Organisational geographies of power: Introduction to special issue

This paper introduces the special issue ‘organisational geographies of power’ by examining the theoretical and empirical context for debates. It does this, firstly, with reference to existing theoretical work on what power is and does as well as work on the construction of power relations. Building on this, the paper then, secondly, examines the way relational and production network approaches have incorporated power into work on transnational corporations before, thirdly, considering how work on neoliberalism has studied the construction of spatial power relations. In doing this the paper highlights four important questions for future research relating to the practices and spatiality of power, the exercising of power and the situated effects of power relations.     

Hydrocarbon biodegradation and soil microbial community response to repeated oil exposure

Bioremediation strategies continue to be developed to mitigate the environmental impact of petroleum hydrocarbon contamination. This study investigated the ability of soil microbiota, adapted by prior exposure, to biodegrade petroleum. Soils from Barrow Is. (W. Australia), a class A nature reserve and home to Australia’s largest onshore oil field, were exposed to Barrow production oil (50 ml/kg soil) and incubated (25 °C) for successive phases of 61 and 100 days. Controls in which oil was not added at Phase I or II were concurrently studied and all treatments were amended with the same levels of additional nutrient and water to promote microbial activity. Prior exposure resulted in accelerated biodegradation of most, but not all, hydrocarbon constituents in the production oil. Molecular biodegradation parameters measured using gas chromatography–mass spectrometry (GC–MS) showed that several aromatic constituents were degraded more slowly with increased oil history. The unique structural response of the soil microbial community was reflected by the response of different phospholipid fatty acid (PLFA) sub-classes (e.g. branched saturated fatty acids of odd or even carbon number) measured using a ratio termed Barrow PLFA ratio (B-PLFAr). The corresponding values of a previously proposed hydrocarbon degrading alteration index showed a negative correlation with hydrocarbon exposure, highlighting the site specificity of PLFA-based ratios and microbial community dynamics. B-PLFAr values increased with each Phase I and II addition of production oil. The different hydrocarbon biodegradation rates and responses of PLFA subclasses to the Barrow production oil probably relate to the relative bioavailability of production oil hydrocarbons. These different effects suggest preferred structural and functional microbial responses to anticipated contaminants may potentially be engineered by controlled pre-exposure to the same or closely related substrates. The bioremediation of soils freshly contaminated with petroleum could benefit from the addition of exhaustively bioremediated soils rich in biota primed for the impacting hydrocarbons.     

Modelling chemistry in the nocturnal boundary layer above tropical rainforest and a generalised effective nocturnal ozone deposition velocity for sub-ppbv NOx conditions

Measurements of atmospheric composition have been made over a remote rainforest landscape. A box model has previously been demonstrated to model the observed daytime chemistry well. However the box model is unable to explain the nocturnal measurements of relatively high [NO] and [O₃], but relatively low observed [NO₂]. It is shown that a one-dimensional (1-D) column model with simple O₃-NO_x chemistry and a simple representation of vertical transport is able to explain the observed nocturnal concentrations and predict the likely vertical profiles of these species in the nocturnal boundary layer (NBL). Concentrations of tracers carried over from the end of the night can affect the atmospheric chemistry of the following day. To ascertain the anomaly introduced by using the box model to represent the NBL, vertically-averaged NBL concentrations at the end of the night are compared between the 1-D model and the box model. It is found that, under low to medium [NO_x] conditions (NO_x?<?1 ppbv), a simple parametrisation can be used to modify the box model deposition velocity of ozone, in order to achieve good agreement between the box and 1-D models for these end-of-night concentrations of NO_x and O₃. This parametrisation would could also be used in global climate-chemistry models with limited vertical resolution near the surface. Box-model results for the following day differ substantially if this effective nocturnal deposition velocity for ozone is implemented; for instance, there is a 9% increase in the following days peak ozone concentration. However under medium to high [NO_x] conditions (NO_x > 1 ppbv), the effect on the chemistry due to the vertical distribution of the species means no box model can adequately represent chemistry in the NBL without modifying reaction rate coefficients.     

Processing of atmospheric organic matter by California radiation fogs

Considerable effort has been put into characterizing the ionic composition of fogs and clouds over the past twenty-five years. Recently it has become evident that clouds and fogs often contain large concentrations of organic material as well. Here we report findings from a series of studies examining the organic composition of radiation fogs in central California. Organic compounds in these fogs comprise a major fraction of total solute mass, with total organic carbon sometimes reaching levels of several tens of mg/L. This organic matter is comprised of a wide variety of compounds, ranging from low molecular weight organic acids to high molecular weight compounds with molecular masses approaching several hundred to a thousand g/mole. The most abundant individual compounds are typically formic acid, acetic acid, and formaldehyde. High concentrations are also observed of some dicarboxylic acids (e.g., oxalate) and dicarbonyls (e.g., glyoxal and methylglyoxal) and of levoglucosan, an anhydrosugar characteristically emitted by biomass combustion. Many other compounds have been identified in fog water by GC/MS, including long chain n-alkanoic acids, n-alkanes, PAH, and others, although these compounds typically comprise a total of only a few percent of fog TOC. Measurements of fog scavenging of organic and elemental carbon reveal preferential scavenging of organic carbon. Tracking of individual organic compounds utilized as source type markers suggests the fogs differentially scavenge carbonaceous particles from different source types, with more active processing of wood smoke than vehicle exhaust. Observations of high deposition velocities of fog-borne organic carbon, in excess of 1 cm/s, indicate that fogs in the region represent an important mechanism for cleansing the atmosphere of pollution.     

Triggering transformative change: a development path approach to climate change response in communities

While climate change action plans are becoming more common, it is still unclear whether communities have the capacity, tools, and targets in place to trigger the transformative levels of change required to build fundamentally low-carbon, resilient, healthy communities. Evidence increasingly supports the finding that this transformation is not triggered by climate policy alone, but rather is shaped by a broad array of decisions and practices that are rooted in underlying patterns of development. Even so, these findings have rarely penetrated the domain of practice, which often remains squarely focused on a relatively narrow set of climate-specific policies. This article builds a conceptual framework for understanding the dynamics of community-level development path transformations that may both dramatically reduce GHG emissions and significantly enhance community resilience. This framework illuminates eight critical enablers of innovation on climate change, each of which is illustrated by compelling examples of community-level experimentation on climate change across the province of British Columbia, Canada. It is concluded that community-based climate (or sustainability) policy might be more likely to trigger development path shifts if it employs a longer time horizon, recognition of adaptability and feedbacks, integrated decision making, and systems thinking.     

Tracing iron-fueled microbial carbon production within the hydrothermal plume at the Loihi seamount

The Loihi hydrothermal plume provides an opportunity to investigate iron (Fe) oxidation and microbial processes in a system that is truly Fe dominated and distinct from mid-ocean ridge spreading centers. The lack of hydrogen sulfide within the Loihi hydrothermal fluids and the presence of an oxygen minimum zone at this submarine volcano’s summit, results in a prolonged presence of reduced Fe within the dispersing non-buoyant plume. In this study, we have investigated the potential for microbial carbon fixation within the Loihi plume. We sampled for both particulate and dissolved organic carbon in hydrothermal fluids, microbial mats growing around vents, and the dispersing plume, and carried out stable carbon isotope analysis on the particulate fraction. The δ¹³C values of the microbial mats ranged from −23‰ to −28‰, and are distinct from those of deep-ocean particulate organic carbon (POC). The mats and hydrothermal fluids were also elevated in dissolved organic carbon (DOC) compared to background seawater. Within the hydrothermal plume, DOC and POC concentrations were elevated and the isotopic composition of POC within the plume suggests mixing between background seawater POC and a ¹³C-depleted hydrothermal component. The combination of both DOC and POC increasing in the dispersing plume that cannot solely be the result of entrainment and DOC adsorption, provides strong evidence for in-situ microbial productivity by chemolithoautotrophs, including a likelihood for iron-oxidizing microorganisms.     

Do asymmetries in ENSO predictability arise from different recharged states?

Climate Dynamics - Prospects for El Niño–Southern Oscillation (ENSO) predictability at long lead-times lie in the subsurface oceanic memory along the equatorial Pacific. Long considered...     

The carbonate-hosted willemite prospects of the Zambezi Metamorphic Belt (Zambia)

Zambian willemite (Zn₂SiO₄) deposits occur in the metasedimentary carbonate rocks of the Proterozoic Katangan Supergroup. The most important orebodies are located around Kabwe and contain both sulphides and willemite in dolomites of low metamorphic grade. The Star Zinc and Excelsior prospects (Lusaka area), discovered in the early 1920s, occur in the metamorphic lithotypes of the late Proterozoic Zambezi Supracrustal sequence, which were deposited in a transtensional basin formed during the oblique collision of the Kalahari and Congo cratons. The deposits are hosted by the limestone and dolomitic marbles of the Cheta and Lusaka Formations. Structural analysis indicates that several fracture sets host the deposits, which may be genetically related to the Pan-African Mwembeshi dislocation zone (a major geotectonic boundary between the Lufilian Arc and the Zambezi Belt). In both prospects, willemite replaces the marbles and is found along joints and fissures with open-space filling textures and locally may develop colloform and vuggy fabrics as well. Silver as well as traces of germanium and cadmium have been detected within the willemite ore, and lead or zinc sulphides are scarce or absent. Calcite locally replaces willemite. Willemite is associated with specular hematite and franklinite and post-dates the Zn-spinel gahnite in the paragenesis. Genthelvite [Zn₄Be₃(SiO₄)₃S] occurs as a minor phase in irregular aggregates. The willemites from the Lusaka area, though Mn-poor, show green cathodoluminescence colours and bright green fluorescence in short-wave UV (as the high-temperature willemites in USA). Thermometric analyses of primary fluid inclusions in willemite yield homogenization temperatures that range from 160°C to 240°C and salinities of 8–16 wt.% equiv. NaCl. The homogenization temperatures suggest a hypogene–hydrothermal origin for the willemite concentrations. The geochemistry of fluid inclusion leachates suggests that the hydrothermal fluids were brines derived from highly evaporated seawater. Precise age constraints are currently lacking for the Lusaka area deposits, though the deposits are not deformed, indicating that they post-date the Lufilian orogeny (~520 Ma). The possibility of precursor ores exists; the gahnite–franklinite–willemite deposits could have been derived from a metamorphosed primary sulphide (or even nonsulphide) concentration that has subsequently been completely destroyed. However, there is no real evidence of such a primary source for the willemite mineral association. The Lusaka zinc ores may have been produced by an extensive hydrothermal system, with fluids discharging along basinal fracture zones controlled by the pre-Pan-African rifting stage. A paragenesis similar to that of the Lusaka prospects has been proposed to be a vector towards massive sulphide ores in several parts of the world; therefore, it is possible that these small willemite showings in Zambia may be part of a much bigger, and still unexplored, zinc province.     

Seasonal,Diel, and Landscape Effects on Resource Partitioning between Juvenile Chinook Salmon (<Emphasis Type="Italic">Oncorhynchus tshawytscha</Emphasis>) and Threespine Stickleback (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>) in the Columbia River Estuary

The objective of this study was to determine if exploitative competition between between juvenile Chinook salmon (Oncorhynchus tshawytscha) and threespine stickleback (Gasterosteus aculeatus) reduces the foraging opportunity of juvenile Chinook salmon in tidal channels of the Columbia River estuary. We sampled Chinook salmon and stickleback diets monthly and over a diel cycle in spatially distinct emergent marshes of the Columbia River estuary. Diets of the two fish species did not differ among marsh systems, but both fish species exhibited diel and seasonal differences in diet composition. Diet overlap between the two fish species was greatest in March and June. Exploitative competition was unlikely based on a comparison between consumption rates and estimated invertebrate production.