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The impact of Hurricanes Katrina and Rita in 2005 on pollution emissions in the Gulf of Mexico region was investigated using tropospheric column amounts of nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) on the NASA Aura satellite. Around New Orleans and coastal Mississippi, we estimate that Katrina caused a 35% reduction in NOx emissions on average in the three weeks after landfall. Hurricane Rita caused a significant reduction (20%) in NOx emissions associated with power generation and intensive oil refining activities near the Texas/Louisiana border. We also found a 43% decrease by these two storms over the eastern Gulf of Mexico Outer Continental Shelf mainly due to the evacuation of and damage to platforms, rigs, and ports associated with oil and natural gas production.  相似文献   
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Predation of calanoid copepods on their own and other copepods’ offspring   总被引:1,自引:0,他引:1  
Predation of eggs and nauplii by adult copepods is often used to explain unexpected death rates in population dynamics studies, but the phenomenon has been rarely investigated or quantified. Therefore, we studied the predatory feeding of adult females (Acartia clausi, Centropages hamatus, Centropages typicus, and Temora longicornis) on their own and other species’ eggs and young nauplii with different densities of single animal-prey, mixtures of animal-prey and in the presence of diatoms. All species preyed on eggs and nauplii of their own and all other species. Maximal egg predation varied between 7 and 64 eggs fem?1 day?1. Ingestion of Centropages spp. eggs was lowest, potentially due to the spiny egg surface. Maximal feeding rates on nauplii ranged from 5 to 45 nauplii fem?1 day?1. T. longicornis preferred eggs, when eggs and nauplii were offered together at the same densities, and the other predators selected for nauplii. At a diatom concentration of 60 μg C l?1 predation on eggs by C. typicus was higher than without algae, whereas A. clausi and T. longicornis did not change their uptake of eggs. Feeding on nauplii in the presence of diatoms was again enhanced in C. typicus, and unaffected in A. clausi and C. hamatus. T. longicornis reduced its feeding on nauplii in the presence of diatoms. Calculated predation rates, using field abundances of predators and prey, suggest that predation of copepods on their own young stages may account for ca. 30 % of total mortality of young stages in North Sea copepod populations.  相似文献   
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We investigated the impact of copepods on the seston community in a mesocosm set-up, and assessed how the changes in food quantity, quality and size affected the condition of the grazers, by measuring the RNA:DNA ratios in different developmental stages of Calanus finmarchicus. Manipulated copepod densities did not affect the particulate carbon concentration in the mesocosms. On the other hand, chlorophyll a content increased with higher copepod densities, and increasing densities had a positive effect on seston food quality in the mesocosms, measured as C:N ratios and 3:6 fatty acid ratios. These food quality indicators were significantly correlated to the nutritional status of C. finmarchicus. In contrast to our expectations, these results suggest a lower copepod growth potential on higher quality food. However, in concordance with earlier studies, we found that when copepods were in high densities the large particles (>1000 µm3) decreased and that the smaller particles (<1000 µm3) increased in number. These patterns were closely linked to the condition of C. finmarchicus, which were of better condition (RNA:DNA ratios) with increasing biovolumes of large particles, and, conversely, lower RNA:DNA ratios with increasing biovolumes of smaller particles. Consequentially, the selective grazing by copepods stimulated increased biovolumes of smaller plankton, and this increase was responsible for the increased food quality, in terms of C:N and 3:6 ratios. Thus, we conclude that the decreasing growth potentials of C. finmarchicus were a result of a decrease of favourably sized food particles, induced by copepod grazing.Communicated by O. Kinne, Oldendorf/Luhe  相似文献   
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Cumulative human impacts across the world's oceans are considerable. We therefore examined a single model taxonomic group, the penguins (Spheniscidae), to explore how marine species and communities might be at risk of decline or extinction in the southern hemisphere. We sought to determine the most important threats to penguins and to suggest means to mitigate these threats. Our review has relevance to other taxonomic groups in the southern hemisphere and in northern latitudes, where human impacts are greater. Our review was based on an expert assessment and literature review of all 18 penguin species; 49 scientists contributed to the process. For each penguin species, we considered their range and distribution, population trends, and main anthropogenic threats over the past approximately 250 years. These threats were harvesting adults for oil, skin, and feathers and as bait for crab and rock lobster fisheries; harvesting of eggs; terrestrial habitat degradation; marine pollution; fisheries bycatch and resource competition; environmental variability and climate change; and toxic algal poisoning and disease. Habitat loss, pollution, and fishing, all factors humans can readily mitigate, remain the primary threats for penguin species. Their future resilience to further climate change impacts will almost certainly depend on addressing current threats to existing habitat degradation on land and at sea. We suggest protection of breeding habitat, linked to the designation of appropriately scaled marine reserves, including in the High Seas, will be critical for the future conservation of penguins. However, large‐scale conservation zones are not always practical or politically feasible and other ecosystem‐based management methods that include spatial zoning, bycatch mitigation, and robust harvest control must be developed to maintain marine biodiversity and ensure that ecosystem functioning is maintained across a variety of scales. Contaminación, Pérdida de Hábitat, Pesca y Cambio Climático como Amenazas Críticas para los Pingüinos  相似文献   
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Transformation of teflubenzuron, the active component in the insecticide commercialized as Nomolt, by soil microorganisms was studied. It was shown that microorganisms, belonging to Bacillus, Alcaligenes, Pseudomonas and Acinetobacter genera are capable to perform the hydrolytic cleavage of the phenylurea bridge of teflubenzuron in different positions, especially active was Bacillus brevis 625. The structure of the intermediates formed was established using TLC, HPLC, mass-spectrometry and 19F NMR techniques. It was shown that for a dose range of 53-132 microM and upon 12 days of fermentation about 30% of the teflubenzuron was modified. About 10-15% was transformed into 2,6-difluorobenzamide, 3-5% into 2,6-difluorobenzoic acid, 10-12% into 2,4-difluoro-3,5-dichloro-aniline. The late compound gave rise to formation of a condensed compound, identified as 1,2-bis(2,4-difluoro-3,5-dichlorophenyl)urea with molecular mass of 420. The results obtained indicate degradation of teflubenzuron by soil microorganisms to be a process to be mediated by microbial consortia, and starting with hydrolysis of the phenylurea bridge by several bacterial species. Subsequent further degradation of the aromatic degradation products has to be mediated by other strains known to be capable of degradation of halogenated aromatics.  相似文献   
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Seasonal lipid dynamics of the copepod Pseudocalanus acuspes were studied in the Bornholm Basin (Central Baltic Sea) on a monthly basis from March 2002 until March 2003 and were interpreted in light of life cycle strategies and diet selection. The individual total lipid content of females ranged from 0.9 to 1.8 μg, with relative wax ester content reaching a significant maximum in May (44% of total lipids) and minimum (17% of total lipids) in April and November. Significant changes in size, lipid content, lipid classes and fatty acid composition of structural as well as storage lipids suggested five characteristic seasonal phases that were induced by different feeding histories and environmental conditions. Storage lipids were characterized by 18:1(n−9) as major component, which ranged between 44% of total fatty acids in June and 23% in February. The strong coherence between 18:1(n−9) in the seston lipids and the occurrence of ciliates emphasized the importance of ciliates in the diet of P. acuspes. As indicated by changes in the amounts of fatty acid markers, other food sources varied over the year, suggesting an opportunistic feeding behavior. The spring period was characterized by an increase in typical diatom and dinoflagellate markers, whereas other sources, potentially cyanobacteria, became more important during summer. The life cycle strategy is discussed with respect to extant adaptations to high latitudinal habitats.  相似文献   
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ABSTRACT: The purpose of this paper is to describe a land use and environmental planning model. Map overlays were used for analyzing and aggregating economic, social, and environmental data. Various land use categories were evaluated using a numerical scoring system. These scores were then used to assist in the development of land use regulations in a coastal county in South Carolina.  相似文献   
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