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881.
盐害(包括土壤次生盐渍化)造成的日益严重的环境问题已在世界范围内引起了广泛关注。大量针对植物耐盐分子机制的研究已开展,旨在更好地了解植物自身的耐盐机制。到目前为止,已获取了大量关于植物耐盐性机制的信息。同时,人们正在形成一个共识,即植物维持自身细胞离子平衡的能力是其具有耐盐性的关键。Na^+/H^+、K^+/H^+和Na^+/K^+逆向转运蛋白及其同源蛋自在植物细胞维持离子平衡中的关键作用受到了人们越来越多的关注。结合前人的研究结果和最新的研究动态,着重阐述了Na^+转运控制和维持细胞离子平衡在植物耐盐过程中的机理及其重要作用。 相似文献
882.
基于联合国环境规划署于2011年年底面向全球发布的《中国2010年上海世博会环境后评估》报告,全面总结了世博会在选址、规划、建设、运营和后续利用等全过程探索应用的低碳理念和宝贵实践,系统提出了"低碳世博"对城市未来发展的启示和借鉴,为国内外发展中城市和其他大型活动的组织实施提供了有益参考。 相似文献
883.
Elodie Jeandel Anne Battani Philippe Sarda 《International Journal of Greenhouse Gas Control》2010,4(6):890-909
The deployment of CCS (carbon capture and storage) at industrial scale implies the development of effective monitoring tools. Noble gases are tracers usually proposed to track CO2. This methodology, combined with the geochemistry of carbon isotopes, has been tested on available analogues.At first, gases from natural analogues were sampled in the Colorado Plateau and in the French carbogaseous provinces, in both well-confined and leaking-sites. Second, we performed a 2-years tracing experience on an underground natural gas storage, sampling gas each month during injection and withdrawal periods.In natural analogues, the geochemical fingerprints are dependent on the containment criterion and on the geological context, giving tools to detect a leakage of deep-CO2 toward surface. This study also provides information on the origin of CO2, as well as residence time of fluids within the crust and clues on the physico-chemical processes occurring during the geological story.The study on the industrial analogue demonstrates the feasibility of using noble gases as tracers of CO2. Withdrawn gases follow geochemical trends coherent with mixing processes between injected gas end-members. Physico-chemical processes revealed by the tracing occur at transient state.These two complementary studies proved the interest of geochemical monitoring to survey the CO2 behaviour, and gave information on its use. 相似文献
884.
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886.
Radon-222 and carbon dioxide concentrations have been measured during several years at several points in the atmosphere of an underground limestone quarry located at a depth of 18 m in Vincennes, near Paris, France. Both concentrations showed a seasonal cycle. Radon concentration varied from 1200 to 2000 Bq m−3 in summer to about 800-1400 Bq m−3 in winter, indicating winter ventilation rates varying from 0.6 to 2.5 × 10−6 s−1. Carbon dioxide concentration varied from 0.9 to 1.0% in summer, to about 0.1-0.3% in winter. Radon concentration can be corrected for natural ventilation using temperature measurements. The obtained model also accounts for the measured seasonal variation of carbon dioxide. After correction, radon concentrations still exhibit significant temporal variation, mostly associated with the variation of atmospheric pressure, with coupling coefficients varying from −7 to −26 Bq m−3 hPa−1. This variation can be accounted for using a barometric pumping model, coupled with natural ventilation in winter, and including internal mixing as well. After correction, radon concentrations exhibit residual temporal variation, poorly correlated between different points, with standard deviations varying from 3 to 6%. This study shows that temporal variation of radon concentrations in underground cavities can be understood to a satisfactory level of detail using non-linear and time-dependent modelling. It is important to understand the temporal variation of radon concentrations and the limitations in their modelling to monitor the properties of natural or artificial underground settings, and to be able to assess the existence of new processes, for example associated with the preparatory phases of volcanic eruptions or earthquakes. 相似文献
887.
盐害(包括土壤次生盐渍化)造成的日益严重的环境问题已在世界范围内引起了广泛关注。大量针对植物耐盐分子机制的研究已开展,旨在更好地了解植物自身的耐盐机制。到目前为止,已获取了大量关于植物耐盐性机制的信息。同时,人们正在形成一个共识,即植物维持自身细胞离子平衡的能力是其具有耐盐性的关键。Na+/H+、K+/H+和Na+/K+逆向转运蛋白及其同源蛋白在植物细胞维持离子平衡中的关键作用受到了人们越来越多的关注。结合前人的研究结果和最新的研究动态,着重阐述了Na+转运控制和维持细胞离子平衡在植物耐盐过程中的机理及其重要作用。 相似文献
888.
Responses of CH(4), CO(2) and N(2)O fluxes to increasing nitrogen deposition in alpine grassland of the Tianshan Mountains 总被引:2,自引:0,他引:2
To assess the effects of nitrogen (N) deposition on greenhouse gas (GHG) fluxes in alpine grassland of the Tianshan Mountains in central Asia, CH4, CO2 and N2O fluxes were measured from June 2010 to May 2011. Nitrogen deposition tended to significantly increase CH4 uptake, CO2 and N2O emissions at sites receiving N addition compared with those at site without N addition during the growing season, but no significant differences were found for all sites outside the growing season. Air temperature, soil temperature and water content were the important factors that influence CO2 and N2O emissions at year-round scale, indicating that increased temperature and precipitation in the future will exert greater impacts on CO2 and N2O emissions in the alpine grassland. In addition, plant coverage in July was also positively correlated with CO2 and N2O emissions under elevated N deposition rates. The present study will deepen our understanding of N deposition impacts on GHG balance in the alpine grassland ecosystem, and help us assess the global N effects, parameterize Earth System models and inform decision makers. 相似文献
889.
Biomineralization-based conversion of carbon dioxide to calcium carbonate using recombinant carbonic anhydrase 总被引:1,自引:0,他引:1
Recently, as a mimic of the natural biomineralization process, the use of carbonic anhydrase (CA), which is an enzyme catalyzing fast reversible hydration of carbon dioxide to bicarbonate, has been suggested for biological conversion of CO2 to valuable chemicals. While purified bovine CA (BCA) has been used in previous studies, its practical utilization in CO2 conversion has been limited due to the expense of BCA preparation. In the present work, we investigated conversion of CO2 into calcium carbonate as a target carbonate mineral by using a more economical, recombinant CA. To our knowledge, this is the first report of the usage of recombinant CA for biological CO2 conversion. Recombinant α-type CA originating in Neisseria gonorrhoeae (NCA) was highly expressed as a soluble form in Escherichia coli. We found that purified recombinant NCA which showed comparable CO2 hydration activity to commercial BCA significantly promoted formation of solid CaCO3 through the acceleration of CO2 hydration rate, which is naturally slow. In addition, the rate of calcite crystal formation was also accelerated using recombinant NCA. Moreover, non-purified crude recombinant NCA also showed relatively significant ability. Therefore, recombinant CA could be an effective, economical biocatalyst in practical CO2 conversion system. 相似文献
890.
Interaction of engineered nanoparticles with various components of the environment and possible strategies for their risk assessment 总被引:1,自引:0,他引:1
Nanoparticles are the materials with at least two dimensions between 1 and 100 nm. Mostly these nanoparticles are natural products but their tremendous commercial use has boosted the artificial synthesis of these particles (engineered nanoparticles). Accelerated production and use of these engineered nanoparticles may cause their release in the environment and facilitate the frequent interactions with biotic and abiotic components of the ecosystems. Despite remarkable commercial benefits, their presence in the nature may cause hazardous biological effects. Therefore, detail understanding of their sources, release interaction with environment, and possible risk assessment would provide a basis for safer use of engineered nanoparticles with minimal or no hazardous impact on environment. Keeping all these points in mind the present review provides updated information on various aspects, e.g. sources, different types, synthesis, interaction with environment, possible strategies for risk management of engineered nanoparticles. 相似文献