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1.
It is shown that the error in an estimate of the population respiration should generally not exceed 10% if the mean body weight is used instead of the full weight distribution. A convenient mathematical formulation of the Krogh-curve is given such that the commonly used exponential temperature dependence (Q10 law) of the respiration rate is only a special case. A formula is derived which expresses the effect of a cyclic temperature relative to a constant temperature on the respiration of an animal, the respiration rate of which follows a Krogh-curve. This formula is shown to provide good estimates of annual population respiration both for cases where the population biomass can be considered as constant over the year and when its variation can be approximated with a sinusfunction. Our methods of estimating population respiration are shown to compare favourably with earlier shortcut methods. 相似文献
2.
Wei Yang 《Ecological modelling》2011,222(2):261-267
In this paper, a multi-objective optimization model has been developed for allocating freshwater to meet the environmental flow requirements of the restored wetlands in the Yellow River Delta, China. The model seeks a rational balance among appropriate water allocation for the wetlands, a healthy ecosystem, and optimum economic returns for the humans that use the wetlands to earn their livelihood, with the degree of ecosystem health represented by the difference between actual and ideal water levels. And then a holistic method has been used for satisfying multiple objectives to avoid the problem of decision-maker subjectivity, and then solved the resulting optimal allocation model for environmental flows of the wetlands using a genetic algorithm. With water from the Yellow River as the source, the model shows how the optimal monthly water release into the restored wetlands can be achieved in dry, average, and wet years. Using the model, 20-56% reductions in water use could be achieved compared with the current pattern of water release, and the optimal water level in each month would coincide better with the ideal value based on an indicator plant community (reeds). The results of the study demonstrate the capability of the multi-objective programming model to optimize ecological water allocation and management for the wetlands of the Yellow River Delta. 相似文献
3.
Expansion of sugarcane ethanol production in Brazil: environmental and social challenges. 总被引:1,自引:0,他引:1
Several geopolitical factors, aggravated by worries of global warming, have been fueling the search for and production of renewable energy worldwide for the past few years. Such demand for renewable energy is likely to benefit the sugarcane ethanol industry in Brazil, not only because sugarcane ethanol has a positive energetic balance and relatively low production costs, but also because Brazilian ethanol has been successfully produced and used as biofuel in the country since the 1970s. However, environmental and social impacts associated with ethanol production in Brazil can become important obstacles to sustainable biofuel production worldwide. Atmospheric pollution from burning of sugarcane for harvesting, degradation of soils and aquatic systems, and the exploitation of cane cutters are among the issues that deserve immediate attention from the Brazilian government and international societies. The expansion of sugarcane crops to the areas presently cultivated for soybeans also represent an environmental threat, because it may increase deforestation pressure from soybean crops in the Amazon region. In this paper, we discuss environmental and social issues linked to the expansion of sugarcane in Brazil for ethanol production, and we provide recommendations to help policy makers and the Brazilian government establish new initiatives to produce a code for ethanol production that is environmentally sustainable and economically fair. Recommendations include proper planning and environmental risk assessments for the expansion of sugarcane to new regions such as Central Brazil, improvement of land use practices to reduce soil erosion and nitrogen pollution, proper protection of streams and riparian ecosystems, banning of sugarcane burning practices, and fair working conditions for sugarcane cutters. We also support the creation of a more constructive approach for international stakeholders and trade organizations to promote sustainable development for biofuel production in developing countries such as Brazil. Finally, we support the inclusion of environmental values in the price of biofuels in order to discourage excessive replacement of natural ecosystems such as forests, wetlands, and pasture by bioenergy crops. 相似文献
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The optimization models presented here represent a synthesis between input-output analysis and mathematical programming models for environmental pollution control. The pivotal construct is a social cost for each unit of consumption; it is derived from the input-output analysis and is used in the objective function of the mathematical programming models which seek to optimize the final value of bill of goods and bads. The theory of optimization with relative bounded variables in nonlinear programming is developed and utilized. 相似文献
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7.
Integrated environmental assessment of freshwater sediments: a chemical and ecotoxicological approach at the Alqueva reservoir 总被引:1,自引:0,他引:1
P. Palma L. Ledo S. Soares I. R. Barbosa P. Alvarenga 《Environmental geochemistry and health》2014,36(2):209-223
In order to study the pollution of an aquatic ecosystem, it is necessary to analyze not only the levels of chemical pollutants in water, but also those accumulated in the sediment matrix, as well as to assess its ecotoxicological status. The Alqueva reservoir, the largest artificial lake in Europe, was chosen as case study as it constitutes the most important water supply source in southern Portugal. It is located in the Guadiana River Basin, in a semi-arid region with high levels of water scarcity and where agriculture is one of the main activities. The evaluation of sediments comprised: (1) physical and chemical analysis (grain size, pH, organic matter, nitrogen, phosphorus); (2) potentially toxic trace elements (Cu, As, Pb, Cr, Cd, Zn and Ni); and (3) ecotoxicological evaluation with Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Heterocypris incongruens. Total trace element concentrations indicated that As, Cd, and Pb surpassed the Canadian levels for the protection of aquatic life, in most of Alqueva’s sites. The results of the toxicity assessment showed that some locations induced acute and chronic toxicity in the species used. Further, the H. incongruens was the most sensitive species as far as the contamination found in the sediment is concerned, followed by the bacteria V. fischeri. This integrative approach, together with the water column quality assessment, allowed a comprehensive evaluation of the environmental quality of this strongly modified water body and will allow the implementation of remediation strategies to obtain a good ecological potential as proposed in the Water Framework Directive. 相似文献
8.
K. Srogi 《Environmental Chemistry Letters》2007,5(4):169-195
Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds with two or more fused aromatic rings. They
have a relatively low solubility in water, but are highly lipophilic. Most of the PAHs with low vapour pressure in the air
are adsorbed on particles. When dissolved in water or adsorbed on particulate matter, PAHs can undergo photodecomposition
when exposed to ultraviolet light from solar radiation. In the atmosphere, PAHs can react with pollutants such as ozone, nitrogen
oxides and sulfur dioxide, yielding diones, nitro- and dinitro-PAHs, and sulfonic acids, respectively. PAHs may also be degraded
by some microorganisms in the soil. PAHs are widespread environmental contaminants resulting from incomplete combustion of
organic materials. The occurrence is largely a result of anthropogenic emissions such as fossil fuel-burning, motor vehicle,
waste incinerator, oil refining, coke and asphalt production, and aluminum production, etc. PAHs have received increased attention
in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic. Eight PAHs
(Car-PAHs) typically considered as possible carcinogens are: benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene,
benzo(a)pyrene (B(a)P), dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene. In particular, benzo(a)pyrene
has been identified as being highly carcinogenic. The US Environmental Protection Agency (EPA) has promulgated 16 unsubstituted
PAHs (EPA-PAH) as priority pollutants. Thus, exposure assessments of PAHs in the developing world are important. The scope
of this review will be to give an overview of PAH concentrations in various environmental samples and to discuss the advantages
and limitations of applying these parameters in the assessment of environmental risks in ecosystems and human health. As it
well known, there is an increasing trend to use the behavior of pollutants (i.e. bioaccumulation) as well as pollution-induced
biological and biochemical effects on human organisms to evaluate or predict the impact of chemicals on ecosystems. Emphasis
in this review will, therefore, be placed on the use of bioaccumulation and biomarker responses in air, soil, water and food,
as monitoring tools for the assessment of the risks and hazards of PAH concentrations for the ecosystem, as well as on its
limitations. 相似文献
9.
Using machine learning to advance synthesis and use of conservation and environmental evidence
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S.H. Cheng C. Augustin A. Bethel D. Gill S. Anzaroot J. Brun B. DeWilde R.C. Minnich R. Garside Y.J. Masuda D.C. Miller D. Wilkie S. Wongbusarakum M.C. McKinnon 《Conservation biology》2018,32(4):762-764
10.
Quantitative polymerase chain reaction (qPCR) for the identification and quantification of microbes has become a common tool
for the study of harmful algal blooms (HABs). We developed a qPCR method for the diatom genus Pseudo-nitzschia. Several species of this genus form toxic blooms through the production of the neurotoxin domoic acid (DA). Outbreaks of
toxicity attributed to DA along the US west coast have caused sickness and death of marine mammals and seabirds through food
web contamination. The method developed here quantifies Pseudo-nitzschia spp. at low abundances in natural samples, thereby, providing a method to improve our understanding of the environmental
conditions leading to blooms of these species. This has been accomplished previously by techniques for identification and
quantification that are slow and laborious compared to qPCR. The approach was successfully tested and validated using eight
species of Pseudo-nitzschia and 33 non-target organisms and employed to follow local bloom dynamics. 相似文献
11.
Characterization of biological responses under different environmental conditions: A hierarchical modeling approach 总被引:1,自引:0,他引:1
A natural river system is organized as a nested hierarchy of interconnected habitats with specific environmental conditions to which the biological community has adapted. Due to this hierarchical structure, identifying the role of different stressors on the biological community is a formidable task. Efforts trying to link stressors to biological integrity have always been bound to the geographic scale of the selected study area, leading to scale-specific results. In this research, an attempt is made to lift this limitation and develop a hierarchical, scale-sensitive methodology that can identify the significant environmental stressors to the biological community at different scales. Sites with similar background environmental conditions are clustered using self-organizing maps (SOM). This is used to identify stressors which affect the biological community throughout the area of study - called environmental gradients or large-scale stressors. Subsequently, these clusters of similar observations (sampling sites) are progressively sub-divided using environmental variables with a significant but localized effect on the biological community - called small-scale stressors. A parent group of sites is split only when the resulting sub-groups have significantly different biological responses. At the end of this recursive sites decomposition procedure, the original set of observations is organized as a tree of environmentally homogeneous groups of observations characterized by unique biological responses to multiple stressors with different geographic extents. The developed hierarchical analysis methodology has been validated using a large-size dataset of environmental observations from the State of Ohio. Our results show that habitat degradation and increased nutrient loading are the large-scale stressors with a widespread impact in Ohio. Other stressors, such as heavy metals, pH or nitrate concentrations have significant albeit localized effects on biological integrity. 相似文献
12.
The Bayes decision is characterized and studied for a two-period decision problem involving a proposed resource development project. It is assumed that development is irreversible and that expectations about benefits and costs during the second period vary with experiences resulting from the first-period action. The amount and types of learning achieved depend upon the particular action taken during the first period. Flexible sequential decision procedures are compared with fixed once-and-for-all decisions. It is shown that under this specification, optimal development decisions are not necessarily more conservative when a sequential procedure is used. The possibility of reneging on a fixed decision is formally specified and studied. 相似文献
13.
Matching species traits to environmental variables: a new three-table ordination method 总被引:4,自引:0,他引:4
S. Dolédec D. Chessel C. J. F. ter Braak S. Champely 《Environmental and Ecological Statistics》1996,3(2):143-166
This paper addresses the question of studying the joint structure of three data tablesR,L andQ. In our motivating ecological example, the central tableL is a sites-by-species table that contains the number of organisms of a set of species that occurs at a set of sites. At the
margins ofL are the sites-by-environment data tableR and the species-by-trait data table Q. For relating the biological traits of organisms to the characteristics of the environment
in which they live, we propose a statistical technique calledRLQ analysis (R-mode linked toQ-mode), which consists in the general singular value decomposition of the triplet (R
t
D
I
LD
J
Q,D
q
,D
p
) whereD
I
,D
J
,D
q
,D
p
are diagonal weight matrices, which are chosen in relation to the type of data that is being analyzed (quantitative, qualitative,
etc.). In the special case where the central table is analysed by correspondence analysis,RLQ maximizes the covariance between linear combinations of columns ofR andQ. An example in bird ecology illustrates the potential of this method for community ecologists. 相似文献
14.
Mesoporous silicas such as MCM-41 and SBA-15 possess high surface areas, ordered nanopores, and excellent thermal stability, and have been often used as catalyst supports. Although mesoporous metal oxides have lower surface areas compared to mesoporous silicas, they generally have more diversified functionalities. Mesoporous metal oxides can be synthesized via a soft-templating or hard-templating approach, and these materials have recently found some applications in environmental catalysis, such as CO oxidation, N2O decomposition, and elimination of organic pollutants. In this review, we summarize the synthesis of mesoporous transition metal oxides using mesoporous silicas as hard templates, highlight the application of these materials in environmental catalysis, and furnish some prospects for future development. 相似文献
15.
Stefano Albanese Pietro Iavazzo Paola Adamo Annamaria Lima Benedetto De Vivo 《Environmental geochemistry and health》2013,35(3):283-297
The Sarno river basin covers an area of 500 km2 collecting the waters of Solofrana and Cavaiola tributaries. Originally it manly represents a source of livelihood for inhabitants by fishing and transporting goods; currently, the Sarno river, still partially used for irrigation, is affected by an extreme environmental degradation as a result of uncontrolled outflow of industrial waste. Within the framework of a wider geochemical prospecting project aiming at characterizing the whole territory of the Campania region, 89 stream sediment samples with a sampling density of 1 sample per 5 km2 were collected in the river basin and analyzed by means of inductively coupled plasma-mass spectrometry in order to assess the environmental conditions at a regional scale. A GIS-aided technique, based on both the actual distribution of potentially harmful elements and their regional background values, was used to generate the maps of the contamination factors and of the contamination degrees for As, Cd, Cr, Cu, Hg, Pb and Zn. Furthermore, a factor analysis was performed to assess the nature and the extent of contamination sources for the river sediments. Results showed that the Sarno river basin could be divided in two “environmental status” units: one, low contaminated, corresponding to the hilly and mountain areas, and the second, from moderately to very highly contaminated, corresponding to the economically developed areas of the valley floor characterized by a high population density. This work was developed within a project that aims to investigate the relationships between environmental pollution and human health by analyzing environmental media (stream sediments, water, soil and vegetation) together with human hair of resident population. In this context, the spatial correlation between the extremely compromised environmental conditions of developed areas and the incidence rate of liver cancer in the same area was also explored posing the need of a careful costs/benefits analysis to assess whether the deterioration of the environment, that could adversely affect the conditions of public health, is worth the economic development. 相似文献
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17.
Yang Dong Yi Liu Jining Chen Yebin Dong Benliang Qu 《Frontiers of Environmental Science & Engineering》2012,6(5):734-742
Forecasts of industrial emissions provide a basis for impact assessment and development planning. To date, most studies have assumed that industrial emissions are simply coupled to production value at a given stage of technical progress. It has been argued that the monetary method tends to overestimate pollution loads because it is highly influenced by market prices and fails to address spatial development schemes. This article develops a land use-based environmental performance index (L-EPI) that treats the industrial land areas as a dependent variable for pollution emissions. The basic assumption of the method is that at a planning level, industrial land use change can represent the change in industrial structure and production yield. This physical metric provides a connection between the state-of-the-art and potential impacts of future development and thus avoids the intrinsic pitfalls of the industrial Gross Domestic Product-based approach. Both methods were applied to examine future industrial emissions at the planning area of Dalian Municipality, North-west China, under a development scheme provided by the urban master plan. The results suggested that the LEPI method is highly reliable and applicable for the estimation and explanation of the spatial variation associated with industrial emissions. 相似文献
18.
Boelens Richard G. V. 《Journal of Coastal Conservation》1996,2(1):169-174
The Irish Sea's distinctive hydrographic features present unique opportunities for research into the complex processes that
regulate shelf-sea ecosystems. Such studies are essential in developing capabilities to detect and evaluate change in marine
environments. A 1993 review showed almost 230 projects underway on the Irish Sea, spanning all the major fields of marine
science. But a large proportion of research projects failed to indicate the purpose of the work; overall, there was a remarkable
absence of clarity and specificity in the objectives. Progress in some fields is also hampered by insufficient coordination
and cohesion; at present there are no standing arrangements between Ireland and the United Kingdom that provide for bilateral,
co-ordination of scientific work in the area. There is clearly a need for a more planned and integrated Irish Sea science
programme to provide information for management purposes and also to advance scientific understanding of the components and
functions of Irish Sea ecosystems, and how and why they change with time. There is a common belief that the first of these
predominantly involves monitoring, and the second research. However, the paper cautions that this is a dubious and unnecessary
distinction. A strategy aimed at better integration of research and monitoring (e.g. a framework of linked objectives and
targets) could substantially increase the information dividend from current investments in Irish Sea science. Based on a joint
Irish/UK review, this paper outlines studies and approaches that are seen as key elements of a future, more relevant and costeffective
research programme for the Irish Sea. 相似文献
19.
This article proposes to use nutrient-orientated environmental efficiency (EE) measures to construct a nutrient total factor productivity index (NTFP). Since nutrient-orientated EE measures are consistent with the materials balance principle, NTFP index is superior to other existing TFP indexes. An empirical study on the environmental performance of an agricultural sector in 30 OECD countries from 1990 to 2003 yielded several important findings. First, these countries should be able to produce current outputs with at least 50% less aggregate eutrophying power, implying that they should have been able to substantially reduce the potential for eutrophication. Second, traditional TFP has grown by 1.6% per annum due to technical progress; however, there are lags in the responses of several countries to this technical progress. Third, environmental TFP has grown at a slower rate than traditional TFP growth due to reductions in nutrient-orientated allocative efficiency. Finally, changes in input combinations could have significantly improved environmental efficiency and productivity. These findings favor policy interventions and faster technological transfer to improve environmental performance. 相似文献
20.
Pascal Monestiez Dominique Courault Denis Allard Françoise Ruget 《Environmental and Ecological Statistics》2001,8(4):297-309
The air temperature is one of the main input data in models for water balance monitoring or crop models for yield prediction. The different phenological stages of plant growth are generally defined according to cumulated air temperature from the sowing date. When these crop models are used at the regional scale, the meteorological stations providing input climatic data are not spatially dense enough or in a similar environment to reflect the crop local climate. Hence spatial interpolation methods must be used. Climatic data, particularly air temperature, are influenced by local environment. Measurements show that the air above dry surfaces is warmer than above wet areas. We propose a method taking into account the environment of the meteorological stations in order to improve spatial interpolation of air temperature. The aim of this study is to assess the impact of these corrected climatic data in crop models. The proposed method is an external drift kriging where the Kriging system is modified to correct local environment effects. The environment of the meteorological stations was characterized using a land use map summarized in a small number of classes considered as a factor influencing local temperature. This method was applied to a region in south-east France (150×250 km) where daily temperatures were measured on 150 weather stations for two years. Environment classes were extracted from the CORINE Landcover map obtained from remote sensing data. Categorical external drift kriging was compared to ordinary kriging by a cross validation study. The gain in precision was assessed for different environment classes and for summer days. We then performed a sensitivity study of air temperature with the crop model STICS. The influence of interpolation corrections on the main outputs as yield or harvest date is discussed. We showed that the method works well for air temperature in summer and can lead to significant correction for yield prediction. For example, we observed by cross validation a bias reduction of 0.5 to 1.0°C (exceptionally 2.5°C for some class), which corresponds to differences in yield prediction from 0.6 to 1.5 t/ha. 相似文献