Field surveys of ozone symptoms in Europe. Problems, reliability and significance for ecosystems (original) (raw)
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Environmental Monitoring and Assessment, 2006
Within the European intensive forest monitoring programme, the native vegetation on permanent Level II plots has been monitored for visible ozone injuries. The main purpose of the programme is to assess the potential risks for the forest vegetation and the natural ecosystems at the intensive monitoring plots. During the first years of the programme the surveys were qualitative, reporting only the number and the name of the symptomatic species in selected Light Exposed Sampling Site. In 2003 a new plot design was tested, based on the distribution of a number of miniplots along the edge of the forest, so as to obtain quantitative findings about the occurrence and distribution of the symptoms. The problems that still persist are related to: (i) the forest edge assessed for ozone symptoms may have a different floristic composition from the Level II plot itself; (ii) the anthropic pressure and the disturbances affecting the forest edge alters the floristic composition; (iii) the variability of the plant composition in the forest edge, which makes comparability difficult between different sites; and (iv) the evaluation of symptoms in several species that have not yet been experimentally tested. Further difficulties are due to the fact that symptoms observed in the field are often aspecific and cannot, therefore, be attributed solely to the phytotoxic action of ozone. To improve the effectiveness of the European programme, it is necessary: (i) to individualise and select common sensitive plant species for homogeneous ecological regions; (ii) to enhance experimental activities to test the sensitivity of a large number of plant species.
Impacts of ozone on forests: a European perspective
New Phytologist, 1998
In comparison with the effects of extended drought periods or severe nutrient stress, those of ozone are generally much milder, at least with respect to growth. However, there is substantial evidence from experiments, in the main using young saplings, that O3 does impose a stress on forest trees under European conditions. Decreased chlorophyll contents and photosynthetic rates, changes in carbon allocation, increased antioxidant activity, and reductions in biomass due to O3 have often been recorded, particularly in fastâgrowing species. Furthermore, 3 appears to weaken the trees' resilience to a range of biotic and abiotic stresses. Interactions between O3 and climatic stress, in particular drought and frost hardiness, are likely to result in potentially detrimental effects.A link between the occurrence of O3 and forest damage is not unequivocally established in Europe, and the problem remains of extrapolating and/or scaling up from studies on seedlings to predict responses to O...
Validation of leaf ozone symptoms in natural vegetation using microscopical methods
''Capsule'': Integration of markers of oxidative stress, from the subcellular to the leaf and needle level, proved to be a useful tool for the differential diagnosis and validation of ozone injury. Abstract Ozone injury to natural vegetation is being increasingly surveyed throughout the northern hemisphere. There exists a growing list of species showing visible 'ozone-like' symptoms which needs to be validated. This study presents the results from a test survey of ozone injury to forest vegetation in the light exposed sites of five Swiss level II plots, for the new ICP-Forests protocol. With AOT40 from 14 to 28 ppm. h in 2000, ten out of 49 woody plant species displayed typical symptoms, and four showed untypical symptoms. Symptom origin was investigated in nine and validated in seven species, using morphological, histological and cellular markers of oxidative stress and ozone-induced plant response. Independent of taxonomic position, ozone effects were characterized by the induction of oxidative stress in the mesophyll resulting in discrete and light-dependent hypersensitive-like responses and in accelerated cell senescence. The presented combination of cellular and morphological markers allows differential diagnosis of visible ozone injury.
2013
Tropospheric ozone concentration has been rising in the last decades, due to industrial and other human activities. For plants, ozone constitutes one of the most damaging air pollutants. Main effects of ozone on forest species are reviewed: visible symptoms caused by acute exposure at the anatomical, structural and metabolic level, and the long run effects on growth and development derived from chronic exposure. Particular attention is given to photosynthesis and the effects on stomatal functioning, as major ozone injuries are inflicted to the plant after entering through the stomata. Plant detoxification capacity, carbohydrate allocation, growth and development are also revised, as well as the effects at the ecosystem level, defence mechanisms of plants against ozone, and their sensitivity and tolerance. The rising problem of tropospheric ozone contamination should awaken the international awareness and measures should be taken to control ozone atmospheric levels considering their transnational implications.
Detecting ozone and demonstrating its phytotoxicity in forested areas of Poland: A pilot study
Environmental Pollution, 1993
were measured and 03 phytotoxicity to tobacco (Nicotiana tabacum L.) was demonstrated in several forest locations in Poland during a pilot study from July-October, 1991. At southern and central locations in Poland, the 24-hour average 03 concentrations measured with a UV absorption photometer were in the range of 32-55 ppb, and the corresponding 1-hour maxima in the range of 39-83 ppb. At these locations longer period (four to fifteen days) average concentrations were determined using 03 passive sampiers (DGA, Inc.) and were reaching 60 ppb, while at Bialowieza in eastern Poland 03 concentrations averaged less than 40 ppb. In Szarow, near the Niepolomice Forest in southern Poland, 1-hour 03 maxima estimated from the data obtained using passive samplers were about 105 ppb in early September. At several locations in southern and central Poland, extensive 03 injury was determined on 03-sensitive Bel W-3 tobacco plants; such injury did not occur in the Bialowieza Forest of eastern Poland The results of this pilot study indicate that 03 is present at phytotoxic levels in southern and central Poland
TheScientificWorldJournal, 2007
The presented study aimed to explore the relationships between ambient ozone (O3) and tree defoliation, specific diversity, and abundance of soil microarthropods, stream macroinvertebrates, and small mammals (mainly rodents) in order to test the hypothesis that changes in the considered objects of the forest ecosystem could be related to changes in ambient O3, concentration of which is below critical level. The observations were carried out from 1994 at three integrated monitoring stations. The obtained data revealed that only peak O3 concentrations (from 125-215 microg x m(-3)) had significant effect on changes in the considered components of forest biota.