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161.
Fatty acid trophic markers elucidate resource partitioning within the demersal fish community of South Georgia and Shag Rocks (Southern Ocean) 总被引:2,自引:1,他引:1
Fatty acid analysis was used to study the trophic ecology of 10 demersal fish species in the South Georgia region. Principal component analysis grouped the species into three general clusters, revealing resource partitioning between species. Two groups were characterised by large proportions of either monounsaturated or polyunsaturated fatty acids, separating species according to their predominant feeding habitat. The third group showed fatty acid signatures overlapping with either or both of the previous two groups, suggesting a more opportunistic feeding behaviour for these species. Intraspecific comparisons furthermore revealed dietary variability with size, year and geographical location in several species. Mackerel icefish (Champsocephalus gunnari) in particular showed inter-annual differences in muscle lipid concentrations closely linked to prey availability with low lipid contents found in years of low krill (Euphausia superba) abundance. Despite the intraspecific differences the majority of species could be easily distinguished from each other, which indicates the utility of this method in the dietary analysis of higher predators. 相似文献
162.
Collins C. Ngwakwe 《国际发展与全球生态学杂志》2013,20(5):442-452
While some previous research has critiqued accounting behaviour towards society and the environment, this paper points in a slightly different direction. With the aid of a chronological chart, it uses sustainability initiatives from the Canadian Institute of Chartered Accountants (CICA) to demonstrate the accounting profession's positive response to societal sustainability culture. Applying the cultural theories of Gray and Hofstede, it argues that society is responsible for alleged negative behaviour in accounting and that society hampers progress in sustainability accounting through political and corporate manoeuvrings. It asserts that, at least within the Canadian context, the more society embraces deeper green culture, the more accounting will transform towards sustainability values. It provides a future research agenda towards extenuating accounting criticisms. The paper suggests some policy implications for government and highlights that the power to condition and moderate accounting behaviour resides within society, governments and the laws of nations; it follows therefore that attaining any goals in sustainable development depends on the choice and commitment of governments and institutions. 相似文献
163.
M. Joshua Collins Phillip L. Williams David L. McIntosh 《Environmental monitoring and assessment》2001,68(2):137-152
Prior to the 1950's, manufactured gas was commerciallyproduced from the pyrolysis of coal, coke, and oil atfacilities that are termed manufactured gas plants (MGPs). The constituents of residual coal tar present on many MGPsites are an environmental health concern because of theirtoxicity and the possibility for their off-site migration viawater and air. Atmospheric concentrations of five volatileorganic compounds (VOCs, e.g., benzene), sixteen polycyclicaromatic hydrocarbons (PAHs, e.g., naphthalene), and particulate matter less than 10 microns in aerodynamicdiameter (PM10) were measured at the site of a former MGP. Air samples were obtained before, during, and after excavationof subterranean coal tar at the site. The results of thisinvestigation indicate that subterranean coal tar was not aprimary source of VOCs and PAHs in the local atmosphere beforeor after remediation of the site. However, excavation,treatment, blending, and transfer of the coal tar duringremediation generated concentrations of selected aromatic andsemi-volatile organic compounds that were substantiallygreater than typical ambient levels. In addition, these datasuggest that blending and mixing of coal tars could lead toexceedance of the U.S. National Ambient Air Quality Standardfor PM10, although additional research is required to fullyevaluate this possibility. Nuisance odors associated with thesite remediation were likely the result of naphthalene andpossibly isomers of xylene. Air pollutant concentrationsmeasured adjacent to the excavation area and at the siteperimeter during remediation activities were less than therelevant occupational and environmental exposure limits. 相似文献
164.
Christa L. Collins Michael W. Mullen Paul M. Stewart E. Cliff Webber 《Journal of the American Water Resources Association》2008,44(3):663-669
Abstract: The purpose of this study was to validate the application of an invertebrate community index (ICI) to assess the biological integrity of urban streams. Validation involved comparing chemical and habitat data to ICI scores from 20 urban streams and four least‐impacted streams in the Choctawhatchee and Pea River watersheds located in Southeast Alabama. Chemical and habitat data were collected to support whether the ICI accurately predicts the health of the streams. A significant difference between urban and least‐impacted ICI scores, habitat evaluation scores, chemical variables, taxa richness, and Shannon‐Wiener diversity were observed when urban sites were compared with least‐impacted sites using Mann‐Whitney U‐test. Urban sites having low ICI scores, low species richness and diversity, and poor habitat showed greater impairment than least‐impacted sites. Cluster analysis of macroinvertebrate assemblages indicated two clusters. Significant differences between clusters in habitat evaluations, chemical parameters, and ICI scores showed that some urban sites were more degraded than other urban sites in the study. Differentiation between least‐impacted and urban sites indicated that the ICI provided valid biotic assessments. Therefore, this study validated that the ICI is capable of predicting the biological integrity of urban streams in the Choctawhatchee and Pea River watersheds. 相似文献
165.
Capped waste sites often are vegetated with commercial turf grasses to increase evapotranspiration and prevent erosion and
possible exposure of the barrier. Fertilizer, frequent watering, and mowing may be required to establish the turf grass and
prevent invasion by trees and shrubs. Oldfield vegetation of grasses and forbs is a possible sustainable alternative to turf
grass communities. To determine if oldfield vegetation can establish on caps, we (1) compared establishment of a dominant
oldfield grass and a commercial turf grass under different combinations of new closure cap management: spring or summer planting
and presence or absence of amendments to alleviate drought (watering, mulch) or increase soil fertility (fertilizer, lime,
a nitrogen-fixing legume); (2) surveyed existing caps to determine if oldfield species establish naturally; and (3) performed
a greenhouse experiment to compare growth of two native grasses under low and amended (added water, soil nutrients) conditions.
Both the commercial grass and oldfield species established under new cap conditions; fertilizer, water, and mulch improved
vegetation establishment in spring or summer, but legumes decreased grass cover. In the greenhouse, both native grasses grew
best with amendments; however, substantial stem and root length were obtained with no fertilizer and only once-weekly watering.
Existing vegetated caps supported planted grasses and naturally established oldfield species. Overall, the results indicate
native grasses can establish on new caps and oldfields can serve as a management model; further work is needed to determine
the management strategy to maintain herbaceous vegetation and slow woody species invasion. 相似文献
166.
Mathias J. Collins 《Journal of the American Water Resources Association》2009,45(2):279-290
Abstract: Long‐term flow records for watersheds with minimal human influence have shown trends in recent decades toward increasing streamflow at regional and national scales, especially for low flow quantiles like the annual minimum and annual median flows. Trends for high flow quantiles are less clear, despite recent research showing increased precipitation in the conterminous United States over the last century that has been brought about primarily by an increased frequency and intensity of events in the upper 10th percentile of the daily precipitation distribution – particularly in the Northeast. This study investigates trends in 28 long‐term annual flood series for New England watersheds with dominantly natural streamflow. The flood series are an average of 75 years in length and are continuous through 2006. Twenty‐five series show upward trends via the nonparametric Mann‐Kendall test, 40% (10) of which are statistically significant (p < 0.1). Moreover, an average standardized departures series for 23 of the study gages indicates that increasing flood magnitudes in New England occurred as a step change around 1970. The timing of this is broadly synchronous with a phase change in the low frequency variability of the North Atlantic Oscillation, a prominent upper atmospheric circulation pattern that is known to effect climate variability along the United States east coast. Identifiable hydroclimatic shifts should be considered when the affected flow records are used for flood frequency analyses. Special treatment of the flood series can improve the analyses and provide better estimates of flood magnitudes and frequencies under the prevailing hydroclimatic condition. 相似文献
167.
The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC50) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. 相似文献
168.
Training programmes that involve agricultural researchers with farmers and extension field-workers have helped national agricultural research systems in sub-Saharan Africa to improve their communication with farmers. The International Institute of Tropical Agriculture (IITA) has worked with national crop research institutes and agricultural extension agencies in building communication links with farmers. In a continent where population growth still outstrips food production increases, feedback from farmers on performance of high-yielding crop varieties and on new farming techniques is essential in boosting food production. 相似文献
169.
James J. Collins Michael Wilken David McBride Noel F. Humphry Peter Herbison Carol J. Burns Kenneth Bodner 《Chemosphere》2009,76(11):1550-1556
This study examined serum levels of 2,3,7,8-substituted chlorinated dioxins and furans, and 15 PCBs for 346 New Zealand employees who worked at a site that manufactured 2,4,5-trichlorophenol (TCP) and 2,4,5-trichlorophenoxy acetic acid (2,4,5-T). Participants with potential TCP or 2,4,5-T exposures had mean lipid-adjusted 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) levels of 9.9 ng kg−1 lipid compared to 4.9 ng kg−1 for workers with no exposure at the site. Among exposed workers, we found evidence of differences in 2,3,7,8-TCDD levels by department and duties. Workers involved in an accidental release had the highest mean 2,3,7,8-TCDD levels, 37.9 ng kg−1, followed by workers in the trichlorophenol plant, 23.4 ng kg−1. Workers with potential intermittent exposures to 2,3,7,8-TCDD in construction, maintenance, mechanics, and transport had 2,3,7,8-TCDD levels above New Zealand background levels of 3.9 ng kg−1, indicating workplace exposures. Among participants with work history indicating no 2,3,7,8-TCDD exposures, we observed some individuals with 2,3,7,8-TCDD levels above background levels. However, in most cases, these workers reported workplace exposures not recorded on their work histories or held other jobs with the potential for 2,3,7,8-TCDD exposures outside the plant. All other dioxin, furan, and PCB levels were similar among the exposed and unexposed workers. 相似文献
170.
I.S.A. Isaksen C. Granier G. Myhre T.K. Berntsen S.B. Dalsøren M. Gauss Z. Klimont R. Benestad P. Bousquet W. Collins T. Cox V. Eyring D. Fowler S. Fuzzi P. Jöckel P. Laj U. Lohmann M. Maione P. Monks A.S.H. Prevot D. Wuebbles 《Atmospheric environment (Oxford, England : 1994)》2009,43(33):5138-5192
Chemically active climate compounds are either primary compounds like methane (CH4), removed by oxidation in the atmosphere, or secondary compounds like ozone (O3), sulfate and organic aerosols, both formed and removed in the atmosphere. Man-induced climate–chemistry interaction is a two-way process: Emissions of pollutants change the atmospheric composition contributing to climate change through the aforementioned climate components, and climate change, through changes in temperature, dynamics, the hydrological cycle, atmospheric stability, and biosphere-atmosphere interactions, affects the atmospheric composition and oxidation processes in the troposphere. Here we present progress in our understanding of processes of importance for climate–chemistry interactions, and their contributions to changes in atmospheric composition and climate forcing. A key factor is the oxidation potential involving compounds like O3 and the hydroxyl radical (OH). Reported studies represent both current and future changes. Reported results include new estimates of radiative forcing based on extensive model studies of chemically active climate compounds like O3, and of particles inducing both direct and indirect effects. Through EU projects like ACCENT, QUANTIFY, and the AeroCom project, extensive studies on regional and sector-wise differences in the impact on atmospheric distribution are performed. Studies have shown that land-based emissions have a different effect on climate than ship and aircraft emissions, and different measures are needed to reduce the climate impact. Several areas where climate change can affect the tropospheric oxidation process and the chemical composition are identified. This can take place through enhanced stratospheric–tropospheric exchange of ozone, more frequent periods with stable conditions favoring pollution build up over industrial areas, enhanced temperature induced biogenic emissions, methane releases from permafrost thawing, and enhanced concentration through reduced biospheric uptake. During the last 5–10 years, new observational data have been made available and used for model validation and the study of atmospheric processes. Although there are significant uncertainties in the modeling of composition changes, access to new observational data has improved modeling capability. Emission scenarios for the coming decades have a large uncertainty range, in particular with respect to regional trends, leading to a significant uncertainty range in estimated regional composition changes and climate impact. 相似文献