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81.
Siri Veland Richard Howitt Dale Dominey-Howes Frank Thomalla Donna Houston 《Global Environmental Change》2013,23(1):314-326
The challenge of reaching common understanding of the processes and significance of environmental change amounts to a procedural vulnerability in climate change research that hinders successfully translating knowledge into equitable and effective adaptation policy. This article presents findings from research with Indigenous participants in West Arnhem, Australia, and identifies a procedural vulnerability to climate change research, where perceptions of change and their meaning have their context in Dreaming that supersedes and parallels Western scientific discourses of hazard and risk, but that are marginalised in studies and policies on climate change. This paper argues that moves to adapt remote Indigenous Australian communities to climate change risk missing the mark if they (a) assume that a strong reliance on particular ecosystem configurations makes Indigenous cultures universally vulnerable to environmental change, (b) do not recognise cosmologically embedded risks that are determined by Indigenous capacity to take care of country, and (c) do not recognise colonisation as an ongoing disaster in Indigenous Nations, and therefore treat secondary disasters such as poverty, ill health and welfare dependence as primary contributors to high climate change vulnerability. Procedural vulnerabilities contribute to policy failure, and in Australian contexts pose a risk of conceiving solutions to climate change vulnerability that involve moving people out of the way of environmental risks as they are conceived within colonial traditions, while moving them into the way of risks as conceived through the eyes of remote Indigenous communities. This research joins recent publications that encourage researchers and policy-makers to epistemologically ground proof risk assessments and to listen and engage in conversations that create ways of ‘seeing with both eyes’, while not being blind to the hazards of colonisation. 相似文献
82.
Michael Marden Colin Mazengarb Alan Palmer Kelvin Berryman Donna Rowan 《Geomorphology》2008,99(1-4):404-419
The sediment flux generated by postglacial channel incision has been calculated for the 2150 km2, non-glacial, Waipaoa catchment located on the tectonically active Hikurangi Margin, eastern North Island, New Zealand. Sediment production both at a sub-catchment scale and for the Waipaoa catchment as a whole was calculated by first using the tensioned spline method within ARC MAP to create an approximation of the aggradational Waipaoa-1 surface (contemporaneous with the Last Glacial Maximum), and second using grid calculator functions in the GIS to subtract the modern day surface from the Waipaoa-1 surface. The Waipaoa-1 surface was mapped using stereo aerial photography, and global positioning technology fixed the position of individual terrace remnants in the landscape. The recent discovery of Kawakawa Tephra within Waipaoa-1 aggradation gravels in this catchment demonstrates that aggradation was coincidental with or began before the deposition of this 22 600 14C-year-old tephra and, using the stratigraphic relationship of Rerewhakaaitu Tephra, the end of aggradation is dated at ca 15 000 14C years (ca 18 000 cal. years BP). The construction of the Waipaoa-1 terrace is considered to be synchronous and broadly correlated with aggradation elsewhere in the North Island and northern South Island, indicating that aggradation ended at the same time over a wide area. Subsequent downcutting, a manifestation of base-level lowering following a switch to postglacial incision at the end of glacial-age aggradation, points to a significant Southern Hemisphere climatic warming occurring soon after ca 15 000 14C years (ca 18 000 cal. years BP) during the Older Dryas interval. Elevation differences between the Waipaoa-1 (c.15 ka) terrace and the level of maximum channel incision (i.e. before aggradation since the turn of the 20th century) suggest about 50% of the topographic relief within headwater reaches of the Waipaoa catchment has been formed in postglacial times. The postglacial sediment flux generated by channel incision from Waipaoa catchment is of the order of 9.5 km3, of which ~ 6.6 km3 is stored within the confines of the Poverty Bay floodplain. Thus, although the postglacial period represented a time of high terrigenous sediment generation and delivery, only ~ 30% of the sediment generated by channel incision from Waipaoa catchment probably reached the marine shelf and slope of the Hikurangi Margin during this time. The smaller adjacent Waimata catchment probably contributed an additional 2.6 km3 to the same depocentre to give a total postglacial sediment contribution to the shelf and beyond of ~ 5.5 km3. Sediment generated by postglacial channel incision represents only ~ 25% of the total sediment yield from this landscape with ~ 75% of the estimated volume of the postglacial storage offshore probably derived from hillslope erosion processes following base-level fall at times when sediment yield from these catchments exceeded storage. 相似文献
83.
The processes of globalization and debt crisis led to dramatic changes in African countries. In the context of a new economic crisis – now on a global scale – it is useful to revisit debates regarding the impact of earlier policies in response to economic crisis on the poor, with a focus on very low‐income informal women workers. In this paper, we adopt a gender analysis framework to examine contending perspectives about the differential impacts of globalization, liberalization and structural adjustment programs on African women and men. We comment on two predominant schools of thought that appear to underlie and define the majority of case studies situated in African countries. While one asserts that globalization and liberalization offer entrepreneurial opportunities for women, an opposing view contends that the neoliberal political and economic reforms connected with structural adjustment policies have been devastating for poor women workers. A review of available empirical research on the responses of informal economy women workers to challenges of increased workload, reduced income and curtailed access to social services, cautions against dogmatic adherence to conceptual perspectives that either assume workers in the informal economy to be dynamic entrepreneurs when they cannot be, or condemn only contemporary policies for conditions that are the product of complex historical processes. 相似文献
84.
Trace metals and organic contaminants concentrations are monitored annually in surface sediments, blue mussel tissue, and winter flounder livers at multiple sites in Long Island Sound by National Oceanic and Atmospheric Administration’s National Status and Trends (NS&T) program for Marine Environmental Quality. The NS&T program is also conducting various studies on the bioeffects of contaminants in the sound. Three years of monitoring results indicate organic and elemental contaminants concentrations in sediments and biota at sites in the western portion of the sound are high on a national scale. Possible decreasing trends in cadmium and chlordane in the sound are suggested by the 1986–1988 data for their concentrations in mussels. A comparison between NS&T Mussel Watch results and those of the Environmental Protection Agency’s Mussel Watch, conducted from 1976 through 1978, indicated a decadal increase in copper concentrations and a decrease in lead in the sound. Bioeffects studies in the sound have revealed responses to contamination only in localized zones where contaminant levels are very high. 相似文献
85.
Growth lines and variation in oxygen and carbon isotope ratios (δ18O and δ13C) in shells of the Pliocene scallop Chesapecten madisonius preserve seasonal chronologies of biological and environmental change. This study evaluated whether (1) prominent growth lines were formed annually, and (2) growth rates estimated using isotope sclerochronology were comparable to rates estimated using visual inspection (measuring the width between external growth lines). We compared both techniques for estimating growth rates and age on three late to mid-Pliocene C. madisonius shells. The first approach located prominent growth lines on the δ18O time series, and differentiated between annual and non-annual (disturbance) growth lines. The second approach assumed all prominent lines were annual. This comparison showed that visual inspection underestimated growth rates and overestimated age. Seasonal timing of annual growth line formation using isotope sclerochronology provided unexpected results. Because this region fell within the warm-temperate paleobiogeographic province, we predicted annual lines formed during summers (most negative δ18O values). Instead, annual growth lines coincided with the most positive δ18O values (winter), typical of bivalves from cold-temperate regions. Moreover, shells recorded seasonal temperatures ranging from 3.2–20.8°C, a range lower than the thermal regime defined for warm-temperate environments (8–25°C). Possibly, the Sea Slope Gyre, which mixed eddies and cold filaments of the Labrador Current and warm waters of the Gulf Stream, penetrated the warm-temperate environment in this region. Alternatively, warm-water fauna from the zoogeographic Carolinian subprovince migrated northward and endured by virtue of warm summer temperatures. Regardless of the explanation, our findings provide a glimpse of mid-latitude seasonal temperature range for a warm climate episode during the mid-Pliocene. 相似文献
86.
Counterclockwise P-T-t trajectory from the metamorphic sole of a Neo-Tethyan ophiolite (Turkey) 总被引:2,自引:0,他引:2
The Kiziltepe ophiolitic thrust sheet in the Bolkar Mountains of Turkey occurs between two subparallel ophiolite belts bounding the Tauride carbonate platform and represents a remnant of the Cretaceous Neo-Tethyan oceanic lithosphere. It is underlain by foliated amphibolite that represents a metamorphic sole developed at the inception of an intra-oceanic subduction zone in the Neo-Tethys 92-90 Ma. Blueschist-facies overprinting of the amphibolite indicates that the metamorphic sole was dragged deeper into the subduction zone where it experienced increasing P/T with cooling. Regional tectonic constraints suggest a Maastrichtian age for the timing of this blueschist-facies metamorphism. Sodic amphibole-rich veins and crossite/Mg-riebeckite rims on hornblende suggest that growth of blueschist-facies minerals was facilitated by infiltration of fluid along fractures and grain boundaries. We infer a counterclockwise P-T-t trajectory during which metamorphism was accompanied/succeeded by rapid uplift along the northern edge of the Tauride belt in Late Cretaceous-early Tertiary time. 相似文献
87.
A multi‐scale statistical approach to assess the effects of connectivity of road and stream networks on geomorphic channel condition 下载免费PDF全文
Alison M. Pechenick Donna M. Rizzo Leslie A. Morrissey Kerrie M. Garvey Kristen L. Underwood Beverley C. Wemple 《地球表面变化过程与地形》2014,39(11):1538-1549
Roads in rural, upland landscapes are important sources of runoff and sediment to waterways. The downstream effects of these sources should be related to the connectivity of roads to receiving waters. Recent studies have explored this idea, but only simple metrics have been used to characterize connectivity and few studies have quantified the downstream effects of road–stream connectivity on sediment or solute budgets and channel morphology. In this study, we evaluated traditional and newly developed connectivity metrics that utilized features of landscape position and delivery pathway to characterize road–stream connectivity in upland settings. Using data on stream geomorphic conditions developed by the Vermont Agency of Natural Resources (Montpelier, VT), we related road connectivity metrics to channel condition on a set of 101 forested, upland streams with minimal development other than predominantly gravel road networks. Logistic regression indicated that measures of road density, proximity and orientation successfully distinguished among categories of stream geomorphic condition at multiple geographic scales. Discriminant function analysis using a set of inherent channel characteristics combined with road connectivity metrics derived at the reach corridor scale successfully distinguished channel condition for over 70% of the channels evaluated. This research contributes to efforts to evaluate the cumulative downstream effects of roads on stream channels and aquatic resources and provides a new means of watershed assessment to derive metrics that can be used to predict channel condition. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
88.
A Schmidt test hammer was employed to assess the aggregate surface hardness of samples of boulders dug out from under late-lying snowpatches at sites in Switzerland, Scotland and Norway. The results were compared with an equivalent set of readings made on boulders at nearby snow-free control sites. The results in every case reveal that the aggregate surface hardness of boulders buried by late-lying snow is significantly less (at the 0·001 level) than that of boulders at the corresponding control sites. This result indicates that late-lying snow significantly enhances rock weathering, probably because boulder and rock surfaces are exposed to prolonged wetting by percolating meltwater under late-lying snowbeds. 相似文献
89.
The effects of oil treatments (one-time addition of 120 ml per plant and weekly addition of 15 ml per plant) and environmental conditions at time of oiling (air conditioned laboratory/diffuse light vs hot, direct sunlight) on the survival and growth of Rhizophora mangle and Avicennia germinans seedlings were examined. No oiled A. germinans survived longer than a few weeks. Both one-time and weekly oiling depressed survival, stem growth, leaf production and maximum leaf size in R. mangle. Significant interaction terms between oil treatment and environmental conditions occurred later (50 and 59 weeks) for R. mangle stem growth and earlier (21 and 23 weeks) for leaf production. Relative to other treatment combinations, R. mangle mortality was greatest and growth lowest in the combination of one-time oiling under hot, bright outdoor conditions. Results indicate that synergistic interactions between oil effects and environmental conditions may contribute to the wide range of effects reported in the literature in studies of oil contamination of mangroves. 相似文献
90.
The Lerokis and Kali Kuning submarine exhalative gold-silver-barite deposits, Wetar Island, Maluku, Indonesia 总被引:1,自引:0,他引:1
Wetar, an island in the southern part of the Banda Arc, is made up submarine volcanic rocks, with the oldest rocks exposed being subvolcanic intrusions and flows dated at 12 Ma. Basaltic andesite pillow lavas and intercalated volcaniclastic sedimentary rocks grade upward into more felsic volcanic lavas, tuffs and breccias, and sedimentary rocks and epiclastic mudflows cap the sequence.Gold-silver mineralization occurs at Lerokis and Kali Kuning, 3.5 km apart on the north coast of the island, in stratiform barite sand, clay or silt. The sediments are underlain by Cu-rich massive pyrite in volcanic breccias and overlain by a limestone dated at about 4 Ma. Foot wall volcanic breccias and lavas show intense clay-pyrite alteration indicating temperatures higher than 230°C.In situ geological resources, prior to the inception of mining in 1990, totalled 2.9 Mt at 3.5 g/t Au, 114 g/t Ag and 40% barite at Lerokis and 2.2 Mt at 5.5 g/t Au, 146 g/t Ag and 60% barite at Kali Kuning. Most of the Au occurs as electrum, associated with limonite, jarosite and goethite, and most of the Ag is in tetrahedrite and sulphosalts. High Pb contents, between 0.5% and 1.4% Pb on average, derive from plumbojarosite, sulphosalts and cerrussite, and there is, on average, between 200 ppm to 900 ppm Cu, 0.2% Sb, 0.1% As, 100 ppm to 200 ppm Zn, and 18 ppm Hg. Underlying massive sulphide mineralization is mainly pyrite-marcasite with zones of Cu enrichment. A significant part of the Cu is contained in enargite.Formation likely took place at less than 600 m water depth in a sea floor caldera setting similar to the Kuroko district in Japan. The ferruginous sediments hosting the Au-barite deposits may have originated through erosion like the ochres of Cyprus. These stratiform Au-barite deposits highlight a new style of sea floor mineralization not clearly recognized before. Modern-day analogues have been described from a variety of sea floor settings. 相似文献