Mapping acidic mine waste with seasonal airborne hyperspectral imagery at varying spatial scales

Airborne imaging spectrometer (also known as hyperspectral) remote sensing has been widely used to characterize mineralogy on mine waste surfaces, which is useful for predicting potential sources of acidity and metal leaching. The most successful applications employ fine spatial resolution—20-m pixels or smaller. Future satellite imaging spectrometer sensors are proposed to provide coarser spatial resolution—30- to 60-m pixels. This study examined the ability to map minerals related to acid mine drainage with visible to shortwave infrared hyperspectral imagery at varying spatial scales (2-, 15-, 30-, 60-m pixels) at the Leviathan mine Superfund site, located in the Eastern Sierra Nevada. Mineral maps were produced using spectral angle mapper and matched filtering algorithms. The 15-m images provided comparable maps to the 2-m images. The 30- and 60-m images lost the ability to identify smaller features; however, they were still able to identify high- and low-priority remediation zones at least 75 m in width. Based on our results, we believe 30-m spatial resolution on a satellite hyperspectral sensor will be sufficient for identifying hazardous surfaces at larger mine waste sites and provide important reconnaissance information that can help prioritize detailed ground-based studies.     

Trace element distribution in Central Dabie eclogites

Coesite-bearing eclogites from Dabieshan (central China) have been studied by ion microprobe to provide information on trace element distributions in meta-basaltic mineral assemblages during high-pressure metamorphism. The primary mineralogy (eclogite facies) appears to have been garnet and omphacite, usually with coesite, phengite and dolomite, together with high-alumina titanite or rutile, or both titanite and rutile; kyanite also occurs occasionally as an apparently primary phase. It is probable that there was some development of quartz, epidote and apatite whilst the rock remained in the eclogite facies. A later amphibolite facies overprint led to partial replacement of some minerals and particularly symplectitic development after omphacite. They vary from very fine-grained dusty-looking to coarser grained Am + Di + Pl symplectites. The eclogite facies minerals show consistent trace element compositions and partition coefficients indicative of mutual equilibrium. Titanite, epidote and apatite all show high concentrations of REE relative to clinopyroxene. The compositions of secondary (amphibolite facies) minerals are clearly controlled by local rather than whole-rock equilibrium, with the composition of amphibole in particular depending on whether it is replacing clinopyroxene or garnet. REE partition coefficients for Cpx/Grt show a dependence on the Ca content of the host phases, with D _REE ^Cpx/Grt decreasing with decreasing D _Ca . This behaviour is very similar to that seen in mantle eclogites, despite differences in estimated temperatures of formation of 650–850 °C (Dabieshan) and 1000–1200 °C (mantle eclogites). With the exception of HREE in garnet, trace elements in the eclogites are strongly distributed in favour of minor or accessory phases. In particular, titanite and rutile strongly concentrate Nb and Zr, whilst LREE–MREE go largely into epidote, titanite and apatite. If these minor/accessory minerals behave in a refractory manner during melting or fluid mobilisation events and do not contribute to the melt/fluid, then the resultant melts and fluids will be strongly depleted in LREE–MREE. Received: 11 February 1999 / Accepted: 31 January 2000     

Water quality assessment for sustainable agriculture in the Wet Tropics--a community-assisted approach

A number of studies in north Queensland over the past two decades have concluded that large amounts of nutrients and sediments are exported from agricultural watersheds, particularly during wet season rainfall events. With the co-operation of a number of growers, runoff from Queensland Wet Tropics banana and cane farm paddocks in two distinct tropical river catchments was examined to provide an estimate of nutrient and sediment concentrations and export, with comparison to water quality of flow through a small urban lakes system. Median total nitrogen concentrations in cane drainage runoff (3110 microg N/L) were higher than for banana paddock drainage (2580 microg N/L), although the maximum concentration was recorded from a banana paddock (20,900 microg N/L). Nitrogen losses during post-event drainage flow were supplemented by high proportions of NO(X) (nitrate + nitrite) sourced from groundwater inputs. Banana paddocks had the highest maximum and median total phosphorus and TSS concentrations (5120 and 286 microg P/L, and 7250 and 75 mg/L respectively) compared to the cane farms (1430 and 50 microg P/L, and 1840 and 14 mg/L respectively). The higher phosphorus and TSS concentrations in the banana runoff were attributed to higher paddock slopes and a greater proportion of exposed ground surface during the wet season. Highest nutrient and TSS concentrations corresponded with samples collected near the peak discharge periods; however, the rising stage of the drainage flows, where the highest nutrient and TSS concentrations are often reported, were difficult to target because of the manual sampling strategy used. This study shows that high concentrations of nutrients and TSS occur in the runoff from cane and banana paddocks. Median total nitrogen, total phosphorus and TSS concentrations in flow through the urban lakes were 369 microg N/L, 16 microg P/L and 11 mg/L, respectively. Flux estimates of 9.2 kg N, 0.8 kg P and 126 kg TSS/ha were determined for drainage runoff from a banana paddock during a single intensive storm event.     

Funding commercial fisheries management: Lessons from New Zealand

The funding of fisheries management in New Zealand over the last two decades is a complex story. It is a tale of fundamental principle, public policy experimentation, legal challenge and collective resolution of difficulties through tens of thousands of hours of research, review and constructive dialogue between stakeholders and the government. Importantly, funding issues cannot be separated from the evolution of fisheries management itself. Reviewing this history and tracing the maturing of fisheries management in New Zealand reveals many legal and institutional design lessons for fisheries managers considering cost recovery regimes in developed and developing countries.     

Preparing Preservice Teachers to Incorporate Geospatial Technologies in Geography Teaching

This study evaluated the efficacy of geospatial technology (GT) learning experiences in two geography curriculum courses to determine their effectiveness for developing preservice teacher confidence and preparing preservice teachers to incorporate GT in their teaching practices. Surveys were used to collect data from preservice teachers at three intervals over one semester. Results indicate preservice teachers' confidence and competencies to successfully integrate GT in their teaching increased over the duration of the study. The findings highlight the value of providing GT learning experiences in geography curriculum courses and contribute to the literature on preparing preservice teachers to incorporate GT in teaching geography.     

Latitudinal Distribution of O2on Ganymede: Observations with the Hubble Space Telescope

To help constrain the spatial variation of oxygen on Jupiter's satellite Ganymede, and hence have more clues to its mode of production and stability, we have obtained spectral data from the Faint Object Spectrograph (FOS) for a single pole-to-pole latitudinal strip, along with several Wide Field Planetary Camera 2 (WFPC2) images in three narrow band visible filters. All observations were made of the trailing hemisphere. In the FOS data we observe both visible absorptions at 0.577 and 0.627 μm, associated with dense-phase oxygen (compressed gases, liquids, or solids). Filter options limited the WFPC2 observations to wavelengths near the weaker oxygen absorption at 0.627 μm. These observations suggest that the dense-phase or dimer oxygen form is predominantly found in equatorial and mid-latitudes. The spectroscopic absorption feature appears in both bright and dark terrains but may be somewhat weaker in dark regions, which is consistent with the smaller mean photon path length in the surface in darker areas. Therefore, the abundance of oxygen appears more dependent on latitude and longitude constraints than surface albedo. At the highest latitudes, where the ratio spectra have a strong upturn toward the blue, the oxygen bands do not appear. This relation suggests that dimer oxygen and ozone (as seen by Galileo) have opposite trends with latitude. Possible causes include competition or variation in the preferred stable form, which depends on temperature, solar ultraviolet flux, and/or surface age; enhancement of O₃at the poles due to plasma interactions; or viewing geometry effects that reduce the oxygen features at the poles when observed from Earth. The predominantly equatorial feature supports the production of O₂through plasma bombardment and favors defect trapping over physical adsorption of the dimer molecules in the surface. We briefly consider the implications of Ganymede's magnetosphere for our understanding of O₂and O₃distribution on Ganymede.     

“Doing Geography”: Evaluating an Independent Geographic Inquiry Assessment Task in an Initial Teacher Education Program

The assessment task of the final course in a bachelor of secondary education program is examined for opportunities for preservice geography teachers to achieve the course aims of integrating, consolidating, applying, and reflecting on the knowledge and skills they have learned during their initial teacher education program. The results show that the preservice teachers did better in some areas (integrating, consolidating, and reflecting) than in others (applying). This has implications for curriculum renewal in geography methods courses—specifically to provide more opportunities for preservice teachers to practice applying the knowledge and skills they have gained during the program, essential for their future roles as senior geography teachers.     

“We Don’t Take the Pledge”: Environmentality and environmental skepticism at the epicenter of US wind energy development

This study analyzes pro-wind, “anti-environmental” discourses prevalent among key stakeholders in Nolan County, Texas, the epicenter of US wind power. We draw upon interviews conducted within a Q-method study to examine environmental views held by key actors in wind-farm development. We frame our analysis within the theoretical field that engages the formation of environmental subjects, defined as the process through which individuals and communities align their environmental practices with state ends. We argue that this is a process that can be incomplete or in tension with other subject positions, which together may lead to unexpected environmental views. We introduce “environmental skepticism,” defined as a rejection of ecological science steeped in deep anthropocentrism and possessive individualism, as a dominant counter-narrative informing certain environmental subjectivities. The remainder of the paper describes Texas wind stakeholders’ views or subject positions on energy and the environment and reveals how environmental skepticism is not overturned even as renewable energy supports the local economy. We analyze wind stakeholders’ environmental subjectivity in terms of emergent subject positions as “reflexive environmental skepticism,” a view that accepts the economic products, processes, and policy innovations advocated by ecological modernization without accepting the core claim that innovations are required to adapt to environmental change.     

Travelling technocrats, embodied knowledges: Globalising privatisation in telecoms and water

The decade from the mid-1980s to the mid-1990s was a key moment in the unfolding of the global privatisation agenda. During this decade privatisation shifted from a nation-state project to become part of the structural adjustment measures associated with economic globalisation. These measures were not only promoted by international institutions such as the World Bank and IMF, but by a range of other organisations and actors who have received little attention. In particular, virtually no attention has been paid to the mid-level technocrats who enacted privatisation strategies and techniques. This paper focuses on these actors through the cases of New Zealand telecommunications engineers and British water engineers. In discussing the significance of these actors we argue for the unpacking of the messy histories, geographies and sociologies of privatisation using both publicly available documents and ethnographic methods. This will allow us to understand why certain courses of action were pursued in particular times and places, why other actions dropped out, and will reveal more about the national imaginaries and embodied knowledges underpinning the globalisation of privatisation.     

Conservation in a complex management environment: The by-catch of sea turtles in North Carolina’s commercial fisheries

Despite a powerful, federal legislative framework established to protect threatened and endangered species in the United States, conservation actions can be hindered by the complexity of the full management structure. This is particularly true when state and federal agencies share the responsibility to conserve endangered species. To illustrate this point, this paper describes the management of sea turtle by-catch in commercial fisheries within the state waters of North Carolina. It reviews past and present by-catches, summarizes state and federal efforts intended to reduce sea turtle by-catch, and discusses the challenges posed by the involvement of multiple agencies with conflicting objectives. It concludes by recommending fundamental changes to this management framework and, in particular, proposes the establishment of a multilayered stakeholder group that would work to reduce sea turtle by-catch while supporting vibrant commercial fisheries in the state.