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Environmental Science and Pollution Research - The objective of this work is to understand the fluctuating nature of wind speed characteristics on different time scales and to find the long-term...  相似文献   
164.
Air pollution has a deleterious impact on public health and the environment. There is few knowledge on the effect of air pollution on terrestrial microbial communities, despite the major role of microbes in ecosystems. Here, we designed an in situ trial ecosystem to assess the impact of moderate atmospheric pollution, below World Health Organization (WHO) thresholds, on an indigenous microbial communities, including bacteria, fungi, ciliates, algae, cyanobacteria, testate amoebae, rotifers and nematodes, extracted from terrestrial bryophytes. These micro-ecosystems were placed at a rural, an urban and an industrial site in France and were thus exposed to various levels of nitrogen dioxide (NO2), from 6.6–67.9 μg·m?3, and particulate matter, from 0.7–7.9 μg·m?3. Microbial analysis was performed by microscopy. We determined atmospheric temperature, relative humidity and particulate matter with diameter lower than 10 µm (PM10), Cu, Cr, Fe, Ni, Pb, Zn in PM10, and (NO2). Results show a significant impact of chronic moderate exposure to NO2 and copper Cu-associated particulate matter on the global microbial network complexity. This is evidenced by a loss of about 40 % of microbial co-occurrence links during incubation. Most lost microbial links are ecologically positive links. Moreover, most changes in community co-occurrence networks are related to testate amoebae, a major top predator of microbes. Overall, our findings demonstrate that air pollution can have strong deleterious effects on microbial interactions, even at levels below WHO thresholds.  相似文献   
165.
Competitiveness and carbon leakage are major concerns for the design of CO2 emissions permits markets. In the absence of a global carbon tax and of border carbon adjustments, output-based allocation is a third-best solution and is actually implemented (Australia, California, New Zealand). The EU has followed a different route; free allowances are allocated to existing or new capacities in proportion to a benchmark, independent of actual production. This paper compares these two schemes in a formal setting and shows that the optimal one is in fact a combination of both schemes, or output-based allocation alone if uncertainty is limited. A key assumption of our analysis is that the short-term import pressure depends both on the existing capacities and the level of demand, which is typical in capital intensive and internationally traded sectors. A calibration of the model is used to discuss the EU scheme for the cement sector in the third phase of the EU-ETS (2013–2020). This allows for a quantification of various policies in terms of welfare, investment, production, company profits, public revenues and leakage.  相似文献   
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Phylogenetic relationships within the copepod family Euchaetidae and between representatives of three copepod orders (Calanoida, Harpacticoida, and Poecilostomatoida) were investigated using partial nucleotide sequences of the mitochondrial 16S rRNA and the nuclear 28S rRNA genes. DNA isolation, polymerase chain reaction, cloning, and DNA sequencing techniques were customized for these crustaceans. Our results support the monophyly of each copepod order, but in contrast to traditional morphology-based phylogenies of copepod orders, the Poecilostomatoida are basal to the Calanoida and Harpacticoida on our DNA-based phylogenetic tree. Phylogenetic trees generated by maximum parsimony, neighbor-joining, and maximum-likelihood analyses support the classification of the genera Euchaeta and Paraeuchaeta in the family Euchaetidae; results, however, suggest that Euchaetaacuta Giesbrecht is more closely related to species of the genus Paraeuchaeta than to those of Euchaeta, although limited taxon sampling may be partially responsible for this result. Phylogenetic mapping using the most parsimonious 16S tree suggests that the morphological synapomorphies distinguishing the genus Euchaeta evolved independently twice during the history of the Euchaetidae. Further, phylogenetic mapping suggests that the most recent common ancestor of the Euchaetidae and the Aetideidae was a deep-living, vertically migrating copepod, and that a bathypelagic, vertically migrating lifestyle characteristic of Paraeuchaeta is an ancestral trait of the family Euchaetidae which was lost apomorphically by Euchaeta. The application of a molecular clock suggests that the sibling species Euchaeta rimana Bradford and Euchaeta marina (Prestandrea) diverged due to the emergence of the Panamanian land bridge. Received: 9 October 1997 / Accepted: 5 August 1998  相似文献   
168.
The osmoregulatory abilities of one freshwater and two brackish water (Baltic Sea) populations of the euryhaline teleost fish Gasterosteus aculeatus were studied with respect to evolutionary physiology. Plasma osmolality, activities of Na+K+-ATPase, citrate synthase, creatine kinase in the gill and free amino acids in liver, axial muscle and pectoral fin muscle were measured. After transfer from 10 to 35 ppt at 15 °C, time-course changes of plasma osmolality and gill Na+K+-ATPase showed no significant fundamental differences between the freshwater and one of the Baltic Sea populations. In a multi-factorial experiment, each population was exposed to four different abiotic regimes. Both brackish water populations had high mortality in freshwater at 4 °C, which is discussed as a failure of osmotic regulation (reduced taurine concentrations). Freshwater specimens had higher levels of glycine in the axial and pectoral fin muscles compared to the brackish water populations. This is interpreted as a genetically based effect. In brackish (20 ppt) water of 15 °C, the freshwater population had high activities of Na+K+-ATPase, but low activities of creatine kinase, whereas both brackish water populations behaved in the opposite way. A fundamental difference between the freshwater and brackish water populations on the level of the osmoregulatory machinery was not observed. Received: 10 December 1998 / Accepted: 22 September 1999  相似文献   
169.
Changing unsustainable natural resource use in agricultural landscapes is a complex social–ecological challenge that cannot be addressed through traditional reductionist science. More holistic and inclusive (or transdisciplinary) processes are needed. This paper describes a transdisciplinary project for natural resource management planning in two regions (Eyre Peninsula and South Australian Murray-Darling Basin) of southern Australia. With regional staff, we reviewed previous planning to gain an understanding of the processes used and to identify possible improvement in plan development and its operation. We then used an envisioning process to develop a value-rich narrative of regional aspirations to assist stakeholder engagement and inform the development of a land use management option assessment tool called the landscape futures analysis tool (LFAT). Finally, we undertook an assessment of the effectiveness of the process through semi-structured stakeholder interviews. The planning process review highlighted the opinion that the regional plans were not well informed by available science, that they lacked flexibility, and were only intermittently used after publication. The envisioning process identified shared values—generally described as a trust, language that is easily understood, wise use of resources, collaboration and inclusiveness. LFAT was designed to bring the best available science together in a form that would have use in planning, during community consultation and in assessing regional management operations. The LFAT provided spatially detailed but simple models of agricultural yields and incomes, plant biodiversity, weed distribution, and carbon sequestration associated with future combinations of climate, commodity and carbon prices, and costs of production. Stakeholders were impressed by the presentation and demonstration results of the software. While there was anecdotal evidence that the project provided learning opportunities and increased understanding of potential land use change associated with management options under global change, the direct evidence of influence in the updated regional plan was limited. This project had elements required for success in transdisciplinary research, but penetration seems limited. Contributing factors appear to be a complexity of climate effects with economic uncertainty, lack of having the project embedded in the plan revision process, limited continuity and capacity of end users and limited after project support and promotion. Strategies are required to minimise the controlling influence that these limitations can have.  相似文献   
170.
The air quality over the Toulouse urban area (France) is recorded daily by the regional "Midi-Pyrénées" atmospheric pollution measurements network (ORAMIP). Relevant data is collected from about 100 analysers spread over more than thirty stations. The regulations covering major indicators of atmospheric pollution (ozone, nitrogen dioxide, sulphur dioxide) have been updated in recent years to include additional compounds like polycyclic aromatic hydrocarbons (PAHs). The ORAMIP, in partnership with the ENSIACET has undertaken background PAH average concentration measurements over the urban agglomeration of Toulouse during spring 2006 for various types of sites (traffic, urban, industrial). The sampling was performed using a low volume air sampler equipped with quartz fiber filters and polyurethane foams For the two urban sites, total atmospheric concentrations between 12 and 20 ng/m(3) have been obtained, whereas for the industrial site the values averaged 22 ng/m(3). In addition, and regardless of site, the average concentrations of benzo[a]pyrene, at present the only regulated PAH, were always less than the 1 ng/m(3) limit.  相似文献   
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