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51.
Milke Kyle P. Mitchell Kiana L. Hayes Sarah M. Green Carlin J. Guerard Jennifer J. 《Environmental science and pollution research international》2022,29(21):31059-31074
Environmental Science and Pollution Research - Despite significant investigation of fly ash spills and mineralogical controls on the release of potentially toxic elements (PTEs) from fly ash,... 相似文献
52.
On estimating the exponent of power-law frequency distributions 总被引:5,自引:0,他引:5
Power-law frequency distributions characterize a wide array of natural phenomena. In ecology, biology, and many physical and social sciences, the exponents of these power laws are estimated to draw inference about the processes underlying the phenomenon, to test theoretical models, and to scale up from local observations to global patterns. Therefore, it is essential that these exponents be estimated accurately. Unfortunately, the binning-based methods traditionally used in ecology and other disciplines perform quite poorly. Here we discuss more sophisticated methods for fitting these exponents based on cumulative distribution functions and maximum likelihood estimation. We illustrate their superior performance at estimating known exponents and provide details on how and when ecologists should use them. Our results confirm that maximum likelihood estimation outperforms other methods in both accuracy and precision. Because of the use of biased statistical methods for estimating the exponent, the conclusions of several recently published papers should be revisited. 相似文献
53.
Chemical fingerprinting techniques recently have been used to track larval dispersal of estuarine species that bear calcified
structures, but the applicability of this important approach may be limited on the open coast where chemical signatures may
be less distinctive and for the many species that do not retain calcified structures throughout development. Externally brooded
embryos of the porcelain crab, Petrolisthes cinctipes, and inductively coupled plasma mass spectrometry were used to determine whether fine-scale variation in trace-elemental
composition occurred along an open coast. Embryos were collected from 16 sites from 37.8° to 39.5° north latitude along the
Pacific Coast of California, USA during late January and early February 2003. Discriminant function analysis revealed that
collection sites, many separated by only a few kilometers along an open coast, could be differentiated with an overall accuracy
of 73%, and combining the sites into three regions increased the accuracy to 88%. Thus, distinctive elemental signatures can
be detected in open coast species even at a fine scale raising the possibility that larval tags can be developed for many
more species than previously thought possible. 相似文献
54.
Response of balanced network models to large-scale perturbation: Implications for evaluating the role of small pelagics in the Gulf of Maine 总被引:1,自引:0,他引:1
Jason Link Laurel Col Vincent Guida David Dow John O’Reilly Jack Green William Overholtz Debra Palka Chris Legault Joseph Vitaliano Carolyn Griswold Michael Fogarty Kevin Friedland 《Ecological modelling》2009
Exploring the response of an ecosystem, and subsequent tradeoffs among its biological community, to human perturbations remains a key challenge for the implementation of an ecosystem approaches to fisheries (EAF). To address this and related issues, we developed two network (or energy budget) models, Ecopath and Econetwrk, for the Gulf of Maine ecosystem. These models included 31 network “nodes” or biomass state variables across a broad range of trophic levels, with the present emphasis to particularly elucidate the role of small pelagics. After initial network balancing, various perturbation scenarios were evaluated to explore how potential changes to different fish, fisheries and lower trophic levels can affect model outputs. Categorically across all scenarios and interpretations thereof, there was minimal change at the second trophic levels and most of the “rebalancing” after a perturbation occurred via alteration of the diet matrix. Yet the model results from perturbations to a balanced energy budget fall into one of three categories. First, some model results were intuitive and in obvious agreement with established ecological and fishing theory. Second, some model results were counter-intuitive upon initial observation, seemingly contradictory to known ecological and fishing theory; but upon further examination the results were explainable given the constraints of an equilibrium energy budget. Finally, some results were counter-intuitive and difficult to reconcile with theory or further examination of equilibrium constraints. A detailed accounting of biomass flows for example scenarios explores some of the non-intuitive results more rigorously. Collectively these results imply a need to carefully track biomass flows and results of any given perturbation and to critically evaluate the conditions under which a new equilibrium is obtained for these types of models, which has implications for dynamic simulations based off of them. Given these caveats, the role of small pelagics as a prominent component of this ecosystem remains a robust conclusion. We discuss how one might use this approach in the context of further developing an EAF, recognizing that a more holistic, integrated perspective will be required as we continue to evaluate tradeoffs among marine biological communities. 相似文献
55.
Deurer M Sivakumaran S Ralle S Vogeler I McIvor I Clothier B Green S Bachmann J 《Journal of environmental quality》2008,37(3):915-924
A new method to diagnose the environmental sustainability of specific orchard management practices was derived and tested. As a significant factor for soil quality, the soil carbon (C) management in the topsoil of the tree-row of an integrated and organic apple orchard was selected and compared. Soil C management was defined as land management practices that maintain or increase soil C. We analyzed the impact of the soil C management on biological (microbial biomass C, basal respiration, dehydrogenase activity, respiratory quotient) and physical (aggregate stability, amount of plant-available water, conductive mean pore diameter near water saturation) soil properties. Soil in the alley acted as a reference for the managed soil in the tree row. The total and hot-water-extractable C amounts served as a combined proxy for the soil C management. The soil C management accounted for 0 to 81% of the degradation or enhancement of biophysical soil properties in the integrated and organic system. In the integrated system, soil C management led to a loss of C in the top 0.3 m of the tree row within 12 yr, causing a decrease in microbial activities. In the tree row of the organic orchard, C loss occurred in the top 0.1 m, and the decrease in microbial activities was small or not significant. Regarding physical soil properties, the C loss in the integrated system led to a decrease of the aggregate stability, whereas it increased in the organic system. Generally, the impact of soil C management was better correlated with soil microbial than with the physical properties. With respect to environmental soil functions that are sensitive to the decrease in microbial activity or aggregate stability, soil C management was sustainable in the organic system but not in the integrated system. 相似文献
56.
C.D. Green 《Agriculture, ecosystems & environment》1985,13(2):175
57.
A method was developed for studies of the phototransformation at UV irradiation of aqueous solutions of tetrabromobisphenol A (TBBPA), tribromobisphenol A (TriBBPA), tetrachlorobisphenol A (TCBPA), 2,4-dichlorophenol at various pHs as well as 2-chlorophenol, 2-bromophenol, 3,4-dichlorophenol and bisphenol A at pH 11. The absorbance spectra of the compounds and the emission spectra of the light-source were determined and used to calculate disappearance quantum yields of the photochemical reactions that were taking place. No major differences between the disappearance quantum yields of TBBPA and TCBPA were observed at pH 10, while the disappearance quantum yield of TriBBPA was approximately two times higher. The rate of decomposition of TBBPA was six times higher at pH 8 than at pH 6. Identification of the degradation products of TBBPA and TriBBPA, by GC-MS analysis and by comparison to synthesised reference compounds, indicated that TBBPA and TriBBPA decompose via different mechanisms. Three isopropylphenol derivatives; 4-isopropyl-2,6-dibromophenol, 4-isopropylene-2,6-dibromophenol and 4-(2-hydroxyisopropyl)-2,6-dibromophenol, were identified as major degradation products of TBBPA while the major degradation product of TriBBPA was tentatively identified as 2-(2,4-cyclopentadienyl)-2-(3,5-dibromo-4-hydroxyphenyl)propane. 相似文献
58.
Source profiles for industrial, mobile, and area sources in the Big Bend Regional Aerosol Visibility and Observational study 总被引:20,自引:0,他引:20
Chow JC Watson JG Kuhns H Etyemezian V Lowenthal DH Crow D Kohl SD Engelbrecht JP Green MC 《Chemosphere》2004,54(2):185-208
Representative PM2.5 and PM10 source emissions were sampled in Texas during the Big Bend Regional Aerosol Visibility and Observa (BRAVO) study. Chemical source profiles for elements, ions, and carbon fractions of 145 samples are reported for paved and unpaved road dust, soil dust, motor vehicle exhaust, vegetative burning, four coal-fired power stations, an oil refinery catalytic cracker, two cement kilns, and residential meat cooking. Several samples were taken from each emitter and source type, and these were averaged by source type, and in source subgroups based on commonality of chemical composition. The standard deviation represents the variability of the chemical mass fractions. BRAVO profiles differed in some respects from profiles measured elsewhere. High calcium abundances in geological dust, high selenium abundances in coal-fired power stations, and high antimony abundances in oil refinery catalytic cracker emissions were found. Abundances of eight thermally evolved carbon fractions [Atmos. Environ. 28 (15) (1994) 2493] differ among combustion sources, and a Monte Carlo simulation demonstrates that these differences are sufficient to differentiate among several carbon-emitters. 相似文献
59.
Coral reef habitat mapping: how much detail can remote sensing provide? 总被引:12,自引:0,他引:12
The capability of satellite and airborne remote-sensing methods for mapping Caribbean coral reefs is evaluated. Reef habitats
were categorised into coarse, intermediate and fine detail, using hierarchical classification of field data (percent cover
in 1 m quadrats and seagrass standing-crop). Habitats were defined as assemblages of benthic macro-organisms and substrata
and were mapped using the satellite sensors Landsat MSS, Landsat TM, SPOT XS, SPOT Pan and merged Landsat TM/SPOT Pan. Habitats
were also mapped using the high-resolution digital airborne sensor, CASI (compact airborne spectrographic imager). To map
areas >60 km in any direction with coarse detail, Landsat TM was the most accurate and cost-effective satellite sensor (SPOT
XS when <60 km). For maps with intermediate habitat detail, aerial photography (from a comparable study in Anguilla) exhibited
similar accuracy to Landsat TM, SPOT XS, SPOT Pan and merged Landsat TM/SPOT Pan. Landsat MSS was consistently the least accurate
sensor. Maps from CASI were significantly (p<0.001) more accurate than satellite sensors and aerial photographs. Maps with detailed habitat information (i.e. >9 reef
classes) had a maximum accuracy of 37% when based on satellite imagery, but aerial photography and CASI achieved accuracies
of 67 and 81%, respectively. Commissioning of new aerial photography does not appear to be a cost-effective option; satellites
are cheaper for coarse habitat-mapping, and detailed habitat-mapping can be conducted more accurately and cheaply with CASI.
The results will guide practitioners in matching survey objectives to appropriate remote-sensing methods.
Received: 11 July 1997 / Accepted: 6 August 1997 相似文献
60.
Using GIS for siting artificial reefs—Data issues, problems and solutions: ‘Real World’ to ‘Real World’ 总被引:1,自引:0,他引:1
As GIS becomes an increasingly more ‘user-friendly’ tool, and more people recognize the benefits of the technology in their
work environment, inevitably greater use will be made of it for a wide range of applications. The ease with which a GIS can
now be used often overshadows the complexity underlying this technology and the potential difficulties that can (and do) arise
when this is not fully understood. In practice, there are two routes open to the application of GIS technology for environmental
studies. The first is to commission new data for the research. The second is to make use of existing data sets. Data are at
the heart of any GIS application. A detailed knowledge about the data sources, the method of collection, capture, scale and
sampling strategy, especially if the data are to be used in any analysis, modelling or simulation studies, is fundamental
to any application. Unfortunately, information about data (metadata) is seldom available, especially for archival or legacy
data sets. Furthermore, although it is now relatively easy to acquire digital data, to input, store, manipulate and display
this data, and to output the results of any GIS analysis in the practical sense, little consideration is given to the problems
associated with data quality and how this will ultimately affect present and future analyses and use of the output for planning
and decision-making. The need to raise awareness about data quality for applications is set in the context of the development
of an environmental database for the Moray Firth. Northeast Scotland, and more specifically the use of selected data sets
from the database to aid in the proposed siting of an artificial reef. Using this example, this contribution explores the
problems associated with the use of both existing analog and digital data sets as the basis for environmental applications,
the problems of data acquisition, data quality, data standards, error and how these can affect the operational use of the
data in GIS analyses. The solution to such problems appears to lie with improved error assessment and reporting. The outcome
of this contribution is an attempt to offer guidance and solutions to researchers and applications specialists undertaking
similar studies, by suggesting to what extent studies, such as the artificial reef siting, can safely make use of existing
data sets without risking the problems associated with judgements based on inadequate information, and generated or inherent
error. 相似文献