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31.
Influence of biochar on nitrogen fractions in a coastal plain soil   总被引:3,自引:0,他引:3  
Interest in the use of biochar from pyrolysis of biomass to sequester C and improve soil productivity has increased; however, variability in physical and chemical characteristics raises concerns about effects on soil processes. Of particular concern is the effect of biochar on soil N dynamics. The effect of biochar on N dynamics was evaluated in a Norfolk loamy sand with and without NHNO. High-temperature (HT) (≥500°C) and low-temperature (LT) (≤400°C) biochars from peanut hull ( L.), pecan shell ( Wangenh. K. Koch), poultry litter (), and switchgrass ( L.) and a fast pyrolysis hardwood biochar (450-600°C) were evaluated. Changes in inorganic, mineralizable, resistant, and recalcitrant N fractions were determined after a 127-d incubation that included four leaching events. After 127 d, little evidence of increased inorganic N retention was found for any biochar treatments. The mineralizable N fraction did not increase, indicating that biochar addition did not stimulate microbial biomass. Decreases in the resistant N fraction were associated with the high pH and high ash biochars. Unidentified losses of N were observed with HT pecan shell, HT peanut hull, and HT and LT poultry litter biochars that had high pH and ash contents. Volatilization of N as NH in the presence of these biochars was confirmed in a separate short-term laboratory experiment. The observed responses to different biochars illustrate the need to characterize biochar quality and match it to soil type and land use.  相似文献   
32.
Operational discharges from oceangoing vessels, including discharges of bilgewater, release oil into marine ecosystems that can potentially damage marine life, terrestrial life, human health, and the environment. Bilgewater is a mix of oily fluids and other pollutants from a variety of sources onboard a vessel. If bilgewater cannot be retained onboard, it must be treated by an oily water separator before discharge for larger ocean-going vessels. We evaluated the effectiveness of bilgewater treatment systems by analyzing land-based type approval data, collecting and analyzing shipboard bilgewater effluent data, assessing bilgewater effluent concentrations compared to regulatory standards, evaluating the accuracy of shipboard oil content monitors relative to analytical results, and assessing additional pollution reduction benefits of treatment systems. Land-based type approval data were gathered for 20 treatment systems. Additionally, multiple samples of influent and effluent from operational bilgewater treatment systems onboard three vessels were collected and analyzed, and compared to the land-based type approval data. Based on type approval data, 15 treatment systems were performing below 5 ppm oil. Shipboard performance measurements verified land-based type approval data for the three systems that were sampled. However, oil content monitor readings were more variable than actual oil concentration measurements from effluent samples, resulting in false negatives and positives. The treatment systems sampled onboard for this study generally reduced the majority of other potentially harmful pollutants, which are not currently regulated, with the exception of some heavy metal analytes.  相似文献   
33.
Ten common mistakes in designing biodiversity indicators for forest policy   总被引:2,自引:0,他引:2  
This paper identifies 10 common 'mistakes' in developing and using forest biodiversity indicators from the standpoint of making better forest management choices. The mistakes relate to a failure to clarify the values-basis for indicator selection and a failure to integrate science and values to design indicators that are concise, relevant and meaningful to decision makers. The combined effects of these ten mistakes include inconsistent and indefensible on-ground management strategies and hidden trade-offs at a policy level. They result in frustrated professionals, a confused public, an inability to assess performance with respect to key forest policy objectives and, almost certainly, types and amounts of biodiversity conservation that fail to achieve either scientifically or socially preferred levels. Correcting the mistakes will help to address these problems and, more generally, recognizes the need to better understand the interface between science, public values, and decision making.  相似文献   
34.
Globally, the issue of energy use and climate change is at the forefront of many national and international agendas, and also an issue central to children's lives and well-being. This paper examines how children are both affected by and contribute to the problems associated with unsustainable energy use as it relates to the growth of car dependent lives. The paper presents the findings of a study of travel as it relates to the everyday lives of children in the city of Dunedin in New Zealand. The study found that children currently lead complex car dependent lives. This extensive car reliance presents a serious and largely unrecognised challenge to the sustainable planning and management of the urban environment. The move towards more sustainable transportation can bring benefits for both the environment and for children's lives.  相似文献   
35.
Abstract

A number of cities around the world are associated with very high levels of private motor car usage, and Auckland provides an example of one of these ‘hyperautomobile’ cities. There are many problems with this system of transportation and dependence on the private car, including environmental, social and city design dimensions. Though there is a clear aspiration to move towards reduced levels of car usage in the city's transport and spatial planning strategies, there are major difficulties in implementation terms. We develop and consider future scenarios to 2041 to reduce these levels of motorization, and subsequent transport CO2 emissions, with a much greater use of public transport, walking and cycling, urban planning, and low emission vehicles. The current implementability of such a ‘sustainable mobility’ future is however questioned in the current political and social context, and critically debated in terms of the available governance mechanisms and the limited attempts to shape the behaviour of the public. We conclude by calling for a reconsideration of the policy measures being considered, including the range and levels of application and investment; with a much wider framing of the transport planning remit, and carried out within a much stronger participatory framework for decision-making.  相似文献   
36.
In areas where rivers have been altered and regulated through dams, the effect on wetland ecosystems can lead to 'wastage' of the land as natural systems are destroyed. In response to the effects of streamflow regulation on a wetland near the city of Albury, on the Murray River, the development of the Wonga Wetlands and associated site rehabilitation addresses two key issues: wasteland and waste water. A Community Advisory Committee has been actively and directly involved in the project, initiated and implemented by the Albury City Council, to restore an area of original wetland into a community ecological resource that utilises 100% of the domestic, commercial and industrial urban 'waste' water from the city's water treatment plant. This project represents a significant direction in the way communities and local governments approach resource recovery. This paper analyses the Wonga Wetlands project from the perspective of sustainable management of waste in terms of water resources and presents it as a model for community-based environmental application and long-term resource sustainability.  相似文献   
37.
Accurate spatial representation of climatic patterns is often a challenge in modeling biophysical processes at the watershed scale, especially where the representation of a spatial gradient in rainfall is not sufficiently captured by the number of weather stations. The spatial rainfall generator (SRGEN) is developed as an extension of the “weather generator” (WXGEN), a component of the Agricultural Policy/Environmental eXtender (APEX) model. SRGEN generates spatially distributed daily rainfall using monthly weather statistics available at multiple locations in a watershed. The spatial rainfall generator as incorporated in APEX is tested on the Cowhouse watershed (1,178 km2) in central Texas. The watershed presented a significant spatial rainfall gradient of 2.9 mm/km in the lateral (north‐south) directions based on four rainfall gages. A comparative analysis between SRGEN and WXGEN indicates that SRGEN performs well (PBIAS = 2.40%). Good results were obtained from APEX for streamflow (NSE = 0.99, PBIAS = 8.34%) and NO3‐N and soluble P loads (PBIAS ≈ 6.00% for each, respectively). However, APEX underpredicted sediment yield and organic N and P loads (PBIAS: 24.75‐27.90%) with SRGEN, although its uncertainty in output was lower than WXGEN results (PBIAS: ?13.02 to ?46.13%). The overall improvement achieved in rainfall generation by SRGEN is demonstrated to be effective in the improving model performance on flow and water quality output.  相似文献   
38.
Studies of urban metabolism provide important insights for environmental management of cities, but are not widely used in planning practice due to a mismatch of data scale and coverage. This paper introduces the Spatial Allocation of Material Flow Analysis (SAMFA) model as a potential decision support tool aimed as a contribution to overcome some of these difficulties and describes its pilot use at the county level in the Republic of Ireland. The results suggest that SAMFA is capable of identifying hotspots of higher material and energy use to support targeted planning initiatives, while its ability to visualise different policy scenarios supports more effective multi-stakeholder engagement. The paper evaluates this pilot use and sets out how this model can act as an analytical platform for the industrial ecology–spatial planning nexus.  相似文献   
39.
Recent molecular data strongly support the monophyly of all extant Australian and New Guinean marsupials (Eomarsupialia) to the exclusion of extant South American marsupials. This, together with available geological and fossil evidence, has been used to argue that the presence of marsupials in Australia is simply the result of a single dispersal event from South America during the latest Cretaceous or Palaeocene, without subsequent dispersals between the two continents. Here, I describe an isolated ankle bone (calcaneus) of a metatherian from the early Eocene Tingamarra Local Fauna in northeastern Australia. Strikingly, this specimen, QM F30060, lacks the ‘continuous lower ankle joint pattern’ (CLAJP), presence of which is a highly distinctive apomorphy of the marsupial clade Australidelphia, which includes Eomarsupialia, the living South American microbiotherian Dromiciops and the Tingamarran fossil marsupial Djarthia. Comparisons with a range of marsupials and stem-metatherians strongly suggest that the absence of the CLAJP in QM F30060 is plesiomorphic, and that this specimen represents the first unequivocal non-australidelphian (‘ameridelphian’) metatherian known from Australia. This interpretation is confirmed by phylogenetic analyses that place QM F30060 within (crown-group) Marsupialia, but outside Australidelphia. Based on these results, the distribution of marsupials within Gondwana cannot be explained by simply a single dispersal event from South America and Australia. Either there were multiple dispersals by marsupials (and possibly also stem-metatherians) between South America and Australia, in one or both directions, or, alternatively, there was a broadly similar metatherian fauna stretching across southern South America, Antarctica and Australia during the Late Cretaceous–early Palaeogene.  相似文献   
40.
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