The audacity of the ocean: Gendered politics of positionality in the Pacific     

Yvonne Te Ruki-Rangi-o-Tangaroa Underhill-Sem 《Singapore journal of tropical geography》2020,41(3):314-328

Throughout the contemporary Pacific, relationships that indigeneity makes possible are emerging as celebrated resistance to post-colonial development anxieties. In the process, lived experience heightens the commitment to decolonize thinking, language and practice in teaching and research. Not only because these imperatives are highly personalized but also because they are gendered and heavy with generational trauma. These gendered dynamics circulate around popular culture and imaginaries of Pacific paradise but also problematically around the challenges of long-standing intolerances especially around gender and race. The paper asks how a gendered politics of positionality engages with emerging positionalities that uncritically allow for such intolerances. I touch on two ways in which colonial continuities of belittlement are often reinforced, but are also offering hopeful and careful decolonial scholarly futures. The first is the naming of the Pacific and the second is supervising women doctoral candidates from the Pacific. In this paper, the audacity of the ocean offers a metaphorical opportunity to carefully reconcile these tensions and provide trajectories for decolonial knowledge-making. However, it also offers a material way of understanding the on-going work with ‘tensions’ and disruptions in their ever present but changeable forms. Oceanic tropes and a feminist Oceanic audacity of embodied engagement in the Pacific offer dynamic and gendered intellectual agility which runs counter to the tropical imageries of languid indifference.

black/is a state of mind like the colour of an island Teaiwa (2017) we sweat and cry salt water, so we know that the ocean is really in our blood Teaiwa (2008)

  相似文献   

A conceptual framework for multi-regional climate change assessments for international market systems with long-term investments     

Julie A. Winkler  Suzanne Thornsbury  Marco Artavia  Frank-M. Chmielewski  Dieter Kirschke  Sangjun Lee  Malgorzata Liszewska  Scott Loveridge  Pang-Ning Tan  Sharon Zhong  Jeffrey A. Andresen  J. Roy Black  Robert Kurlus  Denys Nizalov  Nicole Olynk  Zbigniew Ustrnul  Costanza Zavalloni  Jeanne M. Bisanz  Géza Bujdosó  Lesley Fusina  Yvonne Henniges  Peter Hilsendegen  Katarzyna Lar  Lukasz Malarzewski  Thordis Moeller  Roman Murmylo  Tadeusz Niedzwiedz  Olena Nizalova  Haryono Prawiranata  Nikki Rothwell  Jenni van Ravensway  Harald von Witzke  Mollie Woods 《Climatic change》2010,103(3-4):445-470

A conceptual framework for climate change assessments of international market systems that involve long-term investments is proposed. The framework is a hybrid of dynamic and static modeling. Dynamic modeling is used for those system components for which temporally continuous modeling is possible, while fixed time slices are used for other system components where it can be assumed that underlying assumptions are held constant within the time slices but allowed to vary between slices. An important component of the framework is the assessment of the “metauncertainty” arising from the structural uncertainties of a linked sequence of climate, production, trade and decision-making models. The impetus for proposing the framework is the paucity of industry-wide assessments for market systems with multiple production regions and long-term capital investments that are vulnerable to climate variations and change, especially climate extremes. The proposed framework is pragmatic, eschewing the ideal for the tractable. Even so, numerous implementation challenges are expected, which are illustrated using an example industry. The conceptual framework is offered as a starting point for further discussions of strategies and approaches for climate change impact, vulnerability and adaptation assessments for international market systems.  相似文献   

Determining stellar radii using large separations: an error analysis     

Sarbani Basu  William J. Chaplin  Yvonne Elsworth 《Astrophysics and Space Science》2010,328(1-2):79-82

The Kepler mission will provide large separations for many stars. One of the tasks of Kepler Asteroseismic Consortium is to determine radii of the observed stars from the large separations and other catalogued “classical” data such as effective temperature, metallicities, brightness, distance etc. We present the results of a detailed analysis of errors in the radius estimates caused by errors in the input parameters. This exercise enables us to determine which parameters will benefit from follow-up observations of the interesting cases.  相似文献   

Setting priorities for land management to mitigate climate change     

Böttcher H  Freibauer A  Scholz Y  Gitz V  Ciais P  Mund M  Wutzler T  Schulze ED 《Carbon balance and management》2012,7(1):5-18

Background

No consensus has been reached how to measure the effectiveness of climate change mitigation in the land-use sector and how to prioritize land use accordingly. We used the long-term cumulative and average sectorial C stocks in biomass, soil and products, C stock changes, the substitution of fossil energy and of energy-intensive products, and net present value (NPV) as evaluation criteria for the effectiveness of a hectare of productive land to mitigate climate change and produce economic returns. We evaluated land management options using real-life data of Thuringia, a region representative for central-western European conditions, and input from life cycle assessment, with a carbon-tracking model. We focused on solid biomass use for energy production.

Results

In forestry, the traditional timber production was most economically viable and most climate-friendly due to an assumed recycling rate of 80% of wood products for bioenergy. Intensification towards "pure bioenergy production" would reduce the average sectorial C stocks and the C substitution and would turn NPV negative. In the forest conservation (non-use) option, the sectorial C stocks increased by 52% against timber production, which was not compensated by foregone wood products and C substitution. Among the cropland options wheat for food with straw use for energy, whole cereals for energy, and short rotation coppice for bioenergy the latter was most climate-friendly. However, specific subsidies or incentives for perennials would be needed to favour this option.

Conclusions

When using the harvested products as materials prior to energy use there is no climate argument to support intensification by switching from sawn-wood timber production towards energy-wood in forestry systems. A legal framework would be needed to ensure that harvested products are first used for raw materials prior to energy use. Only an effective recycling of biomaterials frees land for long-term sustained C sequestration by conservation. Reuse cascades avoid additional emissions from shifting production or intensification.  相似文献   

Redox Potential and Seasonal Porewater Biogeochemistry of Three Mountain Wetlands in Southeastern Kentucky, USA     

Yvonne Thompson  Brian C. Sandefur  A. D. Karathanasis  Elisa D’Angelo 《Aquatic Geochemistry》2009,15(3):349-370

Redox potentials (Eh) were monitored bimonthly and porewater chemistry was analyzed seasonally at three slightly-acidic, high-elevation Kentucky wetlands that differed in hydrology, parent materials, and vegetation. At all sites, Eh values were below 300 mV, which indicated that reducing conditions persisted within the upper 90 cm and fluctuated mainly within the range of iron and sulfate reduction. Significant relationships of Eh values with depth were observed only at the Martins Fork wetland, where precipitation was the primary water source. The strongest and most stable reducing conditions, observed at the Kentenia site, reflected consistently high water levels, which were sustained by ground water. The third wetland (Four Level) was distinguished by irregular Eh fluctuations coinciding with strong seasonal ground-water upwelling. Although Fe³⁺ and SO₄ ²⁻ were the primary terminal electron acceptors in all wetlands, porewater chemistry also varied significantly by season and soil depth in response to piezometric water level fluctuations. Additional factors that influenced porewater chemistry included: (1) the presence of limestone parent materials that affected porewater pH, Ca²⁺, and Mg²⁺; and (2) the prevalence of sphagnum moss or graminoid species that influenced dissolved organic carbon, CO₂, and CH₄. Results from this study indicated the diverse range and importance of multiple factors in controlling biogeochemical processes and properties in small, high-elevation Appalachian wetlands.  相似文献   

Aggradational lobe fringes: The influence of subtle intrabasinal seabed topography on sediment gravity flow processes and lobe stacking patterns          下载免费PDF全文

Yvonne T. Spychala  David M. Hodgson  Christopher J. Stevenson  Stephen S. Flint 《Sedimentology》2017,64(2):582-608

Seabed topography is ubiquitous across basin‐floor environments, and influences sediment gravity flows and sediment dispersal patterns. The impact of steep (several degrees) confining slopes on sedimentary facies and depositional architecture has been widely documented. However, the influence of gentle (fraction of a degree) confining slopes is less well‐documented, largely due to outcrop limitations. Here, exceptional outcrop and research borehole data from Unit A of the Permian Laingsburg Formation, South Africa, provide the means to examine the influence of subtle lateral confinement on flow behaviour and lobe stacking patterns. The dataset describes the detailed architecture of subunits A.1 to A.6, a succession of stacked lobe complexes, over a palinspastically restored 22 km across‐strike transect. Facies distributions, stacking patterns, thickness and palaeoflow trends indicate the presence of a south‐east facing low angle (fraction of a degree) lateral intrabasinal slope. Interaction between stratified turbidity currents with a thin basal sand‐prone part and a thick mud‐prone part and the confining slope results in facies transition from thick‐bedded sandstones to thin‐bedded heterolithic lobe fringe‐type deposits. Slope angle dictates the distance over which the facies transition occurs (hundreds of metres to kilometres). These deposits are stacked vertically over tens of metres in successive lobe complexes to form an aggradational succession of lobe fringes. Extensive slides and debrites are present at the base of lobe complexes, and are associated with steeper restored slope gradients. The persistent facies transition across multiple lobe complexes, and the mass flow deposits, suggests that the intrabasinal slope was dynamic and was never healed by deposition during Unit A times. This study demonstrates the significant influence that even subtle basin‐floor topography has on flow behaviour and depositional architecture of submarine lobe complexes. In addition, we present a new aggradational lobe fringe facies associations and recognition criteria for subtle confinement in less well‐exposed and subsurface basin fills.  相似文献   

水文地质研究新动向     

TSang  CF 《地学前缘》1996,3(1):43-48

由于日益增长的社会发展的需要，水文地质研究正在产生巨大变化。人们对各种工农业活动所产生的诸多环境污染问题的关注，以及对“高放”放射性废物和毒性液体的地下深层埋设的安全评价需求，致使水文地质研究产生许多新的生长点。无论是在水文地质研究的学科发展领域，还是在解决重大社会问题方向，水文地质学家均面临着巨大的挑战和机遇。  相似文献   

Microbial fossilization in carbonate sediments: a result of the bacterial surface involvement in dolomite precipitation   总被引：14，自引：1，他引：14  

Yvonne Van Lith  Rolf Warthmann  Crisogono Vasconcelos  Judith A. McKenzie 《Sedimentology》2003,50(2):237-245

ABSTRACT Recent dolomitic sediment samples from Lagoa Vermelha, Brazil, were examined microscopically to study the process of bacterial fossilization in carbonate sediments. Bacteria‐like bodies were intimately associated with carbonate mineral surfaces, and coatings on the former demonstrate the calcification of single bacterial cells. The bacterial fossilization process in Lagoa Vermelha sediments was simulated in the laboratory by cultivation of mixed and pure cultures of sulphate‐reducing bacteria, which were isolated from the Lagoa Vermelha sediments. These cultures produced carbonate minerals that were studied to provide insight into the initiation of the fossilization process. In mixed culture experiments, bacterial colonies became calcified, whereas in pure culture experiments, single bacterial cells were associated with dolomite surfaces. Dolomite nucleated exclusively in bacterial colonies, intimately associated with extracellular organic matter and bacterial cells. Electrophoretic mobility measurements of the bacterial cells in electrolyte solutions demonstrated the specific adsorption of Ca²⁺ and Mg²⁺ onto the cell surfaces, indicating the role of the bacterial surface in carbonate nucleation and bacterial fossilization. The affinity of the cells for Mg²⁺ was related to the capability of the strains to mediate dolomite formation. Combined with sulphate uptake, which dissociates the [MgSO₄]⁰ ion pair and increases the Mg²⁺ availability, the concentration of Mg²⁺ ions in the microenvironment around the cells, where the conditions are favourable for dolomite precipitation, may be the key to overcome the kinetic barrier to dolomite formation. These results demonstrate that bacterial fossilization is a consequence of the cell surface involvement in carbonate precipitation, implying that fossilized bacterial bodies can be used as a tool to recognize microbially mediated carbonates.  相似文献   

The importance of changing oceanography in controlling late Quaternary carbonate sedimentation on a high-energy, tropical, oceanic ramp: north-western Australia   总被引：1，自引：0，他引：1  

Noel P. James  Yvonne Bone†  T. Kurtis Kyser  George R. Dix‡  Lindsay B. Collins§ 《Sedimentology》2004,51(6):1179-1205

The North West Shelf is an ocean‐facing carbonate ramp that lies in a warm‐water setting adjacent to an arid hinterland of moderate to low relief. The sea floor is strongly affected by cyclonic storms, long‐period swells and large internal tides, resulting in preferentially accumulating coarse‐grained sediments. Circulation is dominated by the south‐flowing, low‐salinity Leeuwin Current, upwelling associated with the Indian Ocean Gyre, seaward‐flowing saline bottom waters generated by seasonal evaporation, and flashy fluvial discharge. Sediments are palimpsest, a variable mixture of relict, stranded and Holocene grains. Relict intraclasts, both skeletal and lithic, interpreted as having formed during sea‐level highstands of Marine Isotope Stages (MIS) 3 and 4, are now localized to the mid‐ramp. The most conspicuous stranded particles are ooids and peloids, which ¹⁴C dating shows formed at 15·4–12·7 Ka, in somewhat saline waters during initial stages of post‐Last Glacial Maximum (LGM) sea‐level rise. It appears that initiation of Leeuwin Current flow with its relatively less saline, but oceanic waters arrested ooid formation such that subsequent benthic Holocene sediment is principally biofragmental, with sedimentation localized to the inner ramp and a ridge of planktic foraminifera offshore. Inner‐ramp deposits are a mixture of heterozoan and photozoan elements. Depositional facies reflect episodic environmental perturbation by riverine‐derived sediments and nutrients, resulting in a mixed habitat of oligotrophic (coral reefs and large benthic foraminifera) and mesotrophic (macroalgae and bryozoans) indicators. Holocene mid‐ramp sediment is heterozoan in character, but sparse, most probably because of the periodic seaward flow of saline bottom waters generated by coastal evaporation. Holocene outer‐ramp sediment is mainly pelagic, veneering shallow‐water sediments of Marine Isotope Stage 2, including LGM deposits. Phosphate accumulations at ≈ 200 m water depth suggest periodic upwelling or Fe‐redox pumping, whereas enhanced near‐surface productivity, probably associated with the interaction between the Leeuwin Current and Indian Ocean surface water, results in a linear ridge of pelagic sediment at ≈ 140 m water depth. This ramp depositional system in an arid climate has important applications for the geological record: inner‐ramp sediments can contain important heterozoan elements, mid‐ramp sediments with bedforms created by internal tides can form in water depths exceeding 50 m, saline outflow can arrest or dramatically slow mid‐ramp sedimentation mimicking maximum flooding intervals, and outer‐ramp planktic productivity can generate locally important fine‐grained carbonate sediment bodies. Changing oceanography during sea‐level rise can profoundly affect sediment composition, sedimentation rate and packaging.  相似文献   

Testing bedload transport formulae using morphologic transport estimates and field data: lower Fraser River,British Columbia     

Yvonne Martin  Darren Ham 《地球表面变化过程与地形》2005,30(10):1265-1282

Morphologic transport estimates available for a 65‐km stretch of Fraser River over the period 1952–1999 provide a unique opportunity to evaluate the performance of bedload transport formulae for a large river over decadal time scales. Formulae tested in this paper include the original and rational versions of the Bagnold formula, the Meyer‐Peter and Muller formula and a stream power correlation. The generalized approach adopted herein does not account for spatial variability in flow, bed structure and channel morphology. However, river managers and engineers, as well as those studying rivers within the context of long‐term landscape change, may find this approach satisfactory as it has minimal data requirements and provides a level of process specification that may be commensurable with longer time scales. Hydraulic geometry equations for width and depth are defined using morphologic maps based on aerial photography and bathymetric survey data. Comparison of transport predictions with bedload transport measurements completed at Mission indicates that the original Bagnold formula most closely approximates the main trends in the field data. Sensitivity analyses are conducted to evaluate the impact of inaccuracies in input variables width, depth, slope and grain size on transport predictions. The formulae differ in their sensitivity to input variables and between reaches. Average annual bedload transport predictions for the four formulae show that they vary between each other as well as from the morphologic transport estimates. The original Bagnold and Meyer‐Peter and Muller formulae provide the best transport predictions, although the former underestimates while the latter overestimates transport rates. Based on our findings, an error margin of up to an order of magnitude can be expected when adopting generalized approaches for the prediction of bedload transport. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献