Century‐long records reveal slight,ecoregion‐localized changes in Athabasca River flows

Reports of abruptly declining flows of Canada's Athabasca River have prompted concern because this large, free‐flowing river could be representative for northern North America, provides water for the massive Athabasca oil‐sands projects and flows to the extensive and biodiverse Peace–Athabasca, Slave and Mackenzie River deltas. To investigate historic hydrology along the river and its major tributaries, we expanded the time series with interpolations for short data gaps; calculations of annual discharges from early, summer‐only records; and by splicing records across sequential hydrometric gauges. These produced composite, century‐long records (1913–2011) and trend detection with linear Pearson correlation provided similar outcomes to nonparametric Kendall τ‐b tests. These revealed that the mountain and foothills reaches displayed slight increases in winter discharges versus larger declines in summer discharges and consequently declining annual flows (~0.16% per year at Hinton; p < 0.01). Conversely, with contrasting boreal contributions, the Athabasca River at Athabasca displayed no overall trend in monthly or annual flows, but there was correspondence with the Pacific Decadal Oscillation that contributed to a temporary flow decline from 1970 to 2000. These findings from century‐long records contrast with interpretations from numerous shorter‐term studies and emphasize the need for sufficient time series for hydrologic trend analyses. For Northern Hemisphere rivers, the study interval should be at least 80 years to span two Pacific Decadal Oscillation cycles and dampen the influence from phase transitions. Most prior trend analyses considered only a few decades, and this weakens interpretations of the hydrologic consequences of climate change. Copyright © 2014 John Wiley & Sons, Ltd.     

Multifunctional intervention and market rationality in agricultural governance: a comparative study of England and South Australia

Critiques of the neoliberal governance of agricultural systems have led to a number of political responses which attempt to address the socio-environmental consequences of the dominant regime. In this paper two case study regions (South Australia and England) have been chosen to represent variations in agricultural policy and to highlight subsequent outcomes on the sustainability of agriculture. Interviewed governance stakeholders highlighted issues in regard to the agricultural governance of each area, from social and environmental consequences of minimal policy intervention in South Australia, to issues created by greater economic support in England. As such, the distinct variations in agricultural regimes will continue to demand scholarly attention, in order for the value of diversity within the sector to be more widely understood. The study concludes that it is likely agricultural support will continue to decline in both case study regions. Importantly, however, innovative policy mechanisms that aim to reduce local risks and value local agricultural priorities, without requiring significant financial support, might be the most promising way forward in regard to agricultural system sustainability.     

Developing service-oriented applications in a grid environment

The Open-source Project for a Network Data Access Protocol (OPeNDAP) software framework has evolved over the last 10 years to become a robust, high performance, service oriented architecture for the access and transport of scientific data from a broad variety of disciplines, over the Internet. Starting with version 4.0 of the server release, Hyrax, has at its core, the Back-End Server (BES). The BES offers ease of programming, extensibility and reliability allowing added functionality especially related to high-performance data Grids, that goes beyond its original goal of distributed data access. We present the fundamentals of the BES server as a component based architecture, as well as our experiences using the BES to distribute data processing in Grid-oriented intensive parallel computational tasks.     

Effects of CO2 on benthic biota: An in situ benthic chamber experiment in Storfjorden (Norway)

Carbon capture and storage (CCS) methods, either sub-seabed or in ocean depths, introduces risk of CO₂ leakage and subsequent interaction with the ecosystem. It is therefore important to obtain information on possible effects of CO₂. In situ CO₂ exposure experiments were carried out twice for 10 days during 2005 using a Benthic Chamber system at 400 m depth in Storfjorden, Norway. pCO₂ in the water above the sediment in the chambers was controlled at approximately 500, 5000 and 20,000 μatm, respectively. This article describes the experiment and the results from measured the biological responses within the chamber sediments. The results show effects of elevated CO₂ concentrations on biological processes such as increased nanobenthos density. Methane production and sulphate reduction was enhanced in the approximately 5000 μatm chamber.     

Community resilience,globalization, and transitional pathways of decision-making

This article investigates the impacts of globalization processes on community resilience. It argues that theoretical concepts such as transition theory can provide a lens through which resilience pathways at community level can be better understood, and proposes a framework focused on a social resilience approach for understanding community resilience as the conceptual space at the intersection between economic, social and environmental capital. It argues that certain types of communities are losing resilience through increased embeddedness into globalized pathways of decision-making, while other communities may be gaining resilience, although not one system is either totally resilient or totally vulnerable. Striking the right ‘balance’ between communities and their scalar interactions with the global level is key for maximization of community resilience: while too much isolation of a community may be bad in light of over-dependency on local resources, skills and people, ‘over-globalization’, with possible loss of autonomy and identity, may be equally fraught with problems. In particular, relocalized communities have, so far, not shown much tangible success, as almost all members of the relocalization process at community level are simultaneously embedded within the global capitalist system through their dependencies on global economic processes.     

Bioturbation on a south‐east Australian hillslope: estimating contributions to soil flux

The contribution of bioturbation to downslope soil transport is significant in many situations, particularly in the context of soil formation, erosion and creep. This study explored the direct flux of soil caused by Aphaenogaster ant mounding, vertebrate scraping and tree‐throw on a wildfire‐affected hillslope in south‐east Australia. This included the development of methods previously applied to Californian gopher bioturbation, and an evaluation of methods for estimating the volume of soil displaced by tree‐throw events. All three bioturbation types resulted in a net downslope flux, but any influence of hillslope angle on flux rates appeared to be overshadowed by environmental controls over the spatial extent of bioturbation. As a result, the highest flux rates occurred on the footslope and lower slope. The overall contribution of vertebrate scraping (57.0 ± 89.4 g m^?1 yr^?1) exceeded that of ant mounding (36.4 ± 66.0 g m^?1 yr^?1), although mean rates were subject to considerable uncertainty. Tree‐throw events, which individually cause major disturbance, were limited in their importance by their scarcity relative to faunalturbation. However, tree‐throw might be the dominant mechanism of biotic soil flux on the mid‐slope provided that it occurs at a frequency of at least 2–3 events ha^?1 yr^?1. Although direct biotic soil flux appears to be geomorphologically significant on this hillslope, such transport processes are probably subordinate to other impacts of bioturbation at this site such as the enhancement of infiltration following wildfire. Copyright © 2011 John Wiley & Sons, Ltd.     

The use of reference models from a priori data to guide 2D inversion of electrical resistivity tomography data

Clay-rich till plains cover much of the UK. Such sites are attractive locations for landfills, since clay aquitards lower the risk of landfill leachate entering groundwater. However, such tills often contain sand and gravel bodies that can act as leachate flow routes. Such bodies may not be detected by conventional site investigation techniques such as drilling boreholes and trial pitting. A method of guided inversion, where a priori data are used to construct structural reference models for use in inverting electrical resistivity tomography data, was proposed as a tool to improve the detection of sand and gravel bodies within clay-rich till sequences.
Following a successful 2D guided inversion synthetic modelling study, a field study was undertaken. Wenner 2D electrical resistivity tomography lines, resistivity cone penetrometry bores and electromagnetic induction ground resistivity data were collected over a site on the East Yorkshire coast, England, where sand and gravel lenses were known to exist from cliff exposures. A number of equally valid geoelectrical models were constructed using the electromagnetic and resistivity cone data. These were used as structural reference models in the inversion of the resistivity tomography data. Blind inversion using an homogenous reference model was also carried out for comparison.
It was shown for the first time that the best solution model produced by 2D inversion of one data set with a range of structural reference models could be determined by using the l ₂ model misfit between the solution models and associated reference models (reference misfit) as a proxy for the l ₂ misfit between the solution models and the synthetic model or 'best-guess' geoelectrical model (true misfit). The 2D methodology developed here is applicable in clay-rich till plains containing sand and gravel bodies throughout the UK.     

Wood as a driver of past landscape change along river corridors

The role of wood as a driver of landform development appears to have been overlooked in the interpretation of palaeo‐landscape change along river corridors. Deforested river corridors and wood‐free rivers characterize ‘modern’, managed landscapes, but along natural river corridors both driftwood dynamics and tree reproductive strategies can have a dramatic impact on the style and rate of channel and floodplain development. Therefore, we believe that interpretations of the post‐glacial history of river valleys across the northern temperate climatic zone could be usefully reassessed, incorporating the roles of riparian trees. Copyright © 2008 John Wiley & Sons, Ltd.