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Relationship between trace metal concentrations in the terrestrial moss Pseudoscleropodium purum and in bulk deposition Texto completo
2015
Boquete, M.T. | Fernández, J.A. | Carballeira, A. | Aboal, J.R.
The relationship between trace metal concentrations in Pseudoscleropodium purum (Hedw.) M. Fleish. and bulk deposition (BD) was examined at 21 sites (SS) to ascertain whether the lack of correlations reported in previous studies are due to limitations in the experimental design. Thus, we implemented some improvements to it and examined the correlations in depth. We could conclude that this relationship is determined by other variables rather than by the pollutant inputs themselves (BD). Thus, whether or not moss concentrations and bulk deposition are significantly correlated will depend on the combination of the above referred factors in a given area at a given time. Therefore, P. purum in particular, and most likely native terrestrial mosses in general, are less than ideal biomonitors for yielding absolute values of atmospheric trace metal deposition. We recommend their use as qualitative indicators and the use of classical methods to obtain absolute values.
Mostrar más [+] Menos [-]Ozone induces stomatal narrowing in European and Siebold's beeches: A comparison between two experiments of free-air ozone exposure Texto completo
2015
Hoshika, Yasutomo | Watanabe, Makoto | Kitao, Mitsutoshi | Häberle, Karl-Heinz | Grams, Thorsten E.E. | Koike, Takayoshi | Matyssek, Rainer
Stomata tend to narrow under ozone (O3) impact, leading to limitation of stomatal O3 influx. Here, we review stomatal response under recently conducted free-air O3 exposure experiments on two species of the same tree genus: Fagus sylvatica at Kranzberg Forest (Germany) and F. crenata at Sapporo Experimental Forest (Japan). Both beeches exhibited reduction in stomatal conductance (gs) by 10–20% under experimentally enhanced O3 regimes throughout the summer relative to ambient-air controls. Stomatal narrowing occurred, in early summer, in the absence of reduced carboxylation capacity of Rubisco, although photosynthetic net CO2 uptake rate temporarily reflected restriction to some minor extent. Observed stomatal narrowing was, however, diminished in autumn, suggesting gradual loss of stomatal regulation by O3. Monotonic decline in gs with cumulative O3 exposure or flux in current modeling concepts appear to be unrealistic in beech.
Mostrar más [+] Menos [-]Effects of organic pollution on biological communities of marine biofilm on hard substrata Texto completo
2015
Sanz-Lázaro, C. | Fodelianakis, S. | Guerrero-Meseguer, L. | Marin, A. | Karakassis, I.
We examined the effect of organic enrichment on diatom and bacterial assemblages of marine epilithic biofilms on two locations in the Mediterranean, one situated in Spain and the other in Greece. Total organic carbon, total organic nitrogen, stable isotopes (δ13C and δ15N) and chlorophyll a indicated significant incorporation of organic wastes, increased primary production and trophic niche modifications on the biofilms close to the organic enrichment source. In Spain, where the organic load was higher than in Greece, diatom and, to some extent, bacterial assemblages varied following the organic enrichment gradient. The taxonomic richness of diatom and bacterial communities was not influenced by organic enrichment. Classical community parameters showed consistent patterns to organic pollution in both locations, whereas community assemblages were only influenced when organic pollution was greatest. The successional patterns of these communities were similar to other epilithic communities. The modification of community assemblages induced by organic pollution may affect ecological functions.
Mostrar más [+] Menos [-]Enhanced photosynthetic capacity and antioxidant potential mediate brassinosteriod-induced phenanthrene stress tolerance in tomato Texto completo
2015
Ahammed, Golam Jalal | Li, Xin | Xia, Xiao-Jian | Shi, Kai | Zhou, Yan-Hong | Yu, Jing-Quan
Photosynthesis, the basal manufacturing process in the earth is habitually restricted by airborne micropollutants such as phenanthrene (PHE). Here, we show that 24-epibrassinolide (EBR), a bioactive plant steroid is able to keep higher photosynthetic capacity consistently for a long period under a shoot-imposed PHE stress in tomato. EBR-promoted photosynthetic capacity and efficiency eventually resulted in a 37.5% increase of biomass under PHE stress. As primary response, transcripts of antioxidant genes were remarkably induced by EBR in PHE-treated plants. Activities of antioxidant and detoxification enzymes were also enhanced by EBR. Notably, EBR-induced higher antioxidant potential was associated with reduced levels of H2O2 and O2—, resulting in a 32.7% decrease of content of malondialdehyde in the end of experiment and relatively healthy chloroplast ultrastructure in EBR + PHE treatment compared with PHE alone. These results indicate that EBR alleviates shoot-imposed PHE phytotoxicity by maintaining a consistently higher photosynthetic capacity and antioxidant potential in tomato.
Mostrar más [+] Menos [-]Is guava phenolic metabolism influenced by elevated atmospheric CO2? Texto completo
2015
Mendes de Rezende, Fernanda | Pereira de Souza, Amanda | Buckeridge, Marcos Silveira | Maria Furlan, Cláudia
Seedlings of Psidium guajava cv. Pedro Sato were distributed into four open-top chambers: two with ambient CO2 (∼390 ppm) and two with elevated CO2 (∼780 ppm). Monthly, five individuals of each chamber were collected, separated into root, stem and leaves and immediately frozen in liquid nitrogen. Chemical parameters were analyzed to investigate how guava invests the surplus carbon. For all classes of phenolic compounds analyzed only tannins showed significant increase in plants at elevated CO2 after 90 days. There was no significant difference in dry biomass, but the leaves showed high accumulation of starch under elevated CO2. Results suggest that elevated CO2 seems to be favorable to seedlings of P. guajava, due to accumulation of starch and tannins, the latter being an important anti-herbivore substance.
Mostrar más [+] Menos [-]Effects of environmental cadmium and lead exposure on adults neighboring a discharge: Evidences of adverse health effects Texto completo
2015
Cabral, Mathilde | Touré, Aminata | Garçon, Guillaume | Diop, Cheikh | Bouhsina, Saâd | Dewaele, Dorothée | Cazier, Fabrice | Courcot, Dominique | Tall-Dia, Anta | Shirali, Pirouz | Diouf, Amadou | Fall, Mamadou | Verdin, Anthony
The purpose of the study was to determine Pb and Cd concentrations in humans and to assess the effect of co-exposure to these metals on biomarkers of oxidative stress and nephrotoxicity. Blood and urine levels of Pb and Cd, oxidative stress and urinary renal biomarkers were measured in 77 subjects neighboring a discharge and 52 in the control site. Exposed subjects showed significantly higher levels of lead and cadmium in blood and urine than the controls. Excessive production of reactive oxygen species induced by these metals in exposed subjects conducted to a decrease in antioxidant defense system (GPx, Selenium, GSH) and an increase in lipid peroxidation (MDA). Moreover, changes in markers of nephrotoxicity (high urinary concentrations of total protein, RBP and CC16, as well as GSTα and LDH increased activities) suggested the occurrence of discrete and early signs of impaired renal function for the discharge neighboring population.
Mostrar más [+] Menos [-]The impact of long term exposure to phthalic acid esters on reproduction in Chinese rare minnow (Gobiocypris rarus) Texto completo
2015
Guo, Yongyong | Yang, Yuanjin | Gao, Yong | Wang, Xianfeng | Zhou, Bingsheng
The environmental risk of phthalic acid esters (PAEs) is of great concern. We investigated the reproductive impairment of di-(2-ethylhexyl)-phthalate (DEHP) on Chinese rare minnow, an endemic fish inhabiting the upper streams of the Yangtze River. Chinese rare minnow larvae were exposed to environmentally relevant concentrations of DEHP (0, 4.2, 13.3, and 40.8 μg/L) for 6 months. Plasma testosterone and 17β-estradiol levels decreased in females, accompanied by downregulation of cyp19a and cyp17 gene transcription in ovary. Increases in plasma testosterone concentration were observed in males, accompanied by downregulation of cyp19a gene transcription in testes. Hepatic VTG gene transcription was upregulated in males and females. Exposure to DEHP reduced egg production and inhibited oocyte maturation in females and retarded spermiation in males. Decreased egg protein content was measured in F1 embryos. These results indicate that long-term exposure to low concentrations of DEHP (13.3 μg/L) causes endocrine disruption and impairs fish reproduction.
Mostrar más [+] Menos [-]Urban rivers as hotspots of regional nitrogen pollution Texto completo
2015
Zhang, Xiaohong | Wu, Yiyun | Gu, Baojing
Excess nitrogen inputs to terrestrial ecosystems via human activities have deteriorated water qualities on regional scales. Urban areas as settlements of over half global population, however, were usually not considered in the analysis of regional water pollution. Here, we used a 72-month monitoring data of water qualities in Hangzhou, China to test the role of urban rives in regional nitrogen pollution and how they response to the changes of human activities. Concentrations of ammonium nitrogen in urban rivers were 3–5 times higher than that in regional rivers. Urban rivers have become pools of reactive nitrogen and hotspots of regional pollution. Moreover, this river pollution is not being measured by current surface water monitoring networks that are designed to measure broader regional patterns, resulting in an underestimation of regional pollution. This is crucial to urban environment not only in China, but also in other countries, where urban rivers are seriously polluted.
Mostrar más [+] Menos [-]Spatial analysis of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (Sea-Nine 211) concentrations and probabilistic risk to marine organisms in Hiroshima Bay, Japan Texto completo
2015
Mochida, Kazuhiko | Hano, Takeshi | Onduka, Toshimitsu | Ichihashi, Hideki | Amano, Haruna | Ito, Mana | Ito, Katsutoshi | Tanaka, Hiroyuki | Fujii, Kazunori
We analyzed the spatial distribution of an antifouling biocide, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (Sea-Nine 211) in the surface water and sediments of Hiroshima Bay, Japan to determine the extent of contamination by this biocide. A quantitative estimate of the environmental concentration distribution (ECD) and species sensitivity distributions (SSDs) for marine organisms were derived by using a Bayesian statistical model to carry out a probabilistic ecological risk analysis, such as calculation of the expected potentially affected fraction (EPAF). The spatial distribution analysis supported the notion that Sea-Nine 211 is used mainly for treatment of ship hulls in Japan. The calculated EPAF suggests that approximately up to a maximum of 0.45% of marine species are influenced by the toxicity of Sea-Nine 211 in Hiroshima Bay. In addition, estimation of the ecological risk with a conventional risk quotient method indicated that the risk was a cause for concern in Hiroshima Bay.
Mostrar más [+] Menos [-]Exposure to environmentally-relevant levels of ozone negatively influence pollen and fruit development Texto completo
2015
Gillespie, Colin | Stabler, Daniel | Tallentire, Eva | Goumenaki, Eleni | Barnes, Jeremy
A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions – pollen originating from plants raised in charcoal-Purafil® filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O3. The O3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O3 × CFA and CFA × O3 crossed plants. This suggests O3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol−1 O3 (10 h d−1) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit – a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O3, and potentially other gaseous pollutants, on reproductive biology during ‘risk assessment’ exercises.
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