Lack of evidence for nepotism by workers tending queens of the polygynous termite <Emphasis Type="Italic">Nasutitermes corniger</Emphasis>

Kin selection theory predicts that workers in social insect colonies should preferentially aid close relatives over less related or unrelated individuals if such behaviors increase inclusive fitness. For example, a worker in a polygynous (multiple-queen) colony is predicted to tend its own mother rather than an unrelated queen if this nepotistic behavior increases its mother’s reproductive success in excess of costs. Despite predictions, experimental tests conducted in the social Hymenoptera have found no clear evidence of nepotism. No tests for nepotism have been carried out in the Isoptera (termites), another major insect taxon showing highly developed sociality. We tested for nepotistic behavior in the termite Nasutitermes corniger by determining if workers preferentially fed and groomed their mothers in a laboratory assay. We collected workers from nine naturally occurring multiple-queen colonies as they tended queens and determined their parentage using highly variable microsatellite markers. Our results provide no evidence that workers tend their mothers in preference to co-occurring queens. The absence of evidence for nepotism is consistent with previous results reported from numerous studies of eusocial hymenopterans.     

DEVELOPMENT OF A BACTERIAL TRANSPORT MODEL FOR COARSE SOILS1

ABSTRACT: A bacterial transport model, developed to analyze bacterial translocation in coarse-grained soils, is presented. The complex governing equation is presented first, followed by analyses of each of the major processes influencing bacterial transport. These analyses suggest simplification of the governing equation is feasible when input data on specific processes are limited or unavailable. Model parameters, including bacterial die-off, bacterial distribution, input bacterial concentration, and saturated hydraulic conductivity, were randomly generated using a procedure known to produce either a normal or log-normal distribution of random numbers. Monte Carlo simulations were completed, and the resulting output was used to generate cumulative frequency distributions showing the probability of bacterial transport beyond various soil depths. Results from these simulations indicate that bacteria have a high probability of traveling through coarse-grained soils when low clay content and soil water temperatures limit bacterial retention and die-off.     

Conceptual development of a harmonised method for tracking change and evaluating policy in the agri-environment: The Agri-environmental Footprint Index

An aggregated farm-level index, the Agri-environmental Footprint Index (AFI), based on multiple criteria methods and representing a harmonised approach to evaluation of EU agri-environmental schemes is described. The Index uses a common framework for the design and evaluation of policy that can be customised to locally relevant agri-environmental issues and circumstances. Evaluation can be strictly policy-focused, or broader and more holistic in that context-relevant assessment criteria that are not necessarily considered in the evaluated policy can nevertheless be incorporated. The Index structure is flexible, and can respond to diverse local needs. The process of Index construction is interactive, engaging farmers and other relevant stakeholders in a transparent decision-making process that can ensure acceptance of the outcome, help to forge an improved understanding of local agri-environmental priorities and potentially increase awareness of the critical role of farmers in environmental management. The structure of the AFI facilitates post-evaluation analysis of relative performance in different dimensions of the agri-environment, permitting identification of current strengths and weaknesses, and enabling future improvement in policy design. Quantification of the environmental impact of agriculture beyond the stated aims of policy using an ‘unweighted’ form of the AFI has potential as the basis of an ongoing system of environmental audit within a specified agricultural context.     

Application of Biobarriers for Groundwater Containment at Fractured Bedrock Sites

Biological barriers are a beneficial application of biofilms that aim at reducing the hydraulic conductivity (K) in geological formations. Several studies have shown the potential benefits of creating such barriers either by stimulating the indigenous microbial community (biostimulation) or injecting bacteria (bioaugmentation). For example, laboratory experiments show that groundwater microorganisms attached to a ceramic surface and generated a biofilm as thick as 1,100 μm. In a limestone fracture, this bacterial community clogged a single fracture up to 99.2 percent within 22 days. At the field scale, applications in porous aquifers led to a five‐fold decrease in K after 2.5 days of biostimulation, and a bioaugmentation with a starved, adapted bacterial culture decreased K by 99.4 percent. One promising development of the biobarrier concept is a field application at a fractured bedrock site. Using a multidisciplinary approach and focusing on a well‐characterized fracture system, a field trial was undertaken in Southern Ontario to measure the extent of bioclogging and the stability over time. This article focuses on the literature pertinent to the preparation of this field trial and presents the innovative approach selected to monitor the bioclogging in such a challenging environment.     

Estimation of septic tank setback distances based on transport of E. coli and F-RNA phages

Setback distances between septic tank systems and the shorelines of Lake Okareka, New Zealand were determined from model simulations for a worst-case scenario, using the highest hydraulic conductivity and gradient measured in the field, removal rates of the microbial indicators (Escherichia coli and F-RNA phages) determined from a column experiment, and maximum values of the design criteria for the disposal system, and assuming an absence of an unsaturated zone, a continuous discharge of the raw effluent from a failed or non-complying treatment system (both indicators at concentrations of 1x10(7) counts/100 ml) into the groundwater and no sorption of pathogens in the aquifer. Modelling results suggest that the minimal setback distances were 16 m to satisfy the New Zealand Recreational Water Quality Guidelines for E. coli <126 per 100 ml (Ministry for the Environment, 1999) and 48 m to meet the Drinking-Water Standards for New Zealand 2000 for enteric virus <1 per 100 l (Ministry of Health, 2000). These distances may be applicable for other lakeshores in pumice sand aquifers with groundwater velocities <7 m/day. Findings of laboratory column and batch experiments provided an insight into the microbial attenuation and transport processes in pumice sand aquifers. Bacterial removal was predominately through filtration (87-88%) and partially by die-off (12-13%), while viral removal was by both die-off (45%) and filtration (55%). In addition, microbial die-off in groundwater without aquifer material (i.e., free microbes) was much lower than die-off in groundwater with aquifer material (i.e., sorbed microbes) and contributed only 2-6% to the total removal. This implies that the setback distances estimated from die-off rates for the free microbes, determined in the laboratory without considering aquifer media and other removal processes, which are often reported in the literature, could be larger than necessary.     

Carbon bed fires and the use of carbon canisters for air emissions control on fixed-roof tanks

Fixed-roof tanks are used extensively at manufacturing, waste management, and other facilities to store or process liquids containing volatile organic compounds. Federal and state air standards require the control of organic air emissions from many of these tanks. A common practice used for some fixed-roof tanks that are required to use controls is to vent the tank through an activated carbon canister. When organic vapors are adsorbed on activated carbon, heat is released. Under certain conditions, the temperature of the carbon bed can increase to a level at which the carbon or organic vapors spontaneously ignite, starting a fire in the carbon bed. Bed fires in carbon canisters are not uncommon and can present a significant safety hazard at facilities if proper safety measures are not implemented. This article discusses how carbon adsorber bed fires occur and presents general guidance on safety measures for carbon canisters installed on fixed-roof tanks to reduce the likelihood of a carbon bed fire and to minimize the impact in the event of a fire.     

In and Of the World? Christian Theological Anthropology and Environmental Ethics

Mainstream currents within Christianity havelong insisted that humans, among all creatures, areneither fully identified with their physical bodiesnor fully at home on earth. This essay outlines theparticular characteristics of Christian notions ofhuman nature and the implications of this separationfor environmental ethics. It then examines recentefforts to correct some damaging aspects oftraditional Christian understandings of humanity'splace in nature, especially the notions of physicalembodiment and human embeddedment in earth. Theprimary goal of the essay is not to offer acomprehensive evaluation of Christian thinking aboutnature but rather to identify theological anthropologyas a crucial dimension of, and problem for, Christianenvironmental ethics.     

Phytoremediation of arsenic‐contaminated soil as affected by the chelating agent CDTA and different levels of soil pH

Elevated levels of arsenic can pose a major threat to both human health and the environment. The phytoremediation of heavy metals from soil is emerging as a cost‐effective technology for the remediation of contaminated soils. The present greenhouse study was undertaken to identify plants capable of tolerating and accumulating high concentrations of arsenic. Asparagus fern and rye grass were found to tolerate and accumulate more than 1,100 ppm of arsenic in plant tissue. Arsenic uptake as affected by different levels of the chelating agent trans‐1, 2‐ cyclohexylenedinitrilotetraacetic acid (CDTA) and soil pH were also studied. The application of 5 mmol kg^?1 of CDTA to arsenic‐contaminated medium loam field soil enhanced the accumulation of arsenic by the test plants. Under these conditions, plants accumulated up to 1,400 ppm of arsenic as compared to 950 ppm by the plants grown in soil containing 1,200 ppm of arsenic but without any amendment of the chelating agent. Plants grown in field soil of pH 5 containing 300 ppm of arsenic absorbed higher concentrations of arsenic than at other tested pH levels. Corresponding reductions in arsenic content of soil after plant harvests were observed. © 2001 John Wiley & Sons, Inc.