are consistent with the ecological niche theory. © 2017 Gargallo-Garriga et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Llegeix més

Global patterns of phosphatase activity in natural soils

Margalef O., Sardans J., Fernández-Martínez M., Molowny-Horas R., Janssens I.A., Ciais P., Goll D., Richter A., Obersteiner M., Asensio D., Peñuelas J. (2017) Global patterns of phosphatase activity in natural soils. Scientific Reports. 7: 0-0.
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Doi: 10.1038/s41598-017-01418-8

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Soil phosphatase levels strongly control the biotic pathways of phosphorus (P), an essential element for life, which is often limiting in terrestrial ecosystems. We investigated the influence of climatic and soil traits on phosphatase activity in terrestrial systems using metadata analysis from published studies. This is the first analysis of global measurements of phosphatase in natural soils. Our results suggest that organic P (Porg), rather than available P, is the most important P fraction in predicting phosphatase activity. Structural equation modeling using soil total nitrogen (TN), mean annual precipitation, mean annual temperature, thermal amplitude and total soil carbon as most available predictor variables explained up to 50% of the spatial variance in phosphatase activity. In this analysis, Porg could not be tested and among the rest of available variables, TN was the most important factor explaining the observed spatial gradients in phosphatase activity. On the other hand, phosphatase activity was also found to be associated with climatic conditions and soil type across different biomes worldwide. The close association among different predictors like Porg, TN and precipitation suggest that P recycling is driven by a broad scale pattern of ecosystem productivity capacity. © 2017 The Author(s).

Llegeix més

Shifting from a fertilization-dominated to a warming-dominated period

Peñuelas, J., Ciais, P., Canadell, J.G., Janssens, I.A., Fernández-Martínez, M., Carnicer, J., Obersteiner, M., Piao, S., Vautard, R., Sardans, J. (2017) Shifting from a fertilization-dominated to a warming-dominated period. Nature Ecology and Evolution. 1: 1438-1445.
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Doi: 10.1038/s41559-017-0274-8

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Impacts of global change on Mediterranean forests and their services

Peñuelas, J., Sardans, J., Filella, I., Estiarte, M., Llusià, J., Ogaya, R., Carnicer, J., Bartrons, M., Rivas-Ubach, A., Grau, O., Peguero, G., Margalef, O., Pla-Rabés, S., Stefanescu, C., Asensio, D., Preece, C., Liu, L., Verger, A., Barbeta, A., Achotegui-Castells, A., Gargallo-Garriga, A., Sperlich, D., Farré-Armengol, G., Fernández-Martínez, M., Liu, D., Zhang, C., Urbina, I., Camino-Serrano, M., Vives-Ingla, M., Stocker, B.D., Balzarolo, M., Guerrieri, R., Peaucelle, M., Marañón-Jiménez, S., Bórnez-Mejías, K., Mu, Z., Descals, A., Castellanos, A., Terradas, J. (2017) Impacts of global change on Mediterranean forests and their services. Forests. 8: 0-0.
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Doi: 10.3390/f8120463

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Nutrient availability and climate as the main determinants of the ratio of biomass to NPP in woody and non-woody forest compartments

Fernández-Martínez M., Vicca S., Janssens I.A., Campioli M., Peñuelas J. (2016) Nutrient availability and climate as the main determinants of the ratio of biomass to NPP in woody and non-woody forest compartments. Trees - Structure and Function. 30: 775-783.
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Doi: 10.1007/s00468-015-1319-8

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Key message: Once the effect of stand age has been taken into account, nutrient availability and climate play a crucial role in determining the B:NPPs of woody and non-woody tissues. Abstract: Forest ecosystems accumulate large amounts of carbon in living tissues. The residence time of this carbon in the ecosystem depends largely on the turnover time of these tissues, which can be estimated as a surrogate of the ratio of biomass to net primary production (B:NPP). We used a global forest database of 310 sites containing data for biomass stocks and NPP to investigate the differences of B:NPPs among species and forest compartments and to determine B:NPPs main exogenous (mainly climate and nutrient availability) and endogenous (leaf habit and stand age) drivers. We used asymptotic exponential functions to adjust the B:NPPs of woody compartments to a theoretical stationary state to allow comparisons between forests of different ages. The B:NPPs of woody tissues (branches, stems, and coarse roots) were positively influenced by stand age, conversely to fine roots and leaves, which were weakly dependent on the age of the forest. The B:NPPs of woody tissues were positively correlated with nutrient availability, whereas fine-root B:NPPs decreased with increasing nutrient availability. The foliar B:NPP of evergreen forests was positively correlated with water deficit, and the fine-root B:NPP was correlated positively with the seasonality of precipitation and with annual thermal amplitude but negatively with water deficit. Our results support the influence of climate on the B:NPPs of non-woody compartments and identify nutrient availability as the main influence on the B:NPPs of woody tissues. © 2015, Springer-Verlag Berlin Heidelberg.

Llegeix més

The North Atlantic Oscillation synchronises fruit production in western European forests

Fernández-Martínez M., Vicca S., Janssens I.A., Espelta J.M., Peñuelas J. (2016) The North Atlantic Oscillation synchronises fruit production in western European forests. Ecography. : 0-0.
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Doi: 10.1111/ecog.02296

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Weather and its lagged effects have been associated with interannual variability and synchrony of fruit production for several tree species. Such relationships are used often in hypotheses relating interannual variability in fruit production with tree resources or favourable pollinating conditions and with synchrony in fruit production among sites through the Moran effect (the synchronisation of biological processes among populations driven by meteorological variability) or the local availability of pollen. Climatic teleconnections, such as the North Atlantic Oscillation (NAO), representing weather packages, however, have rarely been correlated with fruit production, despite often being better predictors of ecological processes than is local weather. The aim of this study was to test the utility of seasonal NAO indices for predicting interannual variability and synchrony in fruit production using data from 76 forests of Abies alba, Fagus sylvatica, Picea abies, Pseudotsuga menziesii, Quercus petraea, and Q. robur distributed across central Europe. Interannual variability in fruit production for all species was significantly correlated with seasonal NAO indices, which were more prominently important predictors than local meteorological variables. The relationships identified by these analyses indicated that proximal causes were mostly responsible for the interannual variability in fruit production, supporting the premise that local tree resources and favourable pollinating conditions are needed to produce large fruit crops. Synchrony in fruit production between forests was mainly associated with weather and geographical distance among sites. Also, fruit production for a given year was less variable among sites during warm and dry springs (negative spring NAO phases). Our results identify the Moran effect as the most likely mechanism for synchronisation of fruit production at large geographical scales and the possibility that pollen availability plays a role in synchronising fruit production at local scales. Our results highlight the influence of the NAO on the patterns of fruit production across western Europe. © 2016 Nordic Society Oikos.

Llegeix més

The role of nutrients, productivity and climate in determining tree fruit production in European forests

Fernández-Martínez, M., Vicca, S., Janssens, I.A., Espelta, J.M., Peñuelas, J. (2016) The role of nutrients, productivity and climate in determining tree fruit production in European forests. New Phytologist. : 0-0.
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Doi: 10.1111/nph.14193

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Assessment of the impacts of climate change on Mediterranean terrestrial ecosystems based on data from field experiments and long-term monitored field gradients in Catalonia

Peñuelas, J., Sardans, J., Filella, I., Estiarte, M., Llusià, J., Ogaya, R., Carnicer, J., Bartrons, M., Rivas-Ubach, A., Grau, O., Peguero, G., Margalef, O., Pla-Rabés, S., Stefanescu, C., Asensio, D., Preece, C., Liu, L., Verger, A., Rico, L., Barbeta, A., Achotegui-Castells, A., Gargallo-Garriga, A., Sperlich, D., Farré-Armengol, G., Fernández-Martínez, M., Liu, D., Zhang, C., Urbina, I., Camino, M., Vives, M., Nadal-Sala, D., Sabaté, S., Gracia, C., Terradas, J. (2016) Assessment of the impacts of climate change on Mediterranean terrestrial ecosystems based on data from field experiments and long-term monitored field gradients in Catalonia. Environmental and Experimental Botany. : 0-0.
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Doi: 10.1016/j.envexpbot.2017.05.012

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