Aggressive mating as a tragedy of the commons in the water strider Aquarius remigis

The tragedy of the commons usually refers to the overexploitation of resources such as food or water. Here, we show in a laboratory study that competition among males for females can also result in a tragedy of the commons’ situation. Male water striders (Aquarius remigis) vary widely in their aggressiveness toward pursuing females. The most aggressive males prevent females from feeding and cause them to leave the water surface, where they are unavailable to all males. Groups of nonaggressive males are collectively three times more fit than groups of hyperaggressive males, but hyperaggressive males are more successful than nonaggressive males within mixed groups. This is the classic tragedy of the commons’ situation, and it is likely to occur in many species that exhibit sexual conflict. We have also shown that individual differences in male aggression are stable across time and are not influenced by food or light regime, although all individuals become nonaggressive in the presence of fish predators.     

The ability of conditioned Microplitis croceipes (Hymenoptera: Braconidae) to distinguish between odors of aflatoxigenic and non-aflatoxigenic fungal strains

Summary. The parasitic wasp Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) learns to associate odors with food resources and subsequently exhibits a characteristic food-seeking behavior when encountering the learned odor. Wasps so conditioned, learned and subsequently demonstrated an ability to distinguish among aflatoxigenic and non-aflatoxigenic Aspergillus flavus and A. parasiticus strains. The effects of fungal species, strain, age (5, 10-12, 20, and 30 d) and growth media (potato dextrose agar, peanut agar and corn agar) on the learning and recognition responses of the conditioned wasps were examined. The level of differentiation between fungal strains by conditioned wasps was lowest when working with 5-d-old fungal cultures but increased with age and generally peaked with 20-d-old fungi. Wasps responded generally stronger to the fungal strain conditioned to independent of growth media. This ability of parasitic wasps to learn and distinguish fungal odors can open new avenues in insect learning.     

Carbonation of brine impacted fractionated coal fly ash: implications for CO2 sequestration

Coal combustion by-products such as fly ash (FA), brine and CO(2) from coal fired power plants have the potential to impact negatively on the environment. FA and brine can contaminate the soil, surface and ground water through leaching of toxic elements present in their matrices while CO(2) has been identified as a green house gas that contributes significantly towards the global warming effect. Reaction of CO(2) with FA/brine slurry can potentially provide a viable route for CO(2) sequestration via formation of mineral carbonates. Fractionated FA has varying amounts of CaO which not only increases the brine pH but can also be converted into an environmentally benign calcite. Carbonation efficiency of fractionated and brine impacted FA was investigated in this study. Controlled carbonation reactions were carried out in a reactor set-up to evaluate the effect of fractionation on the carbonation efficiency of FA. Chemical and mineralogical characteristics of fresh and carbonated ash were evaluated using XRF, SEM, and XRD. Brine effluents were characterized using ICP-MS and IC. A factorial experimental approach was employed in testing the variables. The 20-150 μm size fraction was observed to have the highest CO(2) sequestration potential of 71.84 kg of CO(2) per ton of FA while the >150 μm particles had the lowest potential of 36.47 kg of CO(2) per ton of FA. Carbonation using brine resulted in higher degree of calcite formation compared to the ultra-pure water carbonated residues.     

Community resilience,land degradation and endogenous lock-in effects: evidence from the Alento region,Campania, Italy

This study analyses social, economic and political “lock-ins” for understanding community resilience and land degradation. The study focuses on lock-ins from within communities, using four case study communities in Italy affected by land degradation. The analysis highlights the complex interrelationships between various lock-ins, and suggests that the communities are on declining resilience pathways that may lead to increasing difficulties in addressing land degradation issues in future.     

Metalaxyl toxicity, uptake, and distribution in several ornamental plant species

Phytoremediation depends on the ability of plants to tolerate and assimilate contaminants. This research characterized the interaction between several ornamental plant species and the fungicidal active ingredient, metalaxyl [N-(2,6-dimethylphenyl)-N-(methoxyacetyl)alanine methyl ester]. Species evaluated included sweetflag (Acorus gramineus Sol. ex Aiton), canna (Canna hybrida L. 'Yellow King Humbert'), parrotfeather [Myriophyllum aquaticum (Vell.) Verdc.], and pickerelweed (Pontederia cordata L.). Metalaxyl tolerance levels for each species were determined by exposing plants for 7 d to solutions containing 0, 5, 10, 25, 50, 75, or 100 mg metalaxyl L-1 aqueous nutrient media. Response endpoints included fresh mass production after 7 d exposure and 7 d post-exposure and quantum efficiency using dark-adapted (Fv/Fm) and light-adapted (fluorescence yields) plants. Metalaxyl uptake and distribution within the plant was determined by growing plants in aqueous nutrient media containing 1.18 x 10(6) Bq L-1 [14C]metalaxyl (0.909 mg L-1) for 1, 3, 5, or 7 d. Plant tissues were combusted and analyzed by liquid scintillation counting. Metalaxyl had no effects on the endpoints measured, except for fresh mass production of sweetflag at the 75 and 100 mg L-1 treatment levels. However, leaf necrosis was apparent in most species after 5 d exposure to concentrations greater than 25 mg L-1. Metalaxyl removal from the spiked nutrient media ranged from 15 to 60% during the 7-d exposure period. The majority of metalaxyl removed from the solution was detected within individual plants. In nearly all cases, activity from the radiolabeled pesticide accumulated in the leaves. Uptake of metalaxyl was correlated with water uptake throughout the 7 d. These results suggest that all species examined may be good candidates for incorporation into a phytoremediation scheme for metalaxyl.     

Evaluation of a serum bottle technique for assessing the anaerobic biodegradability of organic chemicals under methanogenic conditions

The serum bottle method of Shelton and Tiedje (1984), for assessing the potential of an organic chemical to undergo anaerobic biodegradation, was evaluated using U.K. primary digesting sludges. The method was modified by using the sludge at a known solids content and employing sterile (autoclaved) controls to correct for abiotic gas production. Gas production was measured with a compact hand-held pressure meter, which represented an improvement over previously described techniques. Results obtained confirmed the reliability and precision of this type of simple, screening test for assessing anaerobic biodegradability. However, the test is only applicable to low-sulphate, methanogenic environments and evidence is presented of interference from sulphate-reducing bacteria (SRB) when testing sulphate-containing chemicals.     

The spatial distribution of ammonia emitted from seabirds and its contribution to atmospheric nitrogen deposition in the UK

Simple bioenergetics models were used to derive annual nitrogen excretion rates of each seabird species occurring at colonies in the UK. These were combined with population distribution data and an estimated fraction of nitrogen volatilized to estimate the spatial distribution of NH₃ emissions from seabird colonies at a 1 km resolution. The effect of these emissions on atmospheric NH₃ concentrations and nitrogen deposition in the UK was assessed using the FRAME atmospheric chemistry and transport model. The total emission of NH₃ from the UK seabird colonies is estimated at 2.7 kt yr^?1. Emissions from seabirds are largely concentrated in remote parts of Britain, where agricultural and other anthropogenic emissions are minimal. Although seabirds account for less than 1% of total UK NH₃ emissions (～370 kt yr^?1), their occurrence in remote areas and frequently large colony sizes results in seabirds providing a major fraction of the atmospheric nitrogen deposition for many remote ecosystems.     

MODELING WATER UTILITY FINANCIAL PERFORMANCE1

ABSTRACT: The purpose of this paper is to present a theory and model for assessing the financial health of public water systems. Using financial information from 25 water utilities in Georgia, the paper seeks to identify the causal relationships between the financial performance of a water utility and its fiscal position. The need for a theoretical understanding of water utility financial health is the result of the increasingly stringent performance requirements under the Safe Drinking Water Act (SDWA). The issue has become particularly important for small water systems that will be exposed to significant financial demands. A set of financial ratios were developed and tested in a model that was based on liquid asset theory. The model contained five variables designed to account for the size of liquid assets, current debt, cash-flow, and the level of expenses. The variables fit the need of water utilities: to provide an adequate level of operation and maintenance to meet current and future system needs as well as SDWA standards.     

Organisational resilience following the Darfield earthquake of 2010

This paper presents the preliminary findings of a study on the resilience and recovery of organisations following the Darfield earthquake in New Zealand on 4 September 2010. Sampling included organisations proximal and distal to the fault trace, organisations located within central business districts, and organisations from seven diverse industry sectors. The research captured information on the challenges to, the impacts on, and the reflections of the organisations in the first months of recovery. Organisations in central business districts and in the hospitality sector were most likely to close, while organisations that had perishable stock and livestock were more heavily reliant on critical services. Staff well‐being, cash flow, and customer loss were major concerns for organisations across all sectors. For all organisations, the most helpful factors in mitigating the effects of the earthquake were their relationship with staff members, the design and type of buildings, and critical service continuity or swift reinstatement of services.