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581.
This paper examines the relevance to groundwater management of Ostrom’s design principles for managing common property resources.
Experience in four case studies of groundwater management in the Murray Darling Basin in Australia and the Upper Guadiana
Basin in Spain suggests that while Ostrom’s design principles are relevant, sustainable groundwater management depends on
the effective collaboration between government authorities and water users. A flexible and adaptive management approach is
required, with collaboration between scientists, policy makers, water suppliers, and water users. Key management challenges
include agreeing on a sustainable level of extraction, and establishing effective coordination and collaboration, and monitoring
and control systems. Further case studies of groundwater management and their synthesis could make a useful contribution to
the transition towards sustainable groundwater management regimes. 相似文献
582.
The growing interest in geologic carbon sequestration has highlighted the need for more data on how well cements react to CO2 exposure. This paper describes a series of experiments that was conducted to examine the effects of flowing carbonated brine on well cements. Class H cement pastes were exposed to the ranges of temperature (20–50 °C) and pH (2.4–5) characteristic of geosequestration conditions at a depth of about 1 km. The exposed cements and the reactor effluents were analyzed using multiple techniques including optical microscopy, X-ray diffraction, EPMA, and ICP-OES. The results showed that if the solution was pre-equilibrated with calcium carbonate, as would be expected in a limestone formation, there was no detectable attack. However, under the pH and temperature conditions to be expected in a sandstone formation, the initial rate of attack was on the order of millimeters per month. The outer layers of the cements reacted under sandstone-like conditions were fully degraded based on the results of the XRD and EPMA analyses. Inside the degraded layers there was a calcium carbonate-rich layer, a layer depleted of calcium hydroxide, and an unreacted cement core. The rate of degradation of the cement in these experiments was controlled by the rate of dissolution of the calcium carbonate-rich layer, after its formation, and diffusion through the fully degraded layers. 相似文献
583.
Simon A. Mathias Jon G. Gluyas Curtis M. Oldenburg Chin-Fu Tsang 《International Journal of Greenhouse Gas Control》2010,4(5):806-810
Mathematical tools are needed to screen out sites where Joule–Thomson cooling is a prohibitive factor for CO2 geo-sequestration and to design approaches to mitigate the effect. In this paper, a simple analytical solution is developed by invoking steady-state flow and constant thermophysical properties. The analytical solution allows fast evaluation of spatiotemporal temperature fields, resulting from constant-rate CO2 injection. The applicability of the analytical solution is demonstrated by comparison with non-isothermal simulation results from the reservoir simulator TOUGH2. Analysis confirms that for an injection rate of 3 kg s?1 (0.1 MT yr?1) into moderately warm (>40 °C) and permeable formations (>10?14 m2 (10 mD)), JTC is unlikely to be a problem for initial reservoir pressures as low as 2 MPa (290 psi). 相似文献
584.
S. Kent Hoekman Amber Broch Curtis Robbins Richard Purcell 《International Journal of Greenhouse Gas Control》2010,4(1):44-50
A laboratory-scale reactor system was built and operated to demonstrate the feasibility of catalytically reacting carbon dioxide (CO2) with renewably-generated hydrogen (H2) to produce methane (CH4) according to the Sabatier reaction: CO2 + 4H2 → CH4 + 2H2O. A cylindrical reaction vessel packed with a commercial methanation catalyst (Haldor Topsøe PK-7R) was used. Renewable H2 produced by electrolysis of water (from solar- and wind-generated electricity) was fed into the reactor along with a custom blend of 2% CO2 in N2, meant to represent a synthetic exhaust mixture. Reaction conditions of temperature, flow rates, and gas mixing ratios were varied to determine optimum performance. The extent of reaction was monitored by real-time measurement of CO2 and CH4. Maximum conversion of CO2 occurred at 300–350 °C. Approximately 60% conversion of CO2 was realized at a space velocity of about 10,000 h?1 with a molar ratio of H2/CO2 of 4/1. Somewhat higher total CO2 conversion was possible by increasing the H2/CO2 ratio, but the most efficient use of available H2 occurs at a lower H2/CO2 ratio. 相似文献
585.
Bon-Jun Koo Andrew C. Chang Thomas C. Granato 《Environmental pollution (Barking, Essex : 1987)》2010,158(8):2582-574
Organic acids present in the rhizosphere of growing plants are widely recognized to be responsible for dissolving the solid phase metals in the soil and making them available for plant absorption. We proposed a root exudates-based model to assess the long-term phytoavailability of metals in biosolids-amended soils. The phytoavailability of biosolids-borne metals was defined in terms of a capacity factor and an intensity factor. The plant available metal pool, C0 (capacity factor, mg kg−1), can be estimated by fitting the successive organic acids extraction data to an exponential decay kinetic equation. The field metal removal rate, k (intensity factor, yr−1), can be estimated from the successive extraction-based metal release rate through an effective annual organic acid production in the rhizosphere which was found to be characteristic of plant species. The protocol was successfully used to assess the long-term phytoavailability of metals in biosolids-amended soil from two biosolids land application sites. 相似文献
586.
587.
Elizabeth A. Stone Curtis J. Hedman Jiabin Zhou Mark Mieritz James J. Schauer 《Atmospheric environment (Oxford, England : 1994)》2010,44(3):312-319
This study targets understanding the secondary sources of organic aerosol in Mexico City during the Megacities Impact on Regional and Global Environment (MIRAGE) 2006 field campaign. Ambient PM2.5 was collected daily at urban and peripheral locations. Particle-phase secondary organic aerosol (SOA) products of anthropogenic and biogenic precursor gases were measured by gas chromatography mass spectrometry. Ambient concentrations of SOA tracers were used to estimate organic carbon (OC) from secondary origins (SOC). Anthropogenic SOC was estimated as 20–25% of ambient OC at both sites, while biogenic SOC was less abundant, but was relatively twice as important at the peripheral site. The OC that was not attributed secondary sources or to primary sources in a previous study showed temporal consistency with biomass-burning events, suggesting the importance of secondary processing of biomass-burning emissions in the region. The best estimate of biomass-burning-related SOC was in the range of 20–30% of ambient OC during peak biomass burning events. Low-molecular weight (MW) alkanoic and alkenoic dicarboxylic acids (C2–C5) were also measured, of which oxalic acid was the most abundant. The spatial and temporal trends of oxalic acid differed from tracers for primary and secondary sources, suggesting that it had different and/or multiple sources in the atmosphere. 相似文献
588.
Mae A. Davenport Christopher A. Bridges Jean C. Mangun Andrew D. Carver Karl W. J. Williard Elizabeth O. Jones 《Environmental management》2010,45(4):711-722
Natural resource professionals are increasingly faced with the challenges of cultivating community-based support for wetland
ecosystem restoration. While extensive research efforts have been directed toward understanding the biophysical dimensions
of wetland conservation, the literature provides less guidance on how to successfully integrate community stakeholders into
restoration planning. Therefore, this study explores the social construction of wetlands locally, and community members’ perceptions
of the wetland restoration project in the Cache River Watershed of southern Illinois, where public and private agencies have
partnered together to implement a large-scale wetlands restoration project. Findings illustrate that the wetlands hold diverse
and significant meanings to community members and that community members’ criteria for project success may vary from those
identified by project managers. The case study provides managers with strategies for building community commitment such as
engaging local citizens in project planning, minimizing local burdens, maximizing local benefits, and reducing uncertainty. 相似文献
589.
Extensive research has been conducted globally into conceptual frameworks for ecosystem services, the most notable being the
Millennium Ecosystem Assessment (Millennium ecosystem assessment: ecosystems and human well-being; a framework for assessment.
World Resources Institute, Washington, DC, pp 51, 53–55, 2005). The South East Queensland (SEQ) Ecosystem Services Framework (Australia) aims to provide the tools to enable government,
industry, business, researchers, non-government organizations and land managers to apply the concept of ecosystem services
in their planning and management practices. This article describes the Framework and the process that has produced matrices
and maps that identify and illustrate the linkages between ecosystems, ecosystem functions, ecosystem services and the community’s
well-being. The matrices and maps derived can identify areas in the region where the most ecosystem services are generated.
This allows areas to be considered as valuable natural assets of the region, deserving appropriate protection measures or
significant offsets if they are diminished or degraded in any way. Although the Framework requires further refinement and
ongoing development, the process applied and the products produced has enabled decision makers to turn the concept of ecosystem
services into practical application in SEQ. 相似文献
590.
Andrew P. Barnes 《Regional Environmental Change》2016,16(8):2269-2278
Full-scale technical potential provides a clear horizon for agricultural technology policy to meet the dual and urgent challenge of meeting food security and minimising the effects of climate change. A common stated goal is to double food production by 2050 to meet the needs of 9 billion people. The frontier of full-scale technical potential embodies this goal and provides a panacea for policy makers. However, the pathway between the present adoption of technologies towards this frontier is paved with some hazards which may be insurmountable. We develop a conceptual framework based on adoption levels of technology. The key criteria between current and potential adoption of technologies is the role of enablers, that is interventions which create changes in structural, distributional, technical, social and behavioural cultures. Policy must find optimal mixtures of regulation and voluntary mechanisms to fully encourage uptake of technologies and shift current adoption to meet full-scale technical potential. A range of technologies can be aligned with sustainable intensification and are examined in terms of this enabler framework. Further examination of the framework allows us to conclude that full-scale technical potential will never be achieved due to the stochastic nature of agricultural production, the diversity of motivations and institutional structures operating within food supply chains, as well as unbalanced cost-effectiveness criteria. We argue that sustainable intensification may provide a direction of travel for attaining food security but its poor conception, limited acceptability and understanding amongst the communities of interest lead to over-optimism in determining the journey to this final destination. 相似文献