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881.
Gallagher FJ Pechmann I Bogden JD Grabosky J Weis P 《Environmental pollution (Barking, Essex : 1987)》2008,153(2):351-361
Anthropogenic sources of toxic elements have had serious ecological and human health impacts. Analysis of the soil samples from a brownfield within Liberty State Park, Jersey City, NJ, USA, showed that arsenic, chromium, lead, zinc and vanadium exist at concentrations above those considered ambient for the area. Accumulation and translocation features were characterized for the dominant plant species of four vegetative assemblages. The trees Betula populifolia and Populus deltoides were found to be accumulating Zn in leaf tissue at extremely high levels. B. populifolia, P. deltoides and Rhus copallinum accumulated Cr primarily in the root tissue. A comparison of soil metal maps and vegetative assemblage maps indicates that areas of increasing total soil metal load were dominated by successional northern hardwoods while semi-emergent marshes consisting mostly of endemic species were restricted primarily to areas of low soil metal load. 相似文献
882.
883.
Effect of phosphogypsum and dicyandiamide as additives on NH3, N2O and CH4 emissions during composting 总被引:1,自引:0,他引:1
Yiming Luo Guoxue Li Wenhai Luo Frank Schuchardt Tao Jiang Degang Xu 《环境科学学报(英文版)》2013,25(7):1338-1345
A laboratory scale experiment of composting in a forced aeration system using pig manure with cornstalks was carried out to investigate the effects of both phosphogypsum and dicyandiamide (DCD, C2H4N4) as additives on gaseous emissions and compost quality. Besides a control, there were three amended treatments with different amounts of additives. The results indicated that the phosphogypsum addition at the rate of 10% of mixture dry weight decreased NH3 and CH4 emissions significantly during composting. The addition of DCD at the rate of 0.2% of mixture dry weight together with 10% of phosphogypsum further reduced the N2O emission by affecting the nitrification process. Reducing the phosphogypsum addition to 5% in the presence of 0.2% DCD moderately increased the NH3 emissions but not N2O emission. The additives increased the ammonium content and electrical conductivity significantly in the final compost. No adverse effect on organic matter degradation or the germination index of the compost was found in the amended treatments. It was recommended that phosphogypsum and DCD could be used in composting for the purpose of reducing NH3, CH4 and N2O emissions. Optimal conditions and dose of DCD additive during composting should be determined with different materials and composting systems in further study. 相似文献
884.
Arjan M. Boonman Martijn Boonman Frank Bretschneider Wim A. van de Grind 《Behavioral ecology and sociobiology》1998,44(2):99-107
Daubenton's bat, a trawling vespertilionid bat species, hunts for insects that fly close to, or rest on, the water surface.
During summer, many ponds at which Daubenton's bats hunt become gradually covered with duckweed. The purpose of this study
was to investigate the effects of duckweed cover on the hunting behaviour of Daubenton's bats and on the ultrasound-reflecting
properties of the water surface. Our study revealed the following. (1) Daubenton's bat avoids water surfaces covered with
duckweed. (2) Prey abundance was related to the number of foraging Daubenton's bats but was independent of duckweed cover.
(3) When mealworms were presented among standardized amounts of duckweed to naturally foraging Daubenton's bats, they caught
significantly less mealworms when the duckweed cover was increased. (4) Measurements with ultrasonic signals show that a water
surface covered with duckweed returns a much stronger background echo at small angles (i.e. parallel to the water surface)
compared to an uncovered water surface. It seems likely that a cover of duckweed on the water surface interferes with prey
detection by masking the echoes returning from prey. (5) It was relatively difficult for the bats to discriminate small patches
of duckweed from mealworms. The proposed discrimination mechanism for this trawling bat species suggests that single duckweed
patches can also be mistaken for natural prey by Daubenton's bats.
Received: 4 January 1998 / Accepted after revision: 19 July 1998 相似文献
885.
Erich Zeeck Carsten T. Müller Manfred Beckmann Jörg D. Hardege Ulrich Papke Volker Sinnwell Frank C. Schroeder Wittko Francke 《Chemoecology》1998,8(1):33-38
Summary. In the marine polychaete Nereis succinea (Frey & Leuckart 1847) a sex pheromone was isolated from the coelomic fluid of sexually mature females and identified by
NMR studies and independent synthesis. This pheromone is released by the females during reproduction together with eggs and
coelomic fluid into the free water column and induces sperm release of surrounding males. Its structure was ascertained as
L-cysteine-glutathione disulfide. It exhibited a response threshold of 0.6 · 10−7 M.
Received 15 July 1997; accepted 25 November 1997. 相似文献
886.
Kechavarzi C Pettersson K Leeds-Harrison P Ritchie L Ledin S 《Environmental pollution (Barking, Essex : 1987)》2007,145(1):68-74
The efficiency of rhizosphere biodegradation of petroleum hydrocarbons heterogeneously distributed in soils is dependent on the ability of plant roots to prospect into contaminated zones. Rhizobox experiments were conducted to study the influence of diesel contaminated layers on the spatial distribution and the development of the roots of perennial ryegrass. Root distribution and root and shoot development were monitored over time. The final root and above ground biomass and the final TPH concentration were determined. The spatial distribution of the contaminant as well as the irrigation method used affected root distribution, plant development and TPH degradation and therefore ryegrass remediation potential. The results show that roots colonise fully uncontaminated soil and grow preferentially between zones of contamination. Conversely, when no immediate uncontaminated soil is available, roots grow through contaminated zones in order to prospect for uncontaminated soil. 相似文献
887.
Lev-On M Epperson D Siegell J Ritter K 《Journal of the Air & Waste Management Association (1995)》2007,57(9):1061-1070
This paper describes the development of new "leak/no-leak" emission factors that are suitable for estimating facilities' fugitive emissions when using an alternative work practice (AWP) that is based on optical gas imaging technology for detecting leaking piping system components. These emission factors were derived for valves, pumps, and connectors/flanges for instrument leak detection thresholds ranging from 3 to 60 g/hr using a combination of field data and Monte Carlo statistical simulation techniques. These newly derived leak/no-leak emission factors are designed to replace the U.S. Environment Protection Agency (EPA) 1995 Protocol factors, which were based on Method 21 monitoring of leaks at "uncontrolled" facilities. The emission factors published in the 1995 Protocol have not been updated since the 1970s. This derivation is based on results where the authors document the use of a Monte Carlo simulation technique to quantify the required leak detection thresholds that provide equal--or better--environmental benefits for an AWP. The use of these newly derived emission factors is demonstrated for different methods of computing fugitive emissions from a hypothetical model refinery. The resulting facility emissions calculated by using these new emission factors is compared with the existing emission estimation methods provided in the EPA 1995 Protocol. The results demonstrate that the new emission factors provide an emission estimate that is the closest to that obtained from the direct determination of total emissions by Monte Carlo simulations. 相似文献
888.
Using data from electroretinogram recordings, we designed a submersible light meter with a spectral luminous efficiency comparable
to that of a vertically migrating shrimp. Using this light meter on the “Johnson Sea Link” submersible, we were able to ascend
with the isolumes (preferred light levels) associated with the sergestid and euphausiid shrimp layers. The speed of the submersible's
movement was recorded and correlated with simultaneous measurements of surface irradiance. In situ measurements of the downwelling
spectral distribution were also made with a fiber optic spectrometer. The average measured speed of the sergestid isolume
was 8.8 cm s−1, while that of the shallower euphausiid isolume was 6.7 cm s−1. These values are different from those calculated using average diffuse attenuation coefficients and surface light measurements.
This difference was due to the broadening of the spectral distribution of downwelling light above 120 m and to the variability
of the diffuse attenuation coefficients with depth. These results clearly demonstrate that when investigating the relationship
between light and vertical migration patterns, it is important that: (1) the light measurements be made in situ and (2) such
measurements take into account the spectral sensitivity of the eyes of the migrators.
Received: 7 June 2000 / Accepted: 18 November 2000 相似文献
889.
890.