A commentary on: A synopsis of climatic and vegetational change in Southeast Asia     

Peter H. Raven 《Climatic change》1991,19(1-2):63-64

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Investigation of Possible Contamination of Shallow Ground Water by Deeply Injected Liquid Industrial Wastes     

Suzanne Lesage  Richard E. Jackson  Mark Priddle  Paul Beck  Ken G. Raven 《Ground Water Monitoring & Remediation》1991,11(1):151-159

The objective of this study was to assess the possible impact of deep well disposal operations, conducted between 1958 and 1974, on the ground water quality in a shallow fresh water aquifer beneath Sarnia, Ontario, Canada. Because of the breakout of formation fluids in Sarnia and Port Huron, Michigan, in the early 1970s, it had been hypothesized that liquid waste from the disposal zone in bedrock had leaked through numerous abandoned oil, gas, and salt wells in the area up to the shallow fresh water aquifer and from there to the surface.
A monitoring well network of 29 5cm (2 inch) diameter piezometers was established in the thin sand and shale aquifer system, which exists between 30 and 70m (100 and 230 feet) below ground surface. In addition, a 300m (1000 foot) deep borehole was drilled and instrumented with a Westbay multilevel casing, which permitted sampling of the disposal zone.
Ground water samples from the shallow monitoring wells and the Westbay multilevel casing were analyzed for volatiles by GC/MS. Those volatile aromatics that were conspicuously present in the deep disposal zone, e.g., ethyl toluenes and trimethyl benzene, were not detected in the shallow monitoring wells. Thus, if contaminants from the disposal zone did indeed migrate to the shallow aquifer, contamination was not widespread and probably consisted mostly of displaced chloride-rich formation waters.  相似文献   

Water policy,trust and governance in the Murray-Darling Basin     

Margaret Alston  Kerri Whittenbury  Deb Western  Aaron Gosling 《The Australian geographer》2016,47(1):49-64

Concerns for river health in the Murray-Darling Basin (MDB) area and shifting priorities for water use have led to a significant process of water reform over the last decade. The MDB area, also known as the food bowl of Australia, produces much of the country's food and is home to a significant portion of the population. A long-term drought, historical over-allocation of water for irrigation and climate variability have led to mounting concerns about the long-term viability of the rivers. While the reform process has resulted in the Commonwealth government taking control of the rivers from the States, it has also been influenced by changes in governments and consequent shifts in water allocation priorities from a privileging of agriculture to a broader approach encompassing economic, environmental and social concerns. This had led to uncertainty for the people and communities in the Basin and some confusion between the various layers of governance structures. This paper presents the results of exploratory research conducted with key, high-level stakeholders involved in water reform to examine their perceptions of the evolving water policy process. Despite agreement amongst stakeholders that returning water to the environment to ensure river health is critical, our research reveals significant tensions between stakeholders concerning the evolving process, particularly centred on the potential social outcomes and fairness and equity. This suggests the need for more integrated and transparent governance structures, attention to levels of trust between partners and a common vision that incorporates environmental, economic and social goals.  相似文献   

Farmer’s intended and actual adoption of climate change mitigation and adaptation strategies     

Meredith T. Niles  Margaret Brown  Robyn Dynes 《Climatic change》2016,135(2):277-295

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Beggiatoa in microbial mats at hydrocarbon vents in the Gulf of Mexico and Warm Mineral Springs,Florida     

John Larkin  Margaret C. Henk  Paul Aharon 《Geo-Marine Letters》1994,14(2-3):97-103

Microbial mats were collected from a variety of sites near hydrocarbon vents along the slope in the northern Gulf of Mexico and, for comparison, from Warm Mineral Springs, Florida, USA. A predominant microorganism in each of the mats was the giant bacterium,Beggiatoa. Diameters of the bacterial filaments ranged from about 6 µm to approximately 200 µm. The latter organisms are the largest prokaryotic organisms yet found. All filaments over about 10 µm in diameter contained a large central vacuole, producing a cell with the cytoplasm as a cylindrical tube underlying the cytoplasmic membrane. Sulfur globules were confined to this peripheral layer. Push cores often contained pyrite tubules whose appearance is suggestive of aBeggiatoa origin. Determinations of ¹³C inBeggiatoa mats from vents along the Louisiana slope yielded values in the range of –26.6 to –27.9 (PDB), suggesting an unusually high degree of isotope fractionation (–24.9) relative to the carbon source in the ambient seawater, which is typical of sulfur-oxidizing chemoautotrophs. The presence of S^O (elemental sulfur) within cells ofBeggiatoa resulting from oxidation of H₂S supports the importance of bacterial sulfate reduction processes in the underlying vents for the sustenance of theBeggiatoa mats.  相似文献   

Evidence for exposure of fish to oil spilled into the Columbia river     

Margaret M. Krahn  Lewey J. Kittle Jr  William D. MacLeod Jr 《Marine environmental research》1986,20(4)

On March 19, 1984, more than 170000 gallons of oil were spilled into the Columbia River. We had recently developed analytical methods for estimating the exposure of fish to aromatic compounds by measuring the concentrations of metabolites of these contaminants in fish bile. The oil spill provided an opportunity to field test our methods in assessing the exposure of fish to petroleum aromatic compounds from the spilled oil. Our findings indicated that, within 5 days after the spill, mean concentrations of metabolites of aromatic compounds in the bile of white sturgeon (Acipenser transmontanus) captured 57 miles downstream from the spill were significantly higher than those of sturgeon caught upriver.  相似文献   

Spatio-temporal distribution of dissolved inorganic carbon and net community production in the Chukchi and Beaufort Seas   总被引：2，自引：0，他引：2  

Nicholas R. Bates  Margaret H.P. Best  Dennis A. Hansell 《Deep Sea Research Part II: Topical Studies in Oceanography》2005,52(24-26):3303

As part of the 2002 Western Arctic Shelf–Basin Interactions (SBI) project, spatio-temporal variability of dissolved inorganic carbon (DIC) was employed to determine rates of net community production (NCP) for the Chukchi and western Beaufort Sea shelf and slope, and Canada Basin of the Arctic Ocean. Seasonal and spatial distributions of DIC were characterized for all water masses (e.g., mixed layer, halocline waters, Atlantic layer, and deep Arctic Ocean) of the Chukchi Sea region during field investigations in spring (5 May–15 June 2002) and summer (15 July–25 August 2002). Between these periods, high rates of phytoplankton production resulted in large drawdown of inorganic nutrients and DIC in the Polar Mixed Layer (PML) and in the shallow depths of the Upper Halocline Layer (UHL). The highest rates of NCP (1000–2850 mg C m⁻² d⁻¹) occurred on the shelf in the Barrow Canyon region of the Chukchi Sea and east of Barrow in the western Beaufort Sea. A total NCP rate of 8.9–17.8×10¹² g for the growing season was estimated for the eastern Chukchi Sea shelf and slope region. Very low inorganic nutrient concentrations and low rates of NCP (<15–25 mg C m⁻² d⁻¹) estimated for the mixed layer of the adjacent Arctic Ocean basin indicate that this area is perennially oligotrophic.  相似文献   

Standards for faecal coliform bacterial pollution     

Margaret Loutit  I. L. Vidal  A. A. Collins 《新西兰海洋与淡水研究杂志》2013,47(1-2):214-219

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The Global boundary Stratotype Section and Point （GSSP） of the Drumian Stage （Cambrian） in the Drum Mountains, Utah, USA     

Loren E. Babcock Richard A. Robison Margaret N. Rees Shanchi Peng Matthew R. Saltzman 《《幕》》2007,30(2):85-95

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Modified water regime and salinity as a consequence of climate change: prospects for wetlands of Southern Australia     

Daryl L. Nielsen  Margaret A. Brock 《Climatic change》2009,95(3-4):523-533

The natural Australian landscape sustains a mosaic of wetlands that range from permanently wet to temporary. This diversity of wetland types and habitats provides for diverse biotic communities, many of which are specific to individual wetlands. This paper explores the prospects for southern Australian wetlands under modified water regime and salinity induced by climatic changes. Extended droughts predicted as a consequence of climate change (lower rainfall and higher temperatures) combined with human-induced changes to the natural hydrological regime will lead to reductions in the amount of water available for environmental and anthropogenic uses. Reduced runoff and river flows may cause the loss of some temporary wetland types that will no longer hold water long enough to support hydric communities. Species distributions will shift and species extinctions may result particularly across fragmented or vulnerable landscapes. Accumulation of salts in wetlands shift species-rich freshwater communities to species-poor salt tolerant communities. Wetlands will differ in ecological response to these changes as the salinity and drying history of each wetland will determine its resilience: in the short term some freshwater communities may recover but they are unlikely to survive and reproduce under long term increased salinity and altered hydrology. In the long term such salinized wetlands with altered hydrology will need to be colonized by salt tolerant species adapted for the new hydrological conditions if they are to persist as functional wetlands. As the landscape becomes more developed, to accommodate the need for water in a warmer drying climate, increasing human intervention will result in a net loss of wetlands and wetland diversity.  相似文献