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111.
Laboratory and field experiments were performed to evaluate integrative measurement methods for atmospheric nitrates, sulphate and sulphur dioxide. Denuder tubes and several filter media were tested under laboratory and field conditions. Effects of sampling variables such as temperature and relative humidity, flow rates, concentration, loading capacity and artifacts due to NO, NO2 and SO2 were also evaluated. The integrative filter sampling method and the ion chromatographic analytical procedure gave a measurement precision (relative standard deviation) of ±11.5 percent for particulate NO3 ? on Teflon and ±15.6 percent for gaseous HNO3 on nylon; for both these constituents, the detection limit was about 0.1 μ m?3.  相似文献   
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Ecosystem-based Management (EBM) is an approach that includes different management priorities and requires a balance between anthropogenic and ecological resource demands. Indicators can be used to monitor ecosystem status and trends, and assess whether projects and/or programs are leading to the achievement of management goals. As such, the careful selection of a suite of indicators is a crucial exercise. In this paper we describe an indicator evaluation and selection process designed to support the EBM approach in Puget Sound. The first step in this process was the development of a general framework for selecting indicators. The framework, designed to transparently include both scientific and policy considerations into the selection and evaluation process, was developed and then utilized in the organization and determination of a preliminary set of indicators. Next, the indicators were assessed against a set of nineteen distinct criteria that describe the model characteristics of an indicator. A literature review was performed for each indicator to determine the extent to which it satisfied each of the evaluation criteria. The result of each literature review was summarized in a numerical matrix, allowing comparison, and demonstrating the extent of scientific reliability. Finally, an approach for ranking indicators was developed to explore the effects of intended purpose on indicator selection. We identified several sets of scientifically valid and policy-relevant indicators that included metrics such as annual-7 day low flow and water system reliability, which are supportive of the EBM approach in the Puget Sound.  相似文献   
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Following a global trend, the new policy goals emphasize the need to protect rather than to use the ability of ecosystems to recover from disturbances. This necessitates the adoption of response measurements to quantify ecological condition and monitor ecological change. Response monitoring focuses on properties that are essential to the sustainability of the ecosystem. These monitoring tools can be used to establish natural ranges of ecological change within ecosystems, as well as to quantify conceptually acceptable and unacceptable ranges of change. Through a framework of biological criteria and biological impairment standards, the results of response monitoring can become an integral part of future water resource management strategies in South Africa.  相似文献   
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Summary The attraction of Old World leaf beetles in the genusAulacophora to kairomones and parakairomones which are effective lures for New WorldDiabrotica andAcalymma were investigated. Beetles captured on sticky traps baited with single and multicomponent lures were no different from the control traps for two species ofAulacophora. Yellow colored traps and squash blossoms are attractive toAulacophora beetles which detect sub-microgram quantities of cucurbitacins on silica gel. Leaf feeding behavior and flight activity data are correlated with varietal preference of threeAulacophora species. The common response byDiabrotica andAulacophora to cucurbitacins reinforces the two groups' coevolutionary association with the Cucurbitaceae. The apparent lack of a common response toCucurbita blossom volatiles suggests recent evolutionary pathways are substantially different for these two groups of beetles.  相似文献   
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Much has been said and written in recent years about the greatly increased difficulties faced by the mining industry in meeting the expectations of local communities and in adequately protecting the natural environment. The impression is often given that the industry was completely oblivious of such concerns and needs until the present decade, and that it is now struggling to make up for past neglect. Certainly the standards required by society as a whole have risen, and there is more public discussion than in earlier times, but the managements of many major mining companies have long been fully aware of their obligations to the environment and local communities. To argue otherwise would be to misread the history of the industry and to perform a grave disservice to many dedicated managers of the mining projects of former years.  相似文献   
117.
The known chemical basis of diverse avian eggshell coloration is generated by the same two classes of tetrapyrrole pigments in most living birds. We aimed to extend the evolutionary scope of these patterns by detecting pigments from extinct birds’ eggs. In our samples biliverdin was successfully extracted from subfossil shell fragments of the blue-green egg-laying upland moa Megalapteryx didinus, while protoporphyrin was extracted from the beige eggs of two other extinct moa species. Our data on pigment detection from eggshells of other extant paleognath birds, together with published information on other modern lineages, confirm tetrapyrroles as ubiquitous and conserved pigments contributing to diverse eggshell colours throughout avian evolution.  相似文献   
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The microbial degradation of poly (3-hydroxyalkanoates) (PHAs) under anaerobic conditions with various terminal electron acceptors was examined. Nitrate-reducing consortia were established using activated sludge, and PHAs were shown to be biodegradable under these conditions. A positive correlation between carbon dioxide production and nitrate reduction was demonstrated. Nitrous oxide accumulated as the main N-containing product of nitrate reduction. The amount of PHAs in activated sludge cultures decreased approximately 20% within 40 days of incubation. Attempts were made to establish iron- and sulfate-reducing consortia from spring water, yet it could not be demonstrated that the mixed cultures were capable of degrading PHAs. Pure cultures of iron- and sulfate-reducing bacteria could not utilize PHAs as sole carbon sources. Methanogenic environments sampled included pond sediment and rumen fluid. PHAs were fermented to methane and carbon dioxide after 10 weeks by a sediment consortium, with 43 to 57% of the substrate carbon transformed to methane. Although it could not be demonstrated that PHAs were biodegraded by a rumen fluid consortium, a facultative anaerobic bacterium, identified as aStaphylococcus sp., that could grow on PHAs was isolated from rumen fluid.  相似文献   
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