Early stage litter decomposition across biomes

(2018) Early stage litter decomposition across biomes. . : -.
Enllaç
Doi: 10.1016/j.scitotenv.2018.01.012

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Joining empirical and modelling approaches to estimate dry deposition of nitrogen in Mediterranean forests

García-Gómez H., Izquieta-Rojano S., Aguillaume L., González-Fernández I., Valiño F., Elustondo D., Santamaría J.M., Àvila A., Bytnerowicz A., Bermejo V., Alonso R. (2018) Joining empirical and modelling approaches to estimate dry deposition of nitrogen in Mediterranean forests. Environmental Pollution. 243: 427-436.
Enllaç
Doi: 10.1016/j.envpol.2018.09.015

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In Mediterranean areas, dry deposition is a major component of the total atmospheric N input to natural habitats, particularly to forest ecosystems. An innovative approach, combining the empirical inferential method (EIM) for surface deposition of NO3 − and NH4 + with stomatal uptake of NH3, HNO3 and NO2 derived from the DO3SE (Deposition of Ozone and Stomatal Exchange) model, was used to estimate total dry deposition of inorganic N air pollutants in four holm oak forests under Mediterranean conditions in Spain. The estimated total deposition varied among the sites and matched the geographical patterns previously found in model estimates: higher deposition was determined at the northern site (28.9 kg N ha−1 year−1) and at the northeastern sites (17.8 and 12.5 kg N ha−1 year−1) than at the central-Spain site (9.4 kg N ha−1 year−1). On average, the estimated dry deposition of atmospheric N represented 77% ± 2% of the total deposition of N, of which surface deposition of gaseous and particulate atmospheric N averaged 10.0 ± 2.9 kg N ha−1 year−1 for the four sites (58% of the total deposition), and stomatal deposition of N gases averaged 3.3 ± 0.8 kg N ha−1 year−1 (19% of the total deposition). Deposition of atmospheric inorganic N was dominated by the surface deposition of oxidized N in all the forests (means of 54% and 42% of the dry and total deposition, respectively). The relative contribution of NO2 to dry deposition averaged from 19% in the peri-urban forests to 11% in the most natural site. During the monitoring period, the empirical critical loads provisionally proposed for ecosystem protection (10–20 kg N ha−1 year−1) was exceeded in three of the four studied forests. Dry deposition of atmospheric N in four forests of Quercus ilex represented 77% of the total deposition of N and it was dominated by the surface deposition of oxidized N. © 2018 Elsevier Ltd

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Atmospheric deposition of particulate matter between Algeria and France: Contribution of long and short-term sources

Lequy E., Avila A., Boudiaf Nait Kaci M., Turpault M.-P. (2018) Atmospheric deposition of particulate matter between Algeria and France: Contribution of long and short-term sources. Atmospheric Environment. 191: 181-193.
Enllaç
Doi: 10.1016/j.atmosenv.2018.08.013

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Large worldwide sources of dust, such as the Saharan desert, play a key role in the amounts and composition of atmospheric particulate deposition (APD), but their relative contribution compared to other sources remain unclear. Our study aimed to apportion Saharan, regional, and anthropogenic sources of APD in three sampling along a long transect affected by Saharan outbreaks. We quantified total APD, and analyzed its mineralogical and chemical composition between 2011 and 2012.. Strong markers of Saharan dust, such as large amounts of APD and of a low Al2O3:CaO ratio allowed identifying clear periods influenced by Saharan outbreaks. Nitrogen and phosphorus reflected soil affected by agricultural practices, while Cd, Pb, Sb and Sn tracked traffic and industrial sources – as confirmed by enrichment factors. Then, we designed a conceptual model including sensitivity analyses to estimate the contribution of unanalyzed (10–11%, likely chlorites or sulfates), organic (34–41%), anthropogenic (11–22%), mineral-regional (5–25%) and mineral-Saharan (10–38%) matter over our entire study period. Our study shows the rapidly decreasing contribution of Saharan outbreaks – and the decreasing flux of Ca and Mg, from 40 to 0.4 kg.ha−1 over the study period between Algeria and France. Yet, Saharan outbreaks were still noticeable in APD at a site 1500 km away. Our study also shows the large relative contribution of organic and anthropogenic sources to APD in the three sampling sites, and their possible influence on nutrient budgets. © 2018 Elsevier Ltd

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The Critical Levels of Atmospheric Ammonia in a Mediterranean Holm-Oak Forest in North-Eastern Spain

Aguillaume, L., Avila, A., Pinho, P., Matos, P., Llop, E., Branquinho, C. (2017) The Critical Levels of Atmospheric Ammonia in a Mediterranean Holm-Oak Forest in North-Eastern Spain. Water, Air, and Soil Pollution. 228: 0-0.
Enllaç
Doi: 10.1007/s11270-017-3286-8

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Dry deposition and canopy uptake in Mediterranean holm-oak forests estimated with a canopy budget model: A focus on N estimations

Aguillaume, L., Izquieta-Rojano, S., García-Gómez, H., Elustondo, D., Santamaría, J.M., Alonso, R., Avila, A. (2017) Dry deposition and canopy uptake in Mediterranean holm-oak forests estimated with a canopy budget model: A focus on N estimations. Atmospheric Environment. 152: 191-200.
Enllaç
Doi: 10.1016/j.atmosenv.2016.12.038

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Monitoring and deposition trends in Spain, including Saharan dust [Monitorización y tendencias de la deposición de N en España, incluyendo polvo sahariano]

Avila A., Aguillaume L. (2017) Monitoring and deposition trends in Spain, including Saharan dust [Monitorización y tendencias de la deposición de N en España, incluyendo polvo sahariano]. Ecosistemas. 26: 16-24.
Enllaç
Doi: 10.7818/ECOS.2017.26-1.04

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The chemical composition of the atmosphere has significantly changed in the last century, mostly due to increased emissions of gases and particles derived from human activities. Several studies have analyzed the trends in the chemical composition of rainwater and atmospheric deposition in recent decades in central and northern Europe. However, for Spain there is a lack of studies at national level. Up to now, analyses of decadal trends are only available from a few individual stations. In this paper we first present the different methods to measure atmospheric deposition. Then we compile a list of atmospheric deposition monitoring stations in Spain and review the available time series, for series longer than 10 years, with special attention to the trends of N, S and African dust. Finally, we indicate future research directions to fill the gaps in knowledge about patterns and trends of atmospheric deposition at a national level. © 2017 Los Autores. Editado por la AEET.

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Quantitative study on nitrogen deposition and canopy retention in Mediterranean evergreen forests

Avila, A., Aguillaume, L., Izquieta-Rojano, S., García-Gómez, H., Elustondo, D., Santamaría, J.M., Alonso, R. (2017) Quantitative study on nitrogen deposition and canopy retention in Mediterranean evergreen forests. Environmental Science and Pollution Research. 24: 26213-26226.
Enllaç
Doi: 10.1007/s11356-017-8861-4

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Quantifying dry and wet deposition fluxes in two regions of contrasting African influence: The NE Iberian Peninsula and the Canary Islands

Castillo, S., Alastuey, A., Cuevas, E., Querol, X., Avila, A. (2017) Quantifying dry and wet deposition fluxes in two regions of contrasting African influence: The NE Iberian Peninsula and the Canary Islands. Atmosphere. 8: 0-0.
Enllaç
Doi: 10.3390/atmos8050086

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Ecological impacts of atmospheric pollution and interactions with climate change in terrestrial ecosystems of the Mediterranean Basin: Current research and future directions

Ochoa-Hueso R., Munzi S., Alonso R., Arróniz-Crespo M., Avila A., Bermejo V., Bobbink R., Branquinho C., Concostrina-Zubiri L., Cruz C., Cruz de Carvalho R., De Marco A., Dias T., Elustondo D., Elvira S., Estébanez B., Fusaro L., Gerosa G., Izquieta-Rojano S., Lo Cascio M., Marzuoli R., Matos P., Mereu S., Merino J., Morillas L., Nunes A., Paoletti E., Paoli L., Pinho P., Rogers I.B., Santos A., Sicard P., Stevens C.J., Theobald M.R. (2017) Ecological impacts of atmospheric pollution and interactions with climate change in terrestrial ecosystems of the Mediterranean Basin: Current research and future directions. Environmental Pollution. 227: 194-206.
Enllaç
Doi: 10.1016/j.envpol.2017.04.062

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Mediterranean Basin ecosystems, their unique biodiversity, and the key services they provide are currently at risk due to air pollution and climate change, yet only a limited number of isolated and geographically-restricted studies have addressed this topic, often with contrasting results. Particularities of air pollution in this region include high O3 levels due to high air temperatures and solar radiation, the stability of air masses, and dominance of dry over wet nitrogen deposition. Moreover, the unique abiotic and biotic factors (e.g., climate, vegetation type, relevance of Saharan dust inputs) modulating the response of Mediterranean ecosystems at various spatiotemporal scales make it difficult to understand, and thus predict, the consequences of human activities that cause air pollution in the Mediterranean Basin. Therefore, there is an urgent need to implement coordinated research and experimental platforms along with wider environmental monitoring networks in the region. In particular, a robust deposition monitoring network in conjunction with modelling estimates is crucial, possibly including a set of common biomonitors (ideally cryptogams, an important component of the Mediterranean vegetation), to help refine pollutant deposition maps. Additionally, increased attention must be paid to functional diversity measures in future air pollution and climate change studies to establish the necessary link between biodiversity and the provision of ecosystem services in Mediterranean ecosystems. Through a coordinated effort, the Mediterranean scientific community can fill the above-mentioned gaps and reach a greater understanding of the mechanisms underlying the combined effects of air pollution and climate change in the Mediterranean Basin. © 2017 Elsevier Ltd

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Long-term effects of changing atmospheric pollution on throughfall, bulk deposition and streamwaters in a Mediterranean forest

Aguillaume L., Rodrigo A., Avila A. (2016) Long-term effects of changing atmospheric pollution on throughfall, bulk deposition and streamwaters in a Mediterranean forest. Science of the Total Environment. 544: 919-928.
Enllaç
Doi: 10.1016/j.scitotenv.2015.12.017

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The abatement programs implanted in Europe to reduce SO2, NO2 and NH3 emissions are here evaluated by analyzing the relationships between emissions in Spain and neighboring countries and atmospheric deposition in a Mediterranean forest in the Montseny mountains (NE Spain) for the last 3decades. A canopy budget model was applied to throughfall data measured during a period of high emissions (1995-1996) and a period of lower emissions (2011-2013) to estimate the changes in dry deposition over this time span.Emissions of SO2 in Spain strongly decreased (77%) and that was reflected in reductions for nssSO4 2- in precipitation (65% for concentrations and 62% for SO4 2-S deposition). A lower decline was found for dry deposition (29%).Spanish NO2 emissions increased from 1980 to 1991, remained constant until 2005, and decreased thereafter, a pattern that was paralleled by NO3 - concentrations in bulk precipitation at Montseny. This pattern seems to be related to a higher share of renewable energies in electricity generation in Spain in recent years. However, dry deposition increased markedly between 1995 and 2012, from 1.3 to 6.7kgha-1year- 1. Differences in meteorology between periods may have had a role, since the recent period was drier thus probably favoring dry deposition.Spanish NH3 emissions increased by 13% between 1980 and 2012 in Spain but NH4 + concentrations in precipitation and NH4 +-N deposition showed a decreasing trend (15% reduction) at Montseny, probably linked to the reduction ammonium sulfate and nitrate aerosols to be scavenged by rainfall. NH4 +-N dry deposition was similar between the compared periods.The N load at Montseny (15-17kgha-1year-1) was within the critical load range proposed for Mediterranean sclerophyllous forests (15-17.5kgha-1year-1). The onset of N saturation is suggested by the observed increasing N export in streamwaters. © 2015 Elsevier B.V.

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