The accumulation of nitrogen (N) in moss tissue has proven to be a reliable marker of increasing N deposition. However, this measurement does not offer additional data about the origin of pollution. In this respect, the analysis of the N isotopic ratios might be a helpful tool in providing supplementary information about the nature of the nitrogenous species in biomonitoring surveys. Furthermore, isotopic signatures have been extensively used in the study of N and carbon (C) biogeochemical cycles. The main purpose of this study was to determine N and C elemental contents and their stable isotopes in mosses to investigate atmospheric pollution patterns across Europe. We aimed at identifying the main N polluted areas and evaluating the potential use of isotopic signatures in the attribution of pollution sources at a regional scale. With these objectives in mind, >1300 samples from 15 countries from Europe, all of them participants of the ICP-Vegetation programme 2005–2006, were analyzed for their C and N contents and δ15N and δ13C. The results were compared to those derived from EMEP model, which provided modeled deposition and emission data, as well as to the predominant land uses at the sampling sites (based on CORINE Land Cover). This evaluation suggests that additional measurements of stable C and N isotopes in mosses could be a valuable tool in European environmental surveys. Such measurements not only provide useful information for identifying probable pollution sources but also enable the quantification of their contributions, serving as biological indicators of significant environmental processes. This study presents the first quantitative assessment of major atmospheric nitrogen (N) sources based on stable isotope analysis on a European scale, establishing a framework for evaluating historical changes in N across the region.
Tropospheric ozone (O-3) is a gaseous phytotoxic plant stressor known to reduce wheat (Triticum aestivum) crop yields at current concentrations. O3 is predicted to increase in many crop-growing regions, together with higher frequencies of heatwaves and droughts. In this study, wheat crops were exposed to two levels of O-3 (ambient and similar to 70 ppb) in combination with ambient or elevated temperature (+8 degrees C) and two watering regimes (well-watered and 50% reduced water supply) during the grain-filling period. With this experimental setup, we assessed the interactive effects between O-3, temperature and water supply on wheat yield and grain quality, and measured leaf gas exchange to explore the underlying mechanisms. Overall, O-3, warming and drought all decreased grain yield and average grain mass but increased grain concentration of N and other nutrient elements. Increasing daytime O-3 from 25 to 73 ppb resulted in a 25% yield reduction in treatments with ambient temperature and well-watered soil. Drought reduced the impact of O-3 on light-saturated photosynthesis, grain mass, total aboveground biomass and grain concentrations of K, Ca, Mg, Mo. In contrast, concentrations of K and Ca increased to a larger extent when O-3 stress was combined with elevated temperature. Grain concentrations of N, Ca and Zn were closely and negatively related to grain yield regardless of O-3, heat and drought stress, likely explained by the reduction in grain filling period, with starch accumulation reduced to a larger extent than that of these elements. P, K, Mg, Mn, Mo concentrations were weakly related to grain yield, but were clearly altered by environmental stress. The modifying effect of water availability is crucial to include in assessments of O-3 impacts on global food production in relation to climate change, considering effects on wheat yield variables and grain nutrient concentrations.
Plants are subject to trade-offs among growth strategies such that adaptations for optimal growth in one condition can preclude optimal growth in another. Thus, we predicted that a plant species that responds positively to one global change treatment would be less likely than average to respond positively to another treatment, particularly for pairs of treatments that favor distinct traits. We examined plant species' abundances in 39 global change experiments manipulating two or more of the following: CO2, nitrogen, phosphorus, water, temperature, or disturbance. Overall, the directional response of a species to one treatment was 13% more likely than expected to oppose its response to a another single-factor treatment. This tendency was detectable across the global data set, but held little predictive power for individual treatment combinations or within individual experiments. Although trade-offs in the ability to respond to different global change treatments exert discernible global effects, other forces obscure their influence in local communities.
Ecological communities are being impacted by global change worldwide. Experiments are a powerful tool to understand how global change will impact communities by comparing control and treatment replicates. Communities consist of multiple species, and their associated abundances make multivariate methods an effective approach to study community compositional differences between control and treated replicates. Dissimilarity metrics are a commonly employed multivariate measure of compositional differences; however, while highly informative, dissimilarity metrics do not elucidate the specific ways in which communities differ. Integrating two multivariate methods, dissimilarity metrics and rank abundance curves (RACs), have the potential to detect complex differences based on dissimilarity metrics and detail the how these differences came about through differences in richness, evenness, species ranks, or species identity. Here we use a database of 106 global change experiments located in herbaceous ecosystems and explore how patterns of ordinations based on dissimilarity metrics relate to RAC-based differences. We find that combining dissimilarity metrics alongside RAC-based measures clarifies how global change treatments are altering communities. We find that when there is no difference in community composition (no distance between centroids of control and treated replicates), there are rarely differences in species ranks or species identities and more often differences in richness or evenness alone. In contrast, when there are differences between centroids of control and treated replicates, this is most often associated with differences in ranks either alone or co-occurring with differences in richness, evenness, or species identities. We suggest that integrating these two multi-variate measures of community composition results in a deeper understanding of how global change impacts communities.
Tropospheric ozone can have a detrimental effect on vegetation, including reducing the quantity of crop yield. This study uses modelled ozone flux values (POD 3 IAM; phytotoxic ozone dose above 3 nmol m −2 s −1 , parameterised for integrated assessment modelling) for 2015, together with species-specific flux-effect relationships, spatial data on production and growing season dates to quantify the impact of ozone on the production of common wheat ( Triticum aestivum ) and common beans ( Phaseolus vulgaris ) across Sub-Saharan Africa (SSA). A case study for South Africa was also done using detailed data per province. Results suggest that ozone pollution could decrease wheat yield by between 2 and 13%, with a total annual loss of 453,000 t across SSA. The impact on bean production depended on the season; however, estimated yield losses were up to 21% in some areas of SSA, with an annual loss of ~300,000 t for each of the two main growing seasons. Production losses tended to be greater in countries with the highest production, for example, Ethiopia (wheat) and Tanzania (beans). This study provides an indication of the location of areas at high risk of crop losses due to ozone. Results emphasise that efforts to reduce ozone precursors could contribute to reducing the yield gap in SSA. More stringent air pollution abatement policies are required to reduce crop losses to ozone in the future.
The sensitivity of photosynthesis to temperature has been identified as a key uncertainty for projecting the magnitude of the terrestrial carbon cycle response to future climate change. Although thermal acclimation of photosynthesis under rising temperature has been reported in many tree species, whether tropospheric ozone (O-3) affects the acclimation capacity remains unknown. In this study, temperature responses of photosynthesis (light-saturated rate of photosynthesis (A(sat)), maximum rates of RuBP carboxylation (V-cmax), and electron transport (J(max)) and dark respiration (R-dark) of Populus tremula exposed to ambient O-3 (AO(3), maximum of 30 ppb) or elevated O-3 (EO3, maximum of 110 ppb) and ambient or elevated temperature (ambient +5 degrees C) were investigated in solardomes. We found that the optimum temperature of A(sat) (T-optA) significantly increased in response to warming. However, the thermal acclimation capacity was reduced by O-3 exposure, as indicated by decreased T-optA, and temperature optima of V-cmax (T-optV) and J(max) (T-optJ) under EO3. Changes in both stomatal conductance (g(s)) and photosynthetic capacity (V-cmax and J(max)) contributed to the shift of T-optA by warming and EO3. Neither R-dark measured at 25 degrees C (Rdark25) nor the temperature response of R-dark was affected by warming, EO3, or their combination. The responses of A(sat), V-cmax, and J(max) to warming and EO3 were closely correlated with changes in leaf nitrogen (N) content and N use efficiency. Overall, warming stimulated growth (leaf biomass and tree height), whereas EO3 reduced growth (leaf and woody biomass). The findings indicate that thermal acclimation of A(sat) may be overestimated if the impact of O-3 pollution is not taken into account.
1. Background to the problem Ozone (O3) is a gas that occurs naturally in the air. However, additional ground level ozone forms when pollutants from human activities react together in the presence of sunlight. Activities include vehicle use, industry and biomass burning. Ozone concentrations can be particularly high in agricultural areas downwind of large cities. Certain weather conditions (stable air mass, prolonged dry spells) and high levels of air pollution can lead to “ozone episodes.” Episodes are when ozone concentrations peak for several days at a time. Ozone is a hidden threat when mixed with air because we cannot taste, smell, or see it.
Two contrasting rapeseed (Brassica napus L.) genotypes, Qinyou 8 (drought-sensitive) and Q2 (drought-tolerant), were studied under drought stress with or without pretreatment with melatonin to (i) explore whether melatonin enhances drought resistance by regulating root growth and (ii) determine the relationship between the belowground and aboveground responses to melatonin under drought stress. Results show that the light-saturated rate of photosynthesis (Pn), stomatal conductance (gs), water use efficiency (WUE) and chlorophyll content were decreased by drought for Qinyou 8, whereas drought only decreased Pn and chlorophyll content for Q2. Drought decreased actual photochemical efficiency in saturated light (Fv’/Fm’), actual photochemical efficiency (PhiPSⅡ), quenching of photochemical efficiency (qL) and electron transport rate (ETR) in Qinyou 8. However drought only decreased Fv’/Fm’ and qL in Q2. Drought increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents in the roots of both genotypes. Melatonin had no significant additional effects on root guaiacol peroxidase (POD) and superoxide dismutase (SOD) activities, but enhanced root catalase (CAT) activity of droughted plants further. Melatonin promoted taproot and lateral root growth under drought stress. Melatonin also promoted stomatal opening resulting in enhanced photosynthesis in the two genotypes. The two mechanisms induced by melatonin synergistically enhance drought resistance of rapeseed as indicated by enhanced gas exchange parameters under melatonin pretreatment. The findings provide evidence for a physiological role of melatonin in improving drought resistance, especially in belowground parts.
Elevated tropospheric ozone concentrations induce adverse effects in plants. We reviewed how ozone affects (i) the composition and diversity of plant communities by affecting key physiological traits; (ii) foliar chemistry and the emission of volatiles, thereby affecting plant-plant competition, plant-insect interactions, and the composition of insect communities; and (iii) plant-soil-microbe interactions and the composition of soil communities by disrupting plant litterfall and altering root exudation, soil enzymatic activities, decomposition, and nutrient cycling. The community composition of soil microbes is consequently changed, and alpha diversity is often reduced. The effects depend on the environment and vary across space and time. We suggest that Atlantic islands in the Northern Hemisphere, the Mediterranean Basin, equatorial Africa, Ethiopia, the Indian coastline, the Himalayan region, southern Asia, and Japan have high endemic richness at high ozone risk by 2100.
The tropical-grown crops common bean (Phaseolus vulgaris), mung bean (Vigna radiate), cowpea (Vigna unguiculata), pearl millet (Pennisetum glaucum), finger millet (Eleusine coracana), amaranth (Amaranthus hypochonriacus), sorghum (Sorghum bicolour) and wheat (Triticum aestivum) were exposed to different concentrations of the air pollutant ozone in experimental Solardome facilities. The plants were exposed to ozone treatments for between one and four months, depending on the species. There was a large decrease in yield of protein-rich beans and cowpeas with increasing ozone exposure, partly attributable to a reduction in individual bean/pea weight. Size of individual grains was also reduced with increasing ozone for African varieties of wheat. In contrast, the yield of amaranth, pearl millet and finger millet (all C4 species) was not sensitive to increasing ozone concentrations and there was some evidence of an increase in weight of individual seedheads with increasing ozone for finger millet. Sorghum did not reach yield, but was not sensitive to ozone based on changes in biomass. Dose-response relationships for these crop species demonstrate that tropospheric ozone pollution could reduce yield of important crops, particularly legumes, in tropical regions such as sub-Saharan Africa.
New critical levels for ozone based on accumulated flux through stomata (phytotoxic ozone dose, POD), for temperate perennial grassland (semi-)natural vegetation, have been agreed for use within the Convention on Long-Range Transboundary Air Pollution. These were based on data from several experiments conducted under naturally fluctuating environmental conditions that were combined and analysed to give linear dose-response relationships. Dose-response functions and flux-based critical levels were derived based on biomass and flower number. These parameters showed a statistically significant decline with increasing accumulated stomatal ozone flux. The functions and critical levels derived are based on sensitive species and can be used for risk assessments of the damaging effect of ozone on temperate vegetation communities dominated by perennial grassland species. The critical level based on flower number was lower than that for biomass, representing the greater sensitivity of flower number to ozone pollution.
Atmospheric ozone (O3) and nitrogen (N) pollution have increased since pre-industrial times and pose a threat to natural vegetation. The implications of these pollutants for the perennial temperate grassland species Leontodon hispidus (Rough Hawkbit) and Succisa pratensis (Devil’s-bit Scabious) are largely unknown. Both species are important for pollinators and Succisa pratensis is the host plant for the threatened marsh fritillary butterfly (Euphydryas aurinia).We examine growth and physiological responses (leaf cover, leaf litter, flowering, chlorophyll index [Leontodon hispidus and Succisa pratensis]; photosynthesis and stomatal conductance [Succisa pratensis]) using an outdoor Free Air Ozone Enrichment system. Plants were exposed to Low, Medium and High ozone treatments over three growing seasons (treatment means: 24, 40 and 57 ppb, respectively), with and without the addition of nitrogen (40 kg ha−1 yr−1) during the first year.Decreases in leaf cover (p < 0.001) and chlorophyll index (p < 0.01) were observed with increased O3 for Leontodon hispidus. The addition of N resulted in a higher chlorophyll index only at the uppermost O3 level and also led to an overall increase in litter production of 6%. However, a stronger effect of both O3 and N treatments was observed with Succisa pratensis. Litter production increased with increasing O3 (p < 0.001) and an overall rise of 31% was recorded with added N (p < 0.05). However, O3 had the biggest impact on Succisa pratensis foliage leading to more damaged leaves (p < 0.05). During summer resources were prioritised to new leaves, maintaining stomatal conductance and photosynthesis rates. However, this was not sustained during autumn and accelerated senescence occurred with higher ozone, and rates declined faster with added nitrogen (p < 0.05). Elevated O3 also reduced Succisa pratensis flowering (p < 0.01).These effects have implications for inter- and intra-specific competition, seed establishment, nutrient cycling, as well as the provision of general pollinator resources with specific issues for butterfly larvae. Results highlight the need for concerted action to reduce pre-cursor ozone emissions to go alongside habitat management efforts to protect biodiversity.
Tropospheric (ground-level) ozone is a harmful phytotoxic pollutant, and can have a negative impact on crop yield and quality in sensitive species. Ozone can also induce visible symptoms on leaves, appearing as tiny spots (stipples) between the veins on the upper leaf surface. There is little measured data on ozone concentrations in Africa and it can be labour-intensive and expensive to determine the direct impact of ozone on crop yield in the field. The identification of visible ozone symptoms is an easier, low cost method of determining if a crop species is being negatively affected by ozone pollution, potentially resulting in yield loss. In this study, thirteen staple African food crops (including wheat (Triticum aestivum), common bean (Phaseolus vulgaris), sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum) and finger millet (Eleusine coracana)) were exposed to an episodic ozone regime in a solardome system to monitor visible ozone symptoms. A more detailed examination of the progression of ozone symptoms with time was carried out for cultivars of P. vulgaris and T. aestivum, which showed early leaf loss (P. vulgaris) and an increased rate of senescence (T. aestivum) in response to ozone exposure. All of the crops tested showed visible ozone symptoms on their leaves in at least one cultivar, and ozone sensitivity varied between cultivars of the same crop. A guide to assist with identification of visible ozone symptoms (including photographs and a description of symptoms for each species) is presented.
Different definitions for the concepts of information, information transfer, i.e. communication and its effect and efficiency of false, but also correct information, especially from the environmental sector, are given. "THE TEN ECOLOGICAL COMMANDMENTS" developed by Menke-Glückert at the end of the 1960s and the 9th commandment "Do not pollute information", in particular, are examined in more detail and understood practically as a currently unchanging law in our existing world societies. The "Ethics Consensus", derived from "THE TEN ECOLOGICAL COMMANDMENTS" and developed by Markert at the end of the 1990s, reflects both theoretical and practical levels of action that many people in our highly diverse world societies can support. From a scientific point of view, this article deals in particular with the so-called B & B technologies, i.e. bioindication and biomonitoring of chemical elements, their chemical speciation as well as organic substances.In particular, B & B technologies, which deal with the biological detection of atmospheric deposition of chemical substances on a regional, national and international level, are taken into account. From both an academic and a practical point of view, mosses have prevailed here in the last decades in addition to lichens. The use of mosses is a major focus of international air monitoring, especially in Europe. Furthermore, the phytoremediation of chemical substances in water, soil and air is described as a biological and sustainable biological process, which does not "yet" have the full scope as it is used in bioindication and biomonitoring, as shown in the example of mosses. However, the phytoremediation considers to be an excellent tool to have the leading role in the sustainable pollutant "fight". In the future qualitative and quantitative approaches have been further on developed to fit scientifically and practically B&B Technologies as well the different form of phytotechnological approaches. Finally, the example of lithium, which is optionally derived from the Biological System of Chemical Elements (BSCE), becomes a chemical example that the administration of lithium to ALL mentally conditioned diseases such as manic depression up to smoking of cigarettes become one of the most valuable service for the recovery of our human society on a global level.As a conclusion of these tremendous effects of lithium can be considered: pulled out, in order to make clear that only this chemical element beside a psychiatric care and the involvement of family members, friends, physicians, psychologists and psychiatrists. In addition it is a must, that there is a strong relationship in between patient, psychiatrist(s) and strongly related persons to the patient. First an intensive information transfer via communication has to be guaranteed. After it a psychological support by doctors and, only if it seems necessary Lithium is to be given in a patient specific dose.Keywords. Bioindication, Biomonitoring, B&B Technology, Phytotechnology, The Biological System of Chemical Elements (BSCE), Lithium. Neurological diseases, Functional Food.
To investigate whether nitrogen (N) load affects the ozone (O-3) stomatal flux-effect relationship for birch biomass, three-year old birch saplings were exposed to seven different O-3 profiles (24 h mean of 35-66 ppb) and four different N loads (10, 30, 50 and 70 kg ha(-1) yr(-1)) in precision-controlled hemispherical glasshouses (solardomes) in 2012 and 2013. Stomatal conductance (g(s)) under optimal growth conditions was stimulated by enhanced N supply but was not significantly affected by enhanced O-3 exposure. Birch root, woody (stem + branches) and total biomass (root + woody) were not affected by the Phytotoxic Ozone Dose (POD1SPEC) after two seasons of O-3 exposure, and enhanced N supply stimulated biomass production independent of POD1SPEC (i.e. there were no POD1SPEC x N interactions). There was a strong linear relationship between the stem cross-sectional area and tree biomass at the end of the experiment, which was not affected by O-3 exposure or N load. Enhanced N supply stimulated the stem cross-sectional area at the end of season 2, but not at the end of season 1, which suggests a time lag before tree biomass responded to enhanced N supply. There was no significant effect of POD1SPEC on stem cross-sectional area after either the first or second growing season of the experiment. Contrasting results reported in the literature on the interactive impacts of O-3 and N load on tree physiology and growth are likely due to species-specific responses, different duration of the experiments and/or a limitation of the number of O-3 and N levels tested. (C) 2019 Elsevier B.V. All rights reserved.
Ground-level ozone (O3) pollution is known to adversely affect the production of O3-sensitive crops such as wheat. The magnitude of impact is dependent on the accumulated stomatal flux of O3 into the leaves. In well-irrigated plants, the leaf pores (stomata) tend to be wide open, which stimulates the stomatal flux and therefore the adverse impact of O3 on yield. To test whether reduced irrigation might mitigate O3 impacts on flag leaf photosynthesis and yield parameters, we exposed an O3-sensitive Kenyan wheat variety to peak concentrations of 30 and 80 ppb O3 for four weeks in solardomes and applied three irrigation regimes (well-watered, frequent deficit, and infrequent deficit irrigation) during the flowering and grain filling stage. Reduced irrigation stimulated 1000-grain weight and harvest index by 33% and 13%, respectively (when O3 treatments were pooled), which compensated for the O3-induced reductions observed in well-watered plants. Whilst full irrigation accelerated the O3-induced reduction in photosynthesis by a week, such an effect was not observed for the chlorophyll content index of the flag leaf. Further studies under field conditions are required to test whether reduced irrigation can be applied as a management tool to mitigate adverse impacts of O3 on wheat yield.
Northern, Southern and Equatorial Africa have been identified as among the regions most at risk from very high ozone concentrations. Whereas we know that many crop cultivars from Europe, north America and Asia are sensitive to ozone, almost nothing is known about the sensitivity of staple food crops in Africa to the pollutant. In this study cultivars of the African staple food crops, Triticum aestivum (wheat), Eleusine coracana (finger millet), Pennisetum glaucum (pearl millet) and Phaseolus vulgaris (bean) were exposed to an episodic ozone regime in solardomes in order to assess whether African crops are sensitive to ozone pollution. Extensive visible leaf injury due to ozone was shown for many cultivars, indicating high sensitivity to ozone. Reductions in total yield and 1,000-grain weight were found for T. aestivum and P. vulgaris, whereas there was no effect on yield for E. coracana and P. glaucum. There were differences in sensitivity to ozone for different cultivars of an individual crop, indicating that there could be possibilities for either cultivar selection or selective crop breeding to reduce sensitivity of these crops to ozone.