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1.
Environ Pollut ; 243(Pt A): 427-436, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30212797

RESUMO

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% ±â€¯2% of the total deposition of N, of which surface deposition of gaseous and particulate atmospheric N averaged 10.0 ±â€¯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 ±â€¯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.


Assuntos
Florestas , Nitrogênio/análise , Folhas de Planta/química , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Modelos Químicos , Espanha
2.
Environ Pollut ; 227: 194-206, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28460237

RESUMO

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.


Assuntos
Poluentes Atmosféricos/análise , Atmosfera/química , Mudança Climática , Ecossistema , Monitoramento Ambiental , Poluição do Ar/estatística & dados numéricos , Biodiversidade , Clima , Humanos , Nitrogênio/análise , Pesquisa
3.
Environ Sci Pollut Res Int ; 24(34): 26259-26268, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28455565

RESUMO

Ozone (O3) critical levels have been established under the Long-Range Transboundary Air Pollution Convention to assess the risk of O3 effects in European vegetation. A recent review study has led to the development of O3 critical levels for annual Mediterranean pasture species using plants growing in well-watered pots at a coastal site and under low levels of competition. However, uncertainties remain in the extrapolation of the O3 sensitivity of these species under natural conditions. The response of two O3-sensitive annual Mediterranean pasture Trifolium species at the coastal site was compared with the response of the same species growing at a continental site, in natural soil and subject to water-stress and inter-specific competition, representing more closely their natural habitat. The slopes of exposure- and dose-response relationships derived for the two sites showed differences in the response to O3 between sites attributed to differences in environmental growing conditions, growing medium and the level of inter-specific competition, but the effect of the individual factors could not be assessed separately. Dose-based O3 indices partially explained differences due to environmental growing conditions between sites. The slopes showed that plants were more sensitive to O3 at the continental site, but homogeneity of slopes tests revealed that results from both experimental sites may be combined. Although more experimental data considering complex inter-specific competition situations and the effect of important interactive factors such as nitrogen would be needed, these results confirm the validity of applying the current flux-based O3 critical level under close to natural growing conditions. The AOT40-based O3 critical level derived at the coastal site was also considered a suitable risk indicator in close to natural growing conditions in the absence of soil moisture limitations on plant growth.


Assuntos
Poluentes Atmosféricos/toxicidade , Monitoramento Ambiental/métodos , Ozônio/toxicidade , Trifolium/efeitos dos fármacos , Poluentes Atmosféricos/análise , Ecossistema , Nitrogênio , Ozônio/análise
4.
Environ Pollut ; 194: 69-77, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25094059

RESUMO

Increasing tropospheric ozone (O3) and nitrogen soil availability (N) are two of the main drivers of global change. They both may affect gas exchange, including plant emission of volatiles such as terpenes. We conducted an experiment using open-top chambers to analyze these possible effects on two leguminous species of Mediterranean pastures that are known to have different O3 sensitivity, Ornithopus compressus and Trifolium striatum. O3 exposure and N fertilization did not affect the photosynthetic rates of O. compressus and T. striatum, although O3 tended to induce an increase in the stomatal conductance of both species, especially T. striatum, the most sensitive species. O3 and N soil availability reduced the emission of terpenes in O. compressus and T. striatum. If these responses are confirmed as a general pattern, O3 could affect the competitiveness of these species.


Assuntos
Fabaceae/fisiologia , Ozônio/toxicidade , Terpenos/metabolismo , Trifolium/fisiologia , Monitoramento Ambiental , Fabaceae/efeitos dos fármacos , Fertilizantes/estatística & dados numéricos , Nitrogênio/análise , Nitrogênio/metabolismo , Ozônio/análise , Fotossíntese/efeitos dos fármacos , Folhas de Planta/química , Folhas de Planta/fisiologia , Solo , Terpenos/análise , Trifolium/efeitos dos fármacos
5.
Environ Pollut ; 159(8-9): 2138-47, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21269745

RESUMO

Tropospheric ozone (O(3)) is considered one of the most important air pollutants affecting human health. The role of peri-urban vegetation in modifying O(3) concentrations has been analyzed in the Madrid region (Spain) using the V200603par-rc1 version of the CHIMERE air quality model. The 3.7 version of the MM5 meteorological model was used to provide meteorological input data to the CHIMERE. The emissions were derived from the EMEP database for 2003. Land use data and the stomatal conductance model included in CHIMERE were modified according to the latest information available for the study area. Two cases were considered for the period April-September 2003: (1) actual land use and (2) a fictitious scenario where El Pardo peri-urban forest was converted to bare-soil. The results show that El Pardo forest constitutes a sink of O(3) since removing this green area increased O(3) levels over the modified area and over down-wind surrounding areas.


Assuntos
Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental/métodos , Modelos Químicos , Árvores/fisiologia , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/metabolismo , Cidades , Ozônio/análise , Ozônio/metabolismo , Espanha , Árvores/classificação , Árvores/metabolismo
6.
Environ Pollut ; 155(3): 473-80, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18342418

RESUMO

A sensitivity analysis of a proposed parameterization of the stomatal conductance (g(s)) module of the European ozone deposition model (DO(3)SE) for Quercus ilex was performed. The performance of the model was tested against measured g(s) in the field at three sites in Spain. The best fit of the model was found for those sites, or during those periods, facing no or mild stress conditions, but a worse performance was found under severe drought or temperature stress, mostly occurring at continental sites. The best performance was obtained when both f(phen) and f(SWP) were included. A local parameterization accounting for the lower temperatures recorded in winter and the higher water shortage at the continental sites resulted in a better performance of the model. The overall results indicate that two different parameterizations of the model are needed, one for marine-influenced sites and another one for continental sites.


Assuntos
Poluentes Atmosféricos/metabolismo , Oxidantes Fotoquímicos/metabolismo , Ozônio/metabolismo , Estômatos de Plantas/fisiologia , Quercus/metabolismo , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Geografia , Modelos Biológicos , Oxidantes Fotoquímicos/análise , Ozônio/análise , Transpiração Vegetal , Estações do Ano , Espanha
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