Community vulnerability to changes in the winter road viability and longevity in the western James Bay region of Ontario’s Far North

Regional Environmental Change - A network of winter roads that consists of snow-ice roads over land, muskeg, and frozen lakes and rivers has been and continues to be a critical seasonal lifeline in...     

A flame ionisation detector for the determination of nitrix oxide.

Existing methods for the detection of nitric oxide are described, and their detection limits noted. The use of a flame ionisation detector is proposed, and the means by which its sensitivity toward nitrix oxide can be greatly enhanced is described. Detector operating conditions and response characteristics are given.     

Above- and belowground responses of Arctic tundra ecosystems to altered soil nutrients and mammalian herbivory

Theory and observation indicate that changes in the rate of primary production can alter the balance between the bottom-up influences of plants and resources and the top-down regulation of herbivores and predators on ecosystem structure and function. The exploitation ecosystem hypothesis (EEH) posited that as aboveground net primary productivity (ANPP) increases, the additional biomass should support higher trophic levels. We developed an extension of EEH to include the impacts of increases in ANPP on belowground consumers in a similar manner as aboveground, but indirectly through changes in the allocation of photosynthate to roots. We tested our predictions for plants aboveground and for phytophagous nematodes and their predators belowground in two common arctic tundra plant communities subjected to 11 years of increased soil nutrient availability and/or exclusion of mammalian herbivores. The less productive dry heath (DH) community met the predictions of EEH aboveground, with the greatest ANPP and plant biomass in the fertilized plots protected from herbivory. A palatable grass increased in fertilized plots while dwarf evergreen shrubs and lichens declined. Belowground, phytophagous nematodes also responded as predicted, achieving greater biomass in the higher ANPP plots, whereas predator biomass tended to be lower in those same plots (although not significantly). In the higher productivity moist acidic tussock (MAT) community, aboveground responses were quite different. Herbivores stimulated ANPP and biomass in both ambient and enriched soil nutrient plots; maximum ANPP occurred in fertilized plots exposed to herbivory. Fertilized plots became dominated by dwarf birch (a deciduous shrub) and cloudberry (a perennial forb); under ambient conditions these two species coexist with sedges, evergreen dwarf shrubs, and Sphagnum mosses. Phytophagous nematodes did not respond significantly to changes in ANPP, although predator biomass was greatest in control plots. The contrasting results of these two arctic tundra plant communities suggest that the predictions of EEH may hold for very low ANPP communities, but that other factors, including competition and shifts in vegetation composition toward less palatable species, may confound predicted responses to changes in productivity in higher ANPP communities such as the MAT studied here.     

Development of competitive immunoassays to hydroxyl containing fungicide metabolites

This paper describes the isolation of monoclonal antibodies and the development of competitive immunoassays to pesticide metabolites of the fungicides imazalil, carbendazim and thiabendazole. The metabolite specific hydroxyl residues were used as the reactive group with which to link the metabolite to the carrier proteins Keyhole Limpet Haemocyanin (KLH) and Bovine Serum Albumin (BSA). In each case immune responses in mice were raised and monoclonal antibodies were produced. Antibodies were developed into competitive ELISAs to the appropriate metabolite. The antibody raised to a metabolite of imazalil was optimised into a competitive ELISA format which had an assay IC50 of 7.5 μg/L and a limit of detection (LOD) of 1.1 μg/L. A single antibody isolated against the metabolite of carbendazim had assay IC50s of 3.2 and 2.7 μg/L for the metabolites of carbendazim and thiabendazole respectively with an LOD of 0.38 μg/L for both. These sensitive immunoassays may have application in the monitoring of human exposure to these fungicide residues either by occupational or non-occupational routes.     

A roadmap for carbon capture and storage in the UK

Carbon capture and storage (CCS) technology has been endorsed by the IPCC and the UK government as a key mitigation option but remains on the cusp of wide-scale commercial deployment. Here we present a technology roadmap for CCS, depicted in terms of external factors and short- and long-term pathways for its development, moving from a demonstration to commercialisation era. The roadmap was been developed through a two-phase process of stakeholder engagement; the second phase of this, a high level stakeholder workshop, is documented here. This approach has provided a unique overview of the current status, potential and barriers to CCS deployment in the UK. In addition to the roadmap graphics and more detailed review, five consensus conclusions emerging from the workshop are presented. These describe the need for a monetary CO₂ value and the financing of carbon capture and storage schemes; the lack of technical barriers to the deployment of demonstration scale CCS plant; the role of demonstration projects in developing a robust regulatory framework; key storage issues; the need for a long-term vision in furthering both the technical and non-technical development of CCS.     

Nature and fate of Hudson Bay permafrost

Two aspects of the permafrost of the Hudson Bay region are examined. The first is the climatological conditions that support permafrost especially along the southwestern shore of Hudson Bay. The second is the fate of the permafrost using recent climate change scenarios. The continuous permafrost along the shores of southwestern Hudson Bay is examined from a climatological perspective. Two hypotheses are explored to explain the presence of continuous permafrost in this region in spite of the relatively "warm" local climate. Possible errors in the calculation of thawing degree days and the asymmetries in frozen and unfrozen soil thermal conductivities are successively examined. Only the second hypothesis is likely to explain the presence of permafrost in southwestern Hudson Bay. Sophisticated climate models are used to assess the potential change in permafrost distribution in the Hudson Bay region. Nine simulations using three different versions of the Canadian Centre of Climate Modelling and Analysis (CCCma) general circulation model are used to project permafrost distribution. Two surface temperature thresholds, –5 and –10 °C, are used to diagnose permafrost grid points. All simulations, including those that include reduction of CO₂ emissions, showed at least a 50% reduction of permafrost by 2100 using these temperature thresholds. Electronic Publication     

Testing the validity of a critical sulfur and nitrogen load model in southern Ontario, Canada, using soil chemistry data from MARYP

The validity of a steady-state massbalance model (Arp et al., 1996; referred to asARP) was tested using physicochemical soil data fromthe Monitoring Acid Rain Youth Program (MARYP). FourARP sites were matched with ten MARYP sites accordingto proximity, bedrock type and subsoil pH to test thevalidity of the ARP model for critical loadexceedances. Soil solution pH, base concentration andAl concentration from MARYP sites, which were wellmatched to ARP sites, validated the modelled criticalload exceedances. Higher exceedance areas wereassociated with more acidic pH and lower base andhigher Al concentrations from matched MARYP sites andvice versa. One ARP site was inappropriately matchedwith MARYP sites and could not be validated using baseand Al concentrations. This study also confirmed thesouthern limit of the zero critical load exceedanceisopleth from the model. However, variability of theother exceedance isopleths was noted due to thelimited number of sites used in the model. Thevalidation of these sites in the ARP model and thezero critical load exceedance isopleth nonethelessallows greater confidence in using this model as amanagement tool for acidic deposition.     

Integrated Assessment: an emerging methodology for complex issues

Over recent years Integrated Assessment (IA) has been presented as a new and innovative approach to modern decision making. In this paper we explore some of the key features that we consider characterise IA; we present IA as a framework that allows a flexible approach to uncertainty in decision making and to which a broad palette of expertise can contribute. The example of the development of an international agreement to reduce acidic deposition is used to illustrate the current practical status of an IA. The scientific process leading to this agreement has previously been described as IA but we argue that, although it marks a change from traditional approaches, further progress is still required to satisfy the requirements for a successful and durable IA.