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671.
Wanqi Qi Weiying Li Junpeng Zhang Xuan Wu Jie Zhang Wei Zhang 《Frontiers of Environmental Science & Engineering》2019,13(1):15
672.
Seasonal changes in river water chemistry and in soil atmospheric CO2 concentrations at two depths and drainage water solute composition at two upland peaty podzol sites in north east Scotland were monitored over 12 months. the CO2 concentrations were controlled by changes in soil temperature and moisture status. Highest CO2 concentrations were observed in late summer 1988 when both soil temperatures and the moisture status of the soils were high. Then maximum CO2 concentrations of 4% (v/v) were recorded for one of the sites. No significant correlations between seasonal changes in soil CO2 concentrations and river water solute composition were observed. Nevertheless the field results and laboratory experiments indicated that in upland areas, where soils with acid surface horizons are common, soil CO2 substantially influences river water chemistry at baseflow, increasing the pH and cation concentration of the soil water draining into the river. the results suggest that transfer of carbon as dissolved CO2 in drainage water is a significant pathway for CO2 transfer to the atmosphere. 相似文献
673.
Approximately 37% of forestlands in the conterminous United States are publicly owned; they represent a substantial area of potential carbon sequestration in US forests and in forest products. However, large areas of public forestlands traditionally have been less intensively inventoried than privately owned forests. Thus, less information is available about their role as carbon sinks. We present estimates of carbon budgets on public forestlands of the 48 conterminous states, along with a discussion of the assumptions necessary to make such estimates. The forest carbon budget simulation model, FORCARB2, makes estimates for US forests primarily based on inventory data. We discuss methods to develop consistent carbon budget estimates from inventory data at varying levels of detail. Total carbon stored on public forestlands in the conterminous US increased from 16.3 Gt in 1953 to the present total of 19.5 Gt, while area increased from 87.1 million hactares to 92.1 million hactares. At the same time the proportion of carbon on public forestlands relative to all forests increased from 35% to 37%. Projections for the next 40 years depend on scenarios of management influences on growth and harvest.This article was written and prepared by US Government employees on official time, and it is therefore in the public domain and not subject to copyright. 相似文献
674.
A Brief Overview of Carbon Sequestration Economics and Policy 总被引:2,自引:0,他引:2
Richards KR 《Environmental management》2004,33(4):545-558
This article provides an overview of the issues and challenges involved in analyzing the costs and program design for carbon sequestration. The first section examines some of the pitfalls of comparing the results of carbon sequestration cost studies and suggests some simple ways in which analysts could make their results more useful. The pitfalls in comparing studies include different definitions for the summary statistic dollars per ton, differences in the type of costs that are estimated, and differences in underlying assumptions regarding program design and implementation. Future cost studies will benefit from improved treatment of leakage, general equilibrium interactions, and public finance interactions. The second section reviews issues related to the implementation of a carbon sequestration program, including which policy tools are available and which have received the most attention, some of the challenges for using those policy tools, and one alternative that has received little attention, but may become necessary. The discussion also provides an overview and analysis of the bills introduced in the last two congresses and considers the general policy implications of those proposals. 相似文献
675.
液化石油气瓶站气体泄漏爆炸危险性研究 总被引:2,自引:4,他引:2
针对某个城市居民区的液化气瓶站,采用数值模拟方法计算在液化气钢瓶发生泄漏后,液化石油气发生爆炸对瓶站和周围建筑的冲击波和温度的影响;分析冲击波对建筑可能造成的损坏情况;根据模拟分析结果,提出了改进液化气瓶站安全性的技术措施。笔者计算和分析的结果及提出的安全技术措施,为保障周围建筑和人员安全提供了技术依据。 相似文献
676.
Many revegetated landfills have poor cover including bare areas where plants do not grow. This study, on the Bisasar Road Landfill site in South Africa, assessed grass species preferences to microhabitat conditions in a mosaic of patches of well-established grassed areas and bare, nonvegetated areas. Factors, including soil CO2, CH4, O2, nutrients, and other general soil conditions, were measured in relation to species distribution and grass biomass in the field. Cynodon dactylon was the dominant grass in the established grass areas but was less abundant in the areas bordering the bare areas where Paspalum paspalodes and Sporobolus africanus were common. A number of soil factors measured were significantly correlated with grass biomass and these included Mg, Ca, Zn, Mn, K, temperature, moisture, and CO2. However, a laboratory bioassay using the growth of C. dactylon with soils removed from the landfill indicated that there were no differences in the soils from the bare areas and those that supported high plant biomass. Thus, no nutrient deficiency or chemical toxicity was inherent in the soil in the laboratory. The results of the field investigation and bioassay indicated that soil CO2 as a result of landfill gas infiltration into the root zone was probably the main factor causing bare areas on the landfill where no grass species could colonize and grow and that C. dactylon was more sensitive to elevated soil CO2 than other grass species such as P. paspalodes and S. africanus. 相似文献
677.
678.
Effects of Recreational Impacts on Soil Microbial Communities 总被引:51,自引:0,他引:51
/ The functional diversity of soil microbial communities in heavilyimpacted subalpine campsites and adjacent undisturbed areas was comparedusing the Biolog method of carbon utilization profiles. Principal componentsanalysis of patterns and level of microbial activity indicate that microbialcommunities differentiate in response to disturbance in the top 6 cm of soil,while below 6 cm there were no recognizable differences between disturbed andundisturbed soil communities. Analysis of the factors that differentiate theupper microbial communities between disturbed and undisturbed sites revealedthat the percent of total carbon sources utilized was significantly less inthe disturbed (54%) than in undisturbed areas (95%). Carbonsubstrates important in the discrimination between soil communities includeplant, invertebrate, and microbial derivatives that could not be metabolizedby microbial communities from disturbed sites. Comparisons of totalculturable actinomycetes, bacteria, and fungi reveal no difference in overallnumber of colony forming units (CFU) on disturbed and undisturbed sites, buta marked decrease in actinomycetes on disturbed sites. Biolog andspread-plate data combined indicate a shift in the structure and function ofthe microbial community in campsite soils, which may be a useful indicator ofsoil community disturbance.KEY WORDS: Microbial functional diversity; Anthropogenic disturbance;Recreational impacts; Carbon source profile; Subalpine 相似文献
679.
680.
针对油田开发建设中地面管线及容器等设备的腐蚀、老化、穿孔等问题,以生产和环保为基点,介绍了快速带压堵漏技术在中原油田集输管网上的应用,提出6种快速带压技术,并详述了其优缺点。 相似文献