Characterizing pesticide sorption and degradation in microscale biopurification systems using column displacement experiments

Biopurification systems treating pesticide contaminated water are very efficient, however they operate as a black box. Processes inside the system are not yet characterized. To optimize the performance, knowledge of degradation and retention processes needs to be generated. Therefore, displacement experiments were carried out for four pesticides (isoproturon, bentazone, metalaxyl, linuron) in columns containing different organic mixtures. Bromide, isoproturon and bentazone breakthrough curves (BTCs) were well described using the convection-dispersion equation (CDE) and a first-order degradation kinetic approach. Metalaxyl and linuron BTCs were well described using the CDE model expanded with Monod-type kinetics. Freundlich sorption, first-order degradation and Monod kinetics coefficients were fitted to the BTCs. Fitted values of the distribution coefficient K_f,column were much lower than those determined from batch experiments. Based on mobility, pesticides were ranked as: bentazone > metalaxyl - isoproturon > linuron. Based on degradability, pesticides were ranked as: linuron > metalaxyl - isoproturon > bentazone.     

Transport and degradation of pesticides in a biopurification system under variable flux, part I: A microcosm study

The efficiency of a biopurification system, developed to treat pesticide contaminated water, is to a large extent determined by the chemical and hydraulic load. Insight into the behaviour of pesticides under different fluxes is necessary. The behaviour of metalaxyl, bentazone, linuron, isoproturon and metamitron was studied under three different fluxes with or without the presence of pesticide-primed soil in column experiments. Due to the time-dependent sorption process, retention of the pesticides with intermediate mobility was significantly influenced by the flux. The higher the flux, the slower pesticides will be sorbed, which resulted in a lower retention. Degradation of the intermediate mobile pesticides was also submissive to variations in flux. An increase in flux, led to a decrease in retention, which in turn decreased the opportunity time for biodegradation. Finally, the presence of pesticide-primed soil was only beneficial for the degradation of metalaxyl.     

Democratic Debate and Mediated Discourses on Climate Change: From Consensus to De/politicization

Starting from a risk conflicts perspective, this article challenges two common assumptions of existing research on climate change in public and media discourses. It argues that the evaluation of these discourses on the extent to which these either accurately reflect a scientific consensus or contribute to achieving social consensus insufficiently takes account of the exclusionary mechanisms it starts from. A conceptual and empirical framework is subsequently put forward which allows one to evaluate mediated discourses in terms of the extent to which democratic debate and citizenship are encouraged. Such analysis can reveal the discursive strategies underlying processes of politicization and depoliticization. This perspective is illustrated by an analysis of a local case study: the “Sing for the Climate” campaign. We conclude by calling for a broad systematic research agenda revealing the extent to which de/politicizing discourses are found to influence public and media discourses.     

Sampling procedure for the foliar analysis of deciduous trees

Sampling can be the source of the greatest errors in the overall results of foliar analysis. This paper reviews the variability in heavy metal concentrations in tree crowns, which is a feature that should be known and understood when designing a suitable leaf sampling procedure. The leaf sampling procedures applied in 75 articles were examined. Most of the environmental studies used a closely related form of the UN/ECE-EC leaf sampling procedure, which was developed for the long-term monitoring of forest condition. Studies with objectives outside the UN/ECE-EC field of application should utilize a sampling procedure that is in accordance with the objectives of the study and based on the observed variation in pilot and similar studies. The inherent sources of heavy metal variability inside the stand, i.e. the crown class, stand management, site properties, crown dimensions, infections, seasons, etc. were discussed, but the underlying causes of this variability are rarely understood. The inherent variability in tree crowns is the reason for using leaf sampling as a tool in pollution studies. The objectives of a pollution study determine which sources of variability are utilized by the researcher.     

Vegetation recovery on closed paths in temperate deciduous forests

The objective of this study was to evaluate vegetation recovery on footpaths in woodland that have been closed for access for 6 years. A vegetation survey was conducted in four mesophile forests, in transects perpendicular to the trail. Analyses concentrated on the direction and rate of the recovery process. Vegetation on trail sides in these ecosystems recovered substantially. Non-metric multidimensional scaling based upon species composition separated the four sample locations and each cluster contained representatives of the three major trail zones: path centre, transition and undisturbed zones. Analysis of distribution of life forms, plant strategies and seedbank longevity indices showed no differences between trail zones. This indicates that vegetation on the path centre is likely to recover towards the plant composition of the undisturbed zone. Ellenberg values indicate that environmental variation is not related to former path structures, as significant variability was only observed between the forest sites. Furthermore, the analysis concentrated on characteristics of species relevant to the recovery process.     

Parkmanagement as a tool for careful industrial land‐use planning

During the second half of the 1990s the combination of ecological and economic targets in industrial land‐use planning became an official part of spatial‐economic policy in the Netherlands. A growing number of business locations are now being developed or re‐developed as ‘sustainable business sites’. At the same time, ‘parkmanagement’ came into existence as a new tool for development and control of business sites for industry and services. Parkmanagement is now regarded as one of the obvious instruments to realize sustainable (or ‘careful’) land use on business parks. However, there is now a question about whether it is wrong for local governments (which in the Dutch case are responsible for most land development schemes) to have so much participation in parkmanagement initiatives. There is a threat that local governments are welcoming parkmanagement as a fashionable way to impose new regulations on business establishments, and ignore the evidence from practice. Such evidence shows that parkmanagement is most successful when organized with the involvement of private enterprises. This would also be more in line with the modern interaction‐oriented planning theory (consensus planning). The paper describes the principal dilemmas facing local governments in business site development, the theoretical options for influencing the development process of the sites, and the set of actions that could be part of a parkmanagement strategy. These can be arranged on a ‘ladder’ or range of activities, from rather simple facilities serving individual companies' needs, such as maintenance and security, to more complex co‐operation projects in combined transport or energy supply, and ultimately lead to schemes for connecting material flows of production processes. The successive stages of the ladder of business site facilities can be combined with different forms and stages of process organization.     

Historical processes constrain patterns in global diatom diversity

There is a long-standing belief that microbial organisms have unlimited dispersal capabilities, are therefore ubiquitous, and show weak or absent latitudinal diversity gradients. In contrast, using a global freshwater diatom data set, we show that latitudinal gradients in local and regional genus richness are present and highly asymmetric between both hemispheres. Patterns in regional richness are explained by the degree of isolation of lake districts, while the number of locally coexisting diatom genera is highly constrained by the size of the regional diatom pool, habitat availability, and the connectivity between habitats within lake districts. At regional to global scales, historical factors explain significantly more of the observed geographic patterns in genus richness than do contemporary environmental conditions. Together, these results stress the importance of dispersal and migration in structuring diatom communities at regional to global scales. Our results are consistent with predictions from the theory of island biogeography and metacommunity concepts and likely underlie the strong provinciality and endemism observed in the relatively isolated diatom floras in the Southern Hemisphere.     

Economic and financial analysis on rainwater harvesting for agricultural irrigation in the rural areas of Beijing

Since 2006, around 600 rainwater harvesting systems have been constructed for agricultural irrigation in Beijing. The financial and economic implications of using these systems are discussed less. It is important to understand the effectiveness of the investments spent on the rainwater harvesting systems. The paper aims to analyze economic and financial performance of the constructed rainwater harvesting systems in rural areas of Beijing through the method of cost benefit analysis. The economic analysis focuses on determining the contribution of rainwater harvesting systems to the development of society, carried out from the point of view of government. The financial analysis allows comparison of the financial implications of using groundwater with using rainwater for agricultural irrigation from the point of view of individual participant, namely the local farmers. The results show that the rainwater harvesting systems are economically feasible. This means rainwater harvesting have positive effects for society. However, the financial feasibility of rainwater harvesting systems depends on the charge for groundwater and on the size of the rainwater harvesting systems. If groundwater is not charged, the rainwater harvesting systems are not financially feasible. If groundwater is charged at 2 Yuan/m³, only large size systems are financially feasible while small and middle sizes systems are not financially feasible. Under these circumstances, only large systems can run smoothly, while farmers may not use the small and medium-size systems.     

Ecomorphology and disease: cryptic effects of parasitism on host habitat use, thermoregulation, and predator avoidance

Parasites can cause dramatic changes in the phenotypes of their hosts, sometimes leading to a higher probability of predation and parasite transmission. Because an organism's morphology directly affects its locomotion, even subtle changes in key morphological traits may affect survival and behavior. However, despite the ubiquity of parasites in natural communities, few studies have incorporated parasites into ecomorphological research. Here, we evaluated the effects of parasite-induced changes in host phenotype on the habitat use, thermal biology, and simulated predator-escape ability of Pacific chorus frogs (Pseudacris regilla) in natural environments. Frogs with parasite-induced limb malformations were more likely to use ground microhabitats relative to vertical refugia and selected less-angled perches closer to the ground in comparison with normal frogs. Although both groups had similar levels of infection, malformed frogs used warmer microhabitats, which resulted in higher body temperatures. Likely as a result of their morphological abnormalities, malformed frogs allowed a simulated predator to approach closer before escaping and escaped shorter distances relative to normal frogs. These data indicate that parasite-induced morphological changes can significantly alter host behavior and habitat use, highlighting the importance of incorporating the ubiquitous, albeit cryptic, role of parasites into ecomorphological research.     

Effects of Coffee Management Intensity on Composition, Structure, and Regeneration Status of Ethiopian Moist Evergreen Afromontane Forests

The effect of arabica coffee management intensity on composition, structure, and regeneration of moist evergreen Afromontane forests was studied in three traditional coffee-management systems of southwest Ethiopia: semiplantation coffee, semiforest coffee, and forest coffee. Vegetation and environmental data were collected in 84 plots from forests varying in intensity of coffee management. After controlling for environmental variation (altitude, aspect, slope, soil nutrient availability, and soil depth), differences in woody species composition, forest structure, and regeneration potential among management systems were compared using one way analysis of variance. The study showed that intensification of forest coffee cultivation to maximize coffee production negatively affects diversity and structure of Ethiopian moist evergreen Afromontane forests. Intensification of coffee productivity starts with the conversion of forest coffee to semiforest coffee, which has significant negative effects on tree seedling abundance. Further intensification leads to the conversion of semiforest to semiplantation coffee, causing significant diversity losses and the collapse of forest structure (decrease of stem density, basal area, crown closure, crown cover, and dominant tree height). Our study underlines the need for shade certification schemes to include variables other than canopy cover and that the loss of species diversity in intensively managed coffee systems may jeopardize the sustainability of coffee production itself through the decrease of ecosystem resilience and disruption of ecosystem services related to coffee yield, such as pollination and pest control.