Mining manganese nodules: Potential economic and environmental effects ag]

This article examines the economic implications of mining or of not mining manganese nodules and summarizes potential ecological consequences. Apart from possible net economic benefits to certain countries, mining the nodules is not regarded as an economic or strategic necessity. It is concluded that expansion of basic research on oceanfloor ecosystems must be granted high priority. It is in the best interest of developed countries to become signatories of the LOS Convention in order to participate in the development of the regulatory framework and to avoid the antagonism of the international community.     

Curbside collection of recyclables. II. Simulation and economic analysis

Curbside collection of recyclable material can be expensive because the inherent costs of curbside collection are high, but also because amounts collected per residence are small compared to the total waste stream, and extra activity may be required, such as sorting. In this paper a simulation model is used to investigate the effect of collection method and route characteristics on route time. The simulation models presented calculate set-out amount based on route characteristics, set-out rate (SOR), and participation rate (PR). Route times are estimated for various conditions: constant SOR, constant PR, and constant set-out amount. Furthermore, a method for using route time to estimate vehicle and labor needs is presented, and used to estimate economic costs for one and two-person crew collection methods for the three simulation conditions mentioned above. The two-person crew is found to cost less than the one-person crew, for most simulated conditions.     

The future place of recycling in household waste policy: the case of France

To be rightly implemented, an environmental policy ought to set an institutional framework (goals, rules and instruments) which incents decentralised actors to adopt the appropriate range of technologies. In the household waste management policy, the development of valorisation techniques (and particularly recycling) must be supported by convenient instruments and incentives. The paper analyses the problems encountered with the French household waste policy to ensure the takeoff of recycling techniques. At the moment, a rather under-proportioned institutional setting leads to favour the adoption of incineration with energy recovery at the expenses of recycling. This tends to create a structural bias in favour of incineration.     

Contemporary Western Rural USA Economic Composition: Potential Implications for Environmental Policy and Research

/ The rural West of the United States is considered strongly antienvironment. The traditional economic reliance of the area on natural resources has long explained this antienvironment stance. The region consistently elects federal officials who as a group consistently vote against environmental bills and seek to undo existing federal environmental regulation. These politicians defend their antienvironment actions based on their perception of the economic composition and interests of the region. Recent studies, however, have suggested that rural residents are increasingly concerned about environmental issues. These studies, however, lack a consistent theoretical basis. This article uses an alternative economic typing system to examine the economic composition of rural Idaho and suggests that the results found using the alternative typing system might provide a theoretical basis to explain why some studies are finding increased rural environmental support. The results show that rural Idaho is much more economically diverse using this alternative typing methodology compared to the outcomes of traditional USDA economic methodologies. The policy and research implications of these findings are examined.KEY WORDS: Rural; Environmental policy; Economic composition     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Small Populations and Offspring Sex-Ratio Deviations in Eagles

Abstract:  Stochastic variation of sex ratio has long been appreciated as a potential factor driving small populations to extinction, but it is not the only source of sex-ratio bias in small populations. We examined whether some consequences of sex allocation could affect extinction risk in small populations of size-dimorphic birds such as eagles. We report variations in sex ratio at fledging from a long-term study of a declining population of Spanish Imperial Eagles ( Aquila adalberti ). Nestling sex-ratio deviation apparently was mediated by age of breeders, whereas territory quality had no obvious effect. Adult–adult pairs produced the same proportion of both sexes in high- or low-density situations, but pairs with at least one member in nonadult plumage class produced more males. As the population declined over a period of years, the proportion of breeders with immature plumage increased; consequently, the proportion of fledgling males increased. However, when population density was high, the proportion of breeders with immature plumage decreased and more female offspring were produced. This relationship between population density, composition of breeder age, and fledgling sex ratios allowed us to make predictions of extinction risk due to nonstochastic deviations of sex ratio in small, declining populations. In the study population, on the basis of the Vortex simulation results, an estimated reduction of 42.5% in predicted mean time to extinction was attributed solely to biased sex ratio.     

FDA-PI双色荧光法检测蓝藻细胞活性的研究

对FDA-PI双色荧光法检测水华鱼腥藻和铜绿微囊藻的活性进行了研究,用荧光显微镜对染色结果进行测定.结果表明,在蓝色光激发下(495nm),活细胞被双醋酸荧光素FDA染成亮绿色,死亡细胞被碘化丙锭PI染成红色.染色效率与原植体类型和细胞密度有关.对细胞密度为6×107—7×109个·l-1的铜绿微囊藻,FDA染色效率可达94%以上.对细胞密度为4×107—5×108个·l-1的水华鱼腥藻,FDA染色效率可达91%以上,但细胞密度增大到5×109个·l-1时,由于藻丝体易卷曲在一起,FDA染色率下降到67%.对死亡细胞,PI染色率基本都可达到100%.因此,用FDA-PI检测活细胞和死亡细胞混合的细胞悬液,可根据细胞所发出的不同荧光而判断细胞活性.     

Assessing combined toxic effects of tetracycline and P25 titanium dioxide nanoparticles using Allium cepa bioassay

• UVA pre-irradiation to TiO₂ NPs enhanced its toxicity toward plant A. cepa. • UVA TiO₂ NPs increased intracellular ROS, resulting in more cell damage. • Cell death enhanced cell permeability and increased uptake of NPs. • Being highly toxic (EC₅₀ = 0.097 µmol/L), TC did not increase ROS generation. • Even at a low dose, TC enhanced the toxic potential of TiO₂ NPs significantly. Usage of titanium dioxide nanoparticles (TiO₂ NPs) and tetracycline (TC) has increased significantly in the present era. This leads to their release and accumulation in the environment. Both the compounds, individually, can have adverse toxic effects on the plants. Their binary mixtures can increase this degree of damage. The present study aimed to evaluate the toxicity of both the contaminants in individual and binary mixtures in Allium cepa. Further, the toxicity of TiO₂ NPs upon UVA pre-irradiation was also measured. Results showed that UVA pre-irradiated NPs (UVA-TiO₂ NPs) had a significant decrease in cell viability than their non-irradiated counterparts (NI-TiO₂), denoting an increase in photocatalytic activity upon UVA pre-irradiation. Very low concentrations of TC (EC₁₀ = 0.016 µmol/L) mixed with TiO₂ NPs significantly increased the toxicity for both UVA-TiO₂ and NI-TiO₂ NPs. Intracellular ROS generation was significantly high for UVA-TiO₂ NPs. However, TC did not have any effects on ROS production. Both the compounds exhibited genotoxic potential in A. cepa. Different chromosomal abnormalities like anaphase bridges, telophase bridges, laggard chromosomes, binucleate cells, etc. were observed. The binary mixture of UVA-TiO₂ NPs and TC showed the highest chromosomal aberrations (64.0%±1.26%) than the mixture with NI-TiO₂ or the individual contaminants. This decreased significantly after recovery (46.8%±1.92%), denoting the self-repair processes. This study proved that UVA-TiO₂ NPs were more toxic and could be enhanced further when mixed with a sub-lethal concentration of TC. This work will help to assess the risk of both compounds in the environment.     

Towards a common Mediterranean framework for beach nourishment projects

Integrated Coastal Zone Management as a strategy for achieving conservation and sustainable multiple use of the coastal zone includes various types of management initiatives. Due to natural phenomena such as tides and winds and to social and economic activities, coastal areas undergo transformation. Coastal erosion and the disappearance of beaches as a result of wrong planning decisions and lack of effective legislation are among the most damaging effects and to reverse them requires application of a series of engineering techniques. Beach nourishment projects as a way towards shore protection and utilization through recreational purposes in the Spanish and Italian coasts are noteworthy in this respect. In beach nourishment projects, the roles of various entities, both public and private, should be clearly indicated and in the evaluation and execution stage a series of questions should be answered for the successful completion of any nourishment project. Past projects in the Mediterranean and experiences from recent Italian projects in Anzio and Nettuno confirm this. For example, dredging of the entrance channel of the port of Anzio enabled middle-sized ferryboats once again to enter the port (which had not been possible before). This will in turn increase the tourism potential of the town. Nourishment of two beaches at these sites prevented further erosion and provided more area for recreational purposes. Expected economic contribution of beach nourishments to the regional authority was estimated for Nettuno and Anzio; the resulting theoretical payback period was found to be 3 yr for the former and 15 yr for the latter.     

成渝经济区陆地植被碳储量动态及碳汇战略研究

利用卫星遥感数据,对2000年-2007年间成渝经济区耕地、森林和草地等陆地植被的碳储量进行了估算.结果表明:(1)7年间耕地和草地分别减少了2 388.89 km2和1 231.05 km2,林地增加了2 908.70 km2,其中耕地主要转出为林地和建设用地,草地转出主要为林地和耕地;(2)7年间成渝经济区碳储量呈逐渐增加的趋势,共增加了625.16万tC/a,年增长率为0.21%.其中耕地、草地碳储量分别减少了165.79万tC/a和933.87万tC/a,林地碳储量增加了1 724.81万tC/a.(3)结合碳储量变化的趋势,提出了以打造低碳城市为目标的成渝经济区碳汇战略.