Predicting methyl iodide emission, soil concentration, and pest control in a two-dimensional chamber system

Due to ever-increasing state and federal regulations, the future use of fumigants is predicted on reducing negative environmental impacts while offering sufficient pestcontrol efficacy. To foster the development of a best management practice, an integrated tool is needed to simultaneously predict fumigant movement and pest control without having to conduct elaborate and costly experiments. The objective of this study was (i) to present a two-dimensional (2-D) mathematical model to describe both fumigant movement and pestcontrol and (ii) to evaluate the model by comparing the simulated and observed results. Both analytical and numerical methods were used to predict methyl iodide (MeI) transport and fate. To predict pest control efficacy, the concentration-time index (CT) was defined and a two-parameter logistic survival model was used. Dose-response curves were experimentally determined for MeI against three types of pests (barnyardgrass [Echinochloa crus-galli] seed, citrus nematode [Tylenchulus semipenetrans], and fungi [Fusarium oxysporum]). Methyl iodide transport and pest control measurements collected from a 2-D experiimental system (60 by 60 cm) were used to test the model. Methyl iodide volatilization rates and soil gas-phase concentrations over time were accurately simulated by the model. The mass balance analysis indicates that the fraction of MeI degrading in the soil was underestimated when determined by the appearance of iodide concentration. The experimental results showed that after 24 h of MeI fumigation in the 2-D soil chamber, fungal population was not suppressed; > 90% of citrus nematodes were killed; and barnyardgrass seeds within 20-cm distance from the center were affected. These experimental results were consistent with the predicted results. The model accurately estimated the MeI movement and control of various pests and is a powerful tool to evaluate pesticides in terms of their negative environmental impacts and pest control under various environmental conditions and application methods.     

Mechanistic aspects of the thermal formation of halogenated organic compounds including polychlorinated dibenzo‐p‐dioxins part III†: Thermodegradation of organometallics and polymers

Thermodegradation of organometallics viz. RMX (where M = Mg, Ti, Pd, Sn, Si, Al; and X =halogen atom) provides corresponding haloorganics i.e. RX. 1,2‐Shifts of H and Cl on the carbene species like CH₂F. CF and CFCL₂, CF produced from R. CF. Si F₃ (R = CH₂F, CFCl₂) are preferred to that of fluorine. The thermolysis of R.CF₂. Si Cl₃ (R = CH₂F) produces chloroolefins via halogen exchange. Major products of thermal degradation of poly (vinyl chloride) (PVC) are HCl and benzene but the mechanism of PVC thermodegradation is still a matter of dispute. The thermal cracking of lignins yields substituted phenols.     

Mangrove forest structure and productivity in the Fly River estuary,Papua New Guinea

In April, July and August 1989 and February 1990, the delta region of the Fly River was surveyed to establish the aerial extent of mangrove forests, their species composition, tree densities and basal areas, and potential net primary production. Mangrove forests cover 87 400 ha, mainly on islands within the delta. Twentynine mangrove plant species were recorded, but there were only three major forest types in the delta.Rhizophora apiculata-Bruguiera parviflora forests (hereafterRhizophora-Bruguiera forests) predominated in regions where river water salinities were >10. These forests covered 31 500 ha and had mean total tree densities and basal areas of 2027 stems ha^–1 and 21 m² ha^–1, respectively. Forests of the palmNypa fruticans (hereafterNypa forests) covered 38 400 ha, mainly in regions where river salinities were ~1 to 10, and had mean total densities and basal areas of 4431 stems ha^–1 and 38 m² ha^–1, respectively. Forests dominated byAvicennia marina and/orSonneratia lanceolata (hereafterAvicennia-Sonneratia forests) predominated on accreting banks of sediment and covered 17 500 ha. In very low-salinity (< 1) regions there are large monospecific stands ofS. lanceolata. Mean total densities and basal areas forAvicennia-Sonneratia forests were 7036 stems ha^–1 and 22 m² ha^–1, respectively. Mean net primary productivity (kg C ha^–1 d^–1) was estimated to be 26.7, 27.1 and 19.0 forRhizophora-Bruguiera, Nypa andAvicennia-Sonneratia forests, respectively. Total daily net primary production by all mangrove forests was estimated at 2214 t carbon. Using assumptions based on work in tropical Australia, it was estimated that ~678 t carbon (or 31% of primary production) were exported daily from mangrove forests to the waters of the delta.Contribution No. 550 from the Australian Institute of Marine Science     

Preventing corruption in humanitarian assistance: perceptions, gaps and challenges

Corruption is a threat to the purpose of humanitarian assistance. Until fairly recently, humanitarian assistance has not been considered an important arena in broader efforts aimed at curbing corruption, and corruption has not always been considered a particularly important concern for humanitarian assistance despite the obviously challenging nature of the context of humanitarian emergencies. Corruption, though, is a threat to humanitarian action because it can prevent assistance from getting to the people who most need it, and because it can potentially undermine public support for such assistance. This paper examines perceptions of corruption and its affects, documents best practices, and outlines gaps in understanding. It suggests recommendations for improving the capacity of humanitarian agencies to prevent and manage the risk of corruption. Agencies have taken steps to combat corruption and improve accountability--downwards and upwards--but scope remains for improvement and for greater sharing of learning and good practice.     

Observations on the workshop as a means of improving communication between holders of traditional and scientific knowledge

Traditional ecological knowledge (TEK) and the information and insights it offers to natural resource research and management have been given much attention in recent years. On the practical question of how TEK is accessed and used together with scientific knowledge, most work to date has examined documentation and methods of recording and disseminating information. Relatively little has been done regarding exchanges between scientific and traditional knowledge. This paper examines three workshop settings in which such exchanges were intended outcomes. The Barrow Symposium on Sea Ice, the Exxon Valdez Oil Spill Restoration Program Synthesis/Information Workshops, and the Alaska Beluga Whale Committee illuminate certain features of the preparation, format, and context of workshops or series of workshops and their eventual outcomes and influence. The examples show the importance of long-term relationships among participants and thorough preparation before the actual workshop. Further research should look more systematically at the factors that influence the success of a given workshop and the various ways in which participants perceive success.     

Cautioning against overemphasis of normative constructs in conservation decision making

Questions around how to conserve nature are increasingly leading to dissonance in conservation planning and action. While science can assist in unraveling the nature of conservation challenges, conservation responses rely heavily on normative positions and constructs to order actions, aid interpretations, and provide motivation. However, problems can arise when norms are mistaken for science or when they stymy scientific rigor. To highlight these potential pitfalls, we used the ethics-based tool of argument analysis to assess a controversial conservation intervention, the Pelorus Island Goat Control Program. The program proponents' argument for restorative justice was unsound because it relied on weak logical construction overly entrenched in normative assumptions. Overreliance on normative constructs, particularly the invocation of tragedy, creates a sense of urgency that can subvert scientific and ethical integrity, obscure values and assumptions, and increase the propensity for flawed logic. This example demonstrates how the same constructs that drive biodiversity conservation can also drive poor decision making, spur public backlash, and justify poor animal welfare outcomes. To provide clarity, a decision-making flowchart we devised demonstrates how values, norms, and ethics influence one another. We recommend practitioners follow 3 key points to improve decision making: be aware of values, as well as normative constructs and ethical theories that those values inform; be mindful of overreliance on either normative constructs or ethics when deciding action is justified; and be logically sound and transparent when building justifications. We also recommend 5 key attributes that practitioners should be attentive to when making conservation decisions: clarity, transparency, scientific integrity, adaptiveness, and compassion. Greater attention to the role of norms in decision making will improve conservation outcomes and garner greater public support for actions.     

Consequences of increased terrestrial dissolved organic matter and temperature on bacterioplankton community composition during a Baltic Sea mesocosm experiment

Predicted increases in runoff of terrestrial dissolved organic matter (DOM) and sea surface temperatures implicate substantial changes in energy fluxes of coastal marine ecosystems. Despite marine bacteria being critical drivers of marine carbon cycling, knowledge of compositional responses within bacterioplankton communities to such disturbances is strongly limited. Using 16S rRNA gene pyrosequencing, we examined bacterioplankton population dynamics in Baltic Sea mesocosms with treatments combining terrestrial DOM enrichment and increased temperature. Among the 200 most abundant taxa, 62 % either increased or decreased in relative abundance under changed environmental conditions. For example, SAR11 and SAR86 populations proliferated in combined increased terrestrial DOM/temperature mesocosms, while the hgcI and CL500-29 clades (Actinobacteria) decreased in the same mesocosms. Bacteroidetes increased in both control mesocosms and in the combined increased terrestrial DOM/temperature mesocosms. These results indicate considerable and differential responses among distinct bacterial populations to combined climate change effects, emphasizing the potential of such effects to induce shifts in ecosystem function and carbon cycling in the future Baltic Sea.     

The effects of tourism and globalization over environmental degradation in developed countries

Environmental Science and Pollution Research - This paper focuses on long-term evidence on economic growth, international tourism, globalization, energy consumption and carbon dioxide (CO2)...     

Green defaults: Information presentation and pro-environmental behaviour

There is inconsistency in many people's choice of electricity. When asked, they say they prefer a ‘green’ (i.e., environmentally friendly) source for this energy. Yet, although green electricity is available in many markets, people do not generally buy it. Why not? Motivated by behavioural decision research, we argue that the format of information presentation drastically affects the choice of electricity. Specifically, we hypothesise that people use the kind of electricity that is offered to them as the default. We present two natural studies and two experiments in the laboratory that support this hypothesis. In the two real-world situations, there was a green default, and most people used it. In the first laboratory experiment, more participants chose the green utility when it was the default than when ‘grey’ electricity was the default. In the second laboratory experiment, participants asked for more money to give up green electricity than they were willing to pay for it. We argue that changing defaults can be used to promote pro-environmental behaviour. Potential policy-making applications of this work are discussed.