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6. Spatial and temporal heterogeneity of soil respiration in a bare-soil Mediterranean olive grove.

Author

Aranda-Barranco, Sergio, Serrano-Ortiz, Penélope, Kowalski, Andrew S., and Sánchez-Cañete, Enrique P.

Subjects
SOIL respiration, OLIVE, HETEROGENEITY, RAINFALL
Abstract

Soil respiration (Rs) is an important carbon flux in terrestrial ecosystems and knowledge about this CO2 release process and the drivers involved is a key topic in the context of global change. However, temporal, and spatial variability has not been extensively studied in semiarid systems such as olive groves. In this study, we show a full year of continuous measurements of Rs with six automatic chambers in a fertirrigated olive grove with bare soil in the Mediterranean accompanied by ecosystem respiration (Reco) obtained using the eddy covariance (EC) technique. To study spatial variability, the automatic chambers were distributed equally under the canopy (Rs Under-Tree) and in the center of the alley (Rs Alley), and the gradient of Rs between both locations was measured in several manual campaigns in addition to azimuthal changes about the center of the olive trees. The results indicate that Rs Under-Tree was three times larger than Rs Alley in the annual computations. Higher Rs was found on the south face, and an exponential decay of Rs was observed until the alley's center was reached. These spatial changes were used to weigh and project Rs to the ecosystem scale, whose annual balance was 1.6–2.3 higher than Reco estimated using EC-derived models. The daytime Reco model performs better the greater the influence of Rs Under-Tree and the night-time Reco model and Rs covaried more the higher the fraction of Rs Alley. We found values of Q10 < 1 in the vicinity of the olive tree and Rs Under-Tree represented 39 % of the Rs of the olive grove. CO2 pulses associated with precipitation events were detected, especially in the alley, during dry periods, and after extended periods without rain, but were not accurately detected by EC-derived models. We point out an interaction between several effects that vary in time and are different under the canopy than in the alleys that the accepted models to estimate Q10 and Reco do not consider. These results show a high spatial and temporal heterogeneity in soil respiration and the factors involved, which must be considered in future work in semi-arid agrosystems. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Endogenous circadian regulation of carbon dioxide exchange in terrestrial ecosystems

Author

Dios, Víctor Resco, Goulden, Michael L, Ogle, Kiona, Richardson, Andrew D, Hollinger, David Y, Davidson, Eric A, Alday, Josu G, Barron‐Gafford, Greg A, Carrara, Arnaud, Kowalski, Andrew S, Oechel, Walt C, Reverter, Borja R, Scott, Russell L, Varner, Ruth K, Díaz‐Sierra, Rubén, and Moreno, José M

Subjects
Sleep Research, biosphere-atmosphere interactions, canopy conductance, circadian clock, ecosystem exchange, gas exchange, global change, photosynthesis, source, sink regulation, Environmental Sciences, Biological Sciences, Ecology
Abstract

It is often assumed that daytime patterns of ecosystem carbon assimilation are mostly driven by direct physiological responses to exogenous environmental cues. Under limited environmental variability, little variation in carbon assimilation should thus be expected unless endogenous plant controls on carbon assimilation, which regulate photosynthesis in time, are active. We evaluated this assumption with eddy flux data, and we selected periods when net ecosystem exchange (NEE) was decoupled from environmental variability in seven sites from highly contrasting biomes across a 74° latitudinal gradient over a total of 36 site-years. Under relatively constant conditions of light, temperature, and other environmental factors, significant diurnal NEE oscillations were observed at six sites, where daily NEE variation was between 20% and 90% of that under variable environmental conditions. These results are consistent with fluctuations driven by the circadian clock and other endogenous processes. Our results open a promising avenue of research for a more complete understanding of ecosystem fluxes that integrates from cellular to ecosystem processes. © 2012 Blackwell Publishing Ltd.

Published
2012

11. Studying the Atmospheric Boundary Layer influence on the Surface EnergyBalance Closure combining eddy covariance and Doppler lidar

Author

Aguirre García, Sergio David, primary, Andújar-Maqueda, Juana, additional, Abril-Gago, Jesús, additional, Aranda- Barranco, Sergio, additional, Agea-Plaza, Daniel, additional, Ortiz-Amezcua, Pablo, additional, Sánchez-Cañete, Enrique P., additional, Kowalski, Andrew-S., additional, Serrano-Ortiz, Penélope, additional, and Guerrero-Rascado, Juan-Luis, additional

Published
2023
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16. Soil Water Content Effects on Net Ecosystem CO2 Exchange and Actual Evapotranspiration in a Mediterranean Semiarid Savanna of Central Chile

Author

Meza, Francisco J, Montes, Carlo, Bravo-Martínez, Felipe, Serrano-Ortiz, Penelope, and Kowalski, Andrew S

Subjects
Meteorology And Climatology
Abstract

Biosphere-atmosphere water and carbon fluxes depend on ecosystem structure, and their magnitudes and seasonal behavior are driven by environmental and biological factors. We studied the seasonal behavior of net ecosystem CO2 exchange (NEE), Gross Primary Productivity (GPP), Ecosystem Respiration (RE), and actual evapotranspiration (ETa) obtained by eddy covariance measurements during two years in a Mediterranean Acacia savanna ecosystem (Acacia caven) in Central Chile. The annual carbon balance was −53 g C/sq. m in 2011 and −111 g C/sq. m in 2012, showing that the ecosystem acts as a net sink of CO2, notwithstanding water limitations on photosynthesis observed in this particularly dry period. Total annual ETa was of 128 mm in 2011 and 139 mm in 2012. Both NEE and ETa exhibited strong seasonality with peak values recorded in the winter season (July to September), as a result of ecosystem phenology, soil water content and rainfall occurrence. Consequently, the maximum carbon assimilation rate occurred in wintertime. Results show that soil water content is a major driver of GPP and RE, defining their seasonal patterns and the annual carbon assimilation capacity of the ecosystem, and also modulating the effect that solar radiation and air temperature have on NEE components at shorter time scales.

Published
2018
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19. Volcanic caves: priorities for conserving the Azorean endemic troglobiont species

Author

Sánchez-Cañete Enrique P., Serrano-Ortiz Penélope, Domingo Francisco, and Kowalski Andrew S.

Subjects
buoyancy, carbon dioxide, caves, soil ventilation, ventilation, virtual temperature, Biology (General), QH301-705.5, Geology, QE1-996.5
Abstract

Dynamics and drivers of ventilation in caves are of growing interest for different f ields of science. Accumulated CO2 in caves can be exchanged with the atmosphere, modifying the internal CO2 content, affecting stalagmite growth rates, deteriorating rupestrian paintings, or creating new minerals. Current estimates of cave ventilation neglect the role of high CO2 concentrations in determining air density – approximated via the virtual temperature (Tv) –, affecting buoyancy and therefore the release or storage of CO2. Here we try to improve knowledge and understanding of cave ventilation through the use of Tv in CO2-rich air to explain buoyancy for different values of temperature (T) and CO2 content. Also, we show differences between T and Tv for 14 different experimental sites in the vadose zone, demonstrating the importance of using the correct def inition of Tv to determine air buoyancy in caves. The calculation of Tv (including CO2 effects) is currently available via internet using an excel template, requiring the input of CO2 (%), air temperature (oC) and relative humidity (%).

Published
2013

27. Ecosystem CO2 release driven by wind occurs in drylands at global scale.

Author

Moya, María Rosario, López‐Ballesteros, Ana, Sánchez‐Cañete, Enrique P., Serrano‐Ortiz, Penélope, Oyonarte, Cecilio, Domingo, Francisco, and Kowalski, Andrew S.

Subjects
CARBON cycle, SHRUBLANDS, CARBON emissions, ARID regions, FRICTION velocity, SOIL cracking, ECOSYSTEMS
Abstract

Subterranean ventilation is a non‐diffusive transport process that provokes the abrupt transfer of CO2‐rich air (previously stored) through water‐free soil pores and cracks from the vadose zone to the atmosphere, under high‐turbulence conditions. In dryland ecosystems, whose biological carbon exchanges are poorly characterized, it can strongly determine eddy‐covariance CO2 fluxes that are used to validate remote sensing products and constrain models of gross primary productivity. Although subterranean ventilation episodes (VE) may occur in arid and semi‐arid regions, which are unsung players in the global carbon cycle, little research has focused on the role of VE CO2 emissions in land–atmosphere CO2 exchange. This study shows clear empirical evidence of globally occurring VE. To identify VE, we used in situ quality‐controlled eddy‐covariance open data of carbon fluxes and ancillary variables from 145 sites in different open land covers (grassland, cropland, shrubland, savanna, and barren) across the globe. We selected the analyzed database from the FLUXNET2015, AmeriFlux, OzFlux, and AsiaFlux networks. To standardize the analysis, we designed an algorithm to detect CO2 emissions produced by VE at all sites considered in this study. Its main requirement is the presence of considerable and non‐spurious correlation between the friction velocity (i.e., turbulence) and CO2 emissions. Of the sites analyzed, 34% exhibited the occurrence of VE. This vented CO2 emerged mainly from arid ecosystems (84%) and sites with hot and dry periods. Despite some limitations in data availability, this research demonstrates that VE‐driven CO2 emissions occur globally. Future research should seek a better understanding of its drivers and the improvement of partitioning models, to reduce uncertainties in estimated biological CO2 exchanges and infer their contribution to the global net ecosystem carbon balance. [ABSTRACT FROM AUTHOR]

Published
2022
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31. The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

Author

Pastorello, Gilberto, Trotta, Carlo, Canfora, Eleonora, Chu, Housen, Christianson, Danielle S., Cheah, You-Wei, Poindexter, Cristina, Chen, Jing M., Elbashandy, Abdelrahman, Humphrey, Marty, Isaac, Peter, Polidori, Diego, Ribeca, Alessio, van Ingen, Catharine, Zhang, Leiming, Amiro, Brian, Ammann, Christof, Arain, M. Altaf, Ardö, Junas, Arkebauer, Timothy, Arndt, Stefan K., Arriga, Nicola, Aubinet, Marc, Aurela, Mika, Baldocchi, Daniel, Barr, Alan, Beamesderfer, Eric, Belelli Marchesini, Luca, Bergeron, Onil, Beringer, Jason, Bernhofer, Christian, Berveiller, Daniel, Billesbach, Dave, Black, Thomas Andrew, Blanken, Peter D., Bohrer, Gil, Boike, Julia, Bolstad, Paul V., Bonal, Damien, Bonnefond, Jean-Marc, Bowling, David R., Bracho, Rosvel, Brodeur, Jason, Brümmer, Christian, Buchmann, Nina, Burban, Benoit, Burns, Sean P., Buysse, Pauline, Cale, Peter, Cavagna, Mauro, Cellier, Pierre, Chen, Shiping, Chini, Isaac, Christensen, Torben R., Cleverly, James, Collalti, Alessio, Consalvo, Claudia, Cook, Bruce D., Cook, David, Coursolle, Carole, Cremonese, Eodardo, Curtis, Peter S., D'Andrea, Ettore, Da Rocha, Humberto R., Dai, Xiaoqin, Davis, Kenneth J., De Cinti, Bruno, De Grandcourt, Agnès, De Ligne, Anne, De Oliveira, Raimundo C., Delpierre, Nicolas, Desai, Ankur R., Di Bella, Carlos Marcelo, Di Tommasi, Paul, Dolman, Han, Domingo, Francisco, Dong, Gang, Dore, Sabina, Duce, Pierpaolo, Dufrêne, Eric, Dunn, Allison, Dusek, Jiri, Eamus, Derek, Eichelmann, Uwe, ElKhidir, Hatim Abdalla M., Eugster, Werner, Ewenz, Cacilia M., Ewers, Brent, Famulari, Daniela, Fares, Silvano, Feigenwinter, Iris, Feitz, Andrew, Fensholt, Rasmus, Filippa, Gianluca, Fischer, Marc, Frank, John, Galvagno, Marta, Gharun, Mana, Gianelle, Damiano, Gielen, Bert, Gioli, Beniamino, Gitelson, Anatoly A., Goded, Ignacio, Goeckede, Mathias, Goldstein, Allen H., Gough, Christopher M., Goulden, Michaël L., Graf, Alexander, Griebel, Anne, Gruening, Carsten, Grünwald, Thomas, Hammerle, Albin, Han, Shijie, Han, Xingguo, Ulf Hansen, Birger, Hanson, Chad, Hatakka, Juha, He, Yongtao, Hehn, Markus, Heinesch, Bernard, Hinko-Najera, Nina, Hörtnagl, Lukas, Hutley, Lindsay, Ibrom, Andreas, Ikawa, Hiroki, Jackowicz-Korczynski, Marcin, Janous, Dalibor, Jans, Wilma, Jassal, Rachhpal, Jiang, Shicheng, Kato, Tomomichi, Khomik, Myroslava, Klatt, Janina, Knohl, Alexander, Knox, Sara, Kobayashi, Hideki, Koerber, Georgia, Kolle, Olaf, Kosugi, Yoshiko, Kotani, Ayumi, Kowalski, Andrew S., Kruijt, Bart, Kurbatova, Julia, Kutsch, Werner L., Kwon, Hyojung, Launiainen, Samuli, Laurila, Tuomas, Law, Bev, Leuning, Ray, Li, Yingniam, Liddell, Michael, Limousin, Jean-Marc, Lion, Marryanna, Liska, Adam J., Lohila, Annalea, López-Ballesteros, Ana, López-Blanco, Efrén, Loubet, Benjamin, Loustau, Denis, Lucas-Moffat, Antje, Lüers, Johannes, Ma, Siyan, Macfarlane, Craig, Magliulo, Vincenzo, Maier, Regine, Mammarella, Ivan, Manca, Giovanni, Marcolla, Barbara, Margolis, Hank, Marras, Serena, Massman, William, Mastepanov, Mikhail, Matamala, Roser, Hatala Matthes, Jaclyn, Mazzenga, Francesco, McCaughey, Harry, McHugh, Ian, McMillan, Andrew M. S., Merbold, Lutz, Meyer, Wayne, Meyers, Tilden, Miller, Scott, Minerbi, Stefano, Moderow, Uta, Monson, Russell K., Montagnani, Leonardo, Moore, Caitlin E., Moors, Eddy J., Moreaux, Virginie, Moureaux, Christine, Munger, J. William, Nakai, Taro, Neirynck, Johan, Nesic, Zoran, Nicolini, Giacomo, Noormets, Asko, Northwood, Matthew, Nosetto, Marcelo, Nouvellon, Yann, et al., Pastorello, Gilberto, Trotta, Carlo, Canfora, Eleonora, Chu, Housen, Christianson, Danielle S., Cheah, You-Wei, Poindexter, Cristina, Chen, Jing M., Elbashandy, Abdelrahman, Humphrey, Marty, Isaac, Peter, Polidori, Diego, Ribeca, Alessio, van Ingen, Catharine, Zhang, Leiming, Amiro, Brian, Ammann, Christof, Arain, M. Altaf, Ardö, Junas, Arkebauer, Timothy, Arndt, Stefan K., Arriga, Nicola, Aubinet, Marc, Aurela, Mika, Baldocchi, Daniel, Barr, Alan, Beamesderfer, Eric, Belelli Marchesini, Luca, Bergeron, Onil, Beringer, Jason, Bernhofer, Christian, Berveiller, Daniel, Billesbach, Dave, Black, Thomas Andrew, Blanken, Peter D., Bohrer, Gil, Boike, Julia, Bolstad, Paul V., Bonal, Damien, Bonnefond, Jean-Marc, Bowling, David R., Bracho, Rosvel, Brodeur, Jason, Brümmer, Christian, Buchmann, Nina, Burban, Benoit, Burns, Sean P., Buysse, Pauline, Cale, Peter, Cavagna, Mauro, Cellier, Pierre, Chen, Shiping, Chini, Isaac, Christensen, Torben R., Cleverly, James, Collalti, Alessio, Consalvo, Claudia, Cook, Bruce D., Cook, David, Coursolle, Carole, Cremonese, Eodardo, Curtis, Peter S., D'Andrea, Ettore, Da Rocha, Humberto R., Dai, Xiaoqin, Davis, Kenneth J., De Cinti, Bruno, De Grandcourt, Agnès, De Ligne, Anne, De Oliveira, Raimundo C., Delpierre, Nicolas, Desai, Ankur R., Di Bella, Carlos Marcelo, Di Tommasi, Paul, Dolman, Han, Domingo, Francisco, Dong, Gang, Dore, Sabina, Duce, Pierpaolo, Dufrêne, Eric, Dunn, Allison, Dusek, Jiri, Eamus, Derek, Eichelmann, Uwe, ElKhidir, Hatim Abdalla M., Eugster, Werner, Ewenz, Cacilia M., Ewers, Brent, Famulari, Daniela, Fares, Silvano, Feigenwinter, Iris, Feitz, Andrew, Fensholt, Rasmus, Filippa, Gianluca, Fischer, Marc, Frank, John, Galvagno, Marta, Gharun, Mana, Gianelle, Damiano, Gielen, Bert, Gioli, Beniamino, Gitelson, Anatoly A., Goded, Ignacio, Goeckede, Mathias, Goldstein, Allen H., Gough, Christopher M., Goulden, Michaël L., Graf, Alexander, Griebel, Anne, Gruening, Carsten, Grünwald, Thomas, Hammerle, Albin, Han, Shijie, Han, Xingguo, Ulf Hansen, Birger, Hanson, Chad, Hatakka, Juha, He, Yongtao, Hehn, Markus, Heinesch, Bernard, Hinko-Najera, Nina, Hörtnagl, Lukas, Hutley, Lindsay, Ibrom, Andreas, Ikawa, Hiroki, Jackowicz-Korczynski, Marcin, Janous, Dalibor, Jans, Wilma, Jassal, Rachhpal, Jiang, Shicheng, Kato, Tomomichi, Khomik, Myroslava, Klatt, Janina, Knohl, Alexander, Knox, Sara, Kobayashi, Hideki, Koerber, Georgia, Kolle, Olaf, Kosugi, Yoshiko, Kotani, Ayumi, Kowalski, Andrew S., Kruijt, Bart, Kurbatova, Julia, Kutsch, Werner L., Kwon, Hyojung, Launiainen, Samuli, Laurila, Tuomas, Law, Bev, Leuning, Ray, Li, Yingniam, Liddell, Michael, Limousin, Jean-Marc, Lion, Marryanna, Liska, Adam J., Lohila, Annalea, López-Ballesteros, Ana, López-Blanco, Efrén, Loubet, Benjamin, Loustau, Denis, Lucas-Moffat, Antje, Lüers, Johannes, Ma, Siyan, Macfarlane, Craig, Magliulo, Vincenzo, Maier, Regine, Mammarella, Ivan, Manca, Giovanni, Marcolla, Barbara, Margolis, Hank, Marras, Serena, Massman, William, Mastepanov, Mikhail, Matamala, Roser, Hatala Matthes, Jaclyn, Mazzenga, Francesco, McCaughey, Harry, McHugh, Ian, McMillan, Andrew M. S., Merbold, Lutz, Meyer, Wayne, Meyers, Tilden, Miller, Scott, Minerbi, Stefano, Moderow, Uta, Monson, Russell K., Montagnani, Leonardo, Moore, Caitlin E., Moors, Eddy J., Moreaux, Virginie, Moureaux, Christine, Munger, J. William, Nakai, Taro, Neirynck, Johan, Nesic, Zoran, Nicolini, Giacomo, Noormets, Asko, Northwood, Matthew, Nosetto, Marcelo, Nouvellon, Yann, and et al.

Abstract

The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.

Published
2020

35. Ecologically implausible carbon response?

Author

Magnani, Federico, Mencuccini, Maurizio, Borghetti, Marco, Berninger, Frank, Delzon, Sylvain, Grelle, Achim, Hari, Pertti, Jarvis, Paul G., Kolari, Pasi, Kowalski, Andrew S., Lankreijer, Harry, Law, Beverly E., Lindroth, Anders, Loustau, Denis, Manca, Giovanni, Moncrieff, John B., Tedeschi, Vanessa, Valentini, Riccardo, and Grace, John

Published
2008
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36. Influence of land degradation on ventilation and pressure tidal effect in the CO2 exchange: Evidence from two semi-arid grasslands in the southeast of Spain

Author

Moya, M. Rosario, Pérez Sánchez-Cañete, Enrique, Kowalski, Andrew S., Serrano-Ortiz, Penélope, López-Ballesteros, Ana, Oyonarte, Cecilio, Solé-Benet, Albert, and Domingo, Francisco

Abstract

Trabajo presentado al 9th European Society for Soil Conservation (ESSC) International Congress, celebrado en Tirana (Albania) del 26 al 28 de septiembre de 2019.

Published
2019

37. The human footprint in the carbon cycle of temperate and boreal forests

Author

Magnani, Federico, Mencuccini, Maurizio, Borghetti, Marco, Berbigier, Paul, Berninger, Frank, Delzon, Sylvain, Grelle, Achim, Hari, Pertti, Jarvis, Paul G., Kolari, Pasi, Kowalski, Andrew S., Lankreijer, Harry, Law, Beverly E., Lindroth, Anders, Loustau, Denis, Manca, Giovanni, Moncrieff, John B., Rayment, Mark, Tedeschi, Vanessa, Valentini, Riccardo, and Grace, John

Published
2007
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39. CO 2 Dynamics Are Strongly Influenced by Low Frequency Atmospheric Pressure Changes in Semiarid Grasslands

Author

European Commission, Ministerio de Economía y Competitividad (España), Universidad de Granada, Moya, M. Rosario, Sánchez-Cañete, Enrique P., Vargas, R., López-Ballesteros, Ana, Oyonarte, Cecilio, Kowalski, Andrew S., Serrano-Ortiz, Penélope, Domingo, Francisco, European Commission, Ministerio de Economía y Competitividad (España), Universidad de Granada, Moya, M. Rosario, Sánchez-Cañete, Enrique P., Vargas, R., López-Ballesteros, Ana, Oyonarte, Cecilio, Kowalski, Andrew S., Serrano-Ortiz, Penélope, and Domingo, Francisco

Abstract

Due to their large carbon storage capacity and ability to exchange subterranean CO with the atmosphere, soils are key components in the carbon balance in semi-arid ecosystems. Most studies have focused on shallow (e.g., <30 cm depth) soil CO dynamics neglecting processes in deeper soil layers where highly CO -enriched air can be stored or transported through soil pores and fissures. Here, we examine the relationship among variations in subterranean CO molar fraction, volumetric water content, soil temperature and atmospheric pressure during three years within soil profiles (0.15, 0.50, and 1.50 m depths) in two semi-arid grasslands located in southeastern Spain. We applied a wavelet coherence analysis to study the temporal variability and temporal correlation between the CO molar fraction and its covariates (soil temperature, soil moisture and atmospheric pressure). Our results show that CO dynamics are strongly influenced by changes in atmospheric pressure from semidiurnal, diurnal and synoptic to monthly time-scales for all soil depths. In contrast, only weak daily dependencies were found at the surface level (0.15 m) regarding soil temperature and volumetric water content. Atmospheric pressure changes substantially influence variations in the CO content (with daily fluctuations of up to 2000 ppm) denoting transportation through soil layers. These results provide insights into the importance of subterranean storage and non-diffusive gas transport that could influence soil CO efflux rates, processes that are not considered when applying the flux-gradient approach and, which can be especially important in ecosystems with high air permeability between the unsaturated porous media and the atmosphere.

Published
2019

45. Net ecosystem CO2 exchange in an irrigated olive orchard of SE Spain: Influence of weed cover

Author

Junta de Andalucía, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia e Innovación (España), European Commission, Chamizo, Sonia, Serrano-Ortiz, Penélope, López-Ballesteros, Ana, Sánchez-Cañete, Enrique P., Vicente-Vicente, José Luis, Kowalski, Andrew S., Junta de Andalucía, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia e Innovación (España), European Commission, Chamizo, Sonia, Serrano-Ortiz, Penélope, López-Ballesteros, Ana, Sánchez-Cañete, Enrique P., Vicente-Vicente, José Luis, and Kowalski, Andrew S.

Abstract

No-till management and the establishment of plant cover have been implemented in olive crops in recent years in order to prevent soil erosion and increase soil organic carbon. However, the effect of these conservation practices on the net CO2 exchange at the ecosystem scale has not been explored so far. In this study, we analyze the influence of resident vegetation cover (hereafter weeds) on the net ecosystem CO2 exchange (NEE) in an irrigated olive orchard located in Jaén (SE Spain) by using the eddy covariance technique. NEE was measured in the olive orchard under two treatments, one with weed cover in the alleys from autumn to spring, and another where weed growth was avoided by the application of a glyphosate herbicide. Our study demonstrates that the presence of weeds in the alleys increased carbon assimilation in the weed-cover treatment during the weed growing period (from December to April). However, the net ecosystem CO2 uptake decreased in the weed-cover treatment during late spring (May and June), after weeds were cut and left on the soil, compared to the weed-free treatment, probably due to an increase in soil respiration. On an annual basis, weed removal decreased net carbon uptake by 50% compared to the weed-cover treatment. The annual NEE was −140 g C m−2 y−1 in the weed-cover treatment and −70 g C m−2 y−1 in the weed-free treatment. In summary, our study demonstrates that, during the first year of differential treatment, maintenance of weed cover in olive groves has a positive effect on CO2 uptake and enhances the capacity of the agro-system to act as a net CO2 sink.

Published
2017

47. Winds induce CO2 exchange with the atmosphere and vadose zone transport in a karstic ecosystem

Author

Sánchez-Cañete, Enrique P., Oyonarte, Cecilio, Serrano-Ortiz, Penélope, Jorge Curiel Yuste, Pérez-Priego, Oscar, Domingo, Francisco, Kowalski, Andrew S. C. J. G., Ministerio de Ciencia e Innovación (España), and European Commission

Subjects
Wind increases CO2, Depletion in bare soil, Windy days increased NECB emissions and reduced soil CO2 concentrations, Transport in surface soil and bedrock but not in subsurface, Wind induces CO2, Under plant soil and induces CO2
Abstract

Research on the subterranean CO dynamics has focused individually on either surface soils or bedrock cavities, neglecting the interaction of both systems as a whole. In this regard, the vadose zone contains CO-enriched air (ca. 5% by volume) in the first meters, and its exchange with the atmosphere can represent from 10 to 90% of total ecosystem CO emissions. Despite its importance, to date still lacking are reliable and robust databases of vadose zone CO contents that would improve knowledge of seasonal-annual aboveground-belowground CO balances. Here we study 2.5 years of vadose zone CO dynamics in a semiarid ecosystem. The experimental design includes an integrative approach to continuously measure CO in vertical and horizontal soil profiles, following gradients from surface to deep horizons and from areas of net biological CO production (under plants) to areas of lowest CO production (bare soil), as well as a bedrock borehole representing karst cavities and ecosystem-scale exchanges. We found that CO followed similar seasonal patterns for the different layers, with the maximum seasonal values of CO delayed with depth (deeper more delayed). However, the behavior of CO transport differed markedly among layers. Advective transport driven by wind induced CO emission both in surface soil and bedrock, but with negligible effect on subsurface soil, which appears to act as a buffer impeding rapid CO exchanges. Our study provides the first evidence of enrichment of CO under plant, hypothesizing that CO-rich air could come from root zone or by transport from deepest layers through cracks and fissures., These data were funded by the Andalusian regional government project GEOCARBO (P08-RNM-3721), including European Union ERDF funds, with support from Spanish Ministry of Science and Innovation projects SOILPROF (CGL2011-15276-E), CARBORAD (CGL2011-27493), and GEISpain (CGL2014-52838-C2-1-R). This research was supported by a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Programme, DIESEL project (625988).

Published
2016

48. Quantification and source determination of CO2 exchanges measured over a carbonate ecosystem using the eddy covariance technique and stable carbon isotopes

Author

Serrano Ortiz, Penélope, Cuezva Robleño, Soledad, Kowalski, Andrew S., Sánchez Moral, Sergio, Universidad de Alicante. Departamento de Ciencias de la Tierra y del Medio Ambiente, and Petrología Aplicada

Subjects
lcsh:GE1-350, Ventilación, CO2 exchange, Intercambios de CO2, Isótopos estables, Eddy covariance, Ecología, Discriminación de procesos, Ecosystem discrimination, Ventilation, lcsh:Environmental sciences, Stable isotopes
Abstract

Los intercambios de CO2 entre atmósfera y ecosistemas, así como los procesos que intervienen en dichos intercambios, son de vital interés para la caracterización del ciclo global del carbono y la repercusión del calentamiento global sobre estos ecosistemas naturales. En ecosistemas de origen carbonatado, los procesos biológicos de fotosíntesis y respiración interactúan con procesos de ventilación de cavidades y de disolución y precipitación de carbonatos que pueden incluso dominar el intercambio de CO2 en determinadas épocas del año. En este trabajo, se usó la técnica de eddy covariance junto con análisis de los isótopos estables de carbono y medidas de flujo de CO2 de suelo y otras variables meteorológicas, para determinar la procedencia del CO2 intercambiado. Los resultados obtenidos demuestran que el ecosistema actúa como sumidero o fuente de CO2 en función de las condiciones meteorológicas y la época del año. Bajo condiciones óptimas de temperatura y recursos hídricos, la huella isotópica del carbono (δ13C) del aire alcanza valores muy negativos indicando un origen biológico del intercambio. En épocas de sequía y senescencia biológica estos procesos se reducen considerablemente. La atmósfera externa y la cavidad toman valores de δ13C muy similares indicando un alto grado de ventilación de la cavidad. Net CO2 fluxes in different terrestrial ecosystems and their determinant processes are keys to characterizing the global carbon cycle and to assessing global warming effects on ecosystems. Over carbonate ecosystems biological processes interact with geochemical and ventilation processes in the ecosystem behaviour related with the carbon cycle and can, at least temporarily, dominate the terrestrial carbon exchange with the atmosphere. Here we used the eddy covariance technique together with stable carbon isotopes and soil CO2 fluxes and meteorological measurements to characterize the underlying processes. The carbonate ecosystem acted as a net source or sink of CO2 according to differences in meteorological variables. Under optimal conditions of temperature and water the isotopic composition of the CO2 (δ13C) reached minimum values suggesting a major contribution of biological processes. During dry periods and extremely high temperatures the contribution of such biological processes decreases substantially. Ventilation processes can contribute in the measured CO2 exchange due to similar values of δ13C in the external air and the cavity. Proyecto EXPLORA (CGL2006-26147-E/CLI) concedido por el Ministerio de Ciencia e Innovación, el proyecto INIA (SUM2006-00010-00-00) concedido por Ministerio de Educación y Ciencia y Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria y el proyecto GEOCARBO (RNM-3721) concedido por la junta de Andalucía.

Published
2010

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