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111.
Long-term application of poultry (Gallus gallus domesticus) litter has built high levels of P in certain Coastal Plain soils of north Louisiana. However, soil P/runoff P relationships for soil and environmental conditions of the area have not been examined. This study measured soil P (total, Bray 1, Bray 2, Mehlich 3, resin-exchangeable, and water-extractable) and runoff P (dissolved P, DP; and total P, TP) at four pasture sites previously amended with poultry litter. Sites varied in soil P due to annual litter applications ranging from 1 to more than 20. Three replicated plots at each site were subjected to simulated rainfalls over 2 yr, and concentrations of DP and TP in runoff were measured and related to soil P. This allowed examination of soil P/runoff P relationships and their changes over time. Runoff DP was also related to DP desorbed from surface soil in a miscible displacement experiment. Among measures of soil P, only resin-exchangeable and water-extractable P showed significant decreases over 2 yr. These measures of soil P explained 54 to 64% of the variability in runoff DP data. However, the miscible displacement technique proved the best indicator of runoff DP, explaining 70% of the variability. Runoff varied among sites (decreasing with increasing years of litter application), limiting the predictive capability of the soil extraction methods. Linking runoff characteristics with miscible displacement data may be a useful predictive tool and warrants further examination. 相似文献
112.
Sub-ambient trapping, used to pre-concentrate atmospheric samples for non-methane hydrocarbon (NMHC) analysis by gas chromatography, can also be used to measure ambient methane concentrations. Above a sample volume of 40 ml, a dynamic equilibrium is established between ambient and trapped methane allowing for simultaneous quantitative determinations of methane and NMHC. The temperature stability of the trap is critical for quantitative methane analysis and this can be achieved by Peltier effect cooling. Simultaneous measurements of methane and NMHC reduce the equipment required for field trips and can ease the interpretation and modelling of atmospheric data. The feasibility for deployment of the system in remote locations was demonstrated by running the apparatus virtually unattended for a 5-day period. The correlations between the concentrations of methane, ethane and ethene measured during this period are discussed. 相似文献
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Skuterud L Gaare E Eikelmann IM Hove K Steinnes E 《Journal of environmental radioactivity》2005,83(2):231-252
Transfer of 137Cs in the soil-plant/lichen-reindeer food chain was studied in central (?stre Namdal) and southern Norway (V?g?) during 2000-2003. Reindeer from these areas have been continuously subjected to countermeasure application since the 1986 Chernobyl accident. In both areas no decline in 137Cs concentrations was detectable in reindeer slaughtered in autumn since 1995, or in reindeer slaughtered in winter since 1998-1999. Seasonal differences in 137Cs concentrations in reindeer have been less pronounced in recent years, with 137Cs concentrations occasionally higher in autumn than in winter. Soil-to-plant 137Cs transfer was significantly higher in ?stre Namdal than in V?g?. Climatic influences on lichen growth and abundance, and on soil properties that influence the availability of 137Cs for plant uptake, are hypothesized to have a larger impact on long-term transfer of radiocaesium in the soil-plant/lichen-reindeer food chain than has been previously observed. 相似文献
117.
Skuterud L Gaare E Kvam T Hove K Steinnes E 《Journal of environmental radioactivity》2005,80(1):125-138
Concentrations of (137)Cs were determined in 747 lynxes killed in Norway during the period 1986-2001. Highly variable (137)Cs concentrations and aggregated transfer coefficient values were observed, probably caused by variable (137)Cs concentrations in prey and the lynx's extensive home ranges and roaming distances. Adult lynxes had higher (137)Cs concentrations than sub-adults, and lynxes killed in regions with extensive reindeer grazing areas were more contaminated than others. A model with (137)Cs deposition density, the year lynxes were killed, age, and extent of reindeer grazing area accounted for 50% of the variability in observed (137)Cs concentrations. The analyses were equivocal regarding the influence of stomach content on (137)Cs concentrations in lynx muscle, i.e., on the lynx's specialization in prey species. Gender was not significant. Information on caesium retention in lynx and better estimates of deposition densities in lynxes' home ranges are important for further elucidation of factors influencing (137)Cs contamination in lynxes. 相似文献
118.
Several lines of evidence in the literature indicate that environmental stress such as starvation may initiate reallocation of sea urchin endoskeletal tissue. For example, Aristotle's lantern enlarges under conditions of starvation, and sea urchins tagged with tetracycline and then fed develop a distinct growth line, while starved individuals develop a diffuse pattern. We designed anin vivo system to examine stress-related changes in calcification in the purple sea urchinStrongylocentrotus purpuratus. SmallS. purpuratus (ca. 2 cm test diam) were collected from the Mission Bay jetty or Imperial Beach (San Diego, California, USA) in 1987.45Ca was incorporated from seawater into all body fractions including the organic tissue/coelomic fluid. In an initial experiment, sea urchins were fed or starved for 4 wk and then post-incubated in isotope. Overall, starved individuals deposited new calcite more slowly than did fed individuals; however, allocation was very different and calcification of teeth of starved sea urchins was nearly as great as in fed individuals. In a second experiment,S. purpuratus were first pre-labeled with isotope and then treated by feeding or starving. More of the labeled calcium was mobilized from the soft tissues and coelomic fluid into calcite in fed than in starved individuals. Growth of the teeth in starved sea urchins was significantly greater than in those fed. We conclude that starvation changes the metabolism of calcium in order to preferentially build teeth. However, we also found no evidence that calcium was resorbed from old skeletal calcite in order to build new skeleton. 相似文献
119.
William A. Jury Gideon Sinai Lewis H. Stolzy 《Journal of the American Water Resources Association》1979,15(5):1444-1458
ABSTRACT: Electric generation facility water requirement will increase substantially in the future in the Western United States because new power plants are to be constructed at inland sites rather than on the coast. At the inland locations, power plants will have to compete with agriculture and public users for fresh water supplies, and will be constrained by environmental legislation to dispose of cooling waste water in lined evaporation ponds. The various options for power plant cooling are analyzed in respect to cost, water consumption, and environmental hazard, and also in respect to their compatibility with existing state and federal regulations. Several proposals for balancing the water requirements of various users in water-scarce areas are reviewed and criticized. 相似文献
120.
Repulsion of green sunfish by certain chemicals 总被引:2,自引:0,他引:2