An urban ecohydrological model to quantify the effect of vegetation on urban climate and hydrology (UT&C v1.0)

Increasing urbanization is likely to intensify the urban heat island effect, decrease outdoor thermal comfort and enhance runoff generation in cities. Urban green spaces are often proposed as a mitigation strategy to counteract these adverse effects and many recent developments of urban climate models focus on the inclusion of green and blue infrastructure to inform urban planning. However, many models still lack the ability to account for different plant types and oversimplify the interactions between the built environment, vegetation, and hydrology. In this study, we present an urban ecohydrological model, Urban Tethys-Chloris (UT&C), that combines principles of ecosystem modelling with an urban canopy scheme accounting for the biophysical and ecophysiological characteristics of roof vegetation, ground vegetation and urban trees. UT&C is a fully coupled energy and water balance model that calculates 2 m air temperature, 2 m humidity, and surface temperatures based on the infinite urban canyon approach. It further calculates all urban hydrological fluxes, including transpiration as a function of plant photosynthesis. Hence, UT&C accounts for the effects of different plant types on the urban climate and hydrology, as well as the effects of the urban environment on plant well-being and performance. UT&C performs well when compared against energy flux measurements of eddy covariance towers located in three cities in different climates (Singapore, Melbourne, Phoenix). A sensitivity analysis, performed as a proof of concept for the city of Singapore, shows a mean decrease in 2 m air temperature of 1.1 °C for fully grass covered ground, 0.2 °C for high values of leaf area index (LAI), and 0.3 °C for high values of Vc,max (an expression of photosynthetic activity). These reductions in temperature were combined with a simultaneous increase in relative humidity by 6.5 %, 2.1 %, and 1.6 %, for fully grass covered ground, high values of LAI, and high values of Vc,max, respectively. Furthermore, the increase of pervious vegetated ground is able to significantly reduce surface runoff. These results show that urban greening can lead to a decrease in urban air temperature and surface runoff, but this effect is limited in cities characterized by a hot, humid climate.ISSN:1991-962XISSN:1991-961

Regional isoprenoid emission from Eucalyptus grandis forests in northeastern Argentina

Eucalyptus species are strong source of isoprenoid emission. The objective of the present study was to estimate isoprenoid emissions from Eucalyptus grandis forest crops in the Entre Rios province in the Mesopotamia region of Argentina. The emission rates of isoprene and monoterpenes were measured on individual leaves under; controlled environmental conditions. At 30°C and with a PPFD of 1000 μM m-2 s-1 the emission rate of isoprene emission was 12.5 ± 1.9 nM m-2 s-1 and monoterpenes 15.1 ± 3.1 nM m-2 s-1. Emission was significantly affected by leaf position and decreased significantly from East to West. The most abundant compound emitted was limonene, accounting for between 50 and 68% of the total monoterpene emission. The time course of the isoprene emission course showed its strong dependence on light. On sunny days 42% of the isoprene emission comes from top of the canopy and only 2% from bottom of the canopy. But on overcast days, the relative contribution of diffuse radiation may be larger and can exceed the contribution of direct radiation. A model procedure in a Geographic Information System was implemented to estimate isoprene emissions at a regional scale. A forest inventory, data from a meteorological station and leaf area indices derived from satellite data served as inputs for the model. For the Entre Rios province (78781 km2), the isoprene emission totals up to 39.5 t d-1 on a clear summer day. The methodology applied to estimate isoprenoid emissions on a regional scale contributes to the understanding of carbon exchange between biosphere and atmosphereInst. de Clima y AguaFil: Richter, Klaus. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; ArgentinaFil: Centritto, Mauro. National Research Council. Trees and Timber Institute; ItaliaFil: Di Bella, Carlos Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Posse Beaulieu, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentin

Long-term water stress leads to acclimation of drought sensitivity of photosynthetic capacity in xeric but not riparian Eucalyptus species

Background and Aims Experimental drought is well documented to induce a decline in photosynthetic capacity. However, if given time to acclimate to low water availability, the photosynthetic responses of plants to low soil moisture content may differ from those found in short-term experiments. This study aims to test whether plants acclimate to long-term water stress by modifying the functional relationships between photosynthetic traits and water stress, and whether species of contrasting habitat differ in their degree of acclimation. Methods Three Eucalyptus taxa from xeric and riparian habitats were compared with regard to their gas exchange responses under short- and long-term drought. Photosynthetic parameters were measured after 2 and 4 months of watering treatments, namely field capacity or partial drought. At 4 months, all plants were watered to field capacity, then watering was stopped. Further measurements were made during the subsequent ‘drying-down’, continuing until stomata were closed. Key Results Two months of partial drought consistently reduced assimilation rate, stomatal sensitivity parameters (g1), apparent maximum Rubisco activity (V′cmaxVcmax′) and maximum electron transport rate (J′maxJmax′). Eucalyptus occidentalis from the xeric habitat showed the smallest decline in V′cmaxVcmax′ and J′maxJmax′; however, after 4 months, V′cmaxVcmax′ and J′maxJmax′ had recovered. Species differed in their degree of V′cmaxVcmax′ acclimation. Eucalyptus occidentalis showed significant acclimation of the pre-dawn leaf water potential at which the V′cmaxVcmax′ and ‘true’ Vcmax (accounting for mesophyll conductance) declined most steeply during drying-down. Conclusions The findings indicate carbon loss under prolonged drought could be over-estimated without accounting for acclimation. In particular, (1) species from contrasting habitats differed in the magnitude of V′cmax reduction in short-term drought; (2) long-term drought allowed the possibility of acclimation, such that V′cmax reduction was mitigated; (3) xeric species showed a greater degree of V′cmax acclimation; and (4) photosynthetic acclimation involves hydraulic adjustments to reduce water loss while maintaining photosynthesis

Impact of Farmland Abandonment on Water Resources and Soil Conservation in Citrus Plantations in Eastern Spain

[EN] Due to the reduction in the prices of oranges on the market and social changes such as the ageing of the population, traditional orange plantation abandonment in the Mediterranean is taking place. Previous research on land abandonment impact on soil and water resources has focused on rainfed agriculture abandonment, but there is no research on irrigated land abandonment. In the Valencia Regionthe largest producer of oranges in Europeabandonment is resulting in a quick vegetation recovery and changes in soil properties, and then in water erosion. Therefore, we performed rainfall simulation experiments (0.28 m(2); 38.8 mm h(-1)) to determine the soil losses in naveline orange plantations with different ages of abandonment (1, 2, 3, 5, 7 and 10 years of abandonment) which will allow for an understanding of the temporal changes in soil and water losses after abandonment. Moreover, these results were also compared with an active plantation (0). The results show that the soils of the active orange plantations have higher runoff discharges and higher erosion rates due to the use of herbicides than the plots after abandonment. Once the soil is abandoned for one year, the plant recovery reaches 33% of the cover and the erosion rate drops one order of magnitude. This is related to the delay in the runoff generation and the increase in infiltration rates. After 2, 3, 5, 7 and 10 years, the soil reduced bulk density, increase in organic matter, plant cover, and soil erosion rates were found negligible. We conclude that the abandonment of orange plantations reduces soil and water losses and can serve as a nature-based solution to restore the soil services, goods, and resources. The reduction in the soil losses was exponential (from 607.4 g m(-2) in the active plot to 7.1 g m(-2) in the 10-year abandoned one) but the water losses were linear (from 77.2 in active plantations till 12.8% in the 10-year abandoned ones)This paper is part of the results of research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE-FP7 (ENV.2013.6.2-4)Cerda, A.; Ackermann, O.; Terol, E.; Rodrigo-Comino, J. (2019). Impact of Farmland Abandonment on Water Resources and Soil Conservation in Citrus Plantations in Eastern Spain. Water. 11(4):824-839. https://doi.org/10.3390/w11040824S824839114Stefler, D., Pikhart, H., Kubinova, R., Pajak, A., Stepaniak, U., Malyutina, S., … Bobak, M. (2015). Fruit and vegetable consumption and mortality in Eastern Europe: Longitudinal results from the Health, Alcohol and Psychosocial Factors in Eastern Europe study. European Journal of Preventive Cardiology, 23(5), 493-501. doi:10.1177/2047487315582320Alford, M., Barrientos, S., & Visser, M. (2017). 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Agricultural systems and terrace pattern distribution and preservation along climatic gradient: From sub-humid mediterranean to arid conditions. Quaternary International, 502, 319-326. doi:10.1016/j.quaint.2018.09.032Ackermann, O., Maeir, A. M., Frumin, S. S., Svoray, T., Weiss, E., Zhevelev, H. M., & Horwitz, L. K. (2017). The Paleo-Anthropocene and the Genesis of the Current Landscape of Israel. Journal of Landscape Ecology, 10(3), 109-140. doi:10.1515/jlecol-2017-0029Ackermann, O., Zhevelev, H. M., & Svoray, T. (2013). Sarcopoterium spinosum from mosaic structure to matrix structure: Impact of calcrete (Nari) on vegetation in a Mediterranean semi-arid landscape. CATENA, 101, 79-91. doi:10.1016/j.catena.2012.10.001Ibáñez, J., Contador, J. F. L., Schnabel, S., Fernández, M. P., & Valderrama, J. M. (2014). A model-based integrated assessment of land degradation by water erosion in a valuable Spanish rangeland. 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Surface water and energy fluxes in South America : an integrated approach based on remote sensing and flux measurements

South America is a water-abundant continent, home to the world's largest river basins and rainforest, which plays a crucial role in providing moisture to other regions of the continent through evapotranspiration (). is a crucial indicator of the earth's ecosystem functioning, linking the water, energy, and carbon cycles. Due to the great challenge of obtaining information based on in situ measurements, remote sensing data has become a great opportunity to obtain estimations. Based on measurements and estimations based on remote sensing data, this study aimed to evaluate the dynamics, patterns and controls of water and energy fluxes in South America, seeking to answer three main questions: i) can remote sensing data provide accurate information on the water balance?; ii) how do the factors controlling vary across different biomes and land use and land cover (LULC) conditions? and iii) can remote sensing models represent accurately patterns and its components under different LULC conditions? To answer the first question, we performed a water balance analysis, evaluating the uncertainties of precipitation and estimations using in situ measurements, and conducting an analysis to understand how much these uncertainties can be affected due to the basin’s scales. The results showed that due to the uncertainties related to each of the variable from remote sensing it is not yet possible to achieve the water balance closing. However, the approach proved to be a great alternative to evaluate the dynamics of water fluxes from small to large basins, especially in those where in situ measurement is still scarce. To seek to answer the second question, we evaluated the influence of biotic and abiotic factors on control processes, based on surface and aerodynamic conductances and the decoupling factor, at 20 flux measurement sites in South America. Through this analysis, different patterns of latent () and sensible () heat fluxes were verified, and different degrees of importance of biotic and abiotic controls on the process according to different LULC conditions. Finally, based on 11 flux measurement sites and four models (MOD16, GLEAM, PML and SSEBOP), we assessed the accuracy of estimates in the Amazon basin, and the representation of fluxes in forest, pasture, and soybean areas, in the Tapajós basin. The results showed that obtaining accurate estimates is still a major challenge in the Amazon basin, especially in humid and seasonally flooded sites. Significant discrepancies between the models and between measurements were found, and these discrepancies were even more significant when evaluated the individual components. However, even though each model did not perform significantly under all climatic and vegetation conditions, they present together a great opportunity to improve the accuracy of estimates, leading to an improved understanding of the impacts on water and energy fluxes due to human activities. Thus, these results demonstrate the potential and limitations of hydrological components obtained by remote sensing, especially for , and how LULC changes may modify this flux in South America.A América do Sul é um continente abundante em água, abrigando as maiores bacias hidrográficas e a maior floresta tropical do mundo, a floresta Amazônica. A Amazônia desempenha um papel crucial no fornecimento de umidade para outras regiões do continente por meio da evapotranspiração (). A é um indicador crucial do funcionamento do ecossistema terrestre, interligando os ciclos da água, energia e carbono. Devido ao grande desafio de obtenção de informações de por medições in situ, o uso de dados de sensoriamento remoto tem se mostrado uma grande alternativa para obter estimativas desta variável. Com base em dados medidos e estimados por sensoriamento remoto foi conduzido um estudo que visou analisar a dinâmica, os padrões e os controles dos fluxos de água e energia na América do Sul, buscando responder a três questões principais: i) os dados de sensoriamento remoto podem fornecer informações precisas sobre o balanço hídrico?; ii) como os fatores que controlam a variam em diferentes biomas e condições de uso e cobertura do solo (LULC)?; e iii) os modelos de sensoriamento remoto conseguem representar com acurácia os padrões de e das suas componentes em diferentes condições de LULC? Para responder a primeira pergunta realizou-se uma análise de balanço hídrico, na qual foi avaliada as incertezas das estimativas de precipitação e usando medições in situ, e uma análise do quanto essas incertezas podem ser afetadas devido ao efeito de escala das bacias analisadas. Os resultados mostraram que devido às incertezas relacionadas com cada uma das componentes estimadas por sensoriamento remoto ainda não é possível alcançar o fechamento do balanço hídrico. No entanto, a abordagem demonstrou ser uma grande alternativa para avaliar a dinâmica dos fluxos de água, de pequenas a grandes bacias, especialmente naquelas onde a medição in situ ainda é escassa. Para buscar responder a segunda pergunta analisou-se a influência dos fatores bióticos e abióticos no controle dos processos de , por meio da análise das condutâncias de superfície e aerodinâmica e do fator de desacoplamento em 20 locais de monitoramento de fluxo na América do Sul. Por meio desta análise verificou-se diferentes padrões dos fluxos de calor latente () e sensível (), além de diferentes graus de importância dos controles bióticos e abióticos sobre o processo de e de acordo com as diferentes condições de LULC. Por fim, com base em 11 locais de monitoramento de fluxo e quatro modelos de (MOD16, GLEAM, PML e SSEBOP), analisou-se a acurácia destas estimativas na bacia amazônica, e a representação dos fluxos de em áreas de floresta, pastagem e soja, na bacia do Tapajós. Os resultados mostraram que a obtenção de estimativas acuradas de ainda é um grande desafio na bacia Amazônica, principalmente em locais úmidos e sazonalmente inundados. Discrepâncias significativas entre os modelos e entre as medições foram encontradas, sendo estas discrepâncias ainda mais expressivas quando se analisou as componentes individuais de . No entanto, os resultados deste estudo demonstraram que apesar de cada modelo não apresentar um desempenho significativo em todas as condições climáticas e de vegetação, estes apresentam em conjunto, uma grande oportunidade para melhorar a acurácia das estimativas de , propiciando um aprimoramento na compreensão dos impactos nos fluxos de água e energia devido a atividades antrópicas. Deste modo, estes resultados enfatizam os potenciais e limitações das variáveis hidrológicos obtidas por sensoriamento remoto, especialmente para a , e como as mudanças LULC podem modificar este fluxo na América do Sul

Kana Sera, zang der zwangerschap

Indonesi

AMMONIA EMISSIONS FROM SLURRY APPLICATIONS TO LAND

Over the last 10-15 years there has been increasing concern within Europe as to the effects of ammonia emission and subsequent deposition to sensitive ecosystems, causing eutrophication and soil acidification. Transboundary transport of emissions has led to legislation at EC level with member states being given emission ceiling targets. Research has therefore aimed at quantifying national emissions, modelling emission processes and developing mitigation strategies. Agriculture accounts for >80% of total UK ammonia emission, therefore an accurate and robust model is required to estimate emissions from this sector. National inventory methodology has improved as the database of emission measurements and survey data has grown and as models have evolved from discrete empirical calculations for individual sources to linked nitrogen flow models incorporating more process-based algorithms. Ammonia emissions from agriculture derive mainly from livestock manures (primarily from the urea content of urine) and land application of manures represents a major emission source. Research in this area has therefore aimed to improve our ability to predict losses, taking into account the major influencing factors, in order to improve inventory estimates, improve manure management decision support models for farmers and advisers and to highlight potential mitigation strategies. This requires the ability to make precise, accurate measurements and measurement technology has been developed for a range of scales. A key factor influencing ammonia emissions following applications of livestock slurries to soil is the rate and extent to which slurry infiltrates into the soil, where it will be largely protected from volatilisation. This has not previously been fully incorporated into process-based models and research presented here has provided a mechanism describing the infitration process in which the slurry dry matter concentration and the nature of that dry matter are among the important influencing factors. Measures aimed at reducing emissions from land spreading are generally regarded as the most cost-effective means of reducing emissions from agriculture. A number of slurry application techniques aimed at reducing emissions have been developed and assessed against the conventional method of surface broadcasting. These new techniques rely on either reducing the exposed slurry surface area from which emission occurs, reducing the air flow and temperature at the emitting surface (thereby increasing the resistance to ammonia transport from the emitting surface to the free atmosphere) or increasing the contact between slurry and soil. A more holistic approach to reducing emissions is via dietary manipulation, with the aim of reducing both the amount and form of nitrogen excreted by livestock. This can result in lower ammonia emissions at all stages of manure management i.e. livestock housing, manure storage and application to land.BBSRC Institute of Grassland and Environmental Researc

Kana Sera, zang der zwangerschap

Indonesi

Intercambios de CO2 entre atmósfera y ecosistemas kársticos: Aplicabilidad de las técnicas comúnmente empleadas

La cuantificación del balance anual de carbono en los distintos ecosistemas terrestres así como la identificación de los distintos procesos que intervienen, adquiere mayor importancia con la entrada en vigor en febrero de 2005 del Protocolo de Kyoto, acordado en 1997. En este estudio se pretende abordar dicha temática, cuantificando e identificando los procesos que intervienen en el balance anual de carbono en un ecosistema semiárido de sustrato carbonatado ubicado en la Sierra de Gádor (Almería) en el paraje conocido como El Llano de los Juanes. Con tal fin se realizó un seguimiento del comportamiento de este ecosistema durante aproximadamente tres años (mayo de 2004 hasta septiembre de 2006). Las herramientas empleadas han sido: la técnica eddy covariance, que estima el balance anual de carbono y vapor de agua mediante la cuantificación de flujos turbulentos; las cámaras de flujo de CO2 del suelo, que nos proporcionará información puntual sobre las emisiones de CO2 del suelo, y la técnica de isótopos estables que se emplea para la identificación de los procesos que intervienen en el balance de carbono. La técnica eddy covariance es una de las herramientas más usadas para la cuantificación del balance anual de carbono de un ecosistema (Baldocchi et al., 2001). La aplicación de esta poderosa herramienta requiere unos conocimientos micrometeorológicos previos y una continua búsqueda de nuevos avances en metodologías que resulten efectivas y aplicables (Aubinet et al., 2000). Como paso previo a cualquier interpretación de los resultados de flujos de CO2 obtenidos con esta técnica, es necesario estudiar la idoneidad de la ubicación de la torre de medida dentro del ecosistema. Con ese objetivo se estudia si los flujos de CO2 medidos con esta técnica proceden de un área representativa del ecosistema y si sus dimensiones no superan la extensión de superficie homogénea que rodea a nuestra torre (fetch). Entre todos los modelos disponibles en la bibliografía para análisis del área de medida (footprint) del sistema eddy covariance (EC) se ha seleccionado el modelo FSAM (Flux-Source Area model) (Schmid 1994) por su simplicidad y fácil aplicación. Además de este análisis se han realizado otros estudios para determinar la fiabilidad de los datos obtenido con el sistema EC. Así se ha realizado el análisis del cierre del balance de energía obtenido en nuestro ecosistema, con el fin de estudiar la fiabilidad de las medidas de los flujos turbulentos de calor sensible (H) y latente (LE) realizadas con nuestro sistema EC. Por otro lado se comparó el flujo de CO2 obtenido con el sistema EC con los valores de flujo de CO2 del suelo medidos con el sistema de cámaras LI-8100. Con todos estos análisis hemos verificado la idoneidad del lugar seleccionado para la instalación del sistema y la fiabilidad de los flujos turbulentos medidos en El Llano de los Juanes. Dada la complejidad de técnica EC, es importante tener en cuenta que aún en la actualidad existen numerosas incertidumbres relativas al cálculo del balance anual de carbono y a la aplicación de esta técnica (Dragoni et al., 2007). Por esta razón, cada vez son más numerosos los artículos enfocados a la detección de problemas relacionados con esta técnica y sus posibles soluciones (Baldocchi et al., 2000; Feigenwinter et al., 2004; Burba et al., 2006; Liu et al., 2006a). En este trabajo destacamos la detección de un nuevo problema asociado con una fuente de sobrestimación de la asimilación de carbono por parte del ecosistema. El origen del problema está en los problemas de mantenimiento del analizador de gases en el infrarrojo de trayectoria abierta, que se emplea para medir la densidad promedio de CO2 así como sus fluctuaciones, que son necesarias para el cálculo del flujo de CO2. La exposición de este problema, así como su solución ya ha sido publicada y se recoge en este trabajo (Serrano-Ortiz et al., 2008). Una vez estudiada la fiabilidad de los flujos turbulentos medidos con la técnica EC y resueltos los problemas detectados, estamos en condiciones de analizar los resultados obtenidos. En este trabajo estudiamos la variación estacional e interanual del flujo diurno de CO2 (FC) y la evapotranspiración (ET) en El Llano de los Juanes. Esta variabilidad, es consecuencia de una adaptación a las condiciones ambientales extremas a las que se ve sometido el ecosistema. Analizando la influencia de algunas de las variables medioambientales sobre los intercambios de carbono diurnos, observamos la importancia de la distribución de las lluvias a lo largo del año en la determinación del ciclo fenológico de las plantas y la productividad del ecosistema (Serrano-Ortiz et al., 2007). Además, las campañas de medida mensuales del flujo de CO2 en el suelo, realizadas con el sistema de cámaras LI-8100 nos han permitido estudiar las variables de las que depende la variabilidad estacional de las emisiones de CO2 del suelo. Llegando a la conclusión de que el factor que condiciona la respiración del suelo en nuestro ecosistema semiárido, durante la época de crecimiento biológico, es el contenido de agua en el suelo. Además, para estudiar más a fondo el comportamiento del flujo de CO2 en nuestro ecosistema, hemos recurrido a modelos no lineales ecofisiológicos que relacionan estos intercambios de CO2 con variables medioambientales (Falge et al., 2001b). Estos modelos suponen que el flujo de CO2 medido procede única y exclusivamente de procesos biológicos (fotosíntesis y respiración durante el día y respiración durante la noche). La aplicación de estos modelos a nuestro ecosistema nos confirma que durante la época de crecimiento, sin carencia de agua en el suelo, los modelos ecofisiológicos pueden usarse para describir el comportamiento del flujo de CO2. Sin embargo, estos modelos no son extrapolables a otras épocas del año (Serrano-Ortiz et al., 2007). En épocas de senescencia se detectan emisiones de CO2 a la atmósfera, que no dependen de variables ambientales que condicionan la respiración (temperatura) y por tanto no pueden modelizarse atendiendo a modelos ecofisiológicos. La hipótesis que formulamos en este trabajo es que estas emisiones son consecuencia de fenómenos de ventilación de los macroporos del sistema carbonatado, que parecen estar correlacionadas con la velocidad del viento. La dependencia de estas emisiones con el viento ha sido verificada con el sistema de cámaras LI-8100. En esta línea, estudios de fenómenos de desgasificación de cuevas e intercambios turbulentos de CO2 con la atmósfera, llevados a cabo en la Cueva de Altamira (Cuezva 2008), avalan la teoría de existencia de flujos de CO2 de procedencia geoquímica en ecosistemas localizados sobre sustrato karstico. Para estudiar la procedencia de los flujos de CO2 medidos con nuestro sistema EC en El Llano de los Juanes, hemos usado la técnica de isótopos estables. El análisis de la huella isotópica nos permite discriminar los procesos que intervienen en el intercambio de CO2 entre la atmósfera y nuestro ecosistema, dado que el CO2 de procedencia geoquímica tendrá una huella isotópica distinta al CO2 al procedente de la respiración. Tras analizar isotópicamante el CO2 medido durante épocas de crecimiento biológico y épocas de senescencia observamos que existen diferencias entre la huella isotópica del carbono en ambas estaciones. No obstante, parece oportuno seguir profundizando en la investigación con el fin de confirmar de modo concluyente la contribución de flujos abióticos de CO2 en el ecosistema de estudio. Finalmente, tras casi tres años de medidas, estamos en condiciones de estimar el balance anual de carbono en El Llano de los Juanes (Sierra de Gádor). Nuestro ecosistema actúa como sumidero de carbono asimilando aproximadamente 25 g C m-2 por año. Además vemos cómo la distribución de las lluvias condiciona la funcionalidad de nuestro ecosistema y cómo la duración del periodo de sequía determina la duración de las emisiones de CO2 de procedencia geoquímica, por ventilación del suelo.Tesis Univ. Granada