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Sample records for athabasca lake

  1. Streamflow input to Lake Athabasca, Canada

    Directory of Open Access Journals (Sweden)

    K. Rasouli

    2013-05-01

    Full Text Available The Lake Athabasca drainage area in northern Canada encompasses ecologically rich and sensitive ecosystems, vast forests, glacier-clad mountains, and abundant oil reserves in the form of oil sands. The basin includes the Peace–Athabasca Delta, recognized internationally by UNESCO and the Ramsar Convention as a biologically rich inland delta and wetland that are now under increasing pressure from multiple stressors. In this study, streamflow variability and trends for rivers feeding Lake Athabasca are investigated over the last half century. Hydrological regimes and trends are established using a robust regime shift detection method and the Mann–Kendall (MK test, respectively. Results show that the Athabasca River, which is the main contributor to the total lake inflow, experienced marked declines in recent decades impacting lake levels and its ecosystem. From 1960 to 2010 there was a significant reduction in lake inflow and a significant recession in the Lake Athabasca level. Our trend analysis corroborates a previous study using proxy data obtained from nearby sediment cores suggesting that the lake level may drop 2 to 3 m by 2100. The lake recession may threaten the flora and fauna of the Athabasca Lake basin and negatively impact the ecological cycle of an inland freshwater delta and wetland of global importance.

  2. Streamflow input to Lake Athabasca, Canada

    OpenAIRE

    Rasouli, K.; M. A. Hernández-Henríquez; S. J. Déry

    2012-01-01

    The 271 000 km2 Lake Athabasca drainage in Northern Canada encompasses ecologically-rich and sensitive ecosystems, intensive agricultural lands, vast forests, glacier-clad mountains, and abundant oil reserves in the form of tar-sands. In this study, streamflow variability and trends in eight rivers feeding the 7800 km2 Lake Athabasca are investigated over the period 1960–2010. Hydrological regimes and trends are established using a robust r...

  3. Metals and polycyclic aromatic hydrocarbons in colonial waterbird eggs from Lake Athabasca and the Peace-Athabasca Delta, Canada.

    Science.gov (United States)

    Hebert, Craig E; Weseloh, D V Chip; Macmillan, Stuart; Campbell, David; Nordstrom, Wayne

    2011-05-01

    In 2009, aquatic bird eggs from a variety of species were collected from three sites in northern Alberta, Canada. Two sites were located in receiving waters of the Athabasca River, which drains the oil sands industrial region north of Fort McMurray, Alberta. The third site, located on the Peace River, was remote from the influence of the Athabasca River. Levels of mercury, arsenic, and polycyclic aromatic hydrocarbons (PAHs) were measured in the eggs along with nitrogen stable isotopes (δ¹⁵N) as an indicator of bird trophic position. Levels of As and PAHs in eggs were low, whereas Hg was measureable in all samples. Egg Hg levels increased with δ¹⁵N values (a proxy of food web trophic position); however, some eggs exhibited Hg levels greater than expected based on trophic position. These eggs were from sites in receiving waters of the Athabasca River, namely, Mamawi Lake and Egg Island. Levels of Hg in egg pools were correlated with naphthalene levels, perhaps indicating a common source of contamination. Temporal comparison of Hg levels in California gull (Larus californicus) eggs from the Lake Athabasca colony indicated that egg Hg burdens increased 40% from 1977 to 2009. More research is required to evaluate temporal trends in levels of environmental contaminants and to identify sources. PMID:21312251

  4. Assessing the potential environmental impact of Athabasca oil sands development in lakes across Northwest Saskatchewan

    Science.gov (United States)

    Ahad, J. M.; Cumming, B. F.; Das, B.; Sanei, H.

    2011-12-01

    The continued development of Canada's Athabasca oil sands poses a significant environmental challenge. Low buffered boreal lakes located downwind of the prevailing eastward wind direction may be threatened by acidification and elevated inputs of airborne contaminants such as polycyclic aromatic hydrocarbons (PAHs). An accurate assessment of the impact that increased levels of bitumen production may have on lakes in the region requires an understanding of the historic variability within these systems prior to at least the past several decades. Here we report concentrations of PAHs, δ13C and δ15N of organic matter (OM), Rock-Eval pyrolysis analyses, and distributions of n-alkanes in dated sediment cores from ten lakes located across NW Saskatchewan. Concentrations of PAHs were relatively low (environmental impact on lakes in NW Saskatchewan.

  5. A bioassessment of lakes in the Athabasca Oil Sands Region, Alberta, using benthic macroinvertebrates

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    Keith M. SOMERS

    2010-08-01

    Full Text Available Emissions of sulphur oxides, nitrogen oxides and other pollutants have increased in the Athabasca Oil Sands Region (AOSR in Alberta, Canada. Atmospheric pollutants impact aquatic communities through a number of processes, but due to a lack of regional monitoring programs potential biological impacts have not been assessed. In this study, a bioassessment was conducted using approaches borrowed from a variety of protocols to establish a baseline dataset, determine appropriate methodologies, and to assess the current impact of emissions on benthic macroinvertebrate (BMI communities in the AOSR. As a result, 32 lakes, including 5 test lakes located in a modelled high deposition region, were sampled for water chemistry and BMI. The Reference Condition Approach (RCA was used because a baseline dataset does not exist and data were evaluated using three separate statistical techniques. All of the statistical methods used: One Sample T-Tests, Multivariate Analysis of Variance (MANOVA and Test Site Analysis (TSA, showed that BMI assemblages in test lakes differed from BMI assemblages in reference lakes. Traditional statistics classified all 5 test lakes as "significantly impaired" whereas TSA identified 3 of the 5 test lakes as only potentially impaired and 2 lakes were in "reference condition". The variability in lake attributes present challenges in interpreting BMI data and establishing an accurate biomonitoring program in the AOSR which need to be addressed in future assessment studies.

  6. Palaeolimnological assessment of lake acidification and environmental change in the Athabasca Oil Sands Region, Alberta

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    Sergi PLA

    2010-08-01

    Full Text Available Exploitation of the Athabasca Oil Sands has expanded hugely over the last 40 years. Regional emissions of oxidised sulphur and nitrogen compounds increased rapidly over this period and similar emissions have been linked to lake acidification in other parts of North America and Europe. To determine whether lakes in the region have undergone acidification, 12 lakes within the Regional Municipality of Wood Buffalo and the Caribou Mountains were selected to cover chemical and spatial gradients and sediment cores were obtained for palaeolimnological analyses including radiometric dating, diatom analysis, isotopic analysis of bulk sediment 13C and 15N, and spheroidal carbonaceous particles (SCPs. All lake sediment cores show evidence of industrial contamination based on SCPs, but there is no clear industrial signal in stable isotopes. Most lakes showed changes in diatom assemblages and sediment C:N ratios consistent with nutrient enrichment over various timescales, with potential drivers including climatic change, forest fires and anthropogenic nitrogen deposition. Only one of the 12 lakes investigated showed strong evidence of acidification with a decline in diatom-inferred pH from 6.3 to 5.6 since 1970 linked to increasing relative abundances of the acidophilous diatom species Actinella punctata, Asterionella ralfsii and Fragilariforma polygonata. Analysis of mercury (Hg in the acidified lake showed increasing sediment fluxes over the last 20 years, a possible indication of industrial contamination. The acidified lake is the smallest of those studied with the shortest residence time, suggesting a limited capacity for neutralisation of acid inputs in catchment soils or by inlake processes.

  7. Relationships between lake water chemistry and benthic macroinvertebrates in the Athabasca Oil Sands Region, Alberta

    Directory of Open Access Journals (Sweden)

    Keith M. SOMERS

    2010-08-01

    Full Text Available Sulphur and nitrogen emissions in the Athabasca Oil Sands Region (AOSR are a threat to regional lentic ecosystems. Benthic macroinvertebrates have been used successfully elsewhere to monitor the impacts of acid emissions on water bodies and the opportunity exists to implement a regional lentic biomonitoring program in the AOSR. Metrics are often used to assess the impacts of anthropogenic stressors because they describe biological conditions through a variety of measures. The selection of appropriate metrics is an integral component of any biomonitoring program and it depends on the in situ relationships between water chemistry and benthic macroinvertebrates. In order to establish these relationships we compared lake water chemistry parameters with benthic macroinvertebrate communities and metric scores from 32 lakes in the AOSR through Redundancy Analyses. Lake acidity correlates positively with Hyallelidae and negatively with Chironomidae and Oligochaeta while dissolved organic carbon is also an important determinant of benthic macroinvertebrate community composition. A number of metrics were strongly correlated with lake acidity and the following compositional metrics proved to be the most suitable for monitoring acidification in the AOSR: % Diptera, % Oligochaeta, % EPT, Total Ephemeroptera and Total Trichoptera.

  8. Delayed coking studies on Athabasca bitumen and Cold Lake heavy oil

    Energy Technology Data Exchange (ETDEWEB)

    Govindhakannan, J.; Khulbe, C. [National Centre for Upgrading Technology, Devon, AB (Canada); Natural Resources Canada, Devon, AB (Canada). CanmetENERGY

    2009-07-01

    This poster highlighted the results of a study that quantified the delayed coking product yields of Athabasca bitumen and Cold Lake heavy oil. It also investigated the effect of operating pressure and feed rates on product yield and quality. The effect of pressure on conversion of sulphur and nitrogen was also examined. Experimental results revealed that the yield of liquid products decreases and the yields of coke and gases increase as the operating pressure increases. Sulphur and nitrogen conversions increase with increasing pressure. In this study, the yield and quality of delayed coking products were not influenced by the variation in feed rates. It was concluded that feed rate changes do not significantly affect the yield and quality of delayed coking products because the residual liquid and coke trapped in the coker drum reside there for a duration that approaches infinity, compared to much smaller average residence time for vapor-phase compounds. tabs., figs.

  9. Relationships between lake water chemistry and benthic macroinvertebrates in the Athabasca Oil Sands Region, Alberta

    OpenAIRE

    Keith M. SOMERS; Peter J Dillon; Shaun A. WATMOUGH; Brent G. PARSONS

    2010-01-01

    Sulphur and nitrogen emissions in the Athabasca Oil Sands Region (AOSR) are a threat to regional lentic ecosystems. Benthic macroinvertebrates have been used successfully elsewhere to monitor the impacts of acid emissions on water bodies and the opportunity exists to implement a regional lentic biomonitoring program in the AOSR. Metrics are often used to assess the impacts of anthropogenic stressors because they describe biological conditions through a variety of measures. The selection of ap...

  10. Implications of a 2 degree C global temperature rise on Canada's water resources : Athabasca River and oil sands development : Great Lakes and hydropower production

    International Nuclear Information System (INIS)

    A globally averaged warming of 2 degrees C is expected to occur by the middle of this century unless significant efforts are made in all countries to reduce greenhouse gas (GHG) emissions. This study examined the impacts of a 2 degrees C global warming on: (1) the Athabasca River and oil sands production; and (2) the Great Lakes and hydropower production. The study was based on previous climate predictions from 6 coupled ocean-atmosphere global climate models. The studies showed that the Athabasca River and the Great Lakes regions have seen increases in mean temperatures and changes in precipitation patterns in recent decades. Flows in the Athabasca River decreased by approximately 20 per cent between 1958 and 2003, and water levels in the Great Lakes have remained consistently low between 1998 and 2001. Under the 2 degrees C warming scenario, minimum flows in the Athabasca River are likely to diminish by 7 to 10 per cent, and water levels in the Great Lakes could fall by 0.08 to 1.18 metres, indicating a potential loss of between 2 to 17 per cent in hydropower production on the St. Lawrence River. An increased frequency and severity of hot spells in summer will increase the region's peak summer energy demand. Results also suggested that the projected rate of water use from the Athabasca River for oil sands projects will become more unsustainable under climate change. The impacts of water withdrawal from oil sands projects will have serious consequences beyond the area of the projects themselves, threatening the productivity of the Peace Athabasca Delta, compromising the sharing of water with downstream jurisdictions in the Mackenzie River system, and ecosystem degradation. The study recommended that Alberta should consider withholding approval of oil sands projects until substantial water conservation measures are introduced. Plans should also be developed for alternative energy projects to compensate for declines in hydropower from the Great Lakes system. It was

  11. Have atmospheric emissions from the Athabasca oil sands impacted lakes in northeastern Alberta, Canada?

    International Nuclear Information System (INIS)

    Rates of oil sands production in northeastern Alberta are outpacing attempts to understand the region's ecology. The extent of potential disturbances caused by atmospheric deposition may remain unknown. Studies have demonstrated that atmospheric sulphur dioxide (SO2) and nitrogen oxide (NOx) emissions from the Fort McMurray region of the province have the potential to acidify surface waters. In this study, diatom assemblages in sediment cores from 8 acid-sensitive lakes were analyzed in order to investigate the effects of emissions from oil sands processing plants on boreal lake ecosystems. Diatom stratigraphic data were synthesized using a principal components analysis (PCA) method. A total of 280 diatom taxa were used in the analyses. Results showed that diatom communities in the study lakes have undergone substantial changes over the last century. The study revealed that the lakes showed characteristic changes towards greater alkalinity and productivity. Results suggest that the boreal lakes differ fundamentally from acidified lakes studied in northern Europe and eastern North America. It was concluded that a series of complex interactions involving in-lake alkalinity production, internal nutrient loading, and climate change are responsible for changes in the lake ecosystems. 61 refs., 1 tab., 6 figs

  12. Fluids preserved in variably altered graphitic pelitic schists in the Dufferin Lake Zone, south-central Athabasca Basin, Canada: implications for graphite loss and uranium deposition

    Science.gov (United States)

    Pascal, Marjolaine; Boiron, Marie-Christine; Ansdell, Kevin; Annesley, Irvine R.; Kotzer, Tom; Jiricka, Dan; Cuney, Michel

    2016-06-01

    The Athabasca Basin (Canada) contains the highest grade unconformity-type uranium deposits in the world. Underlying the Athabasca Group sedimentary rocks of the Dufferin Lake Zone are variably graphitic, pelitic schists (VGPS), altered to chlorite and hematite (Red/Green Zone: RGZ). They were locally bleached near the unconformity during paleoweathering and/or later fluid interaction. Overall, graphite was lost from the RGZ and the bleached zone relative to the original VGPS. Fluid inclusions were examined in different generations of quartz veins, using microthermometry and Raman spectroscopy, to characterize and compare the different fluids that interacted with the RGZ and the VGPS. In the VGPS, CH4-, and N2-rich fluid inclusions, which homogenize into the vapor phase between -100 and -74 °C, and -152 and -125 °C, respectively, and CO2-rich fluid inclusions, homogenizing either into vapor or liquid between 20 and 28 °C, are present. Carbonic fluids could be the result of the breakdown of graphite to CH4 + CO2, whereas N2-rich fluid is interpreted to be the result of breakdown of feldspars/micas to NH4 ++N2. In the RGZ, the presence of fluid inclusions with low ice melting temperature (-38 to -16 °C) reflect the presence of CaCl2, and fluid inclusions with halite daughter minerals that dissolve between 190 and 240 °C indicate the presence of highly saline fluids. These fluids are interpreted to be derived from the Athabasca Basin. The circulation of carbonic fluids and brines occurred during two different events related to different P-T conditions of trapping. The carbonic fluids interacted with basement rocks during retrograde metamorphism of the basement rocks before deposition of the Athabasca Basin, whereas the brines circulated after the deposition of the Athabasca Basin. These latter fluids are similar to brines related to uranium mineralization at McArthur River and thus, in addition to possibly being related to graphite depletion in the RGZ, they could

  13. Radionuclide levels in fish from Lake Athabasca February 1993. Northern River Basins Study project report no.26

    International Nuclear Information System (INIS)

    The Northern River Basins Study was initiated through the 'Canada-Alberta-Northwest Territories Agreement Respecting the Peace-Athabasca-Slave River Basin Study, Phase II - Technical Studies' which was signed September 27, 1991. The purpose of the study is to understand and characterize the cumulative effects of development on the water and aquatic environment of the Study Area by coordinating with existing programs and undertaking appropriate new technical studies. This publication reports the method and findings of particular work conducted as part of the Northern River Basins Study. As such, the work was governed by a specific terms of reference and is expected to contribute information about the Study Area within the context of the overall study as described by the Study Final Report. This report has been reviewed by the Study Science Advisory Committee in regards to scientific content and has been approved by the Study Board of Directors for public release. It is explicit in the objectives of the Study to report the results of technical work regularly to the public. This objective is served by distributing project reports to an extensive network of libraries, agencies, organizations and interested individuals and by granting universal permission to reproduce the material. This report contains referenced data obtained from external to the Northern River Basins Study. Individuals interested in using external data must obtain permission to do so from the donor agency. (author). 47 refs., 9 tabs., 2 figs

  14. A rapid in situ method for determining the ages of uranium oxide minerals: Evolution of the Cigar Lake deposit, Athabasca Basin

    International Nuclear Information System (INIS)

    The authors present a rapid and accurate technique for making in situ U-Pb isotopic measurements of uranium oxide minerals that utilizes both electron and ion microprobes. U and Pb concentrations are determined using an electron microprobe, whereas the isotopic composition of Pb for the same area is measured using a high-resolution ion microprobe. The advantages of this approach are: mineral separation and chemical digestion are unnecessary; homogeneous uranium oxide standards, which are difficult to obtain, are not required; and precise and accurate U-Pb ages on ∼10 microm spots can be obtained in a matter of hours. The authors have applied their method to study the distribution of U-Pb ages in complexly intergrown uranium oxides from the unconformity-type Cigar Lake uranium deposit, Saskatchewan, Canada. In situ U-Pb results from early formed uraninite define a well-correlated array on concordia with upper and lower intercepts of 1,467 ± 63 Ma and 443 ± 96 Ma (±1σ), respectively. The 1,467 Ma age is interpreted as the minimum age of mineralization and is consistent with the age of clay-mineral alteration (approximately1477 Ma) and magnetization of diagenetic hematite (1,650 to 1,450 Ma) that is associated with these unconformity-type uranium deposits and early diagenesis of the Athabasca Basin sediments. In situ U-Pb isotopic analysis of uraninite and coffinite can document the Pb*/U heterogeneities that can occur on a scale of 15 to 30 microm, thus providing relatively accurate information regarding the timing of fluid interactions associated with the evolution of these deposits

  15. Advances in the exploration model for Athabasca unconformity uranium deposits

    International Nuclear Information System (INIS)

    This paper covers the genetic model of ore formation and exploration techniques Uranerz Exploration and Mining is presently using to explore for unconformity uranium deposits in the deeper parts of the Athabasca Basin. The main objectives of this paper are: 1) to present a genetic model for unconformity uranium deposits which is being used in our current exploration strategy, and 2) to present the sequence of exploration techniques used by Uranerz to explore for uranium in areas of the Athabasca Basin with up to 1000 m of sandstone cover. The Athabasca unconformity deposits are located in northern Saskatchewan, Canada. Within the Precambrian Athabasca Basin, exploration companies have discovered 18 uranium deposits. These contain more than 500 million kilograms of uranium, with average grades ranging from 0.3 to 12%. Uranerz discovered the Key Lake deposits in 1975, currently the largest and richest open pit uranium mine in the world. Uranerz also holds interests in the Rabbit Lake, Midwest Lake and McArthur River deposits, all in Saskatchewan, and is also actively exploring for uranium worldwide. The first discovery in the eastern Athabasca Basin was in 1968 at Rabbit Lake, followed by Key Lake in 1975. Both deposits had surficial indicators, such as radioactive boulders, strong geochemical anomalies in the surrounding lakes and swamps, and well-defined geophysical signatures. After the Key Lake discovery, an exploration model was devised which incorporated the underlying graphitic horizon and its strong electro-magnetic signature. Since then, there have been numerous new discoveries made by systematically drilling along these electro-magnetic conductors. The advancements in geophysical and geochemical techniques have led to discoveries at increasing depths. In 1988, the McArthur River deposit was discovered at a depth of 500 m. (author). 6 refs

  16. Geology and genesis of the Athabasca basin uranium deposits

    International Nuclear Information System (INIS)

    The Athabasca basin contains some 14% of the reasonably assured, low cost uranium reserves of the western world. It comprises a 1400 m thick, red bed succession, the Athabasca Group of Paleohelikian (ca. 1450 Ma) age and occupies an area of some 100,000 km2. Fluviatile quartz sandstones and conglomerates give way upward to finer marine clastics and tese in turn to stromatolitic and oolitic dolomite. Cross-cutting northwesterly trending diabase dykes are dated at bewteen 938 and 1230 Ma. The Athabasca Group is underlain by a lateritic weathering profile in crystalline basement rocks belonging to two major subdivisions of the Saskatchewan Shield, the Cree Lake (Mobile) Zone and Western Craton. These are separated by a major shear zone, within a zone of low gravity which is locally intruded by Hudsonian (ca. 1750 Ma) uranium enriched 'granite'. Recognizable controls of Athabasca Basin uranium mineralization are: (a) the sub-Athabasca Group unconformity, (b) fracturing and faulting, and (c) graphite in basement rocks. The deposits exhibit, to varying degrees, complex mineralogy and geochemistry (U +- Ni, Co, As, Cu, Pb, Zn, Ag, Au, Pt group elements, Mo, V, Se, Mn and Fe). They are surrounded by extensive argillic alteration haloes in the Athabasca Group and more restricted haloes in the basement. Redox relationships are characteristic of most deposits. Dating of pitchblende and alteration minerals suggests epigenetic emplacement beginning 1350 Ma ago. Fluid inclusion studies indicate deposition from saline mineralizing fluids at temperatures between 150 and 225 deg. C. The most acceptable model of deposit genesis, the diagenetichydrothermal model, involves interaction of hot, oxidized, metalliferous formational waters of the Athabasca Group with the underlying 'reduced' basement. Mineralization was episodic and likely triggered by tectonic events, possibly related to diabase dyke emplacement and/or uplift. 97 refs, 13 figs, 5 tabs

  17. Athabasca asphaltene structures

    Energy Technology Data Exchange (ETDEWEB)

    Dettman, H.; Salmon, S.; Zinz, D. [National Centre for Upgrading Technology, Devon, AB (Canada)

    2009-07-01

    In order to model petroleum behaviour during production and refining processes, it is important to understand the molecular character of oil components. Gas chromatography can be used to separate components with boiling points less than 524 degrees C. However, since asphaltenes have a higher boiling point, gel permeation chromatography (GPC) must be used to separate species before analysis. Analysis of Athabasca asphaltene GPC fractions has shown that asphaltenes consist of 2 types of species, notably crunchy species that are graphitic in appearance, and oily species. The molecular weights range from 400 to 2000 g/mole as measured by low resolution mass spectrometry. This poster described the ongoing effort to separate the asphaltenes by polarity. Athabasca asphaltenes were subfractioned into 4 parts according to differential solubility in pentane and centrifugation. Acidic species were isolated from the asphaltenes using adsorption chromatography. The 4 polarity fractions and acid species have been characterized with particular reference to elemental and metals content. Analyses were performed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) carbon type analyses. This poster provided comparisons of their elution profiles by GPC. tabs., figs.

  18. Experimental PVT property analyses for Athabasca bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Ashrafi, Mohammad; Souraki, Yaser; Karimaie, Hassan; Torsaeter, Ole [Norwegian University of Science and Technology (Norway); Bjorkvik, Bard J.A. [SINTEF Petroleum Research (Norway)

    2011-07-01

    To study fluid behavior in a reservoir it is very important to find out exact and complete data on the rock system, fluid properties, and rock-fluid interactions. PVT properties are among the most critical data that reservoir engineers need to evaluate the reservoir. This paper presents the experimental study of a few PVT properties of Athabasca bitumen. The viscosity of Athabasca heavy crude was measured using a rotational viscometer. These viscosity data are a reliable input for simulation purposes. The Athabasca oil was characterized using gas chromatography analysis. Whole sample molar mass was measured at 534 g/mol by cryoscopy. Density and molar mass were also measured. Based on the experimental study, a formula was derived for Athabasca bitumen density prediction in the temperature and pressure range studied. From the results, the interfacial tension between oil and steam was measured, using the pendant drop method, and found to be between 25 and 18 mN/m.

  19. Has Alberta oil sands development altered delivery of polycyclic aromatic compounds to the Peace-Athabasca Delta?

    Directory of Open Access Journals (Sweden)

    Roland I Hall

    Full Text Available BACKGROUND: The extent to which Alberta oil sands mining and upgrading operations have enhanced delivery of bitumen-derived contaminants via the Athabasca River and atmosphere to the Peace-Athabasca Delta (200 km to the north is a pivotal question that has generated national and international concern. Accounts of rare health disorders in residents of Fort Chipewyan and deformed fish in downstream ecosystems provided impetus for several recent expert-panel assessments regarding the societal and environmental consequences of this multi-billion-dollar industry. Deciphering relative contributions of natural versus industrial processes on downstream supply of polycyclic aromatic compounds (PACs has been identified as a critical knowledge gap. But, this remains a formidable scientific challenge because loading from natural processes remains unknown. And, industrial activity occurs in the same locations as the natural bitumen deposits, which potentially confounds contemporary upstream-downstream comparisons of contaminant levels. METHODS/PRINCIPAL FINDINGS: Based on analyses of lake sediment cores, we provide evidence that the Athabasca Delta has been a natural repository of PACs carried by the Athabasca River for at least the past two centuries. We detect no measureable increase in the concentration and proportion of river-transported bitumen-associated indicator PACs in sediments deposited in a flood-prone lake since onset of oil sands development. Results also reveal no evidence that industrial activity has contributed measurably to sedimentary concentration of PACs supplied by atmospheric transport. CONCLUSIONS/SIGNIFICANCE: Findings suggest that natural erosion of exposed bitumen in banks of the Athabasca River and its tributaries is a major process delivering PACs to the Athabasca Delta, and the spring freshet is a key period for contaminant mobilization and transport. This baseline environmental information is essential for informed management

  20. Changes in the areal extents of the Athabasca River, Birch River, and Cree Creek Deltas, 1950-2014, Peace-Athabasca Delta, Canada

    Science.gov (United States)

    Timoney, Kevin; Lee, Peter

    2016-04-01

    Deltas form where riverborne sediment accumulates at the interface of river mouths and their receiving water bodies. Their areal extent is determined by the net effect of processes that increase their extent, such as sediment accumulation, and processes that decrease their extent, such as erosion and subsidence. Through sequential mapping and construction of river discharge and sediment histories, this study examined changes in the subaerial extents of the Cree Creek and Athabasca River Deltas (both on the Athabasca River system) and the Birch River Delta in northern Canada over the period 1950-2014. The purpose of the study was to determine how, when, and why the deltas changed in areal extent. Temporal growth patterns were similar across the Athabasca and Birch River systems indicative of a climatic signal. Little or no areal growth occurred from 1950 to 1968; moderate growth occurred between 1968 and the early to mid-1980s; and rapid growth occurred between 1992 and 2012. Factors that affected delta progradation included dredging, sediment supply, isostatic drowning, delta front bathymetry, sediment capture efficiency, and storms. In relation to sediment delivered, areal growth rates were lowest in the Athabasca Delta, intermediate in the Birch Delta, and highest in the Cree Creek Delta. Annual sediment delivery is increasing in the Cree Creek Delta; there were no significant trends in annual sediment delivery in the Birch and Athabasca Deltas. There was a lag of up to several years between sediment delivery events and progradation. Periods of delta progradation were associated with low water levels of the receiving basins. Predicted climate-change driven declines in river discharge and lake levels may accelerate delta progradation in the region. In the changing ecosystems of northeastern Alberta, inadequate monitoring of vegetation, landforms, and sediment regimes hampers the elucidation of the nature, rate, and causality of ecosystem changes.

  1. Bird nesting on an Athabasca power line structure

    International Nuclear Information System (INIS)

    SaskPower has recently completed its 400 km Athabasca power line, and is evaluating the predicted environmental impact of the line on the resident population of bald eagles and other raptors. During construction of the line, five major types of impact associated with the line were addressed. Minor route adjustments were made to by-pass nests of bald eagles and osprey to minimize impact of construction on breeding. The proximity of the power line to cliff faces and the north shore of lake Athabasca was maximized, and frequency of stream crossings and proximity to rapids were minimized. Route adjustments were made to ensure that the line was at least 1.6 km from bald eagle nest sites. As structures of the main 115 kV power line allow a minimum separation between conductors and grounded spars of 1.6 m, and between conductors of 4.6 m, electrocution was not considered to be a significant risk. However, on the 25 kV power line in regions of known bald eagle activity and in close proximity to bodies of water, provision was made for special structures to allow birds to perch without danger of electrocution. It was concluded that the resident population of raptors will probably be enhanced, particularly in areas not previously utilized. 8 refs., 5 figs

  2. A review of exploration research and development projects in the NEA/IAEA Athabasca Basin test area, Saskatchewan

    International Nuclear Information System (INIS)

    Twenty-nine integrated geological, geophysical and geochemical studies have been carried out over a 1200 km2 area at the eastern margin of the Athabasca Basin, Saskatchewan. The area contains many of the presently-known Athabasca unconformity-type uranium deposits. The initial uranium discoveries in this region were near to the outcrop edge of the sub-Athabasca Group unconformity. They were, therefore, relatively close to the surface. Later discoveries have been in the interior portions of the Basin at depths of up to 200 m. Because of the small size, but high grade, of the deposits, exploration for deep mineralization is very challenging. Interpretation was carried out on Landsat imagery. The effects of hydrothermal alteraction on the clay mineral assemblage of the Athabasca Group was investigated. Geophysical surveys of the test area included magnetic gradiometry, gravity, airborne gamma-ray spectrometry and airborne electromagnetics. More detailed geophysical surveys near deposits were gravity, induced polarization, resistivity, seismic, gamma-ray spectrometry, borehole, induced polarization, resistivity, seismic, gamma-ray spectrometry, borehole gamma-ray spectrometry, deep-sounding transient electromagnetic and geothermal. A unique water-borne resistivity survey was carried out to map the geology beneath Wollaston Lake. Geochemical surveys of the test area were made using lake sediments and waters and vegetation as sampling media. The parameters determined in lake waters included helium isotopes. More detailed geochemical surveys over known mineralisation utilized: lake sediments and waters, groundwaters, including their gas geochemistry, basal tills, soils and the lithogeochemistry of the Athabasca Group. In the vicinity of the Midwest Deposit a comprenhensive comparison was made of different methods of radon detection in soils

  3. Petrophysical Analysis of Oil Sand in Athabasca

    Science.gov (United States)

    cheong, S.; Lee, H.

    2013-12-01

    Oil sands are the major unconventional energy sources which have great reserves in Alberta, Canada. Recovery techniques such as CSS (Cyclic Steam Stimulation) and SAGD (Steam Assisted Gravity Drainage) enabled to develop deeper bitumen about several hundred meter depth. Before applying CSS and SAGD, reservoir heterogeneity of mud barriers or shale breccias should be clarified to establish injection and production wells successfully. We conducted the integrated petro-physical analysis for oil sands deposits in Athabasca by correlating well logs with seismic data. From 33 well logs and 3D seismic, we have made P-wave impedance by recursive inversion. Target formations of our analysis were the top of Wabiskaw member. Using inverted impedance and multi-attributes, porosity volume was derived at a target depth. Porosity of time slice 375 ms ranged 20 ~ 40 % stretching porous sand body from NE to SW direction. Characteristics of porosity distribution may be useful to design optimum oil sands recovery in Athabasca.

  4. Isotopic Evidence for Oil Sands Petroleum Coke in the Peace-Athabasca Delta.

    Science.gov (United States)

    Jautzy, Josué J; Ahad, Jason M E; Gobeil, Charles; Smirnoff, Anna; Barst, Benjamin D; Savard, Martine M

    2015-10-20

    The continued growth of mining and upgrading activities in Canada's Athabasca oil sands (AOS) region has led to concerns about emissions of contaminants such as polycyclic aromatic hydrocarbons (PAHs). Whereas a recent increase in PAH emissions has been demonstrated within around 50 km of the main center of surface mining and upgrading operations, the exact nature of the predominant source(s) and the geographical extent of the deposition are still under debate. Here, we report a century-long source apportionment of PAHs using dual (δ(2)H, δ(13)C) compound-specific isotope analysis on phenanthrene deposited in a lake from the Athabasca sector of the Peace-Athabasca Delta situated ∼150 km downstream (north) of the main center of mining operations. The isotopic signatures in the core were compared to those of the main potential sources in this region (i.e., unprocessed AOS bitumen, upgrader residual coke, forest fires, coal, gasoline and diesel soot). A significant concurrent increase (∼55.0‰) in δ(2)H and decrease (∼1.5‰) in δ(13)C of phenanthrene over the last three decades pointed to an increasingly greater component of petcoke-derived PAHs. This study is the first to quantify long-range (i.e., >100 km) transport of a previously under-considered anthropogenic PAH source in the AOS region. PMID:26404505

  5. Annual and Seasonal hydroclimatology of the Athabasca River in the context of major modes of climatic variability

    Science.gov (United States)

    Peters, D. L.; Atkinson, D. E.; Baird, D.; Monk, W.; Tenenbaum, D.

    2011-12-01

    The Athabasca River in northwestern Canada, the dominant inflow to Lake Athabasca and Peace-Athabasca Delta complex, continues to be influenced by multiple environmental stressors on its hydrology and aquatic ecology, including land-use change, climate variability/change, and growing industrial water demand. The Athabasca River presents a good opportunity to examine the impact of Pacific climatic variability on the hydroclimatolgy and flow generation because it has some good data sets, it is an unregulated river, and it represents the more climatically subtle northern mid-continental region. Further, recent industrial activities in this watershed give a pragmatic edge to research on this watershed. This project addresses the Athabasca River watershed as a unit, utilizing a recently compiled dataset of hydrometric and climatic station data assessed for long-term trends in runoff and for linkages between hydroclimatic parameters with documented major modes of climatic variability. Daily flow data from stations along the Athabasca River were extracted from the Environment Canada HYDAT archive. Where possible patchy records from nearby stations were merged and brief gaps in-filled, resulting in an optimized set of four data series: Hinton (1915-2008, ), Athabasca (1913-2008), Fort McMurray (1957-2008), and Embarras (1957-2008). Identification of long-term trends was performed using a Mann-Kendall test: all stations showed decreasing trends in median runoff for the open-water season (May-Oct) 1958-2009; Hinton showed a strong decreasing trends for the 1913-2009 period. Runoff during the ice-on season at Hinton was weakly positive, the only station/season to show a positive trend. Initial results for comparisons with indices of climate variability that have been previously demonstrated to exert influence on various aspects of western hydroclimatology (e.g. PNA, PDO, various ENSO, NP) show expected strong to moderate correlations (Kendall-Tau) with air temperature and

  6. The Key Lake project

    International Nuclear Information System (INIS)

    Key Lake is located in the Athabasca sand stone basin, 640 kilometers north of Saskatoon, Saskatchewan, Canada. The three sources of ore at Key Lake contain 70 100 tonnes of uranium. Features of the Key Lake Project were described under the key headings: work force, mining, mill process, tailings storage, permanent camp, environmental features, worker health and safety, and economic benefits. Appendices covering the historical background, construction projects, comparisons of western world mines, mining statistics, Northern Saskatchewan surface lease, and Key Lake development and regulatory agencies were included

  7. Syncrude's Aurora Mine : the key to future Athabasca oil sands development

    International Nuclear Information System (INIS)

    Syncrude's newest mine, the Aurora mine is located 35 km northeast of Syncrude's existing Mildred Lake plant, across the Athabasca River. It has a potential to produce more than 2.5 billion barrels of bitumen. Aurora will eventually consist of two surface mines, the Aurora North and Aurora South. Mining and extraction will occur at Aurora with the resulting bitumen transported as a froth by pipeline back to the existing plant for upgrading to Syncrude Sweet Blend. A total of 120 km of pipeline will be used. Syncrude has developed a new method of sending oilsand from its Athabasca deposit to the extraction plant. The company plans to phase out the dragline, bucketwheel reclaimer, and conveyor ore mining and delivery system in favour of shovel, truck, and hydrotransport technology. The advantages of hydrotransport include significant energy savings and considerably less plant infrastructure. A hydrotransport prototype is at work at Syncrude's base mine where it is responsible for 15 per cent of the production

  8. Syncrude`s Aurora Mine : the key to future Athabasca oil sands development

    Energy Technology Data Exchange (ETDEWEB)

    Kershaw, D. [Syncrude Canada Ltd., Edmonton, AB (Canada)

    1998-09-01

    Syncrude`s newest mine, the Aurora mine is located 35 km northeast of Syncrude`s existing Mildred Lake plant, across the Athabasca River. It has a potential to produce more than 2.5 billion barrels of bitumen. Aurora will eventually consist of two surface mines, the Aurora North and Aurora South. Mining and extraction will occur at Aurora with the resulting bitumen transported as a froth by pipeline back to the existing plant for upgrading to Syncrude Sweet Blend. A total of 120 km of pipeline will be used. Syncrude has developed a new method of sending oilsand from its Athabasca deposit to the extraction plant. The company plans to phase out the dragline, bucketwheel reclaimer, and conveyor ore mining and delivery system in favour of shovel, truck, and hydrotransport technology. The advantages of hydrotransport include significant energy savings and considerably less plant infrastructure. A hydrotransport prototype is at work at Syncrude`s base mine where it is responsible for 15 per cent of the production.

  9. Open Technologies at Athabasca University's Geospace Observatories

    Science.gov (United States)

    Connors, M. G.; Schofield, I. S.

    2012-12-01

    Athabasca University Geophysical Observatories feature two auroral observation sites situated in the subauroral zone of western Canada, separated by approximately 25 km. These sites are both on high-speed internet and ideal for observing phenomena detectable from this latitude, which include noctilucent clouds, meteors, and magnetic and optical aspects of the aurora. General aspects of use of Linux in observatory management are described, with emphasis on recent imaging projects involving control of high resolution digital SLR cameras at low cadence, and inexpensive white light analog video cameras at 30 Hz. Linux shell scripts are extensively used, with image capture controlled by gphoto2, the ivtv-utils package, x264 video coding library, and ffmpeg. Imagemagick allows processing of images in an automated fashion. Image archives and movies are created and can be correlated with magnetic data. Much of the magnetic data stream also uses GMT (Generic Mapping Tools) within shell scripts for display. Additionally, SPASE metadata are generated for most of the magnetic data, thus allowing users of our AUTUMN magnetic data repository to perform SPASE queries on the dataset. Visualization products from our twin observatories will be presented.

  10. Market outlook for Athabasca bitumen: the economics of location

    International Nuclear Information System (INIS)

    The use of steam assisted gravity drainage (SAGD) was shown to have lowered supply costs and made Athabasca bitumen competitive in the North American market for heavy crudes and bitumen. As part of a SAGD commercialization study, the potential market for Athabasca bitumen, its transportation and netback prices were studied. While both Syncrude and Suncor have identified a need for additional bitumen in the future, it was also recognized that Athabasca bitumen prices must be cost competitive with Syncrude's and Suncor's own products. The study also revealed that the most significant obstacle for Athabaska bitumen to being fully competitive in the North American market was the lack of transportation infrastructure. It was suggested that using larger volume pipelines would aid in keeping pipeline tariffs low , which in turn, would improve Athabaska bitumen's competitiveness and enable further development of the deposit. 8 figs., 1 table

  11. Online Planetary Science Courses at Athabasca University

    Science.gov (United States)

    Connors, Martin; Munyikwa, Ken; Bredeson, Christy

    2016-01-01

    Athabasca University offers distance education courses in science, at freshman and higher levels. It has a number of geology and astronomy courses, and recently opened a planetary science course as the first upper division astronomy course after many years of offering freshman astronomy. Astronomy 310, Planetary Science, focuses on process in the Solar System on bodies other than Earth. This process-oriented course uses W. F. Hartmann's "Moons and Planets" as its textbook. It primarily approaches the subject from an astronomy and physics perspective. Geology 415, Earth's Origin and Early Evolution, is based on the same textbook, but explores the evidence for the various processes, events, and materials involved in the formation and evolution of Earth. The course provides an overview of objects in the Solar System, including the Sun, the planets, asteroids, comets, and meteoroids. Earth's place in the solar system is examined and physical laws that govern the motion of objects in the universe are looked at. Various geochemical tools and techniques used by geologists to reveal and interpret the evidence for the formation and evolution of bodies in the solar system as well as the age of earth are also explored. After looking at lines of evidence used to reconstruct the evolution of the solar system, processes involved in the formation of planets and stars are examined. The course concludes with a look at the origin and nature of Earth's internal structure. GEOL415 is a senior undergraduate course and enrols about 15-30 students annually. The courses are delivered online via Moodle and student evaluation is conducted through assignments and invigilated examinations.

  12. Lake

    Science.gov (United States)

    Wien, Carol Anne

    2008-01-01

    The lake is blue black and deep. It is a glaciated finger lake, clawed out of rock when ice retracted across Nova Scotia in a northerly direction during the last ice age. The lake is narrow, a little over a mile long, and deep, 90 to 190 feet in places according to local lore, off the charts in others. The author loves to swim there, with a sense…

  13. Rheological properties of nanofiltered Athabasca bitumen and Maya crude oil

    Czech Academy of Sciences Publication Activity Database

    Hasan, M.D.A.; Fulem, Michal; Bazyleva, A.; Shaw, J.M.

    2009-01-01

    Roč. 23, - (2009), s. 5012-5021. ISSN 0887-0624 Institutional research plan: CEZ:AV0Z10100521 Keywords : viscosity * rheology * Athabasca bitumen * Maya crude oil * phase behavior * asphaltenes * nanofiltration Subject RIV: JJ - Other Materials Impact factor: 2.319, year: 2009

  14. Online Planetary Science Courses at Athabasca University

    Science.gov (United States)

    Connors, M. G.; Bredeson, C.; Munyikwa, K.

    2014-12-01

    Athabasca University offers distance education courses in science, at freshman and higher levels. It has a number of geology courses, and recently opened a planetary science course as the first upper division astronomy course after many years of offering freshman astronomy. Astronomy 310, Planetary Science, focuses on the physics of the Solar System and allows the study of planetary astronomy in a deeper way than what is offered in a freshman course. With a mathematically based approach, it looks at the planets and smaller bodies such as meteoroids, asteroids and comets found in our own solar neighbourhood. It provides an understanding of the basic physics and equations needed for studies of planetary science and looks at the formation of the principal bodies in the Solar System. It investigates the interiors of planets and planetary surface phenomena such as cratering, volcanism and tectonics, and examines the atmospheres of planets, including how they originated and whether planets can keep an atmosphere. As a new course, it has grown rapidly.Geology 415, Earth's Origin and Early Evolution, explores the evidence for the various processes, events, and materials involved in the formation and evolution of Earth. The course provides an overview of objects in the Solar System, including the Sun, the planets, asteroids, comets, and meteoroids. Earth's place in the Solar System is examined and physical laws that govern the motion of objects in the universe are looked at. Various geochemical tools and techniques used by geologists to reveal and interpret the evidence for the formation and evolution of bodies in the Solar System as well as the age of Earth are also explored. After looking at lines of evidence used to reconstruct the evolution of the Solar System, processes involved in the formation of planets and stars are examined. The course concludes with a look at the origin and nature of Earth's internal structure. GEOL415 is a senior undergraduate course and enrols

  15. Exploration for unconformity-associated uranium deposits: Learning from EXTECH IV, Athabasca basin multidisciplinary study, Canada

    International Nuclear Information System (INIS)

    Unconformity-associated uranium (U) deposits in the Athabasca Basin (hereafter 'the Basin') are pods, veins and disseminations of uraninite spatially associated with the basal unconformity of relatively flat, 1-2 km, unmetamorphosed but pervasively diagenetically altered, Paleo- to Mesoproterozoic, red siliciclastic strata. This is one of four such basins in the northwestern Canadian Shield that were filled by westerly flowing rivers with local complexities related to growth faults. Basement metamorphic belts are folded and interleaved Archean and Paleoproterozoic granitoid and supracrustal rocks. The intensely paleoweathered unconformity preserves variable thicknesses of red hematitic, clay-altered saprolite grading down through a green chloritic zone to fresh rock. The world's largest known highgrade unconformity-associated U deposits are along the basement Wollaston-Mudjatik transition domain. Cigar Lake and McArthur River deposits contain 131,400 and ∼190,000 tonnes U at grades of 15% and 23% U, respectively. Uranium dominates in monometallic (generally basement-hosted) deposits and is the principle commodity in polymetallic deposits with variable amounts of Ni + Co + As and traces of Au, Pt, Cu etc. Elsewhere in the basin, high grades have been mined and excellent prospects are being explored. EXTECH IV was a multidisciplinary field and laboratory project to enhance and preserve geoscience data and improve exploration methods for unconformity-associated U deposits. Regional to detailed research was coordinated at exploration sites across the Basin and focused at McArthur River. This report presents the results by discipline, with implications for exploration. New regional basement geology and revised Athabasca group stratigraphy and geological map were reported. Faults, basin and ore deposits are linked, structurally reworked ore is consistent with multiple ore-forming events, paleo-valleys are spatially associated with some Athabasca ore deposits, new

  16. Recent innovative applications of geophysics to new uranium discoveries in the Athabasca Basin

    International Nuclear Information System (INIS)

    (Next) zone, Eagle Point mine area, 2) Zone A, McArthur River Mine area, 3) the Millennium deposit, midway between the McArthur River and Key Lake mines, and 4) a very recent discovery at the Virgin River project, in the south-central part of the basin. These recent successes are related to a variety of themes, notably 1) brownfields - a renewed focus on brownfields to mine-scale exploration and careful use of orientation surveys to characterize and predict deposit response, 2) basement-hosted - a new focus on lower-cost, lower-risk production from basement-hosted uranium to supplement production from the classic unconformity deposits, 3) grid format surveys - a focus on defining the ore system geology in three dimensions through the use of grid format surveys, 4) integration - more integration of the disciplines through 3D visualization, notably through the use of downhole geological, geochemical and geophysical data, and 5) innovation - employing new uses of existing geophysical techniques for faster, better, cheaper exploration. The significance of the Millenium and O2 Next discoveries relates to the presence of a relatively undertested target type in the Athabasca basin located at depths of 50 to 350 m below the unconformity. The off-conductor position of O2 Next bears similarities to Zone O2 which lies 200 m southeast of the Collins Bay fault, as well as the original basement-hosted discovery by Gulf Minerals in 1968 of the Rabbit Lake deposit which is located 200 m into the hanging wall of the graphitic Rabbit Lake fault. Millenium constitutes a potentially different style of basement-hosted mineralization which is footwall to the dominant graphitic structure. The significance of Zone A at the McArthur River mine relates to the recognition that considerable potential remains in this area for both unconformity and basement-hosted styles of mineralization. The message of the Virgin River greenfields discovery is that considerable efficiencies are achievable by

  17. Compound-specific radiocarbon analysis to evaluate the contribution of Peace River floodings to the PAH background in the Peace-Athabasca Delta

    Science.gov (United States)

    Jautzy, J. J.; Ahad, J. M.; Hall, R. I.; Wiklund, J. A.; Gobeil, C.; Savard, M. M.

    2013-12-01

    The oil sands of Northern Alberta, Canada are one of the largest hydrocarbon reserves in the world. The rapid growth of the bitumen exploitation in this region involves large scale mining infrastructure, raising questions about the environmental impact of these operations. One of the main issues is the emission of hazardous organic compounds such as polycyclic aromatic hydrocarbons (PAHs). PAHs, which are found naturally in petroleum, are also produced through incomplete combustion and diagenesis of organic matter. The complex nature of the surrounding geology (natural levels of bitumen) requires tools able to discriminate sources of pollutants. The establishment of the PAH background is crucial in order to investigate the impacts of oil sands mining in the Athabasca region. Here we present a new approach to discriminate the sources of alkylated PAHs (fossil or modern biomass) and their relative contributions. Using a dated sediment sequence from a lake situated in the Peace-Athabasca Delta periodically flooded by the Peace River, 6 different groups of parent and alkylated PAHs were extracted and collected by preparative capillary gas chromatography (PCGC) for natural abundance radiocarbon (14C) measurement. Three grouped layers each comprising approximately 10 years of sedimentation and spanning the period of mining operations (i.e., the past 40 years) were analyzed. We report here the first use of 14C measurements on alkylated PAHs extracted from lake sediments. Our results showed low radiocarbon content for all alkylated and parent PAHs analyzed in the three sediment layers. However, a slight trend toward a more modern PAH input can be seen up-core. PAH isomers ratios pointed to a major influence of petroleum input in the entire lake sequence, supporting the predominance of a fossil carbon source as indicated by the low radiocarbon contents. As the Peace River cuts through the Peace oil sands formation, our results can be explained by the main contribution of

  18. Method for Extraction and Multielement Analysis of Hypogymnia Physodes Samples from the Athabasca Oil Sands Region

    Science.gov (United States)

    A microwave-assisted digestion technique followed by ICPMS (inductively coupled plasma-mass spectrometry) analysis was used to measure concentrations of 43 elements in Hypogymnia physodes samples collected in the Athabasca Oil Sands Region (AOSR) of northern Alberta, Canad...

  19. Quantifying saline groundwater seepage to surface waters in the Athabasca oil sands region

    International Nuclear Information System (INIS)

    Western Canadian oil sands contain over 170 billion barrels of proven unconventional petroleum reserves currently extracted at 1.8 million barrels per day by either surface mining, or by in situ techniques that require subsurface injection of steam and hydrocarbon solvents. Natural high-salinity springs are known to add water and entrained inorganic and organic constituents to the Athabasca River and its tributaries in the region of ongoing bitumen production. However, the magnitude and synoptic distribution of these saline inputs has remained unquantified. Here, a chloride mass balance is used to estimate saline groundwater discharge to the Athabasca River from 1987 to 2010. Results show that the highest saline water discharge rate to the Athabasca River occurs between Ft. McMurray and the Peace-Athabasca Delta, supported by subcrop exposure of lower Cretaceous- and Devonian-aged formations bearing saline waters. Further, the input of saline groundwater is found to be an important control on the chemistry of the lower Athabasca River, despite comprising 10−1 to 3% of the Athabasca River’s discharge. The flux of natural saline groundwater entering the Athabasca does not appear to have increased or decreased from 1987 to 2010. The origin of seep salinity is interpreted as relict subglacial meltwater that has dissolved Devonian-aged evaporites, supported by saline Na-Cl type waters with low 18O/16O and 2H/1H ratios relative to modern precipitation. The magnitude of groundwater discharge and its impact on the Athabasca River’s chemistry in the area of ongoing bitumen development warrants the incorporation of natural groundwater seepages into surface water quality monitoring networks.

  20. Hydrogeochemical exploration for uranium within the Athabasca Basin, northern Saskatchewan

    International Nuclear Information System (INIS)

    As part of exploration programs for unconformity-related uranium deposits, the chemistry of deep ground waters has been studied from throughout the Athabasca Basin. Samples have been collected from routine, small-diameter, exploration diamond drillholes, and considerable emphasis has been placed on ensuring that they represent true ground waters. The authors have measured both major and minor constituents, including various uranium daughter products. Ground-water samples collected from the vicinity of uranium mineralization have consistently high levels of uranium, radium, radon and helium. Although they have not been able to establish the maximum extent of the hydrogeochemical anomalies in this environment, they have detected anomalies at distances of up to tens of meters from known mineralization. (orig.)

  1. Mammalian toxicity of naphthenic acids derived from the Athabasca oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, V.V.

    2003-07-01

    The acidic nature of petroleum is due in part to naphthenic acids, a group saturated mono- and polycyclic carboxylic acids which are natural constituents of petroleum. They account for nearly 4 per cent of crude petroleum by weight. Napthenic acids have received much attention at Alberta's Athabasca oil sand deposit, the world's largest, single bitumen deposit. Extracting the bitumen from oil sands is a complex process that involves mixing the oil sands with hot, alkaline water to separate the bitumen from sand and other waste products. The process produces large quantities of liquid tailings where napthenic acids are solubilized and concentrated. It is estimated that by 2025, approximately 1 billion cubic metres of liquid tailings will have accumulated in large holding ponds near the mine sites. This quantity will be incorporated into the ecosystem under wet and dry landscape reclamation strategies. Several aquatic toxicity studies of naphthenic acids have shown that they are highly toxic to invertebrates and fish at concentrations well below those found in the Alberta oil sand tailings. However, information regarding the mammalian toxicity of naphthenic acids is limited, particularly the effects of repeated, oral exposure. In this mammalian toxicity study, naphthenic acids were isolated from tailings at the Mildred Lake settling pond operated by Syncrude Canada Ltd. An acidification/solvent extraction procedure was performed, followed by ultrafiltration to isolate the naphthenic acids. Chemical analysis revealed a very heterogeneous mixture of acyclic and 1-, 2-, 3- and 4-ringed compounds. Acute testing on Wistar rats showed major behavioural and histopathological effects in both males and females. The study involved dosages of 300 mg/kg body weight of naphthenic acids, which is 50 times higher than the estimated worst-case, single day environmental exposure through drinking water for small mammals. The effects included suppression of appetite and

  2. Aeromagnetic gradiometer results in the Wollaston Lake area, Saskatchewan, Canada

    International Nuclear Information System (INIS)

    The NEA/IAEA study area in the Wollaston Lake region of northern Saskatchewan, Canada was surveyed with the inboard vertical gradiometer system designed and developed by the Geological Survey of Canada. The area occurs over the south-eastern fringe of the Athabasca basin where the search for uranium mineralization is made more difficult by the presence of extensive glacial overburden, lakes, swamps and the overlying Athabasca Group. The high sensitivity of the digital results permits the manipulation and enhancement of these data with computers. The computer coupled with the Applicon colour-jet plotter opens new horizons with the availability of rapid visual displays of the computer output in coloured map format. The application of frequency filters enables a separation of different portions of the magnetic spectrum and the enhancement of different geological structures and features. A pseudo-geological map showing lithologies, fault and alteration zones in the sub-Athabasca basement can be produced. The data also enable the vertical extent of some of the lithological features to be determined. In addition the distribution of magnetic material in the Quaternary glacial deposits overlying the non-magnetic Athabasca Group can be mapped

  3. Ambient air quality observations in the Athabasca oil sands region

    International Nuclear Information System (INIS)

    Both Syncrude and Suncor have plans to develop new oil sands leases and to increase crude oil and bitumen recovery in the Athabasca oil sands region. In recognition of the effects that this will have on the environment, Suncor has proposed modifications to reduce SO2 emissions to the atmosphere, while Syncrude plans to develop additional ambient air quality, sulphur deposition and biomonitoring programs. This report discussed the ambient air quality monitoring that was undertaken in the Fort McMurray-Fort McKay airshed. Twelve continuous ambient air quality stations and 76 passive monitoring stations are maintained in the region. Environment Canada maintains eight precipitation monitoring stations in northern Alberta and Saskatchewan. Source characterization, ambient air quality and meteorology observations, air quality monitoring, and air quality data from continuous sulphur dioxide, hydrogen sulphide, nitrogen oxides, ozone, carbon monoxide, hydrocarbon, acid rain and particulates analyzers were reviewed. The documentation of all computer files used for the analysis of the air quality data is discussed in the Appendix. 47 refs., 39 tabs., 53 figs

  4. Oil sands development contributes elements toxic at low concentrations to the Athabasca River and its tributaries

    International Nuclear Information System (INIS)

    Oil sand mining, processing and tailings pond leakage has raised concerns about pollution of the Athabasca River. This study investigated 13 elements that are considered to be priority pollutants (PPE) under the United States Environmental Protection Agency's Clean Water Act. In particular, it investigated the oil sand industry's release of those 13 elements via air and water to the Athabasca River and its watershed. The PPEs include Sb, As, Be, Cd, Cr, Cu, Pb, Hg, Ni, Se, Ag, Tl, and Zn. Concern also exists over Sb, As, Cd, Cr, Cu, Pb, Ni, and Se concentrations in water or sediment from the Athabasca River. Snowpack studies in 2008 revealed that all PPEs except selenium were greater near oil sands developments than at more remote sites. Bitumen upgraders and local oil sands development were sources of airborne emissions. Concentrations of Hg, Ni, and Tl in winter and all 13 PPEs in summer were greater in tributaries with watersheds disturbed by development than in less disturbed watersheds. During the summer, concentrations of all PPE in the Athabasca River were greater near developed areas than upstream of development. At sites downstream of development and within the Athabasca Delta, concentrations of all PPEs except Be and Se were greater than upstream of development. Canada's or Alberta's guidelines for the protection of aquatic life were exceeded for 7 PPEs in melted snow or water collected near or downstream of development. It was concluded that contrary to claims made by industry and government, the oil sands industry significantly increases loadings of toxic PPEs to the Athabasca River and its tributaries via air and water pathways. 40 refs., 3 figs.

  5. Investing for the future : Athabasca Oil Sands Trust 1998 annual report

    International Nuclear Information System (INIS)

    The Athabasca Oil Sand Trust was created in 1995 when a subsidiary of the Trust, Athabasca Oil Sands Investment Inc., acquired Alberta's 11.74 per cent working interest in the Syncrude Project, which is a joint venture involved in the mining and upgrading of bitumen from the Athabasca oil sands. The Trust is a closed-end investment trust which was created to provide an opportunity for direct public investment in Syncrude and oil sands development in northern Alberta. Syncrude, produced a record 76.7 million barrels of Syncrude Sweet Blend (SSB), and shipped its one billionth barrel on April 16, 1998. Another key achievement in 1998 was the investment the Syncrude Joint Venture Partners of almost half a billion dollars to maintain Syncrude's operations and pursue the Business Plan growth targets outlined in last year's report. By aggressively pursuing this capital investment program despite the current low oil prices, the Syncrude Joint Venture Partners expect to double SSB production to 155 million barrels per year by 2007. The Athabasca Trust's share of these capital expenditures to fuel the projected growth in production is about $ 70 million this year and the next. The report provides operating statistics on production, financial highlights and consolidated balance sheets for 1998, including operating expenditures, capital expenditures, and the usual notes to the consolidated financial statement. 10 tabs., 2 figs

  6. "The Open Library at AU" (Athabasca University): Supporting Open Access and Open Educational Resources

    Science.gov (United States)

    Elliott, Colin; Fabbro, Elaine

    2015-01-01

    To address challenges that learners, course creators, librarians and academics involved with OER and MOOCs are facing when looking for scholarly materials, Athabasca University Library has initiated the development of "the Open Library at AU." This open library is a full library website that provides easy access to open and free…

  7. Alberta's economic development of the Athabasca oil sands

    Science.gov (United States)

    Steinmann, Michael

    This dissertation examines the 61-year evolution of public policies pertaining to development of Alberta's non-conventional source of crude oil. The Athabasca oil sands contain an estimated 1.5 trillion barrels and provide for a safe continental supply. The Provincial Government first sponsored this undertaking in 1943. The period from then to 1971 was one of a transition from a wheat economy to a natural-resource economic base. A stable government emerged and was able to negotiate viable development policies. A second period, 1971 to 1986, was marked by unstable world conditions that afforded the Alberta government the ability to set terms of development with multi-national oil firms. A 50% profit-sharing plan was implemented, and basic 1973 terms lasted until 1996. However, 1986 was a critical year because the Organization of Petroleum Exporting Countries (OPEC) reduced prices, causing the Alberta economy to lapse into recession. During a third period, 1986 to 1996, the Alberta Government was unable to adapt quickly to world conditions. A new leadership structure in 1996 made major changes to create ongoing fiscal and development policies. That history provides answers to two primary research questions: How do public policies affect the behaviors of the modern corporation and visa versa? What are the implications for development theory? Two sources of information were used for this study. First, it was possible to review the Premier's files located in the Provincial Archives. Materials from various government libraries were also examined. Some 7,000 documents were used to show the evolution of government policymaking. Second, interviews with leaders of oil companies and federal research facilities were important. Findings support the thesis that, to facilitate oil sands development, government and the private sector have closely collaborated. In particular, revenue policies have allowed for effective R&D organization. Relying on intensive technological

  8. As long as the rivers flow: Athabasca River knowledge, use and change

    Energy Technology Data Exchange (ETDEWEB)

    Candler, C.; Olson, R.; Deroy, S. [Firelight Group Research Cooperative, Victoria, BC (Canada)

    2010-11-15

    This document is a report supported by specific information gathered by the Athabasca Chipewyan First Nation (ACFN) and the Mikisew Cree First Nation (MCFN), and takes part in an Athabasca River Use and Traditional Ecological Knowledge (TEK) study conducted in 2010. The main objective was to provide a written submission, based on evidence, in order to effectively notify the crown about plans for managing industrial water withdrawals from the lower Athabasca River. The First Nations used the same methods, wrote their community reports as distinguished stand-alone documents and made the choice to present the ACFN and MCFN data in parallel with each other within the same document. The study provides information on the knowledge and uses of the Athabasca River by the community members. Context and background for the study can be found in the part A. It comprises a short discussion of the Treaty No.8 of 1899, the latter confirming the rights of First Nation people. The importance of boat transportation for the community members is mentioned, and a summary of the methods is given. The results of the ACFN and MCFN studies are given in part B and C. The reduction of the quantity and quality of the river has affected the practice of ACFN and MCFN aboriginal and treaty rights. The community perceptions of the changes of the river and how it has influenced their lifestyle is discussed. Some uses of the Athabasca river have been lost because of concerns regarding contamination associated with oil sands operations. The last part of the document provides an analysis of results and suggests two thresholds that define the ability of ACFN and MCFN members to practice their rights and access their territories. This document ends with recommendations for implementation of these thresholds. 22 refs., 12 maps.

  9. As long as the rivers flow: Athabasca River knowledge, use and change

    International Nuclear Information System (INIS)

    This document is a report supported by specific information gathered by the Athabasca Chipewyan First Nation (ACFN) and the Mikisew Cree First Nation (MCFN), and takes part in an Athabasca River Use and Traditional Ecological Knowledge (TEK) study conducted in 2010. The main objective was to provide a written submission, based on evidence, in order to effectively notify the crown about plans for managing industrial water withdrawals from the lower Athabasca River. The First Nations used the same methods, wrote their community reports as distinguished stand-alone documents and made the choice to present the ACFN and MCFN data in parallel with each other within the same document. The study provides information on the knowledge and uses of the Athabasca River by the community members. Context and background for the study can be found in the part A. It comprises a short discussion of the Treaty No.8 of 1899, the latter confirming the rights of First Nation people. The importance of boat transportation for the community members is mentioned, and a summary of the methods is given. The results of the ACFN and MCFN studies are given in part B and C. The reduction of the quantity and quality of the river has affected the practice of ACFN and MCFN aboriginal and treaty rights. The community perceptions of the changes of the river and how it has influenced their lifestyle is discussed. Some uses of the Athabasca river have been lost because of concerns regarding contamination associated with oil sands operations. The last part of the document provides an analysis of results and suggests two thresholds that define the ability of ACFN and MCFN members to practice their rights and access their territories. This document ends with recommendations for implementation of these thresholds. 22 refs., 12 maps.

  10. Limited role for thermal erosion by turbulent lava in proximal Athabasca Valles, Mars

    Science.gov (United States)

    Cataldo, Vincenzo; Williams, David A.; Dundas, Colin M.; Keszthelyi, Laszlo P.

    2015-11-01

    The Athabasca Valles flood lava is among the most recent (factor of ~2.2. If flow viscosity increases with increasing bubble content in the lava, the presence of 30-50 vol % bubbles leads to erosion depths lower than those relative to bubble-free lava by a factor of ~2.4. The presence of 25 vol % ice in the substrate increases erosion depths by a factor of 1.3. Nevertheless, modeled erosion depths, consistent with the emplacement volume and flow duration constraints, are far less than the depth of the channel (~35-100 m). We conclude that thermal erosion does not appear to have had a major role in excavating Athabasca Valles.

  11. A two-dimensional contaminant fate and transport model for the lower Athabasca River

    International Nuclear Information System (INIS)

    The lower Athabasca River flows through the Athabasca Oil Sands deposits in northeastern Alberta. Two oil sands mining/extraction/upgrading plants operate near the river downstream from Fort McMurray. Process water is stored in large tailings ponds. One of the plants (Suncor) has a licensed discharge (mostly cooling water) to the river. This effluent contains low concentrations (≤ 1 microg/L) of various polycyclic aromatic compounds (PACs). Several tributary streams which cut through oil sands deposits are potential sources of hydrocarbons to the Athabasca. The authors have found that river suspended sediments give positive responses in a number of toxicity tests, using both direct and indirect (organic-solvent extract) methods. Several environmental impact assessments are required as a result of industry expansion. To provide an assessment tool for PACs, the authors are developing a two-dimensional contaminant fate and transport model for a 120-km portion of the Athabasca River downstream from Fort McMurray. Hydraulic calibration of the model was done using sodium and chloride from a major tributary as tracers. Two groups of compounds are being modelled: (1) PACs from the Suncor effluent, and (2) PACs from natural/background sources. PAC concentrations in the river were typically < 1 ng/L, requiring large volume extractions and highly sensitive analysis. Processes such as sediment-water partitioning and biodegradation are being estimated from field experiments using river water and suspended sediment. Photodegradation is likely unimportant in this turbid river due to low penetration of 280--350 nm light. Initially, volatilization will be modelled using estimated or literature values for Henry's constants, but may require more refined estimates from laboratory experiments

  12. The Open Library at AU (Athabasca University): Supporting Open Access and Open Educational Resources

    OpenAIRE

    Colin Elliott; Elaine Fabbro

    2015-01-01

    To address challenges that learners, course creators, librarians and academics involved with OER and MOOCs are facing when looking for scholarly materials, Athabasca University Library has initiated the development of the Open Library at AU. This open library is a full library website that provides easy access to open and free resources. Tools and information literacy tutorials are also included to enable learners, researchers, and others to find, evaluate, and use the information they need f...

  13. Seismic reflections outline complex structural setting of the uranium in the Athabasca Basin

    International Nuclear Information System (INIS)

    High-resolution and regional multi-channel seismic reflection profiling was conducted in different localities in the Athabasca Basin, supported by various sponsors. The two overall goals of the seismic program were to test the effectiveness of seismic techniques as tools for uranium exploration, and to contribute to the four-dimensional geoscience framework for uranium exploration within the deeper recesses of the Athabasca Basin. More specifically, objectives of the high-resolution 2D and 3D surveys were: 1) to define the basement structures underlying the basin; 2) to map the stratigraphic architecture of the Athabasca Group Sandstone; 3) to image the sandstone/basement unconformity; 4) to locate faults controlling the uranium deposits; 5) establish possible relationships between sedimentation and deformation and 6) determine the seismic signature of a known uranium deposit. The high-resolution 2D and 3D survey successfully met most of the initial objectives. Despite the difficulties of the acquisition environment, limitations in the survey geometry and elevated noise levels, the final processed data successfully imaged the intricate and subtle stratigraphic and structural features associated with the P2 productive trend. Further efforts will concentrate on the full 3D interpretation, and study of seismic attributes associated with the ore bodies. The present study demonstrates that the seismic method is an extremely valuable exploration tool in the deeper parts of the Athabasca Basin. Following regional to subregional potential geophysical surveys, delineating potential exploration areas, later seismic surveying can offer the opportunity to accurately define small-scale structures and assist the development of a more efficient drilling program

  14. Athabasca basin unconformity-type uranium deposits. A special class of sandstone-type deposits

    International Nuclear Information System (INIS)

    Two major episodes of uranium metallogenesis are recognized in Northern Saskatchewan. The first is of late-Hudsonian age and gave rise to metamorphic-hydrothermal pitchblende deposits of simple mineralogy at Beaverlodge (primary mineralization: 1780+-20 m.y.). The second and more important episode of approximately Grenvillian age rendered unconformity-type deposits in the Athabasca Basin (primary mineralization: 1000-1300 m.y.). The late-Hudsonian deposits at Beaverlodge were overprinted by this second event and new deposits of complex mineralogy were formed in that area. The metallogenetic importance of a third and much later episode which gave rise to mineralization within the Athabasca Formation is uncertain at the moment. With regards to metallogenesis of the unconformity-type deposits, presently available evidence favours a diagenetic-hydrothermal rather than a near-surface supergene or a magmatic/metamorphic hydrothermal model. The diagenetic-hydrothermal model relates uranium mineralization to 'red bed-type' diagenetic processes in the Athabasca Formation involving post-depositional oxidation and leaching, which continued for several hundred million years after deposition. Ore deposits were formed by interaction, under conditions of deep burial at elevated temperatures and pressures, of a uraniferous oxidizing Athabasca aquifer with reducing, graphite-bearing, metamorphic rocks of the basin floor. The large-scale convection required for such interaction may have been induced by mafic magmatic activity coeval with the episode of mineralization. The diagenetic-hydrothermal model displays close similarities with metallogenetic models developed for certain sandstone-type deposits. (author)

  15. And now for something completely different: condensation induced water hammer and steam assisted gravity drainage in the Athabasca Oil Sands

    International Nuclear Information System (INIS)

    Most people will have been exposed to some aspect of the debate about the Athabasca Oil Sands in North-Eastern Alberta and the significant role that the oil sands are expected to play in supplying conventional fossil fuels. Part of the bitumen is recovered from mines and part is recovered from in situ projects utilizing the Steam Assisted Gravity Drainage Process (SAGD). SAGD utilizes a considerable amount of steam, that is injected into geological formations. Hot water, bitumen and some vapour are recovered from the production wells. With significant steam generation, transmission and injection, there is the very real possibility of condensation induced water hammers. There have been a number of catastrophic failures to date. Two major failures will be highlighted: MEG Energy had a steam distribution line fail at the Christina Lake project. Large parts of the pipe, weighing some 2500 kg, were thrown some 800 meters into the bush during the failure; and, Total had a steam release (blowout) at their Joslyn property due to a loss of caprock containment. A number of causes have been postulated. While it is agreed that there was sufficient downhole pressure to hydraulically fracture the formation, questions have been raised about the contribution that condensation induced water hammer made. The situations that have occurred will be outlined, along with some preliminary thermal hydraulic work. The intent of the paper is to provide interesting background information on the in situ oil sands industry. More importantly, to show some interesting and broader applications of thermalhydraulics developed in the nuclear industry. The expertise developed may have potential markets, with some adaptation, to the oil sands industry. Finally, there has been some discussion about using nuclear power for steam generation in the oil sands. (author)

  16. Geology of the uranium deposits related to the sub-Athabasca unconformity, Saskatchewan

    International Nuclear Information System (INIS)

    The Athabasca Basin is a large, oval, dish-shaped structure, 425 km by 225 km (80 000 km2) containing about 1500 m of mainly flat-lying quartz-rich sandstone of the Athabasca Group. The basin lies with marked angular unconformity across a Hudsonian basement of deformed and metamorphosed Archean and Aphebian sedimentary, volcanic and plutonic rocks trending north to northeast beneath the basin. In the Carswell Circular Structure in the central western half of the basin rocks are brought to surface through 1200 m of sandstone. The rocks of the basin are less than one percent exposed. Overburden locally reaches 90 m thick. Uranium deposits have been found near the southeast edge of the basin, within the Carswell Circular Structure, and along the northern rim of the basin. They are (1) at the unconformity as high-grade masses elongated in and parallel to major faults, hosted mainly in highly-altered white clay feldspar-rich basement rocks and associated with graphitic metasediments and calc-silicate rocks; (2) within the first 40 m above the unconformity in grey to black and multicoloured Athabasca sandstones and shales as a coating on quartz grains, as disseminations in the clay matrix and as veins; and (3) within 100 m below the unconformity as fracture fillings and disseminations in basement rocks

  17. Running out of steam? Oil sands development and water use in the Athabasca River watershed : science and market based solutions

    International Nuclear Information System (INIS)

    This paper contained 2 reports conducted to assess the implications of current and planned water withdrawals from the Athabasca River, and options for water management. This first section examined future water flows and human withdrawals from the Athabasca River, and examined forecasted changes in climate in the oil sands region. Issues related to water flow, water quality, and instream flow needs were discussed. The second section examined options available to the industry. Alberta's current water use framework was discussed, and new policy targets and mechanisms were analyzed. 72 refs., 21 figs

  18. Properties Correlations and Characterization of Athabasca Oil Sands-derived Synthetic Crude Oil

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Zhao Suoqi; Xu Chunming; Chung Keng H.

    2007-01-01

    Narrow fractions of Athabasca oil sands-derived synthetic crude oil (SCO) from Canada were obtained by distillation at 20 ℃ to 500 ℃ and characterized. The yield and properties, such as density, refractive index, viscosity,freezing point, sulfur and nitrogen content and UOP K-index, were correlated as a function of boiling temperature (Tb).The properties of naphtha fractions, jet fuel and diesel fractions could be predicted accurately with the correlations, which are useful for process design considerations, such as optimizing operating conditions of refinery processing units. The other key properties and characteristics of naphtha fractions, jet fuel, diesel and vacuum gas oil were also determined.

  19. Origin and geochemistry of saline spring waters in the Athabasca oil sands region, Alberta, Canada

    International Nuclear Information System (INIS)

    Highlights: • Saline groundwater enters the Athabasca and Clearwater rivers in the AOSR via springs. • High TDS is due to subsurface dissolution of Devonian evaporites and carbonates. • Low δ18O values, and 3H and 14C data suggest some Laurentide glacial meltwater input. • Bacterial sulfate reduction, methanogenesis, and CH4 oxidation were identified. • Metal and PAH contents are reported; bitumen does not appear to be major influence. - Abstract: The geochemistry of saline spring waters in the Athabasca oil sands region (AOSR) in Alberta (Canada) discharging from Devonian carbonate rocks into the Athabasca and Clearwater rivers was characterized for major ions, trace elements, dissolved gases, and polycyclic aromatic hydrocarbons (PAHs). In addition, stable isotope analyses of H2O, SO4, dissolved inorganic carbon (DIC), Sr, and CH4 were used to trace the sources of spring waters and their dissolved solutes, and to identify subsurface processes affecting water chemistry. The spring waters had δ18O values as low as −23.5‰, suggesting they are composed of up to 75% Laurentide glacial meltwater. Tritium and radiocarbon age-dating results, analyzed for three spring waters, supported a glacial origin. The high salinity of the spring waters (TDS 7210–51,800 mg/L) was due to dissolution of Devonian evaporite and carbonate deposits in the subsurface. Spring waters were affected by bacterial (dissimilatory) sulfate reduction, methanogenesis, and methane oxidation. Trace elements were present in spring waters at varying concentrations, with only one spring containing several predominant oil sands metals (As, Fe, Mo, Ni, Se, Zn) suggesting bitumen as a source. Five springs contained elements (Al, As, B, Fe, Se) at concentrations exceeding water quality guidelines for the protection of aquatic life. Seven PAHs were detected in spring waters (total PAH concentrations ranged from 7.3 to 273.6 ng/L), but most springs contained a maximum of two PAHs (phenanthrene

  20. [Imperial Oil's Cold Lake oil sands operations

    International Nuclear Information System (INIS)

    Imperial Oil Limited's Cold Lake oil sands resources, production and operations in Alberta are discussed. Cold Lake is the company's largest single asset and its largest source of crude oil production. In 1998, Cold Lake accounted for just under half of Imperial's total liquid production, averaging more than 135,000 barrels of bitumen a day. Despite the very difficult operating conditions experienced by the oil sands industry in 1998, Imperial Oil's Cold Lake operations generated a positive cash flow and earnings. Just as important, the near and long-term potential of Cold Lake property continues to be strong, even with the tough market conditions today and the foreseeable future. Proved reserves at the end of 1997 were 1.3 billions barrels, equal to about 24 years of current production, but even more important is Imperial's resource base in the Athabasca region, which represents 150 years of production at current rates. Although production forecasts for the near future are are revised downward because of production shut-in due to low prices, the company is confident of its long-term prospects mainly because of existing infrastructure, superior reservoir quality, 30 years worth of operating improvements and established bitumen-blend markets. Details of the company's future Cold Lake development plans are discussed. The need to continue technology development, which has been at the core of the industry's growth in the past and will continue to be the key to the future, are emphasized

  1. Microbial processes in the Athabasca Oil Sands and their potential applications in microbial enhanced oil recovery.

    Science.gov (United States)

    Harner, N K; Richardson, T L; Thompson, K A; Best, R J; Best, A S; Trevors, J T

    2011-11-01

    The Athabasca Oil Sands are located within the Western Canadian Sedimentary Basin, which covers over 140,200 km(2) of land in Alberta, Canada. The oil sands provide a unique environment for bacteria as a result of the stressors of low water availability and high hydrocarbon concentrations. Understanding the mechanisms bacteria use to tolerate these stresses may aid in our understanding of how hydrocarbon degradation has occurred over geological time, and how these processes and related tolerance mechanisms may be used in biotechnology applications such as microbial enhanced oil recovery (MEOR). The majority of research has focused on microbiology processes in oil reservoirs and oilfields; as such there is a paucity of information specific to oil sands. By studying microbial processes in oil sands there is the potential to use microbes in MEOR applications. This article reviews the microbiology of the Athabasca Oil Sands and the mechanisms bacteria use to tolerate low water and high hydrocarbon availability in oil reservoirs and oilfields, and potential applications in MEOR. PMID:21853326

  2. Unconformity-related uranium deposits, Athabasca area, Saskatchewan, and East Alligator Rivers area, Northern Territory, Australia

    International Nuclear Information System (INIS)

    Most unconformity-type uranium deposits in Saskatchewan occur within a few tens of metres above and/or below the basal unconformity of the 1.45 b.y. Athabasca Sandstone. Graphitic basement rocks coincident with post-Athabasca faulting or brecciation at or near the unconformity are important in localizing uranium deposits which form as tabular, ribbon-like bodies with grades averaging over 2 percent uranium and containing up to 50,000 tonnes U3O8. Some of these deposits have similar contents of nickel and arsenic. In the genetic model used to explain these deposits, traces of uranium were leached from the sandstone and basement rocks by oxidized formation waters. A thick clay regolith absorbed uranium from the solution, and the fixed uranium was reduced through an indirect reaction with graphite. The clay mineral surfaces were thus continuously cleared to allow further adsorption. Fluid convection was induced by topographic relief and/or crustal heating from radioactive decay, and would continue uranium deposition until all permeability was plugged by minerals. The East Alligator Rivers uranium deposits in Northern Territory, Australia occur within Middle Proterozoic quartz-chlorite and quartz-muscovite schists overlain by sandstone. Highest grades occur in silicified breccias where carbonate beds were leached out. Mineralization ages are both pre- and post-Kombolgie Sandstone, but, to date, no significant uranium mineralization has been found in the sandstone. There are many similarities with Saskatchewan deposits, but also important differences. (auth)

  3. Toxicity of Athabasca River and oil sands sediments to larval fish

    International Nuclear Information System (INIS)

    This presentation reported on a study that evaluated oil sands tailings pond sediments and sediments from the Athabasca River for embryo-larval toxicity in fathead minnows and walleye. Following 20 days of exposure to 5 sediments from the Athabasca River at concentrations up to 25 g/L, there were no observed effects in fathead minnow eggs and larvae. However, at concentrations as low as 0.2 to 1 g wet wt/L, two of three tailings pond sediments were toxic to fathead minnows. Larvae growth was reduced in all three tailings pond sediments. Nine of 18 polycyclic aromatic hydrocarbons (PAHs) measured in tailing pond sediments were found to be above the Freshwater Sediment Quality Guidelines set by the Canadian Council of Ministers of the Environment (CCME), with phenanthrene being the highest. The values for total dry weight PAHs and total naphthenic acids in tailings pond sediment and river sediment were discussed. The cause for the observed toxicity in fathead minnow larvae could not be determined based on the preliminary study results. As part of the ongoing study, walleye eggs and larvae are being exposed to the sediments to compare their relative sensitivity and to determine possible causative compounds.

  4. Characterization of Physically and Chemically Separated Athabasca Asphaltenes Using Small-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Amundaraín Hurtado, Jesús Leonardo; Chodakowski, Martin; Long, Bingwen; Shaw, John M. (Alberta)

    2012-02-07

    Athabasca asphaltenes were characterized using small-angle X-ray scattering (SAXS). Two methods were used to separate asphaltenes from the Athabasca bitumen: namely, chemical separation by precipitation with n-pentane and physical separation by nanofiltration using a zirconia membrane with a 20 nm average pore size. The permeate and chemically separated samples were diluted in 1-methylnaphtalene and n-dodecane prior to SAXS measurements. The temperature and asphaltene concentration ranges were 50-310 C and 1-10.4 wt %, respectively. Model-independent analysis of SAXS data provided the radius of gyration and the scattering coefficients. Model-dependent fits provided size distributions for asphaltenes assuming that they are dense and spherical. Model-independent analysis for physically and chemically separated asphaltenes showed significant differences in nominal size and structure, and the temperature dependence of structural properties. The results challenge the merits of using chemically separated asphaltene properties as a basis for asphaltene property prediction in hydrocarbon resources. While the residuals for model-dependent fits are small, the results are inconsistent with the structural parameters obtained from model-independent analysis.

  5. Toxicity of Athabasca River and oil sands sediments to larval fish

    Energy Technology Data Exchange (ETDEWEB)

    Parrott, J.; Turcotte, D.; Headley, J.; Hewitt, M. [Environment Canada, Ottawa, ON (Canada)

    2010-07-01

    This presentation reported on a study that evaluated oil sands tailings pond sediments and sediments from the Athabasca River for embryo-larval toxicity in fathead minnows and walleye. Following 20 days of exposure to 5 sediments from the Athabasca River at concentrations up to 25 g/L, there were no observed effects in fathead minnow eggs and larvae. However, at concentrations as low as 0.2 to 1 g wet wt/L, two of three tailings pond sediments were toxic to fathead minnows. Larvae growth was reduced in all three tailings pond sediments. Nine of 18 polycyclic aromatic hydrocarbons (PAHs) measured in tailing pond sediments were found to be above the Freshwater Sediment Quality Guidelines set by the Canadian Council of Ministers of the Environment (CCME), with phenanthrene being the highest. The values for total dry weight PAHs and total naphthenic acids in tailings pond sediment and river sediment were discussed. The cause for the observed toxicity in fathead minnow larvae could not be determined based on the preliminary study results. As part of the ongoing study, walleye eggs and larvae are being exposed to the sediments to compare their relative sensitivity and to determine possible causative compounds.

  6. Use of pre-industrial floodplain lake sediments to establish baseline river metal concentrations downstream of Alberta oil sands: a new approach for detecting pollution of rivers

    International Nuclear Information System (INIS)

    In the Alberta oil sands region, insufficient knowledge of pre-disturbance reference conditions has undermined the ability of the Regional Aquatics Monitoring Program (RAMP) to detect pollution of the Athabasca River, because sampling began three decades after the industry started and the river naturally erodes oil-bearing strata. Here, we apply a novel approach to characterize pre-industrial reference metal concentrations in river sediment downstream of Alberta oil sands development by analyzing metal concentrations in sediments deposited in floodplain lakes of the Athabasca Delta during 1700–1916, when they were strongly influenced by Athabasca River floodwaters. We compared results to metal concentrations in surficial bottom sediments sampled by RAMP (2010–2013) at downstream sites of the Athabasca River and distributaries. When normalized to lithium content, concentrations of vanadium (a metal of concern in the oil sands region) and other priority pollutants (Be, Cd, Cr, Cu, Pb, Ni, Zn) in nearly all of the RAMP river sediment samples lie below the upper 95% prediction interval linearly extrapolated from the river-derived lake sediments. Assuming the RAMP protocols obtained recently deposited sediment, this indicates that the metal concentrations in downstream Athabasca River sediment have not increased above pre-disturbance levels. Reference conditions derived from the lake sediment data were used to develop profiles of metal residual concentrations versus time for the RAMP river sediment data, which provides an excellent tool for decision-makers to identify and quantify levels of metal pollution for any given sample, and to monitor for future trends. We recommend that the approach be applied to resurrect the utility of RAMP data at other river sampling locations closer to the development, and for ongoing risk assessment. The approach is also readily transferable to other rivers where insufficient pre-disturbance reference data impairs an ability to

  7. Initial environmental impacts of the Obed Mountain coal mine process water spill into the Athabasca River (Alberta, Canada).

    Science.gov (United States)

    Cooke, Colin A; Schwindt, Colin; Davies, Martin; Donahue, William F; Azim, Ekram

    2016-07-01

    On October 31, 2013, a catastrophic release of approximately 670,000m(3) of coal process water occurred as the result of the failure of the wall of a post-processing settling pond at the Obed Mountain Mine near Hinton, Alberta. A highly turbid plume entered the Athabasca River approximately 20km from the mine, markedly altering the chemical composition of the Athabasca River as it flowed downstream. The released plume traveled approximately 1100km downstream to the Peace-Athabasca Delta in approximately four weeks, and was tracked both visually and using real-time measures of river water turbidity within the Athabasca River. The plume initially contained high concentrations of nutrients (nitrogen and phosphorus), metals, and polycyclic aromatic hydrocarbons (PAHs); some Canadian Council of Ministers of the Environmental (CCME) Guidelines were exceeded in the initial days after the spill. Subsequent characterization of the source material revealed elevated concentrations of both metals (arsenic, lead, mercury, selenium, and zinc) and PAHs (acenaphthene, fluorene, naphthalene, phenanthrene, and pyrene). While toxicity testing using the released material indicated a relatively low or short-lived acute risk to the aquatic environment, some of the water quality and sediment quality variables are known carcinogens and have the potential to exert negative long-term impacts. PMID:27017080

  8. Aquatic baseline report for the Athabasca, Steepbank and Muskeg Rivers in the vicinity of the Steepbank and Aurora Mines

    International Nuclear Information System (INIS)

    Both Suncor Inc., and Syncrude Canada Ltd. plan to expand their operations in the Athabasca oil sands deposit: Suncor in the vicinity of the Steepbank and Athabasca Rivers (Steepbank Mine) and Syncrude in the Muskeg River watershed (Aurora Mine). An aquatic study was conducted in which the current conditions were described with respect to surface water, benthic invertebrates, fish habitat, fish communities and fish health. The study also provided a baseline for future comparisons. River water within the study area was characterized by pHs ranging from 7 to 8, low to moderate dissolved salt concentrations and moderate levels of nutrients. Dissolved organic carbon concentration was high. The major findings in this study were: (1) naturally-occurring hydrocarbons were found in river sediments, but no changes in surface water chemistry were associated with Athabasca oil sands deposits or existing oil sands facilities, (2) benthic invertebrate communities were thriving and showed no indication of negative effects resulting from exposure to naturally-occurring hydrocarbon deposits or existing oil sands developments, (3) fish habitat in the Athabasca River was poor because of the turbid backwaters associated with islands and sandbars, and dynamically shifting sand bottom, (4) high quality habitat was found to exist in the Steepbank and Muskeg Rivers and in some tributaries to these rivers, (5) there were diverse fish communities in the Athabasca, Steepbank and Muskeg River basins, and (6) there was evidence of exposure of fish to naturally-occurring hydrocarbons, however, general indicators suggested that the fish populations were healthy. 112 refs., 100 tabs., 118 figs

  9. Key Lake pit development a formidable design challenge

    International Nuclear Information System (INIS)

    Interest in the mineral potential of the southeast rim of the Athabasca Basin was sparked in 1971 with the discovery of two uraniferous boulders 500 m from Key Lake. It was not until 1975, however, that geologists discovered the Gaertner deposit. The Deilmann deposit was drilled the following year. These two deposits, with combined reserves of over 3.5 million t grading 2.35 per cent U3O8, are the backbone of the non-communist world's largest uranium producer. Construction began at Key Lake in September 1981, following one of the most extensive public hearings ever held for a Canadian mining project. The Key Lake surface lease is one of this country's most stringent. Employment, training, business opportunities, environmental guidelines and monitoring processes are all spelled out in detail

  10. Experimental study of simultaneous Athabasca bitumen recovery and upgrading using ultradispersed catalysts injection

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, R.; Pereira, P. [University of Calgary (Canada)

    2011-07-01

    As the demand for oil is continuously increasing, the need for unconventional resources is rising. Oil extraction from bitumen and heavy oil reservoirs requires advanced techniques in order to decrease the viscosity of the oil. To increase the recovered original oil in place (OOIP) of a reservoir and decrease refining costs, new techniques to upgrade oil in situ are being developed. The current study investigates the use of ultra-dispersed (UD) submicronic catalysts to decrease oil viscosity. The experiment involved the injection of the catalyst and hydrogen gas in a sand pack saturated with Athabasca bitumen. Analysis was carried out by building recovery curves, and by comparing the oil recovery from the catalyzed process with that of catalyst-free processes. The study demonstrated that the oil recovered from the new technique had higher API gravity and lower viscosity, indicating the success of the in situ upgrading process.

  11. Athabasca University: Conversion from Traditional Distance Education to Online Courses, Programs and Services

    Directory of Open Access Journals (Sweden)

    Alan Davis

    2001-01-01

    Full Text Available In its 30 years of operation, Athabasca University has witnessed the full impact of the growth of online distance education. Its conversion from mixed media course production and telephone/ mail tutoring to a variety of electronic information and communication technologies has been heterogeneous across disciplines and programs. Undergraduate programs in business, computing, and some social science programs have largely led the conversion, and all graduate programs have, since their inception, employed various features of online delivery. The parallel conversion of student services has been equally important to the effectiveness of these processes. The implications of this approach for the quality of offerings, support systems, costing, and the primary mandate of the University (which is to remove barriers, not create them are discussed.

  12. The Open Library at AU (Athabasca University: Supporting Open Access and Open Educational Resources

    Directory of Open Access Journals (Sweden)

    Colin Elliott

    2015-04-01

    Full Text Available To address challenges that learners, course creators, librarians and academics involved with OER and MOOCs are facing when looking for scholarly materials, Athabasca University Library has initiated the development of the Open Library at AU. This open library is a full library website that provides easy access to open and free resources. Tools and information literacy tutorials are also included to enable learners, researchers, and others to find, evaluate, and use the information they need for their open learning course or research. Many of the challenges that those involved in open learning face are addressed by the open library and the potential impact it can have on open learning and knowledge sharing is tremendous. http://dx.doi.org/10.5944/openpraxis.7.2.196

  13. Carbon dynamics, food web structure and reclamation strategies in Athabasca oil sands wetlands (CRFAW)

    International Nuclear Information System (INIS)

    This abstract provided details of the Carbon Dynamics, Food Web Structure and Reclamation Strategies in Athabasca Oil Sands Wetlands (CFRAW) program, a collaboration between oil sands industry partners and university laboratories. CFRAW researchers are investigating the effects of mine tailings and process waters on the development, health, and function of wetland communities in post-mining landscapes. The aim of the program is to accurately predict how quickly the reclaimed wetlands will approach conditions seen in reference wetland systems. The program is also examining the effects of hydrocarbons as a surrogate source of carbon after they are metabolized by bacteria. The biological uptake, pathways, and movement through the food web of materials used by the biota in constructed wetlands are also being studied. Flux estimates will be used to determine if wetlands amended with peat will maintain their productivity. A conceptual model of carbon pathways and budgets is also being developed.

  14. Model development for prediction and mitigation of dissolved oxygen sags in the Athabasca River, Canada

    International Nuclear Information System (INIS)

    Northern rivers exposed to high biochemical oxygen demand (BOD) loads are prone to dissolved oxygen (DO) sags in winter due to re-aeration occurring within limited open water leads. Additionally, photosynthesis is reduced by decreased daylight hours, inability of solar radiation to pass through ice, and slower algal growth in winter. The low volumetric flow decreases point-source dilution while their travel time increases. The Athabasca River in Alberta, Canada, has experienced these sags which may affect the aquatic ecosystem. A water quality model for an 800 km reach of this river was customized, calibrated, and validated specifically for DO and the factors that determine its concentration. After validation, the model was used to assess the assimilative capacity of the river and mitigation measures that could be deployed. The model reproduced the surface elevation and water temperature for the seven years simulated with mean absolute errors of 3/s at average BOD load. Climate change scenarios could increase the frequency of this low flow. A three-level warning-system is proposed to manage the BOD load proactively at different river discharges. Other mitigation options were explored such as upgrading the wastewater treatment of the major BOD point source and oxygen injection in the effluents. The model can be used as a management tool with updated SOD values to forecast the DO in low flow years and evaluate mitigation measures. As well, the methodology presented here can be applied to manage other ice-covered rivers. Highlights: ► A water quality model was developed for the Athabasca River in Canada. ► The model was calibrated/validated for hydrodynamics, temperature and DO. ► The SOD was found as the main dissolved oxygen sink in winter. ► The model was applied to estimate the assimilative capacity and mitigation options. ► A variable flow threshold approach for BOD loading was recommended

  15. Snowpack deposition of trace elements in the Athabasca oil sands region, Canada.

    Science.gov (United States)

    Guéguen, C; Cuss, C W; Cho, S

    2016-06-01

    The total recoverable and dissolved concentrations of 29 metals and metalloids were analyzed in snowpack collected at 91 sites in the Athabasca oil sands region, Canada in winter 2011. Based on deposition pattern from geographical centre, three groups were found: Type-1 metals (i.e. dissolved and total recoverable V; Mo) showed a significant exponential decrease with distance, suggesting oil sands development sources; Type-2 elements (e.g. Al, Sb, As, Ba, Fe, Ni, Tl, and Ti and Zn) showed exponentially decline patterns but with some local point sources; Type-3 elements (e.g. Cd, Cl, Cr, Mn, Sr and Th) deposition pattern represented local sources. A self-organizing map showed that sites with the highest elemental concentrations (Cluster I) were mainly located in the vicinity of upgrading facilities and along the north-south transects. The lowest elemental concentration sites (Cluster III) were the most distal sites or located in the western region of the study area. PMID:27031808

  16. Coke yield and heat transfer in reaction of liquid-solid agglomerates of Athabasca vacuum residue

    Energy Technology Data Exchange (ETDEWEB)

    Ali, M.; Courtney, M.; Boddez, L.; Gray, M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2010-02-15

    Delayed coking and fluid-bed coking are the most common commercial processes used by the petroleum industry for the thermal conversion of vacuum residues into petroleum distillate products. This paper presented the results of an experimental study of coke yield at long reaction times from agglomerates of coke particles and Athabasca vacuum residue (AVR). The ultimate coke yield was determined for a range of agglomerate thicknesses, liquid concentrations and reaction temperatures. The agglomerates were heated on Curie-point alloy strips in an induction furnace at 503 and 530 degrees C until all toluene-soluble material was converted. A simple heat transfer model was used to describe the temperature profile within the agglomerates. Coke yield results from agglomerates were compared to the coke yield results from reacting thin films of vacuum residue. The average coke yield from the agglomerates was 23 per cent, while the coke yield from thin films of 20 {mu}m thickness was 11 per cent, which supports the role of mass transfer in coke formation reactions. The ultimate coke yield was insensitive to vacuum residue concentration, agglomerate size, and reaction temperature. According to control experiments on thin films of liquid at different heating rates, the temperature-time history has little effect on the ultimata coke yield. 13 refs., 2 tabs., 10 figs.

  17. Condensation induced water hammer and steam assisted gravity drainage in the Athabasca oil sands

    International Nuclear Information System (INIS)

    Most people will have been exposed to some aspect of the debate about the Athabasca Oil Sands in North-Eastern Alberta and the significant role that the oil sands are expected to play in supplying conventional fossil fuels. Part of the bitumen is recovered from mines and part is recovered from in situ projects utilizing the Steam Assisted Gravity Drainage Process (SAGD). SAGD utilizes a considerable amount of steam, that is injected into geological formations. Hot water, bitumen and some vapour are recovered from the production wells. With significant steam generation, transmission and injection, there is the very real possibility of condensation induced water hammers. There have been a number of catastrophic failures to date. The intent of the paper is to provide interesting background information on the in situ oil sands industry. More importantly, to show some interesting and broader applications of thermalhydraulics developed in the nuclear industry. The expertise developed may have potential markets, with some adaptation, to the oil sands industry. Finally, there has been some discussion about using nuclear power for steam generation in the oil sands. (orig.)

  18. Comparison of the chemical structure of coal hydrogenation products, Athabasca tar sand bitumen and Green River shale oil

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, R.; Yoshida, T.; Nakata, Y.; Hasegawa, Y.; Hino, M.; Ikawa, Y.; Makabe, M.; Bodily, D.M.

    1983-03-01

    Coal hydrogenation products, Athabasca tar sand bitumen, and Green River shale oil produced by retorting were analyzed by the Brown-Ladner method and the Takeya et al. method on the basis of elemental analysis and /sup 1/H-NMR data, by /sup 13/C NMR spectroscopy and by FT-IR spectroscopy. Structural characteristics were compared. The results show that the chemical structure of oils from Green River shale oil and Athabasca tar sand bitumen, and the oils produced in the initial stage of hydrogenation of Taiheiyo coal and Clear Creek, Utah, coal is characterized as monomers consisting of units of one aromatic ring substituted highly with C/sub 5//sub -//sub 6/ aliphatic chains and heteroatom-containing functional groups. The chemical structure of asphaltenes from Green River shale oil and Athabasca tar sand bitumen is characterized by oligomers consisting of units of 1-2 aromatic rings substituted highly with C/sub 3//sub -//sub 5/ aliphatic chains and heteroatom-containing functional groups. The chemical structure of asphaltenes from coal hydrogenation is characterized by dimers and/or trimers of unit structures of 2 to 5 condensed aromatic rings, substituted moderately with C/sub 2//sub -//sub 5/ aliphatic chains and heteroatom-containing functional groups. The close agreement between f/SUB/a(/sup 1/H-NMR) and f/SUB/a(/sup 13/C-NMR) for Green River shale oil derivatives indicates that the assumption of 2 for the atomic H/C ratio of aliphatic structures is reasonable. For coal hydrogenation products, a value of 1.6-1.7 for the H/C ratio of aliphatic structures would be more reasonable. (25 refs).

  19. Dianchi Lake

    OpenAIRE

    Gipouloux, François

    2012-01-01

    This photo is taken in Dianchi lake of Kunming city. After 1970, the industrial zones and farmland areas around Kunming evacuated waste water into Dianchi Lake, resulting in a significant growth of cyanobacteria and serious eutrophication in Dianchi Lake. Although the Kunming city government has been actively trying to solve the problem of pollution in Dianchi Lake, in order to significantly improve water quality, the lake is still at a pollution level far below the level of drinkable water.

  20. Evaluating microbial carbon sources in Athabasca oil sands tailings ponds using natural abundance stable and radiocarbon isotopes

    Science.gov (United States)

    Ahad, J. M.; Pakdel, H.

    2013-12-01

    Natural abundance stable (δ13C) and radiocarbon (Δ14C) isotopes of phospholipid fatty acids (PLFAs) were used to evaluate the carbon sources utilized by the active microbial populations in surface sediments from Athabasca oil sands tailings ponds. The absence of algal-specific PLFAs at three of the four sites investigated, in conjunction with δ13C signatures for PLFAs that were generally within ~3‰ of that reported for oil sands bitumen (~ -30‰), indicated that the microbial communities growing on petroleum constituents were dominated by aerobic heterotrophs. The Δ14C values of PLFAs ranged from -906 to -586‰ and pointed to a significant uptake of fossil carbon (up to ~90% of microbial carbon derived from petroleum), particularly in PLFAs (e.g., cy17:0 and cy19:0) often associated with petroleum hydrocarbon degrading bacteria. The comparatively higher levels of 14C in other, less specific PLFAs (e.g., 16:0) indicated the preferential uptake of younger organic matter by the general microbial population (~50-80% of microbial carbon derived from petroleum). Since the main carbon pools in tailings sediment were essentially 'radiocarbon dead' (i.e., no detectable 14C), the principal source for this modern carbon is considered to be the Athabasca River, which provides the bulk of the water used in the bitumen extraction process. The preferential uptake of the minor amount of young and presumably more biodegradable material present in systems otherwise dominated by recalcitrant petroleum constituents has important implications for remediation strategies. On the one hand, it implies that mining-related organic contaminants could persist in the environment long after tailings pond reclamation has begun. Alternatively, it may be that the young, labile organic matter provided by the Athabasca River plays an important role in stimulating or supporting the microbial utilization of petroleum carbon in oil sands tailings ponds via co-metabolism or priming processes

  1. Model development for prediction and mitigation of dissolved oxygen sags in the Athabasca River, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Nancy, E-mail: nancy@ualberta.ca [Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 2W2 (Canada); McEachern, Preston [Tervita Corporation, AB (Canada); Yu, Tong; Zhu, David Z. [Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 2W2 (Canada)

    2013-01-15

    Northern rivers exposed to high biochemical oxygen demand (BOD) loads are prone to dissolved oxygen (DO) sags in winter due to re-aeration occurring within limited open water leads. Additionally, photosynthesis is reduced by decreased daylight hours, inability of solar radiation to pass through ice, and slower algal growth in winter. The low volumetric flow decreases point-source dilution while their travel time increases. The Athabasca River in Alberta, Canada, has experienced these sags which may affect the aquatic ecosystem. A water quality model for an 800 km reach of this river was customized, calibrated, and validated specifically for DO and the factors that determine its concentration. After validation, the model was used to assess the assimilative capacity of the river and mitigation measures that could be deployed. The model reproduced the surface elevation and water temperature for the seven years simulated with mean absolute errors of < 15 cm and < 0.9 °C respectively. The ice cover was adequately predicted for all seven winters, and the simulation of nutrients and phytoplankton primary productivity were satisfactory. The DO concentration was very sensitive to the sediment oxygen demand (SOD), which represented about 50% of the DO sink in winter. The DO calibration was improved by implementing an annual SOD based on the BOD load. The model was used to estimate the capacity of the river to assimilate BOD loads in order to maintain a DO concentration of 7 mg/L, which represents the chronic provincial guideline plus a buffer of 0.5 mg/L. The results revealed the maximum assimilative BOD load of 8.9 ton/day at average flow conditions, which is lower than the maximum permitted load. In addition, the model predicted a minimum assimilative flow of about 52 m{sup 3}/s at average BOD load. Climate change scenarios could increase the frequency of this low flow. A three-level warning-system is proposed to manage the BOD load proactively at different river

  2. Magnetism of the lower crust: Observations from the Chipman Domain, Athabasca Granulite Terrain, northern Canada

    Science.gov (United States)

    Brown, Laurie L.; Webber, Jeffery; Williams, Michael; Regan, Sean; Seaman, Sheila

    2014-06-01

    Magnetic properties of lower crustal rocks produce anomalies seen in satellite, aeromagnetic, and ground studies, and are assumed to be responsible for observed long wave-length anomalies (LWA) of +/- 20 nT. The soon to be launched SWARM satellites will provide extensive data on the magnetization of the lower to middle crust. In anticipation of this event we are investigating magnetic properties in a superbly exposed section of lower crust in northern Saskatchewan. The Athabasca Granulite Terrain (AGT) is a complex region of felsic and mafic lower crustal rocks, part of the Snowbird Tectonic zone, stretching NE-SW across the Canadian Shield. The AGT is composed of a sequence of rocks identified as lower crustal in origin by their high pressure (> 1.0 GPa) and high temperature (~ 800 °C) metamorphism, dated at 2.6 Ga and 1.9 Ga, with uplift and exhumation at 1.85-1.80 Ga. The AGT is characterized by low (negative) aeromagnetic anomalies with distinct large positive anomalies in the southern and central regions. The Chipman Domain, on the east side, consists of tonalites, mafic granulites, and granite, intruded by the Chipman dike swarm at ~ 1.9 Ga, where anomalies cut across mapped lithologic boundaries. Susceptibility measurements from both field and lab readings range over several orders of magnitude, from 1 × 10- 5 to 3 × 10- 1 SI, with higher values related to both mafic granulite and some tonalite samples. Remanence values also show considerable variability, from 0.1 mA/m to 90 A/m, with the weakest magnetization found in the Chipman dikes and the Fehr granite. Forty samples out of 89 have Koenigsberger ratios greater than 1, but low initial remanence limits its influence on anomalies. Hysteresis and low temperature measurements identify magnetite as the predominant iron oxide. This section of lower crustal rocks has paramagnetic granites and dikes, with ferromagnetic mafic granulites and bimodal tonalites, defined by geographic location.

  3. Variation in toxicity response of Ceriodaphnia dubia to Athabasca oil sands coke leachates.

    Science.gov (United States)

    Puttaswamy, Naveen; Turcotte, Dominique; Liber, Karsten

    2010-07-01

    Coke from the Athabasca (Alberta, Canada) oil sands operations may someday be integrated into reclamation landscapes. It is hypothesized that the metals associated with the solid coke may leach into the surrounding environment. Therefore, the main objectives of this study were to characterize the toxicity and chemistry of coke leachates collected from two field lysimeters (i.e. shallow lysimeter and deep lysimeter) over a period of 20months, as well as from other oil sands coke storage sites. In addition, a batch renewal leaching of coke was conducted to examine the rate of metals release. Chronic toxicity of key metals (e.g. Al, Mn, Ni and V) found in lysimeter coke leachate was evaluated separately. Toxicity test results revealed that whole coke leachates (100% v/v) were acutely toxic to Ceriodaphnia dubia; the 7-day LC50 values were always coke leachate. The deep lysimeter leachate was generally more toxic than the shallow lysimeter leachate, likely because of significantly higher concentrations of vanadium (V) found in the deep lysimeter leachate at all sampling times. Vanadium concentrations were higher than all other metals found in the leachate from both lysimeters, and in the batch renewal leaching study. Furthermore, V found in leachates collected from other oil sands field sites showed a concentration-response relationship with C. dubia survival. Mass balance calculations indicated that 94-98% of potentially leachable V fraction was still present in the coke from two field lysimeters. Evidence gathered from these assessments, including toxic unit (TU) calculations for the elements of concern, suggests that V was the likely cause of toxicity of the deep lysimeter leachate, whereas in the shallow lysimeter leachate both Ni and V could be responsible for the observed toxicity. PMID:20553931

  4. Post-dam vegetation changes and small mammal populations in the Peace-Athabasca delta

    International Nuclear Information System (INIS)

    Research aimed at monitoring wildlife populations is a useful way to estimate the impact and consequences of hydroelectric projects on northern deltas. Such studies could provide valuable insights on the potential effect of the drying of deltas in the context of global climate change. The Peace-Athabasca River Delta, one of the most extensive northern inland deltas in the western hemisphere, represents a unique site to study such effects. Construction of the Bennett Dam in 1968 has had serious effects on the delta's ecological integrity; the resulting lower water levels and colonization of grass meadow communities by willows and the movement of shorelines has affected wildlife distribution and population levels. A study was conducted to estimate the impact of the invasion of grass meadows by willows on small rodent populations in the delta. Live trapping grids were established at three sites. Population estimates were obtained by the minimum number known method and used to calculate biomass of small mammals in willow and meadow grids. Mean trapping estimates (MTEs) of adult meadow voles ranged from under 1 per hectare on willow grids to 28 per hectare on meadow grids. On willow grids only, MTEs for adult populations of deer mice, red-backed voles, and meadow jumping mice reached 6, 6, and less than 1 per hectare respectively. It is estimated that the development of grass meadows into willow shrublands over the next 20-40 y could result in a loss of over 50% of the biomass of small rodents present in 1976. This should have a negative effect on the foraging efficiency and productivity of secondary consumers such as weasel and owl. 109 refs., 16 figs., 29 tabs

  5. Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta

    International Nuclear Information System (INIS)

    The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ∼1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies. -- Highlights: •In-situ bitumen extraction linked to rise in alkyl PAHs in one of two study lakes. •Alkyl PAHs elevated in two soil samples. •PAH contamination likely related to effluent sources, not atmospheric deposition. -- PAHs in sediments and soils were generally low in areas adjacent to in-situ bitumen extraction rigs in the Cold Lake Alberta oil sands, but evidence of localized contamination at some sites was evident

  6. Loadings of polynuclear aromatic compounds and metals to the Athabasca River watershed by oil sands mining and processing

    International Nuclear Information System (INIS)

    The contribution of oil sands operations to pollution in the Athabasca River has not yet been determined. Wastes from oil sands processes include recycled water, sand, silt, clay, bitumen, and polycyclic aromatic compounds (PAC) and metals. Upgrading processes can also release significant quantities of PAC and heavy metals. This paper discussed a study in which PAC and metals in the snow pack and river water of the Athabasca watershed were assessed. The study showed that the oil sands industry is a significant source of contamination. The equivalent of 600 T of bitumen was observed at sites within 50 km of oil sands upgrading facilities. The strongest contamination signals occurred during the summer months, which suggested that the surface run-off of contaminated water was related to recent oil sands developments. Samples taken from tributaries in watersheds with little or no development indicated that increased concentrations of oil sands related contaminants were not caused by natural erosion. The contaminants may contribute to higher levels of mercury (Hg) and cadmium (Cd) in the flesh of fish and wildlife and increase toxicity to the embryos of spring-spawning fish.

  7. The Athabasca Working Group Environmental Monitoring Programme in Northern Saskatchewan - Building Relations Between Indigenous Groups and the Uranium Mining Industry

    International Nuclear Information System (INIS)

    In the 1990s, representatives from the Saskatchewan uranium industry and the seven indigenous bands and communities living in the Athabasca region of northern Saskatchewan formed the Athabasca Working Group (AWG) and signed one of Canada's first Impact Management Agreements. In the agreement, the companies committed to providing compensation for losses of specified resources that could be attributed to emissions from uranium projects. The AWG established an environmental monitoring programme to act as the primary method for assessing whether a loss had occurred. A key element of the monitoring programme is community involvement, which includes community members deciding what environmental components to sample, where to collect the samples and taking part in the sample collections. An independent consultant helps coordinate the programme and presents the results to each community in a user-friendly format. The AWG environmental monitoring programme is currently in its fifth consecutive year of operation and it continues to be an important programme to help build relations between indigenous groups and the uranium mining industry in northern Saskatchewan. (author)

  8. An integrated numerical framework for water quality modelling in cold-region rivers: A case of the lower Athabasca River.

    Science.gov (United States)

    Shakibaeinia, Ahmad; Kashyap, Shalini; Dibike, Yonas B; Prowse, Terry D

    2016-11-01

    There is a great deal of interest to determine the state and variations of water quality parameters in the lower Athabasca River (LAR) ecosystem, northern Alberta, Canada, due to industrial developments in the region. As a cold region river, the annual cycle of ice cover formation and breakup play a key role in water quality transformation and transportation processes. An integrated deterministic numerical modelling framework is developed and applied for long-term and detailed simulation of the state and variation (spatial and temporal) of major water quality constituents both in open-water and ice covered conditions in the lower Athabasca River (LAR). The framework is based on the a 1D and a 2D hydrodynamic and water quality models externally coupled with the 1D river ice process models to account for the cold season effects. The models are calibrated/validated using available measured data and applied for simulation of dissolved oxygen (DO) and nutrients (i.e., nitrogen and phosphorus). The results show the effect of winter ice cover on reducing the DO concentration, and a fluctuating temporal trend for DO and nutrients during summer periods with substantial differences in concentration between the main channel and flood plains. This numerical frame work can be the basis for future water quality scenario-based studies in the LAR. PMID:27376919

  9. Midwest Lake uranium discovery, Saskatchewan, Canada

    International Nuclear Information System (INIS)

    The discovery of the Midwest Lake uranium deposit in Saskatchewan came some ten years after the start of exploration. The original mining rights were acquired on the basis of regional published, geology and proximity to the earlier discovery. Aerial radiometric surveys led to the location of a train of radioactive, glacially transported sandstone boulders and cobbles. The source of these mineralized erratics did not outcrop, and an extensive series of magnetic, electromagnetic, seismic and gravity surveys was carried out in an unsuccessful attempt to identify the source location. These surveys were followed by several programmes of diamond drilling, geochemical surveys and Pleistocene geological studies. None of these programmes or surveys encountered bedrock mineralization. When information about ore controls in the Athabasca Basin became available, a limited programme of three 300-m wildcat diamond-drill holes was proposed. The second of these holes cut weak radioactivity in a poorly cored intersection. This intersection was at an unconformity at a depth of 200 m. The programme terminated prematurely with early melting of lake ice. The first hole in the subsequent winter's follow-up drilling intersected uranium values in excess of 8%. (author)

  10. Carbon dynamics, food web structure and reclamation strategies in Athabasca oil sands wetlands (CFRAW)

    International Nuclear Information System (INIS)

    The remediation and ecology of oilsands constructed wetlands was discussed with reference to a project known as the Carbon dynamics, Food web structure and Reclamation strategies in Athabasca oil sands Wetlands (CFRAW). This joint project between 7 mining partners and 5 universities documents how tailings in constructed wetlands modify maturation leading to natural conditions in a reclaimed landscape. Since wetlands are expected to make up 20-50 per cent of the final reclamation landscape of areas surface mined for oil sands in northeastern Alberta, the project focuses on how quickly wetlands amended with reclamation materials approach the conditions seen in reference wetland systems. This study provided a conceptual model of carbon pathways and budgets to evaluate how the allocation of carbon among compartments changes as newly formed wetlands mature in the boreal system. It is likely that succession and community development will accelerate if constructed wetlands are supplemented with stockpiled peat or topsoil. The bitumens and naphthenic acids found in wetlands constructed with mine tailings materials are initially toxic, but may ultimately serve as an alternate source of carbon once they degrade or are metabolized by bacteria. This study evaluated the sources, biological uptake, pathways, and movement through the food web of materials used by the biota in constructed wetlands, with particular reference to how productivity of new wetlands is maintained. Net ecosystem productivity is being monitored along with rates of organic carbon accumulation from microbial, algal, and macrophyte production, and influx of outside materials. The rates of leaf litter breakdown and microbial respiration are also being monitored to determine how constituents speed or slow food web processes of young and older wetlands. Carbon and nitrogen stable isotope measurements indicate which sources are incorporated into the food web as wetlands age, and how this influences community

  11. Carbon dynamics, food web structure and reclamation strategies in Athabasca oil sands wetlands (CFRAW)

    Energy Technology Data Exchange (ETDEWEB)

    Ciborowski, J.J. [Windsor Univ., ON (Canada); Dixon, G. [Waterloo Univ., ON (Canada); Foote, L. [Alberta Univ., Edmonton, AB (Canada); Liber, K.; Smits, J.E. [Saskatchewan Univ., Regina, SK (Canada)

    2007-07-01

    The remediation and ecology of oilsands constructed wetlands was discussed with reference to a project known as the Carbon dynamics, Food web structure and Reclamation strategies in Athabasca oil sands Wetlands (CFRAW). This joint project between 7 mining partners and 5 universities documents how tailings in constructed wetlands modify maturation leading to natural conditions in a reclaimed landscape. Since wetlands are expected to make up 20-50 per cent of the final reclamation landscape of areas surface mined for oil sands in northeastern Alberta, the project focuses on how quickly wetlands amended with reclamation materials approach the conditions seen in reference wetland systems. This study provided a conceptual model of carbon pathways and budgets to evaluate how the allocation of carbon among compartments changes as newly formed wetlands mature in the boreal system. It is likely that succession and community development will accelerate if constructed wetlands are supplemented with stockpiled peat or topsoil. The bitumens and naphthenic acids found in wetlands constructed with mine tailings materials are initially toxic, but may ultimately serve as an alternate source of carbon once they degrade or are metabolized by bacteria. This study evaluated the sources, biological uptake, pathways, and movement through the food web of materials used by the biota in constructed wetlands, with particular reference to how productivity of new wetlands is maintained. Net ecosystem productivity is being monitored along with rates of organic carbon accumulation from microbial, algal, and macrophyte production, and influx of outside materials. The rates of leaf litter breakdown and microbial respiration are also being monitored to determine how constituents speed or slow food web processes of young and older wetlands. Carbon and nitrogen stable isotope measurements indicate which sources are incorporated into the food web as wetlands age, and how this influences community

  12. Tracing industrial ammonium in atmospheric deposition in the Athabasca Oil Sands Region, Alberta, Canada

    Science.gov (United States)

    Mayer, B.; Proemse, B. C.; Fenn, M. E.

    2013-12-01

    The expanding industrial development in the Athabasca oil sands region (AOSR) in northeastern Alberta, Canada, has raised concerns about increasing nitrogen (N) emissions from oil sands operations and their potential effects on the surrounding terrestrial and aquatic ecosystems. Stable isotope techniques may help to trace industrial emissions provided that they are isotopically distinct from background isotope ratios of atmospheric N compounds. Ammonium deposition rates (NH4-N) typically exceed nitrate deposition rates (NO3-N) in the AOSR (Proemse et al., 2013), suggesting that emissions of reduced nitrogen compounds play a significant role for the atmospheric nitrogen budget in the AOSR. We collected atmospheric ammonium in open field bulk deposition and throughfall using ion exchange resins over ~6 months time periods from summer 2007 to summer 2011 located at distances between 3 to 113 km to one of the major oil sands developments in the AOSR. Ammonium deposition rates and δ15N-NH4 values were determined using ion chromatography and the ammonium diffusion method (Sebilo et al., 2004) on resin extracts. Atmospheric ammonium deposition rates in open field bulk collectors and throughfall collectors ranged from 1.0 to 4.7 kg ha-1 yr-1 NH4-N, and from 1.0 to 18.3 kg ha-1 yr-1 NH4-N, respectively. δ15N-NH4 values varied from -6.3 to +14.8‰ with the highest δ15N values typically associated with elevated NH4-N deposition rates. δ15N-NH4 values of up to +20.1‰ were observed for industrially emitted NH4 in particulate matter (PM2.5) emissions (Proemse et al., 2012) suggesting that industrial NH3 and NH4 emissions are associated with elevated δ15N values providing a potential tracer. Applying a two-end-member mixing analysis using a background δ15N-NH4 value of -3.6‰ for summer and -3.2‰ for winter periods revealed that particularly sites within ~30 km radius from the main oil sands developments are significantly affected by industrial contributions to

  13. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2009-06-01

    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  14. Origin of polycyclic aromatic hydrocarbons in lake sediments of the Mackenzie Delta.

    Science.gov (United States)

    Headley, John V; Marsh, Philip; Akre, Christine J; Peru, Kerry M; Lesack, Lance

    2002-08-01

    The concentrations and distribution of polycyclic aromatic hydrocarbons (PAHs) were assessed in sediment cores from among 14 lakes from three regions comprising a transect across the central Mackenzie Delta. PAHs were consistently found in the lake sediments, with parent concentrations in the 20-200 ng/g range. Concentrations were generally independent of depth in the sediment cores and this pattern was similar among the 3 regions of the delta. Concentrations increased in a westerly direction among the regions. For some lakes, the concentration of PAHs decreased with decreasing flooding frequency, and decreasing sedimentation rates. For the latter, maximum concentrations occurred at shallower depths within the sediment cores as flooding frequency among the lakes decreased. The distributions of C0-C4 alkylated 2- and 3- ring PAHs were consistent with a petrogenic origin, while the corresponding distribution of 4-ring PAHs appears to be more consistent with a biogenic or pyrogenic origin. Based on relative contributions to the overall PAH budget, a petrogenic source appears to be dominant. However, the pyrene/fluoranthene ratio is more consistent with a source derived from peat. The alkylated PAH profiles are inconsistent with those in the Athabasca River system, and supports a previously published hypothesis that the contribution of PAHs from the Athabasca oil sands to the lower Mackenzie River is minimal. A double ratio plot of chrysene vs dibenzothiophene, diagnostic of weathering, suggests most weathering occurred before the sediments were deposited in the lakes, while a double ratio plot of dibenzothiophene vs phenanthrene suggests a common source of PAHs across the delta, despite differing water sources from east to west across the delta. PAH inputs to the delta appear to mirror sediment inputs documented in previous work, where high sediment input from the Mackenzie mainstem during high floods dominates the delta sediment influx and masks any influence of the

  15. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    OpenAIRE

    Petre GÂŞTESCU

    2009-01-01

    Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes), studies lake biotopes, and biological limnology (the biology of lakes), studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904), which focuses on the geology physics, chemistry a...

  16. Chemical characteristics and acid sensitivity of boreal headwater lakes in northwest Saskatchewan

    Directory of Open Access Journals (Sweden)

    Jean S. BIRKS

    2010-08-01

    Full Text Available Boreal ecosystems in northwest Saskatchewan may be threatened by acidification as this area is downwind of atmospheric emissions sources from regional oil sands mining operations. To evaluate the status of lakes in this region, a survey of 259 headwater lakes was conducted during 2007–2008 within ~300 km of Fort McMurray, Alberta. Acid sensitivity by ecoregion increased from Mid-Boreal Upland to Churchill River Upland to Athabasca Plain, with 60% of lakes classified as sensitive (50–200 μeq L–1 acid neutralizing capacity (ANC, and 8% as very sensitive (<50 μeq L–1 ANC to acid deposition. Organic anions dominated the acidity balance in most lakes, but non-marine sulphate varied positively with lake elevation and % upland cover (r2 = 0.24. Base cation concentrations (Ca, Mg, K, Na were correlated with % deciduous forest in the catchment area (r2 = 0.33, while dissolved organic carbon (DOC was related most strongly to % bog and lake flushing variables (r2 = 0.53. Variation in runoff coefficients derived by isotope mass balance corresponded with catchment area attributes that proxy controls on evaporation, infiltration and storage, and showed some ecoregional differences. The findings have implications for assignment of runoff values required to calculate critical loads of acidity. Although acidification appears not to be significantly advanced, many dilute oligotrophic lakes with pH 6.0 to pH 6.5 are vulnerable to acid deposition.

  17. The Long Lake Project : the first field integration of SAGD and upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, R.; Birdgeneau, J.; Pratt, B.; Yang, P.; Nieuwenburg, G. [Nexen Inc., Calgary, AB (Canada); Rettger, P.; Arnold, J.; Bronichi, Y. [OPTI Canada Inc. (Canada)

    2002-07-01

    The Long Lake Project announced by OPTI Canada Inc. involves the construction of a bitumen recovery and upgrader facility near Fort McMurray. The project will make use of in situ filed upgrading technology to convert heavy, thick Athabasca bitumen into light, sweet synthetic crude oil for transport via pipeline. The main feature of the integrated upgrader is the patented OrCrude {sup TM} upgrading process that uniquely combines the processes of distillation, solvent deasphalting and thermal cracking in order to partially upgrade bitumen into the OrCrude product and produce an asphaltene by-product which can then be fed to a gasification system to produce hydrogen for the hydrocracker and syngas fuel for the steam assisted gravity drainage (SAGD) process. The project will economically produce high quality synthetic crude that is superior to other synthetics. The capital cost of the project is expected to be comparable to other integrated Athabasca bitumen and upgrading projects. The process has been pilot tested at a demonstration facility near Cold Lake, Alberta. The project, which is currently under regulatory review, is expected to produce 70,000 bpsd of SAGD product and 70,000 bpsd of upgrading product. Construction is planned for late 2003 with first oil in 2006. 1 tab., 9 figs.

  18. SEM/AIA study of size distribution and mineral content of Athabasca oil sand and its coke residues

    International Nuclear Information System (INIS)

    This paper reports on scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray spectrometry that has been used to characterize Athabasca oil sand (AOS) and various coked residues prepared therefrom for mineral phase and size distribution. The composite mineral particles were classified into ten particle size ranges. Increasing coking time caused an increase in the percentage of small particles of quartz and clay. The AOS is relatively rich in sulfur and iron; 6.17% and 0.173%, respectively. The micrographs of AOS show that the majority of the sand grains are not in direct contact with each other and that the bitumen forms a thin layer between the grains. For the coked residues, the sand grains were connected to one another by their coke bridges

  19. Scavenging ratio of polycyclic aromatic compounds in rain and snow at the Athabasca oil sands region

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2014-07-01

    Full Text Available Athabasca oil sands industry in northern Alberta, Canada is a possible source of polycyclic aromatic compounds (PACs. Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs, alkylated PAHs, and dibenzothiophenes, in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during May 2011 to August 2012 were analyzed to generate a database of scavenging (or washout ratios (Wt for PACs scavenged by both snow and rain. Median precipitation and air concentrations of parent PAHs over the May 2011 to August 2012 period ranged from 0.3–184.9 (chrysene ng L−1 and 0.01–3.9 (naphthalene ng m−3, respectively, which were comparable to literature values. Higher concentrations in precipitation and air were observed for alkylated PAHs and dibenzothiophenes. The median precipitation and air concentrations were 11.3–646.7 (C3-fluoranthene/pyrene ng L−1 and 0.21–16.9 (C3-naphthalene ng m−3, respectively, for alkylated PAHs, and 8.5–530.5 (C4-dibenzothiophene ng L−1 and 0.13–6.6 (C2-dibenzothiophene ng m−3 for dibenzothiophenes and their alkylated derivatives. Median Wt over the measurement period were 6100–1.1 × 106 from snow scavenging and 350–2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations. But Wt for acenaphthylene in snow samples was 2–7 times higher. Some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(apyrene, dibenz(a,hanthracene, and benzo(g,h,iperylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14–20 times greater than gas-phase dominant PACs in snow samples and 7–20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging was ∼9 times greater

  20. Lake George

    OpenAIRE

    Mafabi, P.

    2000-01-01

    Uganda ratified the Ramsar Convention in 1988, and designated Lake George a Ramsar site. Located astride the equator, the lake and associated wetlands support a wide variety of biological resources. The reasons for this are varied, ranging from the good climate to shallow stratified waters (average 2.4m) which allow for a thorough mixing of the different layers, and a high alkalinity and photosynthetic activity. The status of Lake George is varied with most of the wetlands fringing the Lak...

  1. Geology and mineralogy of the Key Lake U-Ni deposits, northern Saskatchewan, Canada

    International Nuclear Information System (INIS)

    The Key Lake deposit is located at the southeastern rim of the Athabasca Basin in northern Saskatchewan. The first orebody (the Gartner) was discovered in the summer of 1975, and the second (the Deilmann) one year later. At the present stage of investigation - drilling still continues -the following features are apparent. Both orebodies occur in approximately northeast-southwest-striking fracture zones, which affected the crystalline basement as well as the overlying Athabasca sandstone formation. The country rock comprises, from top to bottom, various deposits of glacial origin, the Athabasca sandstone and metasediments of the Wollaston Fold Belt. The main mineralization consists of uranium oxides and nickel sulphides/arsenides. Rarely, some gangue occurs in the form of quartz and carbonates. Drilling results to date indicate, for the Gartner orebody, a length of 1500 m, a width of 10 to 40 m, a depth of 80 m and a grade of up to 45% U3O8 + 45% Ni; and, for the Deilmann orebody, a minimum length of 800 m, a width of 10 to more than 100 m, a depth of 150 m and contents of up to 20% U3O8 + 25% Ni. The thickness of the glacial overburden varies between 20 and 100 m. Precise reserve calculations are being made, but several difficulties have delayed their completion. The ore is tectonically and lithologically controlled. The presence of geothermometers, as tetragonal α-U3O7 (formation temperature, 1350C) and bravoite (1370C), in association with intergrowth textures of other ore minerals, points to a low-temperature origin. (author)

  2. Using Tree-Rings and Lake Sediments to Infer Historical Water Availability in Jasper National Park, Alberta, Canada

    Science.gov (United States)

    Kenigsberg, M.; O'Reilly, B.; Moser, K.; Luckman, B.

    2009-05-01

    The headwaters of the Athabasca River in Jasper National Park may experience large-scale, persistent droughts that can have significant economic and environmental impacts downstream for the Oil Sands developments and other water stakeholders. Unfortunately, it is impossible to document the full range of natural climate variation or determine the frequency, magnitude or duration of large-scale drought from the few short climate records available for this area. This research will create two independent drought records using a network of 22 annually resolved, precipitation sensitive Douglas fir (Pseudotsuga menziesii) tree-ring chronologies and three 2000-year long high-resolution (one sample per 5-10 years) lake records from the headwaters of the Athabasca River. This paper will present the preliminary results from 7 new tree-ring sites and discuss some of the early limitations in the diatom analyses from the lake sites. It is hoped that this multi- proxy approach to paleo-climate reconstruction will maximize resolution and allow for mutual verification, creating a higher degree of confidence and a more robust picture of natural climate variability than either proxy alone. The resulting reconstructions will document long-term water availability in the headwaters over a 1- 2000 year period for an area where downstream industrial demands for water have drastically increased and where promises of future water allocations have been determined based on a short instrumental record.

  3. Interim report on studies of uranium, thorium, and lead migration at Key Lake, Saskatchewan, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, D.B.; Gancarz, A.J.

    1980-07-01

    The redistribution of uranium, thorium, and lead is being examined in samples representing several million cubic meters of sandstone and metamorphased sediments in the Athabasca Basin which is located in the northwest corner of the Canadian province of Saskatchewan. The region of study includes zones of uranium mineralization at Key Lake. Mineralization occurs at the unconformity between the Athabasca sandstone and the underlying metasediments and in fault zones within the metasediments. Lead isotopes record a radiometric age of 1300 +- 150 m.y. in samples from above and below the unconformity. This age probably reflects the time of deposition of the sandstones and an associated redistribution of uranium and/or lead in the underlying rocks. Many of the samples have been fractionated with respect to radiogenic lead and the actinide parent elements since that time. Sandstones and altered rocks from the region above the unconformity have been a transport path and are a repository for lead. In contrast, mineralized rocks are deficient in radiogenic lead and must be an important source of lead in the local geologic environment. However, the isotopic composition of lead missing from the ores is different from that found in the overlying sandstones. The two types of rocks do not appear to represent complements with respect to a source and a repository for lead.

  4. Playa Lakes

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital dataset provides information about the spatial distribution of soil units associated with playa lakes. Specific soil types have been designated by the...

  5. Lake Ponkapog

    Institute of Scientific and Technical Information of China (English)

    蓝洋

    2002-01-01

    @@ Thirty years ago,Lake Ponkapog in Hartwell,New Jersey,was full of life.Many birds and animals rived beside the water,which was frill of fish.Now there are few birds.animals and fish.The lake water is polluted(污染的).It is in a colour of dirty brown,and it is filled with strange plants.

  6. Compromised metamorphosis and thyroid hormone changes in wood frogs (Lithobates sylvaticus) raised on reclaimed wetlands on the Athabasca oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Hersikorn, Blair D., E-mail: blair.hersikorn@usask.c [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, Saskatchewan, S7N 5B3 (Canada); Smits, Judit E.G., E-mail: judit.smits@ucalgary.c [Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6 (Canada)

    2011-02-15

    The wet landscape approach to oil sands tailings reclamation in the Athabasca Oil Sands region involves creating wetlands from fluid tailings in mined-out pits. We measured time to metamorphosis, thyroid hormone status, and detoxification enzyme (EROD) induction in Wood frog (Lithobates sylvaticus) tadpoles raised on reclaimed oil sands wetlands of different ages [young ({<=}7 yr) vs. old (>7 yr)] and compared data with tadpoles raised on reference (control) wetlands. Metamorphosis was delayed or never occurred in tadpoles raised in young tailings; those exposed to older tailings developed similarly to those in reference wetlands. Thyroid hormone disruption likely played an important role in the metamorphosis delay as the T3:T4 ratio was lowest in tadpoles raised in young, tailings-affected wetlands. Our findings suggest tailings wetlands become less toxic with age, and that these amphibians will be able to complete their life cycle in tailing wetlands that have sufficiently detoxified with age. - This work provides guidance for reclamation of oil sands tailings and shows the usefulness of frogs and caging studies in environmental toxicology.

  7. Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region.

    Science.gov (United States)

    Zhang, Yifeng; Shotyk, William; Zaccone, Claudio; Noernberg, Tommy; Pelletier, Rick; Bicalho, Beatriz; Froese, Duane G; Davies, Lauren; Martin, Jonathan W

    2016-02-16

    Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks. PMID:26771587

  8. Athabasca oil sands process water: characterization by atmospheric pressure photoionization and electrospray ionization fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Barrow, Mark P; Witt, Matthias; Headley, John V; Peru, Kerry M

    2010-05-01

    The Athabasca oil sands in Canada are a less conventional source of oil which have seen rapid development. There are concerns about the environmental impact, with particular respect to components in oil sands process water which may enter the aquatic ecosystem. Naphthenic acids have been previously targeted for study, due to their implications in toxicity toward aquatic wildlife, but it is believed that other components, too, contribute toward the potential toxicity of the oil sands process water. When mass spectrometry is used, it is necessary to use instrumentation with a high resolving power and mass accuracy when studying complex mixtures, but the technique has previously been hindered by the range of compounds that have been accessible via common ionization techniques, such as electrospray ionization. The research described here applied Fourier transform ion cyclotron resonance mass spectrometry in conjunction with electrospray ionization and atmospheric pressure photoionization, in both positive-ion and negative-ion modes, to the characterization of oil sands process water for the first time. The results highlight the need for broader characterization when investigating toxic components within oil sands process water. PMID:20359201

  9. Indicators of early successional trends in environmental condition and community function in constructed wetlands of the Athabasca Oilsands region

    International Nuclear Information System (INIS)

    This presentation reported on a study that compared interannual environmental variation in post-mining Athabasca oil sands landscapes. In particular, it compared biological, ecotoxicological and carbon dynamic aspects of sixteen 5 to 30 year old wetlands with different ages, reclamation materials and stockpiled surface materials such as peat. In addition to determining carbon fluxes, standing stocks of hydrocarbons were measured along with organic substrate, bacterioplankton, phytoplankton, biofilm, macrophytes, litter, zoobenthos, and aquatic insect emergence. Gas fluxes, microbial, plant, zoobenthic, amphibian, and tree swallow nestling production, and stable isotope signatures were used to determine carbon pathways, fluxes and budgets. Coarse taxon richness in reference wetlands reached an asymptote in 5 to 7 years. Richness, composition and emergent plant cover of oilsands-affected wetlands converged over a 15 to 20 year period with reference wetland patterns. The development of emergent but not submergent plant cover and associated biota accelerated with the addition of peat. Water chemistry was found to be more important than sediment in terms of regulating submergent biological properties. The study showed that the most important regulator of community composition may be residual salinity. Compared to more temperate biomes, the successional trends were slower.

  10. Compromised metamorphosis and thyroid hormone changes in wood frogs (Lithobates sylvaticus) raised on reclaimed wetlands on the Athabasca oil sands

    International Nuclear Information System (INIS)

    The wet landscape approach to oil sands tailings reclamation in the Athabasca Oil Sands region involves creating wetlands from fluid tailings in mined-out pits. We measured time to metamorphosis, thyroid hormone status, and detoxification enzyme (EROD) induction in Wood frog (Lithobates sylvaticus) tadpoles raised on reclaimed oil sands wetlands of different ages [young (≤7 yr) vs. old (>7 yr)] and compared data with tadpoles raised on reference (control) wetlands. Metamorphosis was delayed or never occurred in tadpoles raised in young tailings; those exposed to older tailings developed similarly to those in reference wetlands. Thyroid hormone disruption likely played an important role in the metamorphosis delay as the T3:T4 ratio was lowest in tadpoles raised in young, tailings-affected wetlands. Our findings suggest tailings wetlands become less toxic with age, and that these amphibians will be able to complete their life cycle in tailing wetlands that have sufficiently detoxified with age. - This work provides guidance for reclamation of oil sands tailings and shows the usefulness of frogs and caging studies in environmental toxicology.

  11. Indicators of early successional trends in environmental condition and community function in constructed wetlands of the Athabasca Oilsands region

    Energy Technology Data Exchange (ETDEWEB)

    Ciborowski, J.; Kovalenko, K. [Windsor Univ., ON (Canada); Dixon, G.; Farwell, A. [Waterloo Univ., ON (Canada); Foote, L.; Mollard, F.; Roy, M. [Alberta Univ., Edmonton, AB (Canada); Smits, J.; Turcotte, D. [Saskatchewan Univ., Saskatoon, SK (Canada)

    2010-07-01

    This presentation reported on a study that compared interannual environmental variation in post-mining Athabasca oil sands landscapes. In particular, it compared biological, ecotoxicological and carbon dynamic aspects of sixteen 5 to 30 year old wetlands with different ages, reclamation materials and stockpiled surface materials such as peat. In addition to determining carbon fluxes, standing stocks of hydrocarbons were measured along with organic substrate, bacterioplankton, phytoplankton, biofilm, macrophytes, litter, zoobenthos, and aquatic insect emergence. Gas fluxes, microbial, plant, zoobenthic, amphibian, and tree swallow nestling production, and stable isotope signatures were used to determine carbon pathways, fluxes and budgets. Coarse taxon richness in reference wetlands reached an asymptote in 5 to 7 years. Richness, composition and emergent plant cover of oilsands-affected wetlands converged over a 15 to 20 year period with reference wetland patterns. The development of emergent but not submergent plant cover and associated biota accelerated with the addition of peat. Water chemistry was found to be more important than sediment in terms of regulating submergent biological properties. The study showed that the most important regulator of community composition may be residual salinity. Compared to more temperate biomes, the successional trends were slower.

  12. Native bitumens in surficial soils of the Athabasca oil sands region : preliminary characterization and assessment of contaminant mobility

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, M.; Fleming, I. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Civil and Geological Engineering; Headley, J. [Environment Canada, Saskatoon, SK (Canada). National Hydrology Research Centre

    2009-07-01

    A study was conducted on bitumen tarballs located in surficial soils in Alberta's Athabasca region. The tarballs occur in every soil type in the region, and pose a challenge to oil sands operators who hope to use the soils for reclamation activities. Chromatographic analyses have shown that the tarballs contain variable petroleum hydrocarbon concentrations and possess a characteristic chromatographic footprint. The Canadian Council of Ministers of the Environment has characterized the hydrocarbons according to various fractions. A soil-column leaching study is also being conducted by the University of Saskatchewan on heavily-impacted tarball soil under unsaturated conditions. Results of the study have indicated that the soil has low levels of contaminant mobility and degradation. Hydrocarbon concentrations in leachate water are less than 20 per cent of ground water guidelines for Alberta. It was concluded that after respiration over 9 months, the most active soil column in the study degraded only 2.7 g of an estimated 650 g.

  13. Exploring the biodegradation and toxicity of naphthenic acids present in Athabasca oil sands process affected waters using simulated wetlands

    International Nuclear Information System (INIS)

    Naphthenic acids (NAs) are a persistent group of dissolved organic acids found in oil sands process affected water (OSPW) from the Athabasca Oil Sands (AOS) in northern Alberta. This study investigated the feasibility of reducing the toxicity of OSPW in wetland environments, and proposed a strategy for reclamation at the AOS. Laboratory microcosms were used to mimic natural wetlands. The purpose was to determine if the toxicities of OSPWs generated by Syncrude Canada Ltd. (Syncrude) and Suncor Energy Inc. (Suncor) change with time as a result of aging and biodegradation. Experiments involved 2 types of OSPW obtained from Syncrude and Suncor. Nutrient availability (nitrogen and phosphorus enrichment) was increased for both short and long hydraulic retention times (40 and 400 days). The NAs found in the OSPW were tracked over the course of one year using Fourier Transform Infrared Spectroscopy, Gas Chromatography/Mass Spectrometry and Microtox bioassays. The objective was to determine the relationships between total NA concentrations, the degree to which different sub-groups of NAs are biodegraded and any potential reduction in OSPW toxicity

  14. Water balance and nutrient status in a reclamation research trial in the Athabasca oil sands region, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Tan, X.; Dubyk, C.; Kuzmic, F.; Martindale, D. [Shell Canada Energy, Fort McMurray, AB (Canada). Albian Sands Project

    2010-07-01

    This paper discussed a reclamation research trial undertaken in the Athabasca oils sands region to examine water balance and nutrient status in reclamation materials constructed on a northeast-facing slope. The soil covers comprise a peat-mineral mixture overlying clean tailings sand on top of a compacted base of lean soil. Water balance in terms of water runoff, interflow, water storage and evapotranspiration was evaluated by placing field instruments along the slope. For chemistry analyses, runoff and interflow water samples, rainfall, and in-situ water were collected during the growing season. A trend shown in the 5-year data was a decrease in interflow volumes since the start of monitoring. The water balance showed that roughly one-third of the precipitation was lost to runoff. The soil moisture condition remains well above the permanent wilting point during the non-frozen period. In general, the nutrients available in the reclamation system were low. As the vegetation on the slope develops further, the water status and the nutrient status will continue to be monitored. Shifts in the contribution of the different components of water balance are expected as nutrients become more available for plants to uptake.

  15. Lake Victoria: the Changing Lake.

    OpenAIRE

    Mwirigi, P.; Rutagemwa, D.; Gikuma-Njuru, P.; Njuguna, H.; Matovu, A.; Waya, R.; Mwebaza-Ndawula, L.; Ssenfuma-Nsubuga, M.; Kinobe, J.; Abuodha, J.; Hecky, R

    2005-01-01

    Water quality monitoring activities were carried out on physical-chemical parameters, water chemistry and biotic indices at selected littoral and pelagic stations along north-south and east-west transects over an annual cycle between 2000 and 2005. The activities were aimed at collecting baseline information and data for use to define the current lake conditions and make a water quality assessment of the lake in relation to nutrient/ pollutant loadings as a basis for future monitoring surveys...

  16. Technical support document for the regional sustainable development strategy for the Athabasca Oil Sands Area

    International Nuclear Information System (INIS)

    The Regional Sustainable Development Strategy (RSDS) builds on the current environmental and resource management system in Alberta, and it features a framework for: providing support for continued economic development in the region that addresses environmental needs and resource sustainability; creating an enhanced management framework that will adapt to the changing needs of the area which will guide government environmental and resource managers; developing a strong foundation of environmental information and science to assist in making decisions on sustainable resource and environmental management in the region; and creating a way to identify priority regional environmental issues and to organize the science and monitoring work needed to comprehend those issues. Blueprints for action were identified to attack issues within three group categories. The first category, which is based on information gaps and urgency, includes sustainable ecosystems, cumulative impacts on wildlife, soil and plant species diversity, effects of air emissions on human health, wildlife and vegetation, and bioaccumulation of heavy metals. The second category, which is based on information gaps and work underway, includes access management, cumulative impacts on fish habitat and populations, effects of tailings ponds emissions, effects of acid deposition on sensitive receptors, and impacts on surface water quality. The third category, which is based on information gaps, work underway and lower level of urgency, includes end pit lake water quality, impacts on surface water quantity, and impacts on groundwater quantity and quality

  17. Cameco Corporation - The Key Lake uranium mill. Current status and vision for the future

    International Nuclear Information System (INIS)

    The Key Lake mill located approximately 570 km north of Saskatoon, Saskatchewan, Canada and is currently the world's largest primary producer of uranium producing 8. 106 kg U3O8 annually. The feed to the Key Lake mill currently originates from the McArthur River mine, an underground mine located approximately 80 kilometers north of the Key Lake mill. The McArthur River mine, located within the Athabasca Basin, is the world's largest high-grade uranium deposit with proven and probable reserve, as of 31 December 2003 of 190 million kg U3O8. Approximately 700 people are employed at Key Lake and McArthur River of which 57% of the workforce are residents of Saskatchewan's north. The mine site and mill are remote and employees commute via air travel to and from the sites from Saskatoon, Saskatchewan as well as communities throughout northern Saskatchewan. Employees work a 7-day in/7-day out work rotation and reside in permanent camps during the work week at the mine and mill. (author)

  18. Natural radiation-induced damage in quartz. III. A new ozonide radical in drusy quartz from the Athabasca Basin, Saskatchewan

    International Nuclear Information System (INIS)

    Quartz crystals collected in druses, including one annealed at 400oC, from a fracture in the hanging-wall sandstone at the McArthur River uranium deposit in the Paleoproterozoic Athabasca basin, northern Saskatchewan, have been investigated by single-crystal X-band electron paramagnetic resonance (EPR) spectroscopy at room temperature and 110 K. The single-crystal EPR spectra allow us to distinguish eight paramagnetic defects, including one new center and seven previously reported centers. These centers, most of which were discovered in artificially irradiated crystals and only a few had been suggested to occur in natural quartz by powder EPR, are herewith positively established for the first time as natural radiation-induced defects by single-crystal EPR. The new center is similar in principal g-factor values to the ozonide radical (O3-) in various minerals and synthetic compounds, and is characterized by its g-maximum and g-minimum axes approximately parallel to two O-O edges of the SiO4 quasi-tetrahedron in the quartz structure. This geometry is also compatible with an ozonide radical formed from a silicon vacancy. The observed linewidths of the new ozonide radical vary from 0.087 to 0.257 mT, which are attributed to unresolved site-splittings or unresolved hyperfine splittings. This new ozonide radical is distinct from a previously reported ozonide radical in citrine quartz, which is characterized by the presence of a small 27Al hyperfine structure. The new ozonide radical is probably linked to a Si atom in the neighboring tetrahedron and hence represents a general case in quartz, whereas the previously reported ozonide radical linked to a neighboring Al atom is a special variant in Al-bearing quartz. The presence of natural radiation-induced defects in drusy quartz is attributable to the presence of uranium in mineralized assemblages nearby or late hydrothermal fluids. (author)

  19. Natural radiation-induced damage in quartz. III. A new ozonide radical in drusy quartz from the Athabasca Basin, Saskatchewan

    Energy Technology Data Exchange (ETDEWEB)

    Botis, S.M.; Pan, Y.; Nokhrin, S. [Univ. of Saskatchwan, Dept. of Geological Sciences, Saskatoon, Saskatchewan (Canada); Nilges, M.J. [Univ. of Illinois at Urbana-Champaign, Illinois EPR Research Center, Urbana, Illinois (United States)

    2008-02-15

    Quartz crystals collected in druses, including one annealed at 400{sup o}C, from a fracture in the hanging-wall sandstone at the McArthur River uranium deposit in the Paleoproterozoic Athabasca basin, northern Saskatchewan, have been investigated by single-crystal X-band electron paramagnetic resonance (EPR) spectroscopy at room temperature and 110 K. The single-crystal EPR spectra allow us to distinguish eight paramagnetic defects, including one new center and seven previously reported centers. These centers, most of which were discovered in artificially irradiated crystals and only a few had been suggested to occur in natural quartz by powder EPR, are herewith positively established for the first time as natural radiation-induced defects by single-crystal EPR. The new center is similar in principal g-factor values to the ozonide radical (O{sub 3}{sup -}) in various minerals and synthetic compounds, and is characterized by its g-maximum and g-minimum axes approximately parallel to two O-O edges of the SiO{sub 4} quasi-tetrahedron in the quartz structure. This geometry is also compatible with an ozonide radical formed from a silicon vacancy. The observed linewidths of the new ozonide radical vary from 0.087 to 0.257 mT, which are attributed to unresolved site-splittings or unresolved hyperfine splittings. This new ozonide radical is distinct from a previously reported ozonide radical in citrine quartz, which is characterized by the presence of a small {sup 27}Al hyperfine structure. The new ozonide radical is probably linked to a Si atom in the neighboring tetrahedron and hence represents a general case in quartz, whereas the previously reported ozonide radical linked to a neighboring Al atom is a special variant in Al-bearing quartz. The presence of natural radiation-induced defects in drusy quartz is attributable to the presence of uranium in mineralized assemblages nearby or late hydrothermal fluids. (author)

  20. Nitrogen and sulphur deposition and the growth of Sphagnum fuscum in bogs of the Athabasca Oil Sands Region, Alberta

    Directory of Open Access Journals (Sweden)

    Melanie A. VILE

    2010-08-01

    Full Text Available One of the consequences of ongoing development of the oil sands reserve in the Athabasca Oil Sands Region (AOSR near Fort McMurray, Alberta, Canada (56° 39' N, 111° 13' W is an increase in emissions of nitrogen (N and sulphur (S, with an attendant increases in regional atmospheric N and S deposition. Regional land cover across northeastern Alberta is a mixture of Boreal Mixedwood, Boreal Highlands, and Subarctic areas. Peatlands occupy between 22 and 66% of these natural regions, and the land cover of bogs varies between 6.7% in the Mixedwood Region to 46% in the Subarctic Region. Ombrotrophic bog ecosystems may be especially sensitive to atmospheric deposition of N and S. Across 10 ombrotrophic bog sites in the AOSR over four years (2005– 2008, we found no evidence of elevated deposition of NH4 +-N, NO3 –-N, total inorganic nitrogen (TIN; NH4 +-N plus NO3 –-N, or SO4 2–-S, with values measured using ion exchange resin collectors averaging 0.61 ± 04, 0.20 ± 0.01, 0.81 ± 0.04, and 1.14 ± 0.06 kg ha–1 y–1, respectively. Vertical growth and net primary production of Sphagnum fuscum, an indicator of elevated deposition, did not differ consistently across sites, averaging 11.8 ± 0.2 mm y–1 and 234 ± 3.3 g m–2 y–1, respectively, over the four years. Neither vertical growth nor net primary production of S. fuscum was correlated with growing season atmospheric N or S deposition. Our data provide a valuable benchmark of background values for monitoring purposes in anticipation of increasing N and S deposition over a broader geographic region within the AOSR.

  1. Multicomponent seismic reservoir characterization of a steam-assisted gravity drainage (SAGD) heavy oil project, Athabasca oil sands, Alberta

    Science.gov (United States)

    Schiltz, Kelsey Kristine

    Steam-assisted gravity drainage (SAGD) is an in situ heavy oil recovery method involving the injection of steam in horizontal wells. Time-lapse seismic analysis over a SAGD project in the Athabasca oil sands deposit of Alberta reveals that the SAGD steam chamber has not developed uniformly. Core data confirm the presence of low permeability shale bodies within the reservoir. These shales can act as barriers and baffles to steam and limit production by prohibiting steam from accessing the full extent of the reservoir. Seismic data can be used to identify these shale breaks prior to siting new SAGD well pairs in order to optimize field development. To identify shale breaks in the study area, three types of seismic inversion and a probabilistic neural network prediction were performed. The predictive value of each result was evaluated by comparing the position of interpreted shales with the boundaries of the steam chamber determined through time-lapse analysis. The P-impedance result from post-stack inversion did not contain enough detail to be able to predict the vertical boundaries of the steam chamber but did show some predictive value in a spatial sense. P-impedance from pre-stack inversion exhibited some meaningful correlations with the steam chamber but was misleading in many crucial areas, particularly the lower reservoir. Density estimated through the application of a probabilistic neural network (PNN) trained using both PP and PS attributes identified shales most accurately. The interpreted shales from this result exhibit a strong relationship with the boundaries of the steam chamber, leading to the conclusion that the PNN method can be used to make predictions about steam chamber growth. In this study, reservoir characterization incorporating multicomponent seismic data demonstrated a high predictive value and could be useful in evaluating future well placement.

  2. Dissolved organic carbon in a constructed and natural fens in the Athabasca oil sands region, Alberta, Canada.

    Science.gov (United States)

    Khadka, Bhupesh; Munir, Tariq M; Strack, Maria

    2016-07-01

    In the Athabasca oil sands region near Fort McMurray, Alberta, Canada, peatlands are disturbed extensively in order to recover bitumen below the surface. Hence, following oil sands mining, landscape reclamation is a part of the mine closure process in order to return functioning ecosystems, including peatlands, to the region. This study was conducted at a pilot fen reclamation project and three other diverse natural (poor, rich and saline) fens in the oil sands region during the growing seasons of 2013 and 2014, the first and second year post-construction. Ecosystem functioning of the constructed fen (CF) was evaluated with reference to natural fens based on pore water dissolved organic carbon (DOC) concentration and chemistry. Significant variation of DOC concentration among the reference fens was observed, varying from an average of 42.0mg/L at the rich fen (RF) to 70.8mg/L at the saline fen (SF). Dissolved organic carbon concentration at CF was significantly lower than at all reference fens, but increased significantly over the first two years. Seasonal variation of DOC concentration was also observed in each site with concentration increasing over the growing season. At CF, DOC was comprised of larger, more humic and complex aromatic compounds than reference fens in the first year post-construction based on its spectrophotometric properties; however, these differences were reduced in the second year. Initial DOC concentration and chemistry at CF was indicative of the source being largely the peat placed during fen construction. Changes in chemistry and increasing concentration of DOC in the second growing season likely resulted from increasing inputs from plants established on site. These results suggest that DOC concentration is likely to increase in future at CF as vascular plant productivity increases and in response to salinity sourced from tailing sand used to construct the catchment. PMID:27037879

  3. Total and methyl mercury concentrations in sediment and water of a constructed wetland in the Athabasca Oil Sands Region.

    Science.gov (United States)

    Oswald, Claire J; Carey, Sean K

    2016-06-01

    In the Athabasca Oil Sands Region in northeastern Alberta, Canada, oil sands operators are testing the feasibility of peatland construction on the post-mining landscape. In 2009, Syncrude Canada Ltd. began construction of the 52 ha Sandhill Fen pilot watershed, including a 15 ha, hydrologically managed fen peatland built on sand-capped soft oil sands tailings. An integral component of fen reclamation is post-construction monitoring of water quality, including salinity, fluvial carbon, and priority pollutant elements. In this study, the effects of fen reclamation and elevated sulfate levels on mercury (Hg) fate and transport in the constructed system were assessed. Total mercury (THg) and methylmercury (MeHg) concentrations in the fen sediment were lower than in two nearby natural fens, which may be due to the higher mineral content of the Sandhill Fen peat mix and/or a loss of Hg through evasion during the peat harvesting, stockpiling and placement processes. Porewater MeHg concentrations in the Sandhill Fen typically did not exceed 1.0 ng L(-1). The low MeHg concentrations may be a result of elevated porewater sulfate concentrations (mean 346 mg L(-1)) and an increase in sulphide concentrations with depth in the peat, which are known to suppress MeHg production. Total Hg and MeHg concentrations increased during a controlled mid-summer flooding event where the water table rose above the ground surface in most of the fen. The Hg dynamics during this event showed that hydrologic fluctuations in this system exacerbate the release of THg and MeHg downstream. In addition, the elevated SO4(2-) concentrations in the peat porewaters may become a problem with respect to downstream MeHg production once the fen is hydrologically connected to a larger wetland network that is currently being constructed. PMID:27017139

  4. Carbon dynamics, food web structure and reclamation strategies in Athabasca oil sands wetlands (CFRAW) : overview and progress

    International Nuclear Information System (INIS)

    Seven oil sand mining partners and 5 university labs have joined forces to study the effects of mine tailings and process waters on development, health and function of wetland communities formed in post-mining landscapes. The collaborative effort, know as the carbon dynamics, food web structure and reclamation strategies in Athabasca oil sands wetlands (CRFAW), aims to identify the materials and strategies most effective and economical in producing a functioning reclamation landscape. This presentation reported on part of the study that tested predictions about how quickly wetlands amended with reclamation materials approach the conditions of reference wetland systems. It provided a conceptual model of carbon pathways and budgets to assess how the allocation of carbon among compartments changes as newly formed wetlands mature in the boreal system. It was assumed that stockpiling constructed wetlands with peat or topsoil would accelerate succession and community development. Although the bitumen and the naphthenic acids found in constructed wetlands are initially toxic, they may serve as an alternate source of carbon once they degrade. This study also assessed the sources, biological uptake, pathways, and movement through the food web of materials used by the biota in constructed wetlands. Additional studies are examining how the productivity of new wetlands is maintained. Net ecosystem productivity is being monitored along with rates of organic carbon accumulation from microbial, algal, and macrophyte production, and influx of outside materials. The rates of leaf litter breakdown and microbial respiration are being compared to determine how constituents speed or slow food web processes of young and older wetlands. Carbon and nitrogen isotope values in food web compartments indicate which sources are incorporated into the food web as wetlands age. The values are used to determine how this influences community development, food web structure and complexity, and the

  5. Carbon dynamics, food web structure and reclamation strategies in Athabasca oil sands wetlands (CFRAW) : overview and progress

    Energy Technology Data Exchange (ETDEWEB)

    Ciborowski, J. [Windsor Univ., Windsor, ON (Canada); Dixon, D.G. [Waterloo Univ., Waterloo, ON (Canada); Foote, L. [Alberta Univ., Edmonton, AB (Canada); Liber, K.; Smits, J.E. [Saskatchewan Univ., Saskatoon, SK (Canada)

    2009-07-01

    Seven oil sand mining partners and 5 university labs have joined forces to study the effects of mine tailings and process waters on development, health and function of wetland communities formed in post-mining landscapes. The collaborative effort, know as the carbon dynamics, food web structure and reclamation strategies in Athabasca oil sands wetlands (CRFAW), aims to identify the materials and strategies most effective and economical in producing a functioning reclamation landscape. This presentation reported on part of the study that tested predictions about how quickly wetlands amended with reclamation materials approach the conditions of reference wetland systems. It provided a conceptual model of carbon pathways and budgets to assess how the allocation of carbon among compartments changes as newly formed wetlands mature in the boreal system. It was assumed that stockpiling constructed wetlands with peat or topsoil would accelerate succession and community development. Although the bitumen and the naphthenic acids found in constructed wetlands are initially toxic, they may serve as an alternate source of carbon once they degrade. This study also assessed the sources, biological uptake, pathways, and movement through the food web of materials used by the biota in constructed wetlands. Additional studies are examining how the productivity of new wetlands is maintained. Net ecosystem productivity is being monitored along with rates of organic carbon accumulation from microbial, algal, and macrophyte production, and influx of outside materials. The rates of leaf litter breakdown and microbial respiration are being compared to determine how constituents speed or slow food web processes of young and older wetlands. Carbon and nitrogen isotope values in food web compartments indicate which sources are incorporated into the food web as wetlands age. The values are used to determine how this influences community development, food web structure and complexity, and the

  6. Spatial and temporal distribution of ambient nitric acid and ammonia in the Athabasca Oil Sands Region, Alberta

    Directory of Open Access Journals (Sweden)

    Diane ALEXANDER

    2010-08-01

    Full Text Available Monthly average ambient concentrations of gaseous nitric acid (HNO3 and ammonia (NH3 were monitored at the Athabasca Oils Sands Region (AOSR, Alberta, Canada, between May 2005 and September 2008. Generally, concentrations of both pollutants were elevated and highly variable in space and time. The highest atmospheric concentrations occurred in the vicinity of the major mining and oil extraction activities of Fort Murray and Fort McKay. Maximum monthly average concentrations of HNO3 decreased from >6 μg m–3 2005 and 2006 to <4 μg m–3 in 2007 and 2008. While the HNO3 summer seasonal averages in 2005 and 2006 approached ~2 μg m–3 at some sites, in the subsequent summers and during winter seasons it rarely exceeded 1 μg m–3 and no clear differences between summer and winter occurred. Concentrations of NH3 were elevated during the entire study and frequently reached 6 μg m–3. Generally, NH3 stayed higher in summer than in winter; the summer seasonal averages often exceeded 4 μg m–3 while those for winter only on two occasions were above 3 μg m–3. In summer 2008, an expansion of the area with elevated NH3 levels was observed extending to remote locations. Ammonia is of a much higher concern from a perspective of possible biological effects, because of its potential for direct toxic effect on lichens and its contribution to the elevated N dry deposition with possible negative consequences for forests and other ecosystems.

  7. Koontz Lake

    OpenAIRE

    Zebell, Dennis A; Medors, Sky K; Delgado, Dan G

    2013-01-01

    A case study of the SR 23 replacement at the Koontz Lake Dam will be presented. The dam replacement, road re-alignment, and labyrinth spillway will be discussed. The design criteria and processes associated with each of those items will be discussed as well as the coordination with and expectations of the multiple owners involved with the project.

  8. The recovering Dian Lake

    OpenAIRE

    Ai, Chi-Han

    2013-01-01

    Dian Lake, also known as Kunming Lake, is the largest freshwater lake in Yunnan Province. However, the value of tourism isn't a perpetual blessing for Dian Lake. Since 1980, due to the rapid urbanization in China, water pollution in Dian Lake has worsened year by year.

  9. Application of solid state silicon-29 and carbon-13 nuclear magnetic resonance spectroscopy to the characterization of inorganic matter-humic complexes in Athabasca oil sands

    International Nuclear Information System (INIS)

    In Athabasca oil sands there is a fraction of non-crystalline solids tightly bound to humic matter. It is believed, that the presence of this fraction, which resists subsequent wetting by water, introduces serious problems in bitumen recovery when using water based processes. In the present work, 29Si and 13C solid state magic angle spinning (MAS) NMR techniques were applied to characterize these solids which were isolated from Athabasca oil sands of estuarine and marine origin. On the basis of 29Si results it is suggested that there is a short-range disorder in these samples. It is also shown that aluminum is present in the nearest-neighbor environment of the silicon atoms, thus demonstrating that these solids are comprised of disordered alumino-silicates (allophanes). 13C CP/MAS NMR spectra of demineralized inorganic matter-humic complexes derived from both estuarine and marine oil sands indicate that the distribution of carbon types in each region of the spectra is similar, with aromatic carbon being the predominant type of carbon

  10. Bathymetry of Lake Ontario

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Ontario has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  11. Designated Wildlife Lakes - points

    Data.gov (United States)

    Minnesota Department of Natural Resources — This is a point shapefile of Designated Wildlife Lakes in Minnesota. This shapefile was created by converting lake polygons from the Designated Wildlife Lakes...

  12. Bathymetry of Lake Michigan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Michigan has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  13. Bathymetry of Lake Huron

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  14. Hydrography - Lakes Assessments - Attaining

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...

  15. Bathymetry of Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Superior has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  16. Great Lakes Bathymetry

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lakes Michigan, Erie, Saint Clair, Ontario and Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological...

  17. Geochemical element mobility during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin (Saskatchewan, Canada)

    International Nuclear Information System (INIS)

    In order to understand the mechanisms of migration and deposition of ore elements, it is essential to determine the timing, source, and destination of the geochemical element mass transfers and/or transportation on a scale encompassing the great sedimentary basins. The purpose of this study is to trace and to date the element migrations that occurred during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin, which hosts the world's largest and richest uranium deposits. As this geological environment was proved to be efficient to preserve high grade ore deposits for over more than one billion years, it provides an opportunity to study some natural analogues of deep geological nuclear waste storage. Five research topics were studied: 3D modelling of the distribution of normative minerals and trace elements on a basin-wide scale; U-Pb and Rb-Sr systematics; average chemical age estimation; thermodynamic modelling of the major mineralogical assemblages; U-Pb geochronology of uranium oxides. Some elements have remained immobile (Zr) since their initial sedimentary deposition, or were transferred from one phase to another (Al, Th). Other elements have been transported during fluid flow events that occurred: (1) on a basin wide scale during diagenesis (REE, Y, Sr, Fe), (2) at the unconformity and in the vicinity of the fault zones that represent preferential fluid flow pathways between the basement and the sandstone cover (U, Ni, As, B, Mg, K, Fe, Sr, REE), (3) during the late fault reactivation events associated with the basin uplift (U, Pb, Ni, S, Sr, REE). The successive tectonic events related to the geodynamical context that lead to the formation of these high-grade U concentrations (1460 Ma, 1335 Ma and 1275 Ma in the McArthur River deposit), did not however systematically occur in the whole basin (1275 Ma only at Shea Creek). The exceptionally high grade and tonnages of some deposits seem to be related to a larger number of U

  18. U-Pb isotope systematics and compared evolution of uraniferous mineralizations in the Athabasca basin (Saskatchewan, Canada): Case of deposits from the Carswell and Cigar Lake structure

    International Nuclear Information System (INIS)

    The aim of the study is to obtain geochronologic data on the formation of mineralizations, to define main processes for uranium remobilization and to replace these data in proposed model for deposit genesis and evolution

  19. Oil sands development and its impact on atmospheric wet deposition of air pollutants to the Athabasca Oil Sands Region, Alberta, Canada.

    Science.gov (United States)

    Lynam, Mary M; Dvonch, J Timothy; Barres, James A; Morishita, Masako; Legge, Allan; Percy, Kevin

    2015-11-01

    Characterization of air pollutant deposition resulting from Athabasca oil sands development is necessary to assess risk to humans and the environment. To investigate this we collected event-based wet deposition during a pilot study in 2010-2012 at the AMS 6 site 30 km from the nearest upgrading facility in Fort McMurray, AB, Canada. Sulfate, nitrate and ammonium deposition was (kg/ha) 1.96, 1.60 and 1.03, respectively. Trace element pollutant deposition ranged from 2 × 10(-5) - 0.79 and exhibited the trend Hg oil sands development, urban activities and forest fires were deposited. High deposition of the elements Sr, Mn, Fe and Mg which are tracers for soil and crustal dust implies land-clearing, mining and hauling emissions greatly impacted surrounding human settlements and ecosystems. PMID:26277649

  20. A multi-isotope approach for estimating industrial contributions to atmospheric nitrogen deposition in the Athabasca oil sands region in Alberta, Canada

    International Nuclear Information System (INIS)

    Industrial nitrogen (N) emissions in the Athabasca oil sands region (AOSR), Alberta, Canada, affect nitrate (NO3) and ammonium (NH4) deposition rates in close vicinity of industrial emitters. NO3–N and NH4–N open field and throughfall deposition rates were determined at various sites between 3 km and 113 km distance to the main oil sand operations between May 2008 and May 2009. NO3 and NH4 were analyzed for δ15N–NO3, δ18O–NO3, Δ17O–NO3 and δ15N–NH4. Marked differences in the δ18O and Δ17O values between industrial emissions and background deposition allowed for the estimation of minimum industrial contributions to atmospheric NO3 deposition. δ15N–NH4 values also allowed for estimates of industrial contributions to atmospheric NH4 deposition. Results revealed that particularly sites within ∼30 km radius from the main oil sands developments are significantly affected by industrial contributions to atmospheric NO3 and NH4 deposition. -- Highlights: •Atmospheric NO3 and NH4 deposition rates are elevated near industrial emitters. •δ18O and Δ17O values of NO3 at high N deposition sites are isotopically distinct. •Industrial contributions to NO3 deposition are estimated using δ18O and Δ17O values. •Elevated δ15N values of NO3 and NH4 deposition indicate industrial contributions. -- Distinct δ18O, Δ17O, and δ15N values were used to estimate industrially derived N contributions to atmospheric nitrate and ammonium deposition in the Athabasca oil sands region

  1. Longevity of Lake Superior lake trout

    Science.gov (United States)

    Schram, Stephen T.; Fabrizio, Mary C.

    1998-01-01

    The age structure of mature lake trout Salvelinus namaycush from the Wisconsin waters of Lake Superior increased following a population recovery that has taken place since the 1960s. As the population aged, it became apparent that scales were unreliable aging structures. Beginning in 1986, we examined both scale and sagittal otolith ages from tagged fish with a known period at liberty. We found large discrepancies in scale and sagittal otolith ages of mature fish, such that scale ages were biased low. We estimated lake trout living up to 42 years, which is greater than previously reported from Lake Superior. Investigators studying lake trout population dynamics in the Great Lakes should be aware that lake trout can live longer than previously thought.

  2. Reverse Flow in a Northern Freshwater Lake-Delta-Wetland Ecosystem

    Science.gov (United States)

    Peters, D. L.; Prowse, T. D.

    2004-05-01

    A distinctive hydrological attribute of the Peace-Athabasca Delta is that flow in the channels that drain this lake-delta-wetland system reverses direction when the stage on the Peace River is higher than the central lakes, typically during the spring ice break-up and summer high flow periods, diverting a portion of the river water to the lakes. The hydrology of this system has experienced natural and human induced changes in recent times. A hydrodynamic model was used to produce a naturalized flow record (no dam & no weirs). The purpose of this study was to examine the occurrences of flow reversals to this cold regions delta during the pre-regulated, regulated and naturalized periods. Short duration reverse flow events during the spring were found to be common occurrences. Analysis of the available data revealed that there was no significant difference between the mean magnitude of all spring events that occurred before and after regulation. For the open-water period, the Peace River was found to contribute some reverse flow to the delta lakes each year prior to regulation, but after regulation, more than half the years were estimated to not have experienced any reversal, and those that did were characterized by much smaller events. Overall, the mean volume and duration of reverse flow for the regulated period was significantly less than for the period prior to closure of the dam. On average, the reversals estimated under the regulated regime were significantly less than those under a naturalized scenario. A major implication of this finding was a lowered flooding potential of perched wetlands via the lateral expansion of the delta lakes beyond their normal shorelines.

  3. A coupled isotope tracer method to characterize input water to lakes

    Science.gov (United States)

    Yi, Yi; Brock, Bronwyn E.; Falcone, Matthew D.; Wolfe, Brent B.; Edwards, Thomas W. D.

    2008-02-01

    SummaryWe develop a new coupled isotope tracer method for characterizing the isotopic composition of input water to lakes, and apply it in the context of ongoing hydrological process studies in the Peace-Athabasca Delta, a large, remote, riparian ecosystem in the boreal region of western Canada. The region has a highly seasonal climate, with floodplain lakes typically receiving input only during the 4-6 month open-water season from varying proportions of spring snowmelt, summer rains and river flooding. These possible input sources have distinct ranges of isotopic compositions that are strongly constrained to a well-defined local meteoric water line, thus affording the opportunity to derive lake-specific estimates of the integrated isotopic composition of input waters after accounting for the effects of secondary evaporative isotopic enrichment. As shown by comparison of the results of isotopic surveys of delta lakes prior to freeze-up in 2000 and 2005, this isotopic characterization of input waters can be combined with other data and field observations to provide new insight into spatial and temporal variability in delta lake recharge processes. This includes evidence that summer rainfall in 2000 played an important role in replenishing shallow basins delta-wide, especially in the central low-lying region, compensating for below-average snow accumulation during the previous winter. In contrast, 2005 was marked by greater relative contributions from both snowmelt and river flooding because of high winter snow accumulation and a spring ice-jam that caused river floodwaters to enter some basins in the southern part of the delta. The method is readily transferable to investigations in other remote regions that are sparsely monitored by conventional hydrometric networks.

  4. Bathymetry of Lake Erie and Lake Saint Clair

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Erie and Lake Saint Clair has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and...

  5. ZHOUZHUANG, A "TOWN IN LAKES"

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Zhouzhuang Town islocated in thesouthwestern part ofKunshan City,neighboring WujiangCity, Suzhou City andQingpu District ofShanghai City, andsurrounded by ChengLake, Changbai Lake,Dianshan Lake, BaiyiLake and South Lake, asknown as a "town in lakes".

  6. Inter-annual variations in water yield to lakes in northeastern Alberta: implications for estimating critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Roderick HAZEWINKEL

    2010-08-01

    Full Text Available Stable isotopes of water were applied to estimate water yield to fifty lakes in northeastern Alberta as part of an acid sensitivity study underway since 2002 in the Athabasca Oil Sands Region (AOSR. Herein, we apply site-specific water yields for each lake to calculate critical loads of acidity using water chemistry data and a steady-state water chemistry model. The main goal of this research was to improve site-specific critical load estimates and to understand the sensitivity to hydrologic variability across a Boreal Plains region under significant oil sands development pressure. Overall, catchment water yields were found to vary significantly over the seven year monitoring period, with distinct variations among lakes and between different regions, overprinted by inter-annual climate-driven shifts. Analysis of critical load estimates based on site-specific water yields suggests that caution must be applied to establish hydrologic conditions and define extremes at specific sites in order to protect more sensitive ecosystems. In general, lakes with low (high water yield tended to be more (less acid sensitive but were typically less (more affected by interannual hydrological variations. While it has been customary to use long-term water yields to define a static critical load for lakes, we find that spatial and temporal variability in water yield may limit effectiveness of this type of assessment in areas of the Boreal Plain characterized by heterogeneous runoff and without a long-term lake-gauging network. Implications for predicting acidification risk are discussed for the AOSR.

  7. National Lakes Assessment Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Lakes Assessment (NLA) is a first-ever statistically-valid survey of the biological condition of lakes and reservoirs throughout the U.S. The U.S....

  8. DNR 24K Lakes

    Data.gov (United States)

    Minnesota Department of Natural Resources — Medium scale lake polygons derived from the National Wetlands Inventory (NWI) polygons and MnDOT Basemap lake delineations. Integrated with the DNR 24K Streams...

  9. Technologies for lake restoration

    OpenAIRE

    Helmut KLAPPER

    2003-01-01

    Lakes are suffering from different stress factors and need to be restored using different approaches. The eutrophication remains as the main water quality management problem for inland waters: both lakes and reservoirs. The way to curb the degradation is to stop the nutrient sources and to accelerate the restoration with help of in-lake technologies. Especially lakes with a long retention time need (eco-) technological help to decrease the nutrient content in the free water. The microbial and...

  10. Testing ground : Imperial conducting SA-SAGD pilot at Cold Lake

    Energy Technology Data Exchange (ETDEWEB)

    Roche, P.

    2009-03-15

    Imperial Oil Limited will test a variation of its patented steam assisted gravity drainage (SAGD) process at its Cold Lake holdings, where oilsand deposits are interspersed with thin shale layers. Most of the deposit is developed using cyclic steam stimulation (CSS). However, Imperial Oil developed the solvent assisted SAGD (SA-SAGD) process for use in areas where CSS does not work due to the degree of heat loss, such as oilsands with top gas and bottom water. In such cases, the challenge lies in minimizing the amount of steam wasted in water and gas thief zones. A pilot plant has been constructed to compare resource recovery performance of SA-SAGD with conventional SAGD. The long term potential for both processes for certain reservoir areas will also be evaluated. SA-SAGD pilot tests conducted at Cold Lake have revealed that the process may also be applicable to portions of the Athabasca oilsands. The pilot test is being conducted on the southwestern portion of the Cold Lake property near the Mahkeses plant which includes facilities for steam generation, bitumen treating and electricity generation. The pilot scale tests involve the use of 2 horizontal well pairs and 6 observation wells. Steam injection is expected to be underway in the second half of 2009. The solvent composition will be similar to the diluent used at Cold Lake, which is usually a natural gas condensate. It was concluded that SA-SAGD should not be confused with the Liquid Addition to Steam to Enhance Recovery (LASER) process, where a small amount of solvent is added to steam injection into CSS wells. 1 fig.

  11. Some Lake Level Control Alternatives for the Great Salt Lake

    OpenAIRE

    Allen, Marvin E.; Christensen, Ronald K.; Riley, J. Paul

    1983-01-01

    Fluctuations of the level of the Great Salt Lake cause large changes in both surface area and shoreline. Developments adjacent to the lake have been damaged by both high and low lake levels; and unless measures are implemented to regulate lake level fluctuations or otherwise to protect these developments, damages will continue. Various possible managment alternatives for mitigating potential damages from lake leve...

  12. Variation in immune function, body condition, and feather corticosterone in nestling Tree Swallows (Tachycineta bicolor) on reclaimed wetlands in the Athabasca oil sands, Alberta, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Jane Harms, N., E-mail: naomi.harms@usask.c [University of Saskatchewan, Western College of Veterinary Medicine, Department of Veterinary Pathology, 52 Campus Drive, Saskatoon, SK, S7N 5B4 (Canada); Fairhurst, Graham D., E-mail: graham.fairhurst@usask.c [University of Saskatchewan, Department of Biology, 112 Science Place, Saskatoon, SK, S7N 5E2 (Canada); Bortolotti, Gary R., E-mail: gary.bortolotti@usask.c [University of Saskatchewan, Department of Biology, 112 Science Place, Saskatoon, SK, S7N 5E2 (Canada); Smits, Judit E.G., E-mail: judit.smits@usask.c [University of Saskatchewan, Western College of Veterinary Medicine, Department of Veterinary Pathology, 52 Campus Drive, Saskatoon, SK, S7N 5B4 (Canada)

    2010-03-15

    In the Athabasca oil sands region of northern Alberta, mining companies are evaluating reclamation using constructed wetlands for integration of tailings. From May to July 2008, reproductive performance of 40 breeding pairs of tree swallows (Tachycineta bicolor), plus growth and survival of nestlings, was measured on three reclaimed wetlands on two oil sands leases. A subset of nestlings was examined for i) feather corticosterone levels, ii) delayed-type hypersensitivity response, and iii) innate immune function. Nestlings on one of two wetlands created with oil sands process affected material (OSPM) were heavier and had greater wing-lengths, and mounted a stronger delayed-type hypersensitivity response compared those on the reference wetland. Corticosterone was significantly higher in male nestlings on one of two OSPM-containing wetland compared to the reference wetland. Body condition of 12-day-old female nestlings was inversely related to feather corticosterone. Under ideal weather conditions, reclaimed wetlands can support healthy populations of aerially-insectivorous birds. - Under ideal weather conditions, tree swallow nestlings on reclaimed OSPM-affected wetlands are in good body condition and mount strong cell-mediated immune responses.

  13. Beyond Naphthenic Acids: Environmental Screening of Water from Natural Sources and the Athabasca Oil Sands Industry Using Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Science.gov (United States)

    Barrow, Mark P.; Peru, Kerry M.; Fahlman, Brian; Hewitt, L. Mark; Frank, Richard A.; Headley, John V.

    2015-09-01

    There is a growing need for environmental screening of natural waters in the Athabasca region of Alberta, Canada, particularly in the differentiation between anthropogenic and naturally-derived organic compounds associated with weathered bitumen deposits. Previous research has focused primarily upon characterization of naphthenic acids in water samples by negative-ion electrospray ionization methods. Atmospheric pressure photoionization is a much less widely used ionization method, but one that affords the possibility of observing low polarity compounds that cannot be readily observed by electrospray ionization. This study describes the first usage of atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (in both positive-ion and negative-ion modes) to characterize and compare extracts of oil sands process water, river water, and groundwater samples from areas associated with oil sands mining activities. When comparing mass spectra previously obtained by electrospray ionization and data acquired by atmospheric pressure photoionization, there can be a doubling of the number of components detected. In addition to polar compounds that have previously been observed, low-polarity, sulfur-containing compounds and hydrocarbons that do not incorporate a heteroatom were detected. These latter components, which are not amenable to electrospray ionization, have potential for screening efforts within monitoring programs of the oil sands.

  14. Variation in immune function, body condition, and feather corticosterone in nestling Tree Swallows (Tachycineta bicolor) on reclaimed wetlands in the Athabasca oil sands, Alberta, Canada

    International Nuclear Information System (INIS)

    In the Athabasca oil sands region of northern Alberta, mining companies are evaluating reclamation using constructed wetlands for integration of tailings. From May to July 2008, reproductive performance of 40 breeding pairs of tree swallows (Tachycineta bicolor), plus growth and survival of nestlings, was measured on three reclaimed wetlands on two oil sands leases. A subset of nestlings was examined for i) feather corticosterone levels, ii) delayed-type hypersensitivity response, and iii) innate immune function. Nestlings on one of two wetlands created with oil sands process affected material (OSPM) were heavier and had greater wing-lengths, and mounted a stronger delayed-type hypersensitivity response compared those on the reference wetland. Corticosterone was significantly higher in male nestlings on one of two OSPM-containing wetland compared to the reference wetland. Body condition of 12-day-old female nestlings was inversely related to feather corticosterone. Under ideal weather conditions, reclaimed wetlands can support healthy populations of aerially-insectivorous birds. - Under ideal weather conditions, tree swallow nestlings on reclaimed OSPM-affected wetlands are in good body condition and mount strong cell-mediated immune responses.

  15. Lake retention of manufactured nanoparticles

    NARCIS (Netherlands)

    Koelmans, A.A.; Quik, J.T.K.; Velzeboer, I.

    2015-01-01

    For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hy

  16. Pollution at Lake Mariut

    International Nuclear Information System (INIS)

    Lake Mariut, south Alexandria, Egypt suffered in the recent decades from intensive pollution as a result of a continuous discharge of huge amounts of agriculture wastewater that contains a large concentration of the washed pesticides and fertilizers in addition to domestic and industrial untreated wastewater. The over flow from the lake is discharged directly to the sea through El-Max pumping station via EI-Umum drain. Lake Mariout is surrounded by a huge number of different industrial activities and also the desert road is cutting the lake, this means that a huge number of various pollutants cycle through the air and settle down in the lake, by the time and during different seasons these pollutants after accumulation and different chemical interactions will release again from the lake to the surrounding area affecting the surrounding zone

  17. Origins of rainbow smelt in Lake Ontario

    Science.gov (United States)

    Bergstedt, Roger A.

    1983-01-01

    The first rainbow smelt (Osmerus mordax) to enter Lake Ontario were probably migrants from an anadromous strain introduced into New York's Finger Lakes. Since the upper Great Lakes were originally stocked with a landlocked strain from Green Lake, Maine, subsequent migration to Lake Ontario from Lake Erie makes Lake Ontario unique among the Great Lakes in probably having received introductions from two distinct populations.

  18. Boat Dwellers of Weishan Lake

    Institute of Scientific and Technical Information of China (English)

    JENNIFER; LIM

    1998-01-01

    IN the south of Shandong Province, Weishan Lake is the largest freshwater lake in northern China. Under the bright blue sky, it gleams like a large mirror. "As the sun is about to set, Weishan Lake is quiet…" Humming

  19. Hydrography - Lakes Assessments - Non Attaining

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This layer shows only non attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water...

  20. Benthic diatoms in lakes

    OpenAIRE

    Gottschalk, Steffi

    2014-01-01

    In order to protect or improve surface waters ecosystem response to pressures needs to be quantified. Diatoms are frequently used for assessing ecological status in streams and for reconstructing water quality of lakes. However, ecological status assessment of European lakes based on extant diatom assemblages is rare. The overall aim of this thesis is to facilitate the application of benthic diatoms in water quality assessment of boreal lakes, using methods developed for stream assessmen...

  1. Yellowstone Lake Nanoarchaeota

    OpenAIRE

    Scott eClingenpeel; Jinjun eKan; Rich eMacur; Tanja eWoyke; Dave eLovalvo; John eVarley; Inskeep, William P.; Kenneth eNealson; Tim eMcDermott

    2013-01-01

    Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park (YNP), where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR) were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1349 bp clone and could confound diversity estimates ...

  2. A lake without water

    OpenAIRE

    Nagoli, Joseph

    2016-01-01

    This thesis explores the human-environment interaction within the climate-sensitive socio-ecological system of Lake Chilwa in Malawi. It uses the livelihoods framework to analyse various coping strategies to resource scarcity due to lake recessions. The main aim is to understand the processes by which decision-making takes place and the influence of various agents of change on coping with environmental shocks, i.e. water recessions. Lake Chilwa undergoes periodic water recessions with up to t...

  3. Marine lakes of Indonesia

    OpenAIRE

    Becking, Leontine Elisabeth

    2012-01-01

    The objective of this thesis was to obtain insight into the processes that play a role in biodiversity patterns of tropical marine species by using marine lakes as a model. Marine lakes are landlocked water bodies that maintain a marine character through narrow submarine connections to the sea. Two regions in Indonesia were studied: Berau (East Kalimantan) and Raja Ampat (West Papua). The following questions were addressed: 1. What are the different types of marine lakes in Indonesia? 2. Are ...

  4. Great Lakes Literacy Principles

    Science.gov (United States)

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

    Lakes Superior, Huron, Michigan, Ontario, and Erie together form North America's Great Lakes, a region that contains 20% of the world's fresh surface water and is home to roughly one quarter of the U.S. population (Figure 1). Supporting a $4 billion sport fishing industry, plus $16 billion annually in boating, 1.5 million U.S. jobs, and $62 billion in annual wages directly, the Great Lakes form the backbone of a regional economy that is vital to the United States as a whole (see http://www.miseagrant.umich.edu/downloads/economy/11-708-Great-Lakes-Jobs.pdf). Yet the grandeur and importance of this freshwater resource are little understood, not only by people in the rest of the country but also by many in the region itself. To help address this lack of knowledge, the Centers for Ocean Sciences Education Excellence (COSEE) Great Lakes, supported by the U.S. National Science Foundation and the National Oceanic and Atmospheric Administration, developed literacy principles for the Great Lakes to serve as a guide for education of students and the public. These “Great Lakes Literacy Principles” represent an understanding of the Great Lakes' influences on society and society's influences on the Great Lakes.

  5. Jackson Lake Limnology

    OpenAIRE

    Wurtsbaugh, Wayne

    2014-01-01

    The limnology of Jackson Lake has been studied very little, despite the fact that it is the uppermost large lake on the headwaters of the Snake River, one of the larger rivers in the country (Hayden 1969). It is also an important fishery, largely for introduced lake trout. In 2014 we took our incoming graduate students to the Jackson Hole and one part of this introductory course focused on the limnology of the lake. Prior to the arrival of the students, a nutrient addition bioassay was initia...

  6. Paleolimnology of Kluane Lake

    OpenAIRE

    Brahney, Janice Lynne

    2007-01-01

    Causes and consequences of late Holocene fluctuations of Kluane Lake in Yukon Territory have been reconstructed from several sediment cores. In the last 5000 years the level of Kluane Lake has varied from ~27 m below its present level to 12 m above, primarily due to changes in inputs of water from Slims and Duke rivers. Discharge form the Slims River catchment into Kluane Lake is associated with glacial advances. During periods when neither Duke nor Slims rivers flowed into Kluane Lake, the l...

  7. Lake Qinghai, China

    OpenAIRE

    Yu, Junqing

    2006-01-01

    Lake Qinghai lies on the northeast corner of the Tibet-Qinghai Plateau. It is a closed-basin lake and the largest water body in China with an area of about 4437 km2. Aragonite and calcite are precipitating from the brackish (TDS 12-14 g/l) and alkaline water (pH 9.1-9.4). Summer rainfall exerts an important control on changes in both lake level and water chemistry. As the lake today is situated at the outer margin of the Asian summer monsoon, past climate changes were sensitively documented i...

  8. Examining indirect effects of lake trout recovery

    Science.gov (United States)

    With the recovery of lake trout populations in Lake Superior, there are indications of decreased forage fish abundance and density-dependence in lake trout. In Lake Superior, lean lake trout historically occupied depths trout occupied depths > 60 m...

  9. Structural and hydrothermal modification of the Gaertner uranium deposit, Key Lake, Saskatchewan, Canada

    International Nuclear Information System (INIS)

    The Key Lake uranium deposits are located at the southeastern edge of the Athabasca Basin, approximately 240 km north of La Ronge, Saskatchewan. Key Lake Mining Corporation is at present the world's largest uranium producer with an annual rated production of approximately 12 million pounds of U3O8. The Gaertner deposit consists of massive aggregates of uranium and nickel minerals immediately above the Early/Middle Proterozoic unconformity at its intersection with the Key Lake structural zone. Peripheral ore shoots extend along fractures into the wall rocks. The main ore minerals are uraninite and coffinite which are accompanied by Ni-arsenides, Ni-sulpharsenides and Ni-, Fe-, Pb-, Co- and Cu-sulphides. Radially textured anisotropic uraninite in the Gaertner deposit represents the oldest mineralization phase dated at 1255+-12 Ma. A series of tectonic events and accompanying hydrothermal mobilization and alteration resulted in modifications of the original monomineralic uranium orebody. Based on ore microscopic examinations and field observations in the Gaertner open pit, the following modification stages are identified: 1. ∼900 Ma: Fracturing of radially textured anisotropic uraninite, the oldest recognised uranium ore, subsequent introduction of Ni, As, S, Fe, Co and Cu. Radiometric dating of associated coffinite indicates an age of approximately 900 Ma. 2. ∼300 Ma: Renewed fracturing of the nickeliferous uranium ore stockwork, hydrothermal carbonate and clay alteration with dispersion of mobilized elements into the wall rocks, and multiple redistribution/introduction of U under varying physico-chemical conditions. On the basis of isotropy and optical reflectivity, four uraninite/pitchblende generations are distinguished in addition to a second nickel mineral suite and a coffinite phase. 3. <300 Ma: Vertical offset within the deposit under shallow conditions. Hydrothermal activity is not apparent. (author). 13 refs, 10 figs

  10. Modeling and mapping the effects of heat and pressure outside a SAGD steam chamber using time-lapse multicomponent seismic data, Athabasca oil sands, Alberta

    Science.gov (United States)

    Zeigler, Loren Michelle

    The field of study is a bitumen producing reservoir within the McMurray Formation. The deposit is a part of the Athabasca oil sands trend in Northeastern Alberta, Canada. This field contains 16 well pads that are, combined, producing more than 41,000 BOPD. Bitumen reservoirs are unique as a result of their high viscosity, low API gravity oil. This oil in this field has been produced by means of a method called Steam Assisted Gravity Drainage (SAGD), since 2007. In this method, two vertically stacked, horizontal wells are drilled. The upper well injects high temperature, high pressure steam and as the viscosity of the bitumen decreases it will begin to flow, via gravity, down to the lower producing well. Reservoir monitoring in this field is very important for multiple reasons, including the shallow depth and the large velocity changes that result from SAGD production. In order to map these changes, time-lapse multicomponent data were incorporated with rock physics modeling in order to map and interpret changes in Vp/Vs with production. When fluid substitution results and pressure estimations are combined, the resulting velocities are consistent with the core sample modeling done by Kato et al. (2008). These results were then compared with the seismic data in order to identify areas affected by steam, heat, and pressure within the reservoir through time-lapse Vp/Vs. PP time-lapse results show the location of the steam chamber within the reservoir, however these data do not give any information about the effects of pressure or heat. Converted-wave (PS) data can be used to image pressure and viscosity changes in the reservoir. When these data are combined into a Vp/Vs volume, the effects of steam, heat and pressure can be identified. Vp/Vs areas of little to no difference indicate steamed zones while the surrounding areas with large differences indicate heated and pressured zones.

  11. Formation and evolution of the Cigar Lake uranium deposit based on U-Pb and K-Ar isotope systematics

    International Nuclear Information System (INIS)

    A systematic geochronological study was conducted on the Cigar Lake uranium deposit. U-Pb and Pb-Pb systematics were applied to different types of uranium ore, and various associated sheet silicates were dated by the K-Ar method. These two approaches define a widespread retrograde metamorphic event in the basement, which occurred at about 1780 Ma during the Hudsonian orogeny, and a four-stage evolutionary model for the ore deposit. This model is compatible with the history of other unconformity-type uranium deposits in the Athabasca Basin. The first stage in the evolution of the Cigar Lake uranium deposit is marked by uraninite crystallization at 1341 ± 17 Ma, which, in association with arsenides and sulfarsenides, constitutes the mineralization of economic interest (main orebody). The second stage, characterized by a Fe-kaolinite and Fe-illite paragenesis, occurred locally at about 900 Ma. The third stage involved uranium mobilization at about 325 Ma and is characterized by (i) preferential loss of radiogenic lead from primary uraninite and crystallization of pitchblende at the rims of uraninite grains and (ii) formation of pitchblende associated with Fe sulfides or hematite in the main and perched orebodies. The last stage is characterized by recent alteration and coffinitization which have affected all ore types. 40 refs., 8 figs., 3 tabs

  12. Great Lakes: Great Gardening.

    Science.gov (United States)

    New York Sea Grant Inst., Albany, NY.

    This folder contains 12 fact sheets designed to improve the quality of gardens near the Great Lakes. The titles are: (1) "Your Garden and the Great Lakes"; (2) "Organic Gardening"; (3) "Fruit and Vegetable Gardening"; (4) "Composting Yard Wastes"; (5) "Herbicides and Water Quality"; (6) "Watering"; (7) "Soil Erosion by Water"; (8) "Soil…

  13. Marine lakes of Indonesia

    NARCIS (Netherlands)

    Becking, Leontine Elisabeth

    2012-01-01

    The objective of this thesis was to obtain insight into the processes that play a role in biodiversity patterns of tropical marine species by using marine lakes as a model. Marine lakes are landlocked water bodies that maintain a marine character through narrow submarine connections to the sea. Two

  14. Beautiful Yamzhog Yumco Lake

    Institute of Scientific and Technical Information of China (English)

    SAMXUBAGONJORYUNDAIN

    2003-01-01

    Yamzhog Yumco Lake is one of the three sacred lakes in Tibetan snow area, located in Nangarze County of Shannan Prefecture.Nangarze County is a semi-agricultural and semi-pastoral district, and because the husbandry prioritizes the agriculture,it was named "Yamzhog (meadow landin high mountains)". The Yamzhog

  15. Lake Wobegon Dice

    Science.gov (United States)

    Moraleda, Jorge; Stork, David G.

    2012-01-01

    We introduce Lake Wobegon dice, where each die is "better than the set average." Specifically, these dice have the paradoxical property that on every roll, each die is more likely to roll greater than the set average on the roll, than less than this set average. We also show how to construct minimal optimal Lake Wobegon sets for all "n" [greater…

  16. A POSSIBLE TSUNAMI IN THE LABRADOR SEA RELATED TO THE DRAINAGE OF GLACIAL LAKE AGASSIZ ~8400 YEARS B.P.

    Directory of Open Access Journals (Sweden)

    N. Nirupama

    2005-01-01

    Full Text Available For thousands of years, the thick Laurentide Ice Sheet covered a large part of northern North America, damming northward-draining rivers. As this ice retreated, large lakes formed along its margin. Glacial Lake Agassiz was the largest of these ice-marginal lakes, covering an area of >800,000 km2 (more than twice the size of the largest lake in the modern world, the Caspian Sea before it drained catastrophically into the Labrador Sea. Even before that, Lake Agassiz had periodically released large volumes of water into the ocean via the Great Lakes-St. Lawrence and the Athabasca-Mackenzie River systems. The last and largest of these outbursts released >150,000 km3 through Hudson Bay and Hudson Strait in 6-12 months; the average flux over that period was ~5 Sv (1 Sv = 1×106 m3s-1.When a volume of water this large is discharged into a coastal sea like the Labrador Sea, it may generate a surface flood wave or a tsunami if the water mass is large enough and introduced in a short time. To our knowledge no previous calculations have been made to estimate the potential impact of a flood burst on the generation of solitary waves. Using analogies of tsunamis generated by submarine landslides and ocean earthquakes, the amplitude of a Lake Agassiz generated tsunami is estimated to have been at least 2 m. Directionality considerations, as well as the effect of the Coriolis Force in the Northern Hemisphere, suggest that the resulting tsunami probably traveled 50-100 km along the west coast of the Labrador Sea, south of Hudson Strait where the outburst entered the ocean, before being dissipated. The erosional and depositional affects of historic and prehistoric tsunamis are present in the geological record, and provide guidance in seeking evidence for the Lake Agassiz flood burst and subsequent tsunami. This record may be found along the western coast of the Labrador Sea as well as along the shores of Hudson Strait.

  17. Lake metabolism scales with lake morphometry and catchment conditions

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Baastrup-Spohr, Lars; Jensen, Kaj Sand;

    2012-01-01

    We used a comparative data set for 25 lakes in Denmark sampled during summer to explore the influence of lake morphometry, catchment conditions, light availability and nutrient input on lake metabolism. We found that (1) gross primary production (GPP) and community respiration (R) decline with lake...... area, water depth and drainage ratio, and increase with algal biomass (Chl), dissolved organic carbon (DOC) and total phosphorus (TP); (2) all lakes, especially small with less incident light, and forest lakes with high DOC, have negative net ecosystem production (NEP <0); (3) daily variability of GPP...... decreases with lake area and water depth as a consequence of lower input of nutrients and organic matter per unit water volume; (4) the influence of benthic processes on free water metabolic measures declines with increasing lake size; and (5) with increasing lake size, lake metabolism decreases...

  18. Lake whitefish and lake herring population structure and niche in ten south-central Ontario lakes

    Science.gov (United States)

    Carl, Leon M.; McGuiness, Fiona

    2006-01-01

    This study compares simple fish communities of ten oligotrophic lakes in south-central Ontario. Species densities and population size structure vary significantly among these lake communities depending on fish species present beyond the littoral zone. Lake whitefish are fewer and larger in the presence of lake herring than in their absence. Diet analysis indicates that lake whitefish shift from feeding on both plankton and benthic prey when lake herring are absent to a primarily benthic feeding niche in the presence of lake herring. When benthic round whitefish are present, lake whitefish size and density decline and they move lower in the lake compared to round whitefish. Burbot are also fewer and larger in lakes with lake herring than in lakes without herring. Burbot, in turn, appear to influence the population structure of benthic coregonine species. Lower densities of benthic lake whitefish and round whitefish are found in lakes containing large benthic burbot than in lakes with either small burbot or where burbot are absent. Predation on the pelagic larvae of burbot and lake whitefish by planktivorous lake herring alters the size and age structure of these populations. As life history theory predicts, those species with poor larval survival appear to adopt a bet-hedging life history strategy of long-lived individuals as a reproductive reserve.

  19. Hydrogeologic Controls on Lake Level at Mountain Lake, Virginia

    OpenAIRE

    Roningen, Jeanne Marie

    2011-01-01

    Mountain Lake in Giles County, Virginia, has a documented history of severe natural lake-level changes involving groundwater seepage [Jansons, 2004] that extend over the past 4200 years [Cawley, 1999], and as of December 2010 the lake was about 2% full by volume. Situated in the Valley and Ridge physiographic province on the axis of a plunging anticline and straddling contacts between three upper Ordovician and lower Silurian formations, the lake is one of two natural lakes in Virginia. ...

  20. The ecology of Bassenthwaite Lake (English Lake District)

    OpenAIRE

    Thackeray, Stephen; Maberly, Stephen; Winfield, Ian

    2005-01-01

    Bassenthwaite Lake is, in many ways, different from the other major lakes in the English Lake District: it is the most northerly, the shallowest, has the largest catchment and the shortest mean retention time. There is also considerable temporal variation in lake level. This article summarises the limnological features of Bassenthwaite Lake, the catchment and physical characteristics before describing the water chemistry, phytoplankton, macrophytes, zooplankton, invertebrates, fish, mammal an...

  1. Yellowstone Lake Nanoarchaeota

    Directory of Open Access Journals (Sweden)

    Scott eClingenpeel

    2013-09-01

    Full Text Available Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park, where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1,349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels. However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (70 pyrosequencing reads was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  2. Sm-Nd, Pb-Pb, and Rb-Sr systematics of the basement in the Cigar Lake area, Saskatchewan, Canada

    International Nuclear Information System (INIS)

    The Sm-Nd, Pb-Pb, and Rb-Sr isotope geochemistry of graphitic metapelitic gneisses and their altered equivalents from the Cigar Lake area (Saskatchewan, Canada) has been investigated. Some granitic gneisses were also analyzed for Pb-Pb and Rb-Sr. Sm-Nd data show that the metapelitic gneisses are composed of detritus from heterogeneous, mainly mantle-derived Archean rocks (2.5-2.6 Ga) and that the Sm-Nd system has not been significantly perturbed during subsequent alteration and metamorphic events. The Pb-Pb age for samples of the less altered graphitic metapelitic gneisses is 1.77 ± 0.03 Ga. The crustal common Pb is located on the Pb-Pb isochron, but there are different zones with high and variable U/Pb ratios (μ 15-280). The Pb-Pb age for the granitic gneisses is 1.79 ± 0.11 Ga. The Pb isotope data show that there has been no major uranium redistribution in the basement after the Hudsonian orogeny. However, there has been a strong perturbation of the U-Pb system in the regolithic zone beneath the Athabasca cover. In some samples, uranium was added during the mineralizing event. The Rb-Sr system in the graphitic metapelitic gneisses was also affected. The 87Sr/86Sr ratio in pitchblende is 0.709. At 1.3 Ga, there is a strong contrast between the 87Sr/86Sr ratio in the Athabasca sandstones (0.706-0.710) and the 87Sr/86Sr ratio in the metapelitic gneisses from the basement (0.725-0.775). The upper zone of the regolith is characterized by a low 87Sr/86Sr ratio (0.705-0.707). The Pb-Pb and Pb-Sr data are consistent with the circulation of a fluid with a low 87Sr/86Sr ratio, derived from sedimentary cover; this fluid passed through the most permeable zones of the basement rocks, especially the regolith. The mineralizing fluid had a 87Sr/86Sr value typical of a fluid in equilibrium with the Athabasca sandstones. 36 refs., 9 figs., 6 tabs

  3. LAKE RESTORATION BY DILUTION: MOSES LAKE, WASHINGTON

    Science.gov (United States)

    Dilution water, low in macronutrients, was added to Moses Lake on three occasions in 1977 and once in 1978 during the spring-summer period. The addition resulted in reducing the annual average inflow concentration of phosphorus from about 130-140 micrograms/l to 100 micrograms/l....

  4. Valuing Great Lakes Beaches

    OpenAIRE

    Song, Feng; Lupi, Frank; Kaplowitz, Michael D.

    2010-01-01

    This study aims to estimate the recreational use values of Great Lakes beaches using a two-level nested logit Random Utility Model. The choice set contains all 594 public Great Lakes beaches in Michigan. Beach sites located in the same Great Lakes water body are arranged into a nest. The trip data were obtained from a 2006 online survey using a web-panel of Michigan adults accessed through Survey Sampling International (SSI). The variables that affect the amount of utility derived from a part...

  5. Great Lakes Ice Charts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002...

  6. Lake Transect : 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1986. Lists of the plant species found...

  7. Lake Transect : 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1988. Lists of the plant species found...

  8. Lake Transect : 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1987. Lists of the plant species found...

  9. Lake Transect : 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1990. Lists of the plant species found...

  10. Lake Transect : 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1989. Lists of the plant species found...

  11. Lake Mason trip report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a summary of the August 31, 1998 trip to Lake Mason to review the hydrology, current conditions, habitat and wildlife. This site visit occurred due...

  12. History of Lake Andes

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Information about the history and management of Lake Andes is compiled in this report. It is intended to help future refuge managers become acquainted with the...

  13. Lake Level Reconstructions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past lake levels, mostly related to changes in moisture balance (evaporation-precipitation). Parameter keywords describe what was measured in this data...

  14. Halls Lake 1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify...

  15. Chase Lake Wetland Management District, Chase Lake National Wildlife Refuge, Chase Lake Prairie Project: Annual narrative report: 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake NWR, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1997...

  16. Archaea in Yellowstone Lake

    OpenAIRE

    Kan, Jinjun; Clingenpeel, Scott; Macur, Richard E.; Inskeep, William P.; Lovalvo, Dave; Varley, John; Gorby, Yuri; McDermott, Timothy R.; Nealson, Kenneth

    2011-01-01

    The Yellowstone geothermal complex has yielded foundational discoveries that have significantly enhanced our understanding of the Archaea. This study continues on this theme, examining Yellowstone Lake and its lake floor hydrothermal vents. Significant Archaea novelty and diversity were found associated with two near-surface photic zone environments and two vents that varied in their depth, temperature and geochemical profile. Phylogenetic diversity was assessed using 454-FLX sequencing (∼51 ...

  17. Integrated Lake Management Project

    OpenAIRE

    Goverment of Uganda; Department for International Development (DFID) of the UK Government

    2007-01-01

    In 1999, the Integrated Co-management of Lakes through Beach Management Units project was started in an effort to implement a new approach to the management of lake resources in Uganda. The main components of this plan involved decentralization, local community management, and improving the livelihood of the poor. In order to finance the management of these areas, the Beach Management Units (BMU's) are charging user fees to those individuals who obtain benefit from the natural resources. Thes...

  18. Phytoplankton of Lake Kivu

    OpenAIRE

    Sarmento, Hugo; Darchambeau, François; Descy, Jean-Pierre

    2012-01-01

    This chapter reviews taxonomic composition, biomass, production and nutrient limitation of the phytoplankton of Lake Kivu. Present Lake Kivu phytoplankton is dominated by cyanobacteria – mainly Synechococcus spp. and thin filaments of Planktolyngbya limnetica – and by pennate diatoms, among which Nitzschia bacata and Fragilaria danica are dominant. Seasonal shifts occur, with cyanobacteria developing more in the rainy season, and the diatoms in the dry season. Other groups present are cryptop...

  19. Resilience and Restoration of Lakes

    Directory of Open Access Journals (Sweden)

    Kathryn L. Cottingham

    1997-06-01

    Full Text Available Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

  20. Is Lake Chabot Eutrophic?

    Science.gov (United States)

    Pellegrini, K.; Logan, J.; Esterlis, P.; Lew, A.; Nguyen, M.

    2013-12-01

    Introduction/Abstract: Lake Chabot is an integral part of the East Bay watershed that provides habitats for animals and recreation for humans year-round. Lake Chabot has been in danger of eutrophication due to excessive dumping of phosphorous and nitrogen into the water from the fertilizers of nearby golf courses and neighboring houses. If the lake turned out to be eutrophified, it could seriously impact what is currently the standby emergency water supply for many Castro Valley residents. Eutrophication is the excessive richness of nutrients such as nitrogen and phosphorus in a lake, usually as a result of runoff. This buildup of nutrients causes algal blooms. The algae uses up most of the oxygen in the water, and when it dies, it causes the lake to hypoxify. The fish in the lake can't breathe, and consequently suffocate. Other oxygen-dependant aquatic creatures die off as well. Needless to say, the eutrophication of a lake is bad news for the wildlife that lives in or around it. The level of eutrophication in our area in Northern California tends to increase during the late spring/early summer months, so our crew went out and took samples of Lake Chabot on June 2. We focused on the area of the lake where the water enters, known on the map as Honker Bay. We also took readings a ways down in deeper water for comparison's sake. Visually, the lake looked in bad shape. The water was a murky green that glimmered with particulate matter that swirled around the boat as we went by. In the Honker Bay region where we focused our testing, there were reeds bathed in algae that coated the surface of the lake in thick, swirling patterns. Surprisingly enough, however, our test results didn't reveal any extreme levels of phosphorous or nitrogen. They were slightly higher than usual, but not by any significant amount. The levels we found were high enough to stimulate plant and algae growth and promote eutrophication, but not enough to do any severe damage. After a briefing with a

  1. Tewaukon – Clouds LakeLake Elsie – Storm Lake and Wild Rice Refuges Narrative Reports : 1939-1956 : From Sand Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These narrative reports summarize refuge activities from 1939 to 1956 for Lake Tewaukon Refuge, Clouds Lake Refuge, Lake Elsie Refuge, Storm Lake Refuge, Wild Rice...

  2. Distribution of Total Dissolved Solids in McMurray Formation Water in the Athabasca Oil Sands Region, Alberta, Canada: Implications for Oil Sands Mining and In Situ Resource Development

    Science.gov (United States)

    Cowie, B.; Mayer, B.

    2013-12-01

    Saline water management is a significant environmental challenge for mining and in-situ resource development in the Athabasca oil sands region (AOSR), Alberta, Canada. In the AOSR, the Cretaceous aged McMurray formation that bears the majority of the oil sands resources is underlain by saline Devonian formations containing saline water. Vertical connectivity between Devonian and Cretaceous aquifer systems has been uncovered by mining operations in the AOSR over the past several years, inducing occasional and local saline water flow into mining areas. The observed upward flow of groundwater from Devonian to Cretaceous systems necessitates detailed characterization of the spatial extent of high salinity formation waters to improve water management decisions in the AOSR. This study used published data from recent government reports and Environmental Impact Assessments to map total dissolved solids (TDS) of 355 McMurray formation water samples across the Athabasca oil sands region (54 to 58° N and 110 to 114° W). McMurray formation waters varied from non-saline (TDS 100 000 mg/L) with a locally high salinity formation waters trending parallel to the dissolution edge of the Devonian-aged Prairie evaporite formation across the AOSR. The simplest hydrogeological explanation for the observed formation water salinity data is that Devonian aquifers are locally connected to the McMurray formation via conduits in the sub-Cretaceous karst system in the region overlying the partial dissolution edge of the Prairie evaporite formation. The driving force for upward formation water flow was provided by the Pleistocene glaciation events that reversed the regional flow system in the Devonian strata over the past 2 Ma. This study demonstrates that a detailed approach to hydrogeological assessment is required to elucidate total dissolved solids concentrations in McMurray formation waters at an individual lease-area scale, and to manage potential impacts from high salinity formation

  3. Lake Morphometry for NHD Lakes in Ohio Region 5 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  4. Lake Morphometry for NHD Lakes in Tennessee Region 6 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  5. Lake Morphometry for NHD Lakes in California Region 18 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  6. Winter Lake Breezes near the Great Salt Lake

    Science.gov (United States)

    Crosman, Erik T.; Horel, John D.

    2016-05-01

    Case studies of lake breezes during wintertime cold air pools in Utah's Salt Lake Valley are examined. While summer breezes originating from the Great Salt Lake are typically deeper, of longer duration, and have higher wind speeds than winter breezes, the rate of inland penetration and cross-frontal temperature differences can be higher during the winter. The characteristics of winter breezes and the forcing mechanisms controlling them (e.g., snow cover, background flow, vertical stability profile, clouds, lake temperature, lake sheltering, and drainage pooling) are more complex and variable than those evident in summer. During the afternoon in the Salt Lake Valley, these lake breezes can lead to elevated pollution levels due to the transport of fine particle pollutants from over the Great Salt Lake, decreased vertical mixing depth, and increased vertical stability.

  7. Meteotsunami in Lake Michigan

    Science.gov (United States)

    Wu, C.; Bechle, A.; Schwab, D. J.; Anderson, E. J.; Roebber, P. J.

    2012-12-01

    Meteotsunamis, or meteorological induced tsunamis, are meteorological in origin but exhibit long-period tsunami characteristics. Both meteotsunamis and seismic tsunamis have wave periods of 2 minutes to 2 hours and undergo resonant amplification that transforms relatively small waves in the open water into destructive forces at the coast. There are a number of amplification mechanisms including Proudman resonance, edge wave Greenspan resonance, as well as shoaling and harbor resonance. In this talk, we discuss several incidences of meteotsunamis in the Great Lakes. In Lake Michigan, an unexpected and destructive meteotsunami event occurred on June 26, 1954 when a 3 meter high wave struck the Chicago waterfront, resulting in seven fatalities. Ten days later on July 6, 1954, another meteotsunami event in southern Lake Michigan resulted in edge waves in excess of 1 m height. Nevertheless, these two events were generated by storms of vastly different size and propagation direction. More recently, in 2008 at least 25 meteotsunamis events with amplitudes of to 30 ~ 45 cm were observed in several major Lake Michigan harbors and were correlated with high-frequency pressure fronts passing along the west coast of Lake Michigan. Historical water level and meteorological records are analyzed to determine the mechanisms responsible for these meteotsunami events. Finally, a three-dimensional hydrodynamic model is employed to simulate select events to further explore in detail the possible meteotsunami mechanisms in the Great Lakes. Our ultimate goal is to provide real-time warning system to assess the coastal hazard and risk areas associated with meteotsunamis in the Great Lakes.

  8. Lake Michigan lake trout PCB model forecast post audit

    Science.gov (United States)

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  9. Mono Lake Excursion Reviewed

    Science.gov (United States)

    Liddicoat, J. C.; Coe, R. S.

    2007-05-01

    The Mono Lake Excursion as recorded in the Mono Basin, CA, has an older part that is about negative 30 degrees inclination and about 300 degrees declination during low relative field intensity. Those paleomagnetic directions are closely followed by greater than 80 degrees positive inclination and east declination of about 100 degrees during higher relative field intensity. A path of the Virtual Geomagnetic Poles (VGPs) for the older part followed from old to young forms a large clockwise loop that reaches 35 degrees N latitude and is centered at about 35 degrees E longitude. That loop is followed by a smaller one that is counterclockwise and centered at about 70 degrees N latitude and 270 degrees E longitude (Denham & Cox, 1971; Denham, 1974; Liddicoat & Coe, 1979). The Mono Lake Excursion outside the Mono Basin in western North America is recorded as nearly the full excursion at Summer Lake, OR (Negrini et al., 1984), and as the younger portion of steep positive inclination/east declination in the Lahontan Basin, NV. The overall relative field intensity during the Mono Lake Excursion in the Lahontan Basin mirrors very closely the relative field intensity in the Mono Basin (Liddicoat, 1992, 1996; Coe & Liddicoat, 1994). Using 14C and 40Ar/39Ar dates (Kent et al., 2002) and paleoclimate and relative paleointensity records (Zimmerman et al., 2006) for the Mono Lake Excursion in the Mono Basin, it has been proposed that the Mono Lake Excursion might be older than originally believed and instead be the Laschamp Excursion at about 40,000 yrs B.P. (Guillou et al., 2004). On the contrary, we favor a younger age for the Mono Lake Excursion, about 32,000 yrs B.P., using the relative paleointensity in the Mono Basin and Lahontan Basin and 14C dates from the Lahontan Basin (Benson et al., 2002). The age of about 32,000 yrs B.P. is also in accord with the age (32,000- 34,000 yrs B.P.) reported by Channell (2006) for the Mono Lake Excursion at ODP Site 919 in the Irminger Basin

  10. Great Lakes Environmental Database (GLENDA)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Environmental Database (GLENDA) houses environmental data on a wide variety of constituents in water, biota, sediment, and air in the Great Lakes...

  11. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    Science.gov (United States)

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences. PMID:27104923

  12. The Lake Ohrid SCOPSCO project

    OpenAIRE

    Wagner, Bernd; Wilke, Thomas; Krastel , Sebastien; Zanchetta, Giovanni; Sulpizio, Roberto; Leng, Melanie J.; Francke, Alexander; Baumgarten, Henricke; Cvetkoska, Aleksandra; Giacco, Biagio; Lacey, Jack H.; Leicher, Niklas

    2015-01-01

    The ICDP SCOPSCO project at Lake Ohrid in Macedonia and Albania was one of the most successful lake drilling campaigns worldwide. Drilling took place from April to June 2013 and yielded more than 2000 m of sediments from four different sites in the lake. The maximum penetration was 569 m below lake floor and the overall recovery at all drill sites was > 95 %. Almost two years after the drilling operation, core opening and processing as well as biological and geological analyses ar...

  13. Special Stamps:Qinghai Lake

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    On July 20, 2002, the State Postal Bureau issued a set of three stamps picturing the Qinghai Lake shore, Bird Island, and the distant view.Located on the northeastern Qinghai-Tibet Plateau, in West China’s Qinghai Province, Qinghai Lake is 3,196 meters above sea level, and the biggest inland lake in China. Oils have been used to capture its magnificence.Bird Island on Qinghai Lake is a

  14. The Lake Albert light fishery

    OpenAIRE

    2009-01-01

    Fishing using light to attract fish (The light fishery) was introduced on Lake AIbert from Lake Victoria where it is used to catch mukene Rastrineobola argentea. The light fishery on Lake Albert targets ragoge brycinus nurse and mukene/muziri (Neobola bredoi), These species species now contribute to more than 50% of the catches from this lake. Ragoge and muziri were until the early 1990's not important in the commercial fishery but only served as food to the large predatory fis...

  15. HYDRODYNAMIC CHARACTERISTICS OF LAKE YANAKA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As part of a major effort to undersand and quantify the cnvironmental conditions in Lake Yanaka, the circulation patterns in Lake Yanaka were analyzed through the application of a three-dimensional hydrodynamic model. The model was validated with field observation, and then used to study the response of the lake to different forcing. The information on flow structures obtained in the present study is useful for further study of water quality in the lake.

  16. A Lake Dream in Asia

    Institute of Scientific and Technical Information of China (English)

    Yang Wei

    2009-01-01

    @@ When William Wordsworth,representative of Lake Poets wrote his Ode to Night ingale nearby the Lake District of England at the turn of the nine-teenth century,he never imagined a century later,a similar romantic lake dream has been created in China,Asia.

  17. Michigan: The Great Lakes State

    Science.gov (United States)

    McKay, Sandra Lee; La Luzerne-Oi, Sally

    2009-01-01

    Although Michigan is often called the "Wolverine State," its more common nickname is the "Great Lakes State." This name comes from the fact that Michigan is the only state in the United States that borders four of the five Great Lakes. Also referred to as the "Water Wonderland," Michigan has 11,000 additional lakes, 36,000 miles of streams, and…

  18. HYDROMETEOROLGICAL ANALISIS OF DOJRAN LAKE

    Directory of Open Access Journals (Sweden)

    VIOLETA GJESOVSKA

    2011-03-01

    Full Text Available Dojran Lake with its hydrological basin is a closed hydrologicalsystem with natural inflow of water to the lake, but no natural outflow. Rechargeof the lake is from direct surface and underground inflow. Within the period 1950-1960 the lake faced with extremely high water level that was not favorable for thedevelopment of fishing. It was built an artificial channel to regulate the water levelin the lake and control the water use at Greek side of the lake. In the period 1988-2000, the water level in the lake continuously was declining. Water leveldeclination caused ecological catastrophe for the flora and fauna in the lake andlake’s basin that was inconvenience for the basic economy in the region, tourismand fishing. The reasons for declining the water level in the lake are not clearlyidentified, and they are located in unfavorable hydrological conditions expressedthrough longer dried period or uncontrolled usage the water from the lake.In 2002, the Republic of Macedonia finished a project to build a system forbringing water from Gjavato wells near Vardar River with capacity of 1 m3/s. Thewater level in the lake has recently increased. In order to define the causes ofchanges in the lake requires detailed hydrological and meteorological analysis.This paper will present the results of hydrological and meteorological analysis onthe basis of historical data of measured water level, precipitation, and airtemperature from hydrometeorological station New Dojran for the period 1961-2008. Some comments on impact factors will be presented as well.

  19. Sediments of Ypacarai Lake

    International Nuclear Information System (INIS)

    Bottom and sestonic sediments of Ypacarai Lake were investigated with XRF and Moessbauer techniques. The 120 km2 lake, depth averages 1.8 m. In addition to the lakes use for recreation, its basin has economic significance. Sediments play an important role in the distribution of trace elements in the aquatic system and as a sink for metals. Bottom and seston samples were taken from 4 different sampling stations which were selected according the morphology and population sites on the shore. The concentration of toxic metals was found to be low and no adverse ecological impact should be expected. The main metallic ion component is iron (1.68%). Moessbauer studies showed this element appears as Fe3+. Iron2+ was not detected. We suggest that Fe3+ acts as the limiting element which controls the eutrophication process. (author) 13 refs.; 2 tabs

  20. Interesting Ziandao Lake

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    LOCATED in Chun’an County, Zhejiang Province, Qiandao Lake (Lake of a Thousand Isles) is a state-level scenic spot and a bright pearl of the golden tourism line between Hangzhou’s West Lake and Anhui’s Huangshan Mountain. Last autumn, we went to Chun’an. It took only three to four hours by coach to travel from Hangzhou to Chun’an. Flanked by mountains on the west, the small county faces water on the east. A street goes across the county; it takes less than half an hour to walk from one end to the other. Small restaurants and shops line the western side of the road,

  1. Dust is the dominant source of "heavy metals" to peat moss (Sphagnum fuscum) in the bogs of the Athabasca Bituminous Sands region of northern Alberta.

    Science.gov (United States)

    Shotyk, William; Bicalho, Beatriz; Cuss, Chad W; Duke, M John M; Noernberg, Tommy; Pelletier, Rick; Steinnes, Eiliv; Zaccone, Claudio

    2016-01-01

    Sphagnum fuscum was collected from twenty-five ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca Bituminous Sands (ABS) in northern Alberta (AB) in order to assess the extent of atmospheric contamination by trace elements. As a control, this moss species was also collected at a bog near Utikuma (UTK) in an undeveloped part of AB and 264km SW of the ABS region. For comparison, this moss was also collected in central AB, in the vicinity of the City of Edmonton which is approximately 500km to the south of the ABS region, from the Wagner Wetland which is 22km W of the City, from Seba Beach (ca. 90km W) and from Elk Island National Park (ca. 45km E). All of the moss samples were digested and trace elements concentrations determined using ICP-SMS at a commercial laboratory, with selected samples also analyzed using instrumental neutron activation analysis at the University of Alberta. The mosses from the ABS region yielded lower concentrations of Ag, As, Bi, Cd, Cu, Pb, Sb, Tl, and Zn compared to the moss from the Edmonton area. Concentrations of Ni and Mo in the mosses were comparable in these two regions, but V was more abundant in the ABS samples. Compared with the surface vegetation of eight peat cores collected in recent years from British Columbia, Ontario, Quebec and New Brunswick, the mean concentrations of Ag, As, Bi, Cd, Cu, Mo, Ni, Pb, Sb, Tl and Zn in the mosses from the ABS region are generally much lower. In fact, the concentrations of these trace elements in the samples from the ABS region are comparable to the corresponding values in forest moss from remote regions of central and northern Norway. Lithophile element concentrations (Ba, Be, Ga, Ge, Li, Sc, Th, Ti, Zr) explain most of the variation in trace metal concentrations in the moss samples. The mean concentrations of Th and Zr are greatest in the moss samples from the ABS region, reflecting dust inputs to the bogs from open pit mines, aggregate

  2. Isotopic characterization of nitrate, ammonium and sulfate in stack PM2.5 emissions in the Athabasca Oil Sands Region, Alberta, Canada

    Science.gov (United States)

    Proemse, Bernadette C.; Mayer, Bernhard; Chow, Judith C.; Watson, John G.

    2012-12-01

    Stable isotope techniques may be a suitable tool for tracing industrial emissions in the atmosphere and the environment provided that the isotopic compositions of industrial emissions are distinct. We determined the isotopic compositions of nitrate, ammonium and sulfate in PM2.5 emitted from two industrial stacks at a large upgrader site in the Athabasca oil sands region (AOSR), northeastern Alberta, Canada, and compared them to the nitrogen and sulfur isotopic compositions of source materials and upgrading by-products. We found distinct isotopic compositions of nitrate and ammonium in PM2.5 compared to those reported for atmospheric nitrate and ammonium in the literature. Nitrate in PM2.5 had δ15N values of 9.4‰ (Stack A) and 16.1 ± 1.2‰ (Stack B) that were significantly enriched in 15N compared to the feedstock materials (˜2.5‰), by-products of upgrading (-0.3-1.3‰), and atmospheric N2 (0‰). δ15N of ammonium in PM2.5 showed a large range with values between - 4.5 to +20.1‰ (Stack B). We report the first measurements of the triple oxygen isotopic composition of industrial emitted nitrate. Nitrate emitted as PM2.5 is not mass-independently enriched in 17O resulting in Δ17O = 0.5 ± 0.9‰ (Stack B) and is therefore distinct from atmospheric nitrate, constituting an excellent indicator of industrial derived nitrate. δ18O values of nitrate in PM2.5 (36.0 and 17.6 ± 1.8‰ for Stack A and B, respectively) were also significantly lower than δ18O values of atmospheric nitrates and hence isotopically distinct. δ34S values of sulfate in PM2.5 were with 7.3 ± 0.3‰ (Stack A) and 9.4 ± 2.0‰ (Stack B) slightly enriched in 34S compared to δ34S in bitumen (4.3 ± 0.3‰) and coke (3.9 ± 0.2‰). δ18O values of sulfate in PM2.5 were 18.9 ± 2.9‰ and 14.2 ± 2.8‰ for Stack A and Stack B, respectively. The isotopic composition of sulfate in PM2.5 was not sufficiently different from δ34S and δ18O values of sulfate in long-range atmospheric

  3. Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  4. Transient Tsunamis in Lakes

    Science.gov (United States)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  5. Lakes on Mars

    CERN Document Server

    Cabrol, Nathalie A

    2014-01-01

    On Earth, lakes provide favorable environments for the development of life and its preservation as fossils. They are extremely sensitive to climate fluctuations and to conditions within their watersheds. As such, lakes are unique markers of the impact of environmental changes. Past and current missions have now demonstrated that water once flowed at the surface of Mars early in its history. Evidence of ancient ponding has been uncovered at scales ranging from a few kilometers to possibly that of the Arctic ocean. Whether life existed on Mars is still unknown; upcoming missions may find critic

  6. Lake Way uranium project

    Energy Technology Data Exchange (ETDEWEB)

    Eskell, S.; French, R.R.

    1982-01-01

    Several years ago Lake Way was considered by many to be too small and too low in grade to compete with the larger high grade deposits in other parts of Australia, and particularly in the Northern Territory. The pendulum has now swung and as far as Australian uranium resources are concerned Lake Way now has many advantages over the larger, richer deposits in other parts of Australia. These advantages are set out under appropriate headings (size, location, aboriginals, operating procedures, shipping, equity, and timing).

  7. Technologies for lake restoration

    Directory of Open Access Journals (Sweden)

    Helmut KLAPPER

    2003-09-01

    Full Text Available Lakes are suffering from different stress factors and need to be restored using different approaches. The eutrophication remains as the main water quality management problem for inland waters: both lakes and reservoirs. The way to curb the degradation is to stop the nutrient sources and to accelerate the restoration with help of in-lake technologies. Especially lakes with a long retention time need (eco- technological help to decrease the nutrient content in the free water. The microbial and other organic matter from sewage and other autochthonous biomasses, causes oxygen depletion, which has many adverse effects. In less developed countries big reservoirs function as sewage treatment plants. Natural aeration solves problems only partly and many pollutants tend to accumulate in the sediments. The acidification by acid rain and by pyrite oxidation has to be controlled by acid neutralizing technologies. Addition of alkaline chemicals is useful only for soft waters, and technologies for (microbial alkalinization of very acidic hardwater mining lakes are in development. The corrective measures differ from those in use for eutrophication control. The salinization and water shortage mostly occurs if more water is used than available. L. Aral, L. Tschad, the Dead Sea or L. Nasser belong to waters with most severe environmental problems on a global scale. Their hydrologic regime needs to be evaluated. The inflow of salt water at the bottom of some mining lakes adds to stability of stratification, and thus accumulation of hydrogen sulphide in the monimolimnion of the meromictic lakes. Destratification, which is the most used technology, is only restricted applicable because of the dangerous concentrations of the byproducts of biological degradation. The contamination of lakes with hazardous substances from industry and agriculture require different restoration technologies, including subhydric isolation and storage, addition of nutrients for better self

  8. Reclaiming the lake

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2016-01-01

    belonging during a weeklong uprising in defense of Lake Conococha. Highlighting the collective actions and personal narratives from participants in the region-wide blockade, the article therefore seeks to understand how dispossessions of environmental resources perceived as common property are cast in terms...... of individual rights that move well beyond the site of conflict. It is therefore argued that the actions to reclaim Lake Conococha were not only a battle for natural resources and clean water, but more fundamentally an attempt to repossess a citizenship that may be constitutionally secured but all...

  9. Lake contamination models…

    OpenAIRE

    Varekamp, Johan C.

    2005-01-01

    "The time to reach steady state in a perfectly mixed reservoir can be derived from the time that it takes for the term exp[-t/R] go to ≈ zero, which occurs if t = 6R, when 99.75% of Cssp has been reached (600 months in the case of the model lake)." J.C. Varekamp. 2003. Lake contamination models for evolution towards steady state. J. Limnol., 62(Suppl.1): 67-72. The above sentence deserves critical consideration on the grounds of physical and experimental arguments. In an elementary physical s...

  10. Reevaluation of lake trout and lake whitefish bioenergetics models

    Science.gov (United States)

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  11. 77 FR 41686 - Safety Zone; Sheffield Lake Fireworks, Lake Erie, Sheffield Lake, OH

    Science.gov (United States)

    2012-07-16

    ... DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Sheffield Lake Fireworks, Lake Erie, Sheffield Lake, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard...

  12. Fish of Bear Lake, Utah

    OpenAIRE

    Palacios, Patsy; Luecke, Chris; Robinson, Justin

    2007-01-01

    There are 13 species of fish found in the waters of Bear Lake. Of those 13, 4 are endemic (found only in Bear Lake). The 4 endemics species are Bonneville cisco, Bonneville whitefish, Bear Lake whitefish, and Bear Lake sculpin. Five of the remaining 9 fish species are native to the region, and 4 are exotic introductions. These native fishes are the Bonneville cutthroat trout, Utah sucker, redside shiner, speckled dace and Utah chub. The exotic fishes are lake trout, common carp, yellow p...

  13. Plutonium in the Great Lakes

    International Nuclear Information System (INIS)

    Since 1971 plutonium concentrations have been measured annually in Lake Michigan and Lake Ontario and at less frequent intervals in the other Great Lakes. The concentrations of plutonium in the water column have decreased only slightly during the 7 y of measurement. The residence times for plutonium in the lakes have been estimated by simple time-concentration models. The apparent sinking rates for plutonium have been found to be essentially constant in all the Great Lakes, which suggest that the basic processes that control the concentrations of dissolved plutonium are similar despite considerable differences in chemical, biological, and physical characteristics of the lakes. Analyses of plutonium in water, suspended solids, material from sediment traps, and sediment cores show that considerable resuspension of previously sedimented material into the hypolimnion occurs throughout a major part of the year. A mechanism is proposed to account for the seasonal cycling of plutonium in the epilimnion of Lake Michigan

  14. Temperature Trends in Montane Lakes

    Science.gov (United States)

    Melack, J. M.; Sadro, S.; Jellison, R.

    2014-12-01

    Long-term temperature trends in lakes integrate hydrological and meteorological factors. We examine temperature trends in a small montane lake with prolonged ice-cover and large seasonal snowfall and in a large saline lake. Emerald Lake, located in the Sierra Nevada (California), is representative of high-elevation lakes throughout the region. No significant trend in outflow temperature was apparent from 1991to 2012. Snowfall in the watershed accounted for 93% of the variability in average summer lake temperatures. Mono Lake (California) lies in a closed, montane basin and is hypersaline and monomictic or meromictic. Temperature profiles have been collected from 1982 to 2010. In the upper water column, the July-August-September water temperatures increased 0.8-1.0°C over the 29 years. This rate of warming is less than published estimates based on satellite-derived skin temperatures and will discussed in the context of general limnological interpretation of temperature trends.

  15. Echoes of Bark Lake.

    Science.gov (United States)

    Duenkel, Nicky; Hemstreet, Jeff

    1997-01-01

    Two former staff members reflect on their feelings about the August 1995 closing of Bark Lake Leadership Centre (Ontario, Canada), which for 49 years had offered outdoor adventure and environmental education courses to youth and adults. They discuss their experiences as both students and teachers at the center, which helped shape their careers in…

  16. Lake Ontario: Nearshore Variability

    Science.gov (United States)

    We conducted a high-resolution survey with towed electronic instrumentation along the Lake Ontario nearshore (720 km) at a 20 meter contour. The survey was conducted September 6-10, 2008 with a shorter 300 km survey conducted August 14-15 for comparing of temporal variability. ...

  17. Kunming-Green Lake

    OpenAIRE

    Ai, Chi-Han

    2012-01-01

    Green Lake of Kunming is near Yunnan University. It is a comfortable place for leisure. As Kunming is known as the "city of eternal spring", its perpetual spring-like weather and its annual average temperature of 15 ° C, it is nice to take a walk in the park.

  18. Cold Lake profitability improvement

    International Nuclear Information System (INIS)

    For the past ten years, Imperial Oil Ltd. has been carrying out a world scale commercial project, using cyclic steam stimulation (CSS) to extract bitumen from the Cold Lake area. Because of the very heavy and viscous nature of Cold Lake bitumen, Imperial Oil has employed CSS as a means of in-situ enhanced recovery. Although this method has been very effective, production has been challenged by the cost of generating and treating steam. To comply with pipeline constraints, Cold Lake bitumen has had to be blended with a diluent. The blended product has been a desirable refinery feedstock, however, it sells for less that light sweet crude, clearly indicating the need for unit cost reduction. Since the start-up of operations nearly a decade ago cost reductions have been achieved in many areas, including production technology, water management, fuel efficiency, services and maintenance, people productivity, electricity costs, and chemical costs. The combined value of these reductions was claimed to be about one third of production costs, resulting in significantly improved competitive position and profitable development of the Cold Lake deposit. 5 figs

  19. Lake level variability in Silver Lake, Michigan: a response to fluctuations in lake levels of Lake Michigan

    Science.gov (United States)

    Fisher, Timothy G.; Loope, Walter L.

    2004-01-01

    Sediment from Silver Lake, Michigan, can be used to constrain the timing and elevation of Lake Michigan during the Nipissing transgression. Silver Lake is separated from Lake Michigan by a barrier/dune complex and the Nipissing, Calumet, and Glenwood shorelines of Lake Michigan are expressed landward of this barrier. Two Vibracores were taken from the lake in February 2000 and contain pebbly sand, sand, buried soils, marl, peat, and sandy muck. It is suggested here that fluctuations in the level of Lake Michigan are reflected in Silver Lake since the Chippewa low phase, and possibly at the end of the Algonquin phase. An age of 12,490 B.P. (10,460±50 14C yrs B.P.) on wood from a buried Entisol may record the falling Algonquin phase as the North Bay outlet opened. A local perched water table is indicated by marl deposited before 7,800 B.P. and peat between 7,760-7,000 B.P. when Lake Michigan was at the low elevation Chippewa phase. Continued deepening of the lake is recorded by the transition from peat to sandy muck at 7,000 B.P. in the deeper core, and with the drowning of an Inceptisol nearly 3 m higher at 6,410 B.P. in the shallower core. A rising groundwater table responding to a rising Lake Michigan base level during the Nipissing transgression, rather than a response to mid-Holocene climate change, explains deepening of Silver Lake. Sandy muck was deposited continually in Silver Lake between Nipissing and modern time. Sand lenses within the muck are presumed to be eolian in origin, derived from sand dunes advancing into the lake on the western side of the basin.

  20. Modelling of radiocaesium in lakes - lake sensitivity and remedial strategies

    International Nuclear Information System (INIS)

    A given fallout of radiocesium (e.g. after the Chernobyl accident) will be distributed and taken up by biota very differently in various types of lake. Thus, lakes have different ''sensitivities'' to radiocesium. Important environmental factors regulating the biouptake of 137Cs are the lake water retention time and the K concentration of the water. Several practically useful and ecologically relevant methods exist to remediate lakes contaminated by radiocesium, e.g. liming, potash treatment and fertilization of low-productive lakes. The basic aim of this paper is to use a validated, state-of-the-art model for radiocesium in lakes, the VAMP model, first to illustrate the fact that different lakes have different 'sensitivities' and then to simulate the effects of alternative remedial methods. Target variables in these tests are Cs concentrations in lake water and in predatory fish. These results emanate from IAEAs VAMP project. The lakes included in this work cover a wide range of lake and catchment characteristics. (Author)

  1. The fisheries resources of Lake Nakivali

    OpenAIRE

    2010-01-01

    Lake Nakivali is one of the four small lakes that form what is known as the koki lake sysyem. It is 14km long,6km wide.26km sqaured in area and has maximum depth of 3.5m at high water level. The lake is located in lake-swamp complex with river Rwizi as the principle inflow, and a number of peripheral lakes among which are four major ones,i.e Lake Nakivali, Mburo, Kachira and Kijanebalola. Lake Nakivali is a controlled lake with four official landing sites, namely: Kikusi, Kahirimbi, Kashojwa ...

  2. Potential strategies for recovery of lake whitefish and lake herring stocks in eastern Lake Erie

    Science.gov (United States)

    Oldenburg, K.; Stapanian, M.A.; Ryan, P.A.; Holm, E.

    2007-01-01

    Lake Erie sustained large populations of ciscoes (Salmonidae: Coregoninae) 120 years ago. By the end of the 19th century, abundance of lake whitefish (Coregonus clupeaformis) had declined drastically. By 1925, the lake herring (a cisco) population (Coregonus artedii) had collapsed, although a limited lake herring fishery persisted in the eastern basin until the 1950s. In the latter part of the 20th century, the composition of the fish community changed as oligotrophication proceeded. Since 1984, a limited recovery of lake whitefish has occurred, however no recovery was evident for lake herring. Current ecological conditions in Lake Erie probably will not inhibit recovery of the coregonine species. Recovery of walleye (Sander vitreus) and efforts to rehabilitate the native lake trout (Salvelinus namaycush) in Lake Erie will probably assist recovery because these piscivores reduce populations of alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), which inhibit reproductive success of coregonines. Although there are considerable spawning substrates available to coregonine species in eastern Lake Erie, eggs and fry would probably be displaced by storm surge from most shoals. Site selection for stocking or seeding of eggs should consider the reproductive life cycle of the stocked fish and suitable protection from storm events. Two potential sites in the eastern basin have been identified. Recommended management procedures, including commercial fisheries, are suggested to assist in recovery. Stocking in the eastern basin of Lake Erie is recommended for both species, as conditions are adequate and the native spawning population in the eastern basin is low. For lake herring, consideration should be given to match ecophenotypes as much as possible. Egg seeding is recommended. Egg seeding of lake whitefish should be considered initially, with fingerling or yearling stocking suggested if unsuccessful. Spawning stocks of whitefish in the western basin of Lake

  3. Lake Mead--clear and vital

    Science.gov (United States)

    Wessells, Stephen M.; Rosen, Michael

    2013-01-01

    Lake Mead – Clear and Vital” is a 13 minute documentary relating the crucial role of science in maintaining high water quality in Lake Mead. The program was produced coincident with release of the Lakes Mead and Mohave Circular a USGS publication covering past and on-going research in the lakes and tributaries of the Lake Mead National Recreation Area.

  4. Predicting Maximum Lake Depth from Surrounding Topography

    Science.gov (United States)

    Lake volume aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate lake volume (i.e. bathymetry) are usually only collected on a lake by lake basis and are difficult to obtain across broad regions. ...

  5. Citizen volunteer water monitoring on Smith Lake

    OpenAIRE

    Alabama Water Watch

    2005-01-01

    Publication includes: Lake Facts and Figures; Long-term Trends in Lake Water Quality; Impacts on the Lake and What's Being Done About It; Trouble Waters; Watershed-level Water Quality Differences; Timeline of AAW (Alabama Water Watch), SLCA (Smith Lake Civic Association) and SLEPC (Smith Lake Environmental Protection Committee); and Alabama's Rich Water Resources and AAW.

  6. Aeolian sand preserved in Silver Lake: a new signal of Holocene high stands of Lake Michigan

    Science.gov (United States)

    Fisher, Timothy G.; Loope, Walter L.

    2005-01-01

    Aeolian sand within lake sediment from Silver Lake, Michigan can be used as a proxy for the timing of high lake levels of Lake Michigan.We demonstrate that the sand record from Silver Lake plotted as percent weight is in-phase with the elevation curve of Lake Michigan since the mid-Holocene Nipissing Phase. Because fluctuations in Lake Michigan's lake level are recorded in beach ridges, and are a response to climate change, the aeolian sand record within Silver Lake is also a proxy for climate change. It appears that increases in dune activity and lake sand are controlled by similar climatic shifts that drive fluctuations in lake level of Lake Michigan. High lake levels destabilize coastal bluffs that drive dune sand instability, and along with greater wintertime storminess, increase niveo-aeolian transport of sand across lake ice. The sand is introduced into the lake each spring as the ice cover melts.

  7. Life history of lake herring in Lake Superior

    Science.gov (United States)

    Dryer, William R.; Beil, Joseph

    1964-01-01

    The average annual commercial catch of lake herring (Coregonus artedi) in U.S. waters of Lake Superior was nearly 12 million pounds in 1929-61. This production contributed 62.4 percent of the total U.S. take of lake herring for the Great Lakes. About 90 percent of the annual catch is taken from small-mesh gill nets during the November-December spawning season. The life-history studies were based on 12,187 fish collected in 1950-62; past growth was computed for 3,779 specimens collected from commercial landings at: Duluth, Minn.; Bayfield, Wis.; and Portage Entry and Marquette, Mich.

  8. Lake Kivu, Limnology and Biogeochemistry of a Tropical Great Lake

    OpenAIRE

    2012-01-01

    In the heart of Africa, a unique lake has attracted the attention of scientists since the beginning of the 20th century. At the foot of the Virunga volcano chain, Lake Kivu harbors a vast amount of dissolved carbon dioxide and methane, making it the most dangerous lake on Earth. But the lake also furnishes many goods and services for surrounding populations and may soon become the most important energy supplier in the area. At the beginning of gas exploitation, the time has come to gather the...

  9. Isotope tracing of throughflow, residency and runoff to lakes for regional assessment of critical acid loadings to aquatic ecosystems

    International Nuclear Information System (INIS)

    Full text: Mining, forestry and hydroelectric development are placing increasing stress on aquatic ecosystems of the Boreal Forest of Canada, particularly within the Athabasca Oil Sands Region of northeastern Alberta (near Ft. McMurray). Evaluation of the sensitivity of various aquatic ecosystems to such disturbances requires an improved understanding of the basic processes that control ecosystem health including water balance, biogeochemical interactions between lakes and their watersheds, acid sensitivity, and potential future modifications to these conditions under changing climate. One of the more pressing issues in Oil Sands development is the capacity of soils and water to buffer acidic emissions and deposition associated with mining and upgrading of bitumen. Current operations emit up to one tonne of SOX and NOx per thousand barrels of oil produced. Many new projects are improving on these emission rates, however, improvements are at considerable cost and future projections are still as much as 600 tonnes of SOX and NOx per day from operations near Ft. McMurray. Sulfur and nitrogen emissions are oxidized in the atmosphere producing sulfate and nitrate anions, reducing the pH of atmospheric moisture and producing acid rain that is deposited on soils and vegetation. Positively charged cations are subsequently mobilized from the soil matrix and leach to surface waters with the deposited nitrate and sulfate reducing the buffering capacity of soils. While most of Alberta's soils have a large cation reserve and capacity to buffer acid deposition, a significant proportion of the landscape in the Ft. McMurray area contains soils with poor buffering capacity, which is expected to enhance the sensitivity of surface waters to acid deposition. The ability of surface waters to buffer acidic deposition is currently being evaluated using a steady state acid-loading model, the Henriksen model, although future efforts also include dynamic modelling. The Henriksen model for

  10. A plant taxonomic survey of the Uranium City region, Lake Athabasca north shore, emphasizing the naturally colonizing plants on uranium mine and mill wastes and other human-disturbed sites

    International Nuclear Information System (INIS)

    A goal of this study was to acquire more complete baseline data on the existing flora of the Uranium City region, both in natural and human-disturbed sites. Emphasis was given to determining which plant species were naturally revegetating various abandoned uranium mine and mill waste disposal areas, other human-disturbed sites, and ecologically analogous sites. Another goal was to document the occurrence and distribution in the study region of rare and possibly endangered species. A further objective was to suggest regionally-occurring species with potential value for revegetating uranium mine and mill waste sites. Field investigations were carried out in the Uranium City region during August, 1981. During this time 1412 plant collections were made; a total of 366 plant species - trees, shrubs, forbs, graminoids, lichens, and bryophytes were recorded. The report includes an annotated checklist of plant species of the Uranium City region and a reference index of plant taxa indicating species that have high revegetation potential

  11. Great Lakes Energy Institute

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, J. Iwan [Case Western Reserve Univ., Cleveland, OH (United States)

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  12. Zooplankton of Lake Kivu

    OpenAIRE

    Darchambeau, François; Isumbisho, Mwapu; Descy, Jean-Pierre

    2012-01-01

    The dominant species of the crustacean plankton in Lake Kivu are the cyclopoid copepods Thermocyclops consimilis and Mesocyclops aequatorialis and the cladoceran Diaphanosoma excisum. Mean crustacean biomass over the period 2003–2004 was 0.99 g C m−2. The seasonal dynamics closely followed variations of chlorophyll a concentration and responded well to the dry season phytoplankton peak. The mean annual crustacean production rate was 23 g C m−2 year−1. The mean trophic transfer efficiency betw...

  13. Bryozoans of Banyoles lake

    OpenAIRE

    Rieradevall i Sant, Maria; Busquets, Josep M.

    1990-01-01

    Data for bryozoan species from Banyoles lake (NE Spain) are presented. Three species have been recorded: Fredericella sultana, Lophopus crystallinus and Plurnatella repens, the first two for the first time in the Iberian peninsula. An examination of the F. sultana colony and the statoblast observations of L. crystallinus and P. repens with the scanning electron rnicroswpe made possible the identification. Details of the floatoblast structure are given.

  14. Lake Urmia is disappearing

    OpenAIRE

    Khatami, Sina

    2015-01-01

    The present article is a translation—to Farsi—of an article by Dr. Ali Mirchi (postdoctoral research associate at the Department of Civil and Environmental Engineering, Michigan Technological University), Dr. Kaveh Madani (lecturer in Environmental Management at the Centre for Environmental Policy, Imperial College London) and Dr. Amir Aghakouchak (assistant professor at the Department of Civil and Environmental Engineering, University of California, Irvine), entitled "Lake Urmia: how Ir...

  15. The Lake Theatre

    OpenAIRE

    Weller, Samantha Joanne

    2015-01-01

    At the beginnings of this thesis, the importance was solely focused on the design of an independent multipurpose theater and the transitions between the public area and backstage. As the year and project progressed, it changed to become a realization and study of architectural experiences within a space. After choosing a site within the Snoqualmie National Forest in Seattle overlooking Lake Serene, decisions were made to design a theater that would not hinder the natural landscape but im...

  16. Bear Lake-Minidoka - Phragmites Control

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bear Lake: Phragmites patches were sprayed on the refuge & north of the lake proper. Minidoka: patches along the Snake River & Lake Walcott were treated...

  17. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Wintering River Easement Refuge, Cottonwood Lake Easement Refuge, Sheyenne Lake Easement Refuge : Narrative report : 1969

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge including Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Cottonwood Lake...

  18. PALEOCLIMATIC CHANGES IN DABUSU LAKE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Study on the carbonate content and oxygen isotope of a sediment section in Dabusu Lake revealed that this region has experienced several cold-wet and warm-dry climatic cycles since 15400 a BP. It was about 6740 a BP when the climate in the region reached a relatively stable warm stage, so that the lake water was gradually condensed and finally a saline lake was formed.

  19. On China's lake fisheries development

    OpenAIRE

    Wu, W.; Yang, N.; Jin, L.

    1991-01-01

    An account is given of the current situation regarding the lake fisheries and fish culture practices in China. The modern lake fisheries take advantage of the 3-D spaces of lakes to fully develop the resources. Currently, the fisheries concentrate on the following 3 aspects: bringing the water body into full play; various types of aquaculture enclosures; and selective measures in resources protection, stocking and aquaculture.

  20. Surface seiches in Flathead Lake

    OpenAIRE

    G. Kirillin; Lorang, M. S.; T. C. Lippmann; C. C. Gotschalk; S. Schimmelpfennig

    2014-01-01

    Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion and bottom sediment transport and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spat...

  1. Lake Evaporation: A Model Study

    OpenAIRE

    Amayreh, Jumah

    1995-01-01

    Reliable evaporation data are an essential requirement in any water and/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured using advanced research instruments (Bowen Ratio and Eddy Correlation). Actual over-lake evapor...

  2. Resilience and Restoration of Lakes

    OpenAIRE

    Cottingham, Kathryn L.; Carpenter, Stephen R.

    1997-01-01

    Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regi...

  3. Algae Bloom in a Lake

    Directory of Open Access Journals (Sweden)

    David Sanabria

    2008-01-01

    Full Text Available The objective of this paper is to determine the likelihood of an algae bloom in a particular lake located in upstate New York. The growth of algae in this lake is caused by a high concentration of phosphorous that diffuses to the surface of the lake. Our calculations, based on Fick's Law, are used to create a mathematical model of the driving force of diffusion for phosphorous. Empirical observations are also used to predict whether the concentration of phosphorous will diffuse to the surface of this lake within a specified time and under specified conditions.

  4. Studies of colloids and suspended particles, Cigar Lake uranium deposit, Saskatchewan, Canada

    International Nuclear Information System (INIS)

    The Cigar Lake U deposit located in the eastern part of the Athabasca Sandstone Basin, consists of a high-grade ore body (up to 55% U) located at a depth of ∼ 430 m. As part of a study to evaluate the analog features of this deposit with respect to a disposal vault for waste nuclear fuel, colloids (1-450 nm) and suspended particles (> 450 nm) in groundwater have been investigated to evaluate their effect on element transport. The results show that particle compositions are similar to the composition of minerals in the sandstones and ore body, suggesting that particles in groundwater are generated by the erosion of fracture-lining minerals and concentrations are affected by the integrity of the host rock. The observed colloid and suspended particle concentrations in the deep groundwaters are too low to have a significant impact on radionuclide migration, provided that radionuclide sorption is reversible. If radionuclides are irreversibly sorbed to particles they cannot sorb to the host rock and their migration can only be evaluated with an understanding of particle mobility. The data for dissolved and particulate U, Th and Ra were used to calculate field-derived distribution ratios (Rd) between particles and groundwater. The wide range of observed Rd values indicates that these radionuclides in particulate form are not in equilibrium with groundwater. U-series isotope data indicated that most of the U and Ra on particles was derived from groundwater. Some particles could have retained their U for as long as 8000 a. The U and Ra contents of particles in the ore and surrounding clay zones are significantly higher than in particles from sandstone, suggesting that the clay has been an effective barrier to particle migration. (author)

  5. Hydrogeochemistry and uranium fixation in the Cigar Lake uranium deposit, northern Saskatchewan

    International Nuclear Information System (INIS)

    The 1.3 billion year old Cigar Lake uranium deposit, discovered by COGEMA in 1981, is a very rich and large mineralization of uraninite-pitchblende and coffinite in the Athabasca Sandstone in northern Saskatchewan. The mineralization occurs at the -450 m deep unconformity contact of the sandstone with the underlying high-grade rocks of the basement. The sandstone, particularly its basal unit, is the regional aquifer and, due to permeability caused by extensive fracturing, groundwater is found in all parts of the deposit. The composition of this groundwater has been studied in detail over the past 3 years. The compositions of the groundwaters from different parts of the deposit reveal a reduced, redox-buffered, steady-state system of water interaction with the ore and host rock. All groundwaters, including those in contact with the mineralization, are dilute, neutral pH waters containing low concentrations of dissolved uranium (∼10-7.9 to 10-9 mol/L U). Concentrations of dissolved radium-226 and radon-222 are also low except in groundwaters sampled within the ore zone. The redox chemistry is controlled by a number of different processes, including inorganic and organic reactions, bacterial activity and radiolysis of water in the ore zone. The iron-redox couple is the main process controlling the redox conditions in the present dynamic system. The formation of iron colloids in the ore zone and the retention of these colloids in the bordering clay zone restrict the migration of naturally occurring radionuclides, such as uranium, thorium and radium, from the ore. Information from the redox, colloid and isotope chemistries is used to discuss the history of uranium fixation in this deposit. (author)

  6. Glacial lakes Buni and Jezerce: Albania

    OpenAIRE

    Milivojević Milovan; Kovačević-Majkić Jelena

    2005-01-01

    The paper presents glacial lakes and glacial relief forms at the foothill of the peak Maja Jezerce in Mt. Prokletije in Albania, near the border with Montenegro. The group of lakes Buni and Jezerce, which consists of six lakes and which genetically belongs to glacial-erosional lakes, is analyzed. Lakes are situated at the cirque bottom, between the moraines and limestone ridges. Except presented morphometric characteristics of lake basins, data about cirque are given, as well as the reconstru...

  7. THE LAKES IN ROMANIA - AN ACTUAL SYNTHESIS

    OpenAIRE

    Petre GÂŞTESCU

    2010-01-01

    The article offers a synthesis of the lakes of Romania. We addressed the following questions: genetic types of lakes, geographical distribution and their use in various fields of activities. Thus, in the territory of Romania is a large genetic diversity of lakes distributed on all major forms of relief and recovery in many economic areas. Romania is particularly present fluvial lakes, glacial lakes and anthropogenic lakes (especially reservoirs).

  8. Lake Charles CCS Project

    Energy Technology Data Exchange (ETDEWEB)

    Leib, Thomas [Leucadia Energy, LLC, Salt Lake City, UT (United States); Cole, Dan [Denbury Onshore, LLC, Plano, TX (United States)

    2015-06-30

    In late September 2014 development of the Lake Charles Clean Energy (LCCE) Plant was abandoned resulting in termination of Lake Charles Carbon Capture and Sequestration (CCS) Project which was a subset the LCCE Plant. As a result, the project was only funded through Phase 2A (Design) and did not enter Phase 2B (Construction) or Phase 2C (Operations). This report was prepared relying on information prepared and provided by engineering companies which were engaged by Leucadia Energy, LLC to prepare or review Front End Engineering and Design (FEED) for the Lake Charles Clean Energy Project, which includes the Carbon Capture and Sequestration (CCS) Project in Lake Charles, Louisiana. The Lake Charles Carbon Capture and Sequestration (CCS) Project was to be a large-scale industrial CCS project intended to demonstrate advanced technologies that capture and sequester carbon dioxide (CO2) emissions from industrial sources into underground formations. The Scope of work was divided into two discrete sections; 1) Capture and Compression prepared by the Recipient Leucadia Energy, LLC, and 2) Transport and Sequestration prepared by sub-Recipient Denbury Onshore, LLC. Capture and Compression-The Lake Charles CCS Project Final Technical Report describes the systems and equipment that would be necessary to capture CO2 generated in a large industrial gasification process and sequester the CO2 into underground formations. The purpose of each system is defined along with a description of its equipment and operation. Criteria for selection of major equipment are provided and ancillary utilities necessary for safe and reliable operation in compliance with environmental regulations are described. Construction considerations are described including a general arrangement of the CCS process units within the overall gasification project. A cost estimate is provided, delineated by system area with cost breakdown showing equipment, piping and materials

  9. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.J.; Tillitt, D.E. [National Biological Service, Columbia, MO (United States). Midwest Science Center

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.

  10. The Lake Ohrid SCOPSCO project

    Science.gov (United States)

    Wagner, Bernd; Wilke, Thomas; Krastel, Sebastian; Zanchetta, Giovanni; Sulpizio, Roberto; Leng, Melanie J.; Francke, Alexander; Baumgarten, Henrike; Cvetkoska, Aleksandra; Giacco, Biagio; Lacey, Jack H.; Leicher, Niklas; Levkov, Zlatko; Lindhorst, Katja; Reed, Jane M.; Zhang, Xiaosen; Sadori, Laura; Vogel, Hendrik; Wagner-Cremer, Friederike; Wonik, Thomas

    2015-04-01

    The ICDP SCOPSCO project at Lake Ohrid in Macedonia and Albania was one of the most successful lake drilling campaigns worldwide. Drilling took place from April to June 2013 and yielded more than 2000 m of sediments from four different sites in the lake. The maximum penetration was 569 m below lake floor and the overall recovery at all drill sites was > 95 %. Almost two years after the drilling operation, core opening and processing as well as biological and geological analyses are still ongoing. However, most of the cores from the main drill site, the so-called DEEP site in the centre of the lake, are meanwhile opened and reveal a unique record of lake history. The extraordinary quality of seismic, borehole logging and core data allows us to achieve the major goals of the SCOPSCO project. Seismic data, diatoms and coarse-grained sediments in the basal cores indicate that Lake Ohrid had no marine origin, as it was speculated in the past. The data show that Lake Ohrid established in a highly dynamic pull-apart basin with varying fluvial and shallow water conditions. On top of these basal sediments, borehole logging data, XRF scanning data, carbonate, and the amount of organic matter indicate a complete and high resolution succession of glacial / interglacial cycles and interspersed stadials and interstadials. This allows us to determine the establishment of Lake Ohrid by means of chronostratigraphic tuning to about 1.3 to 1.5 Ma ago. Additional, independent age control is given by paleomagnetic data and by numerous tephra layers, which can be correlated with well-dated proximal tephra deposits in Italy. The uppermost 350 m of the sediment record contain more than 30 tephras, which makes the Lake Ohrid record to the rosetta stone of distal Italian tephra deposits in the Balkan region. The unique sediment record of Lake Ohrid is fundamental to obtain crucial information on the overall goal of the SCOPSCO project, i.e. to clarify why Lake Ohrid has one of highest

  11. Forecasting Lake-Effect Snow in the Great Lakes Using NASA Satllite Data

    Science.gov (United States)

    Cipullo, Michelle; Molthan, Andrew; Shafer, Jackie; Case, Jonathan; Jedlovec, Gary

    2011-01-01

    This slide presentation reviews the forecast of the lake effect snow in the Great Lakes region using models and infrared estimates of Great Lake Surface Temperatures (GLSTs) from the MModerate Resolution Imaging Spectroradiometer (MODIS) instrument on Terra and Aqua satellites, and other satellite data. This study analyzes Lake Erie and Lake Ontario which produce storm total snowfall ranged from 8-18 inches off of Lake Ontario and 10-12 inches off of Lake Erie for the areas downwind.

  12. Pyramid Lake Renewable Energy Project

    Energy Technology Data Exchange (ETDEWEB)

    John Jackson

    2008-03-14

    The Pyramid Lake Paiute Tribe is a federally recognized Tribe residing on the Pyramid Lake Reservation in western Nevada. The funding for this project was used to identify blind geothermal systems disconnected from geothermal sacred sites and develop a Tribal energy corporation for evaluating potential economic development for profit.

  13. Surface seiches in Flathead Lake

    Science.gov (United States)

    Kirillin, G.; Lorang, M. S.; Lippmann, T. C.; Gotschalk, C. C.; Schimmelpfennig, S.

    2015-06-01

    Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion, and bottom sediment transport, and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spatial characteristics of different seiche modes, we used the original procedure of determining the seiche frequencies from the primitive equation model output with subsequent derivation of the spatial seiche structure at fixed frequencies akin to the tidal harmonic analysis. The proposed procedure revealed specific seiche oscillation features in Flathead Lake, including maximum surface level amplitudes of the first fundamental mode in straights around the largest island; several higher modes appearing locally in the vicinity of the river inflow; the "Helmholtz" open harbor mode, with the period approximately twice that of the longest seiche mode, generated by a large shallow bay connected to the main lake basin; and several rotating seiche modes potentially affecting the lake-wide circulation. We discuss lake management problems related to the spatial seiche distribution, such as shoreline erosion, floods, and transport of sediments and invasive species in Flathead Lake.

  14. PYRAMID LAKE RENEWEABLE ENERGY PLAN

    Energy Technology Data Exchange (ETDEWEB)

    HIGH DESERT GEOCULTURE, LLC

    2009-06-06

    The Pyramid Lake Renewable Energy Plan covers these areas: energy potential (primarily focusing on geothermal resource potential, but also more generally addressing wind energy potential); renewable energy market potential; transmission system development; geothermal direct use potential; and business structures to accomplish the development objectives of the Pyramid Lake Paiute Tribe.

  15. Europa's Great Lakes

    Science.gov (United States)

    Schmidt, B. E.; Blankenship, D. D.; Patterson, G. W.; Schenk, P. M.

    2012-04-01

    Unique to the surface of Europa, chaos terrain is diagnostic of the properties and dynamics of its icy shell. While models have suggested that partial melt within a thick shell or melt-through of a thin shell may form chaos, neither model has been able to definitively explain all observations of chaos terrain. However, we present a new model that suggests large melt lenses form within the shell and that water-ice interactions above and within these lenses drive the production of chaos. Our analysis of the geomorphology of Conamara Chaos and Thera Macula, was used to infer and test a four-stage lens-collapse chaos formation model: 1) Thermal plumes of warm, pure ice ascend through the shell melting the impure brittle ice above, producing a lake of briny water and surface down draw due to volume reduction. 2) Surface deflection and driving force from the plume below hydraulically seals the water in place. 3) Extension of the brittle ice lid generates fractures from below, allowing brines to enter and fluidize the ice matrix. 4) As the lens and now brash matrix refreeze, thermal expansion creates domes and raises the chaos feature above the background terrain. This new "lense-collapse" model indicates that chaos features form in the presence of a great deal of liquid water, and that large liquid water bodies exist within 3km of Europa's surface comparable in volume to the North American Great Lakes. The detection of shallow subsurface "lakes" implies that the ice shell is recycling rapidly and that Europa may be currently active. In this presentation, we will explore environments on Europa and their analogs on Earth, from collapsing Antarctic ice shelves to to subglacial volcanos in Iceland. I will present these new analyses, and describe how this new perspective informs the debate about Europa's habitability and future exploration.

  16. Lake-floor sediment texture and composition of a hydrothermally-active, volcanic lake, Lake Rotomahana

    Science.gov (United States)

    Pittari, A.; Muir, S. L.; Hendy, C. H.

    2016-03-01

    Young volcanic lakes undergo a transition from rapid, post-eruptive accumulation of volcaniclastic sediment to slower pelagic settling under stable lake conditions, and may also be influenced by sublacustrine hydrothermal systems. Lake Rotomahana is a young (129 year-old), hydrothermally-active, volcanic lake formed after the 1886 Tarawera eruption, and provides a unique insight into the early evolution of volcanic lake systems. Lake-bottom sediment cores, 20-46 cm in length, were taken along a transect across the lake and characterised with respect to stratigraphy, facies characteristics (i.e., grain size, componentry) and pore water silica concentrations. The sediments generally comprise two widespread facies: (i) a lower facies of light grey to grey, very fine lacustrine silt derived from the unconsolidated pyroclastic deposits that mantled the catchment area immediately after the eruption, which were rapidly reworked and redeposited into the lake basin; and (ii) an upper facies of dark, fine-sandy diatomaceous silt, that settled from the pelagic zone of the physically stable lake. Adjacent to sublacustrine hydrothermal vents, the upper dark facies is absent, and the upper part of the light grey to grey silt is replaced by a third localised facies comprised of hydrothermally altered pale yellow to yellowish brown, laminated silt with surface iron-rich encrustations. Microspheres, which are thought to be composed of amorphous silica, although some may be halloysite, have precipitated from pore water onto sediment grains, and are associated with a decrease in pore water silicon concentration. Lake Rotomahana is an example of a recently-stabilised volcanic lake, with respect to sedimentation, that shows signs of early sediment silicification in the presence of hydrothermal activity.

  17. Choking Lake Winnipeg

    Science.gov (United States)

    Byrne, J. M.; Little, L. J.; Dodgson, K. A.; MacDonald, R. J.; Graham, J.

    2009-12-01

    The problems of waterway eutrophication and coastal zone hypoxia are reaching epidemic proportions. Fresh water and coastal marine environments around the world are suffering unprecedented pollution loadings. We are developing an education program to address the dramatic need for public, community and K-12 education about the harsh impacts of elevated nutrient loads on fresh and marine water environments. The Lake Winnipeg watershed is adopted as the poster child of fresh water eutrophication in western North America. The watershed, one of the largest on the continent, is in rapid decline due to pollution, population pressures and water diversion. A concerted education program is needed to change personal and society actions that negatively impact the Winnipeg watershed; and the confluence of the watershed - Lake Winnipeg. But the education program goes beyond Lake Winnipeg. Negative impacts of nutrient loads are adversely affecting environments right to the oceans. Major dead zones that are expanding on our continental shelves due to nutrient overloading threaten to coalesce into extensive regions of marine life die-off. This presentation outlines the documentary education production process under development. We are building a series of Public Service Announcements (PSAs) for national television networks. The PSAs will direct educators, stakeholders and citizens to an associated website with educational video clips detailing the issues of eutrophication and hypoxia. The video clips or webisodes, present interviews with leading scientists. The discussions address the causes of the problems, and presents workable solutions to nutrient overloads from a variety of sources. The webisodes are accompanied by notes and advice to teachers on ways and means to use the webisodes in classrooms. The project is fully funed by a group of Canadian Community Foundations, with the understanding the work wil be available free to educators anywhere in the world. Our education

  18. L-Lake macroinvertebrate community

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  19. L-Lake macroinvertebrate community

    International Nuclear Information System (INIS)

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake's macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors

  20. Using biofilms and grazing chironomids (Diptera: Chironomidae) to determine primary production, nitrogen stable isotopic baseline and enrichment within wetlands differing in anthropogenic stressors and located in the Athabasca oil sands region of Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, K.; Ciborowski, J.J. [Windsor Univ., Windsor, ON (Canada); Wytrykush, C.M. [Syncrude Canada Ltd., Edmonton, AB (Canada)

    2009-07-01

    This presentation reported on a study that investigated the effects of oil sands process materials (OSPM) and construction disturbances on primary production and nitrogen stable isotope enrichment in reclaimed and reference wetlands at oil sands mines in the Athabasca basin. Productivity and food web analyses were instrumental in evaluating the succession and viability of reclaimed wetlands. Primary production was estimated through chlorophyll a (Chl a) concentrations and biomass. Carbon (C) and nitrogen (N) stable isotope ratios were used to identify energy sources, storage and the magnitude and direction of energy transfer within food webs. The objectives were to determine primary productivity, the N baseline, and N enrichment from biofilms and grazing invertebrates colonizing artificial substrates immersed in the water column of two OSPM-affected, two constructed reference and two natural reference wetlands. The lower biomass and Chl a concentrations in OSPM-affected and constructed wetlands suggests that both anthropogenic disturbance and OSPM have an adverse effect on primary productivity and overall wetland function.

  1. 77 FR 9652 - Proposed CERCLA Administrative Cost Recovery Settlement; Lake Linden Superfund Site in Lake...

    Science.gov (United States)

    2012-02-17

    ... AGENCY Proposed CERCLA Administrative Cost Recovery Settlement; Lake Linden Superfund Site in Lake Linden... administrative settlement for recovery of past response costs concerning the Lake Linden Superfund Site in Lake..., Chicago, Illinois, C-14J, 60604, (312) 886-6609. Comments should reference the Lake Linden Superfund...

  2. 75 FR 20920 - Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ

    Science.gov (United States)

    2010-04-22

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ... temporary safety zone upon the navigable waters of Lake Havasu on the Colorado River in Lake Havasu City, Arizona for the Lake Havasu Grand Prix. This temporary safety zone is necessary to provide for the...

  3. 27 CFR 9.127 - Cayuga Lake.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Cayuga Lake. 9.127 Section... Lake. (a) Name. The name of the viticultural area described in this section is “Cayuga Lake.” (b) Approved maps. The appropriate map for determining the boundaries of the Cayuga Lake viticultural area...

  4. Citizen volunteer water monitoring on Lake Mitchell

    OpenAIRE

    Deutsch, W.

    2005-01-01

    Publication includes a timeline of AWW and the Lake Mitchell Home Owners and Boat Owners Association as well as: Lake Facts and Figures; Lake Oxygen and Temperature Cycles; Lake Clarity and Eutrophication; Water Quality Differences in the Watershed; Why Is Volunteer Monitoring Important?; and Alabama's Rich Water Resources and AWW.

  5. Hazards within the Bear Lake basin, Utah

    OpenAIRE

    Palacios, Patsy; Luecke, Chris; Robinson, Justin

    2007-01-01

    The Bear Lake basin developed from fault subsidence that continues today, slowly deepening the lake along the eastern side. The Bear Lake graben is about 5 miles long and 4.3-8.6 miles wide. It extends across the Utah-Idaho border and involves faults on both eastern and western sides of Bear Lake....

  6. Three Visits to Yamzhog Yumco Lake

    Institute of Scientific and Technical Information of China (English)

    QIAN

    2005-01-01

    The Yamzhog Yumco Lake is one of the three great holy lakes in Tibet. It is located in Nanggarze County in southern Tibet at an elevation of more than 4,400 meters. It covers some 800 square km and is the largest freshwater lake in the lake basin zone on the northern side of the Himalayas.

  7. 33 CFR 125.08 - Great Lakes.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Great Lakes. 125.08 Section 125... VESSELS § 125.08 Great Lakes. The term Great Lakes as used in the regulations in this subchapter shall include the Great Lakes and their connecting and tributary waters....

  8. 27 CFR 9.34 - Finger Lakes.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Finger Lakes. 9.34 Section... Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural...

  9. Benthos of Spanish lakes and reservoirs

    OpenAIRE

    Prat i Fornells, Narcís; Real i Ortí, Montserrat; Rieradevall i Sant, Maria

    1992-01-01

    A summary of the results from the study of benthos of lakes and reservoirs in Spain is provided, with a list of the species found to date. Spanish natural lakes are smaller than European lakes; the largest is Lake Sanabria, of glacial origin, which is 3 Km long and half a kilorneter wide. Many are very small and situated in the mountains; more than 200 hundred have been recorded in Spain, but only in Lake Sanabria and Lake Banyoles have the benthos been studied. Lake Sanabria is a cold oligot...

  10. Analysis of Drought in Poyang Lake

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed.[Result] Drought occurred frequently in Poyang Lake and the consecutive serious drought occurred now and then.The water level in Poyang Lake since 21st century was lower.The drought in Poyang Lake was due to reduction of precipitation,low water level in Yangtze River and "five lakes",hydraulic ...

  11. The Great Lakes' regional climate regimes

    Science.gov (United States)

    Sugiyama, Noriyuki

    For the last couple of decades, the Great Lakes have undergone rapid surface warming. In particular, the magnitude of the summer surface-warming trends of the Great Lakes have been much greater than those of surrounding land (Austin and Colman, 2007). Among the Great Lakes, the deepest Lake Superior exhibited the strongest warming trend in its annual, as well as summer surface water temperature. We find that many aspects of this behavior can be explained in terms of the tendency of deep lakes to exhibit multiple regimes characterized, under the same seasonally varying forcing, by the warmer and colder seasonal cycles exhibiting different amounts of wintertime lake-ice cover and corresponding changes in the summertime lake-surface temperatures. In this thesis, we address the problem of the Great Lakes' warming using one-dimensional lake modeling to interpret diverse observations of the recent lake behavior. (Abstract shortened by ProQuest.).

  12. Salt transport in Songkhla Lake

    Directory of Open Access Journals (Sweden)

    Pornpinatepong, S.

    2005-07-01

    Full Text Available Salinity surveys in 1997 revealed that in the dry season salinity in Thale Sap Songkhla, Thale Sap and Thale Luang reached the maximum values of 30, 11 and 5 ppt, respectively. Among the complex system of the lake, Khlong Pak Ro showed a complicate seawater transport with a maximal salinity of 20 ppt. Incomplete mixing with a stratification at a depth of 2-3 m occured. The difference in salinity between the surface and the bottom was about 3 ppt. A vertically-averaged salt transport model was employed to simulate the salinity intrusion in the lake. The results showed quite good agreement with the observation. The model depicted a sharp drop of the water level at the entrance from the Gulf into the lake. The tidal energy then spread widely in Thale Sap Songkhla and continuously decreased to Thale Luang. The predicted salinity indicated that salt transport in the lake is governed by tide and water losses from the lake. Tidal movement generated a quasi-steady state of salinity in three months. The water losses for two months caused the salinity to rise 5.8 ppt/1 mm/day loss (~13 m3/sat Pak Ro. With a loss of 2.3 mm/day (~28 m3/s, the whole lake became brackish in three months. The salt entered the lake mainly through Khlong Luang, and only for 13 percent through Ao Thong Ben.

  13. Rehabilitation of Delavan Lake, Wisconsin

    Science.gov (United States)

    Robertson, Dale M.; Goddard, Gerald L.; Helsel, D.R.; MacKinnon, Kevin L.

    2009-01-01

    A comprehensive rehabilitation plan was developed and implemented to shift Delavan Lake, Wisconsin, from a hypereutrophic to a mesotrophic condition. The plan was threefold: (1) reduce external phosphorus (P) loading by applying Best Management Practices in the watershed, enhance an existing wetland, and short-circuit the inflows through the lake, (2) reduce internal P loading by treating the sediments with alum and removing carp, and (3) rehabilitate the fishery by removing carp and bigmouth buffalo and adding piscivores (biomanipulation). The first and second parts of the plan met with only limited success. With only minor reductions in internal and external P loading, P concentrations in the lake returned to near pre-treatment concentrations. The intensive biomanipulation and resulting trophic cascade (increased piscivores, decreased planktivores, increased large zooplankton populations, and reduced phytoplankton populations) eliminated most of the original problems in the lake (blue-green algal blooms and limited water clarity). However, now there is extensive macrophyte growth and abundant filamentous algae. Without significantly reducing the sources of the problems (high P loading) in Delavan Lake, the increased water clarity may not last. With an improved understanding of the individual components of this rehabilitation program, better future management plans can be developed for Delavan Lake and other lakes and reservoirs with similar eutrophication problems.

  14. Advance and application of lake optics research

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The mainstreams of lake optics research in recent decades include optical properties of lakewater,observation, transmission and calculation of underwater radiation, determination of absorption coefficient S of yellow substance, influence of UV-B radiation of lake primary productivity by bio-optical model. Major lake optics applications, such as calculation of lake primary productivity and chl-a, analysis of factors restricting eutrophication, and protection against lake eutrophication are summarized.

  15. Monitoring Change in Great Salt Lake

    Science.gov (United States)

    Naftz, David; Angeroth, Cory; Freeman, Michael; Rowland, Ryan; Carling, Gregory

    2013-08-01

    Great Salt Lake is the largest hypersaline lake in the Western Hemisphere and the fourth largest terminal lake in the world (Figure 1). The open water and adjacent wetlands of the Great Salt Lake ecosystem support millions of migratory waterfowl and shorebirds from throughout the Western Hemisphere [Aldrich and Paul, 2002]. In addition, the area is of important economic value: Brine shrimp (Artemia franciscana) residing in Great Salt Lake support an aquaculture shrimp cyst industry with annual revenues as high as $60 million.

  16. Algae Bloom in a Lake

    OpenAIRE

    David Sanabria

    2008-01-01

    The objective of this paper is to determine the likelihood of an algae bloom in a particular lake located in upstate New York. The growth of algae in this lake is caused by a high concentration of phosphorous that diffuses to the surface of the lake. Our calculations, based on Fick's Law, are used to create a mathematical model of the driving force of diffusion for phosphorous. Empirical observations are also used to predict whether the concentration of phosphorous will diffuse to the surface...

  17. Key Lake spill. Final report

    International Nuclear Information System (INIS)

    On January 5, 1984 contaminated water overflowed a storage reservoir at the Key Lake uranium mill onto the ice on a neighboring lake, into a muskeg area and onto a road. Outflow continued for two days, partially undercutting a retaining dyke. This report concludes the spill was the result of poor operation by the Key Lake Mining Corp.. The environmental impact will be minimal after cleanup. Improvements can be made in the regulatory process, and it is necessary to prepare for possible future mishaps

  18. 2010 Great Lakes Restoration Initiative Bathymetric Lidar: Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data contained in this file contain hydrographic and topographic data collected by the Fugro LADS Mk II system along the Lake Superior coast of Minnessota,...

  19. Near the Lake and around the Lake: Artists and Baikal

    OpenAIRE

    Marina Tkacheva; Iraida Fedchina

    2013-01-01

    The article considers several aspects of how Lake Baikal influences artists’ work:Baikal as a theme for painting and exhibiting;Creative events at Baikal;Baikal as a place where artists live;Half-amateur paintings for sale.

  20. Chase Lake Wetland Management District, Chase Lake Prairie Project: Annual narrative report: Calendar year 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1994 calendar year. The...

  1. Chase Lake Wetland Management District, Chase Lake Prairie Project: Annual narrative report - 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1993 calendar year. The...

  2. Annual narrative report 1995: Chase Lake Wetland Management District, Chase Lake Prairie Project

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1995 calendar year. The...

  3. Holocene lake deposits of Bosten Lake, southern Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    B. Wünnemann; CHEN Fahu; F. Riedel; ZHANG Chengjun; S. Mischke; CHEN Guangjie; D. Demske; MING Jin

    2003-01-01

    A 9.25-m-long sediment core from Bosten Lake, Xinjiang, provides detailed information about changes in the water budget and biological acticity over the last 8400 calendar years. The chronology is constructed from six AMS radiocarbon dates on the terrestrial plant remains. Based on analyses of TOC, CO3, detrital compounds and biogenic SiO2, lake level fluctuations and periods of remarkably-negative water budget appeared at 8.4-8.2 cal ka, 7.38-7.25 cal ka, 5.7-5.5 cal ka, 3.7-3.4 cal ka and 3.3-2.9 cal ka, respectively. As they are in-phase with low lake levels at Sumxi Co and Bangong Co in western Tibet Plateau and with paleolakes in Inner Mongolia, a climate-induced change to somewhat drier andwarmer conditions is inferred. A further drop in lake level after 1320 AD of about 200 yr duration may be attributed to a negative water balance prior to the main phase of the Little Ice Age. Deep and stable lake phases of 1500 yr and 1800yr duration at 7.2-5.7 cal ka and 5.5-3.7 cal ka coincide with maximum moisture during the Holocene Megathermal in China. The long term trend towards ariditysince about 4.3 cal ka can clearly be recognised. The reduced water budget of Bosten Lake from 640-1200 AD may be attributed to local effects.

  4. Big Lake Dam Inspection Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes an inspection of the Big Lake Dam that was done in September of 1983. The inspection did not reveal any conditions that constitute and...

  5. Isotope investigation of Lake Malawi

    International Nuclear Information System (INIS)

    A vertical tritium and stable isotope profile shows that in the meromictic Lake Malawi water mixes slowly but at a significantly higher rate than in Lake Tanganyika, which has similar morphological characteristics. The tritium balance indicates that half or more of the tritium stored in the lake derives from molecular exchange with the atmospheric moisture. The tritium profile enables the vertical mixing rate in the lake to be computed. For this, a three-box model is used corresponding to epilimnion, metalimnion and hypolimnion. The computation indicates that on the average about 25% of the water is exchanged every year between the epilimnion and the metalimnion and about 20% between the metalimnion and the hypolimnion. (author)

  6. Great Lakes Initiative (GLI) Clearinghouse

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Initiative Toxicity Data Clearinghouse is a central location for information on criteria, toxicity data, exposure parameters and other supporting...

  7. Management recommendations: Sand Lake Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Sand Lake National Wildlife Refuge, by a land use specialist. Recommendations, time frame and...

  8. Devils Lake WMD Summer Tour

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is for a tour of Devils Lake Wetland Management District in North Dakota. It includes maps and summaries of the WMD objectives and management...

  9. Folsom Lake 2005 Sedimentation Survey

    Data.gov (United States)

    US Bureau of Reclamation, Department of the Interior — The Bureau of Reclamation (Reclamation) surveyed Folsom Lake in the fall of 2005 via an interagency agreement with the U.S. Army Corps of Engineers (Corps of...

  10. Management recommendations: Benton Lake Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Benton Lake Complex, by a land use specialist. Recommendations, time frame and additional comments are...

  11. Great Lakes Environmental Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — NOAA-GLERL and its partners conduct innovative research on the dynamic environments and ecosystems of the Great Lakes and coastal regions to provide information for...

  12. The Formation of Lake Stars

    CERN Document Server

    Tsai, Victor C

    2007-01-01

    Star patterns, reminiscent of a wide range of diffusively controlled growth forms from snowflakes to Saffman-Taylor fingers, are ubiquitous features of ice covered lakes. Despite the commonality and beauty of these ``lake stars'' the underlying physical processes that produce them have not been explained in a coherent theoretical framework. Here we describe a simple mathematical model that captures the principal features of lake-star formation; radial fingers of (relatively warm) water-rich regions grow from a central source and evolve through a competition between thermal and porous media flow effects in a saturated snow layer covering the lake. The number of star arms emerges from a stability analysis of this competition and the qualitative features of this meter-scale natural phenomena are captured in laboratory experiments.

  13. Benton Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report describes the history of Benton Lake NWR including refuge development, accomplishments, management, wildlife, and waterfowl. Future management plans are...

  14. Lake Turkana National Parks Kenya.

    OpenAIRE

    2005-01-01

    Lake Turkana is the largest, most northerly and most saline of Africa's Rift Valley lakes and an outstanding laboratory for the study of plant and animal communities. The three National Parks are a stopover for migrant waterfowl and are major breeding grounds for the Nile crocodile and hippopotamus. The Koobi Fora deposits are rich in pre-human, mammalian, molluscan and other fossil remains and have contributed more to the understanding of Quaternary palaeoenvironments than any other site on ...

  15. The size-distribution of Earth's lakes.

    Science.gov (United States)

    Cael, B B; Seekell, D A

    2016-01-01

    Globally, there are millions of small lakes, but a small number of large lakes. Most key ecosystem patterns and processes scale with lake size, thus this asymmetry between area and abundance is a fundamental constraint on broad-scale patterns in lake ecology. Nonetheless, descriptions of lake size-distributions are scarce and empirical distributions are rarely evaluated relative to theoretical predictions. Here we develop expectations for Earth's lake area-distribution based on percolation theory and evaluate these expectations with data from a global lake census. Lake surface areas ≥8.5 km(2) are power-law distributed with a tail exponent (τ = 1.97) and fractal dimension (d = 1.38), similar to theoretical expectations (τ = 2.05; d = 4/3). Lakes distributed. An independently developed regional lake census exhibits a similar transition and consistency with theoretical predictions. Small lakes deviate from the power-law distribution because smaller lakes are more susceptible to dynamical change and topographic behavior at sub-kilometer scales is not self-similar. Our results provide a robust characterization and theoretical explanation for the lake size-abundance relationship, and form a fundamental basis for understanding and predicting patterns in lake ecology at broad scales. PMID:27388607

  16. Spatial distribution and compositional variation of APS minerals related to uranium deposits in the Kiggavik-Andrew Lake structural trend, Nunavut, Canada

    Science.gov (United States)

    Riegler, Thomas; Quirt, Dave; Beaufort, Daniel

    2016-02-01

    The Kiggavik-Andrew Lake structural trend consists of four mineralized zones, partially outcropping, lying 2 km south of the erosional contact with the unmetamorphosed sandstone and basal conglomerates of the Paleoproterozoic Thelon Formation. The mineralization is controlled by a major E-W fault system associated with illite and sudoite alteration halos developed in the Archean metagraywackes of the Woodburn Lake Group. Aluminum phosphate sulfate (APS) minerals from the alunite group crystallized in association with the clay minerals in the basement alteration halo as well as in the overlying sandstones, which underwent mostly diagenesis. APS minerals are Sr- and S-rich (svanbergite end-member) in the sedimentary cover overlying the unconformity, whereas they are light rare earth elements (LREE)-rich (florencite end-member) in the altered basement rocks below the unconformity. The geochemical signature of each group of APS minerals together with the petrography indicates three distinct generations of APS minerals related to the following: (1) paleoweathering of continental surfaces prior to the basin occurrence, (2) diagenetic processes during the burial history of the lower unit of the Thelon sandstones, and (3) hydrothermal alteration processes which accompanied the uranium deposition in the basement rocks and partially overlap the sedimentary-diagenetic mineral parageneses. In addition, the association of a first generation of APS minerals with both detrital cerium oxide and aluminum oxy-hydroxide highlights the fact that a part of the detrital material of the basal Thelon Formation originated from eroded paleolaterite (allochthonous regolith). The primary rare earth element (REE)-bearing minerals (e.g., monazite, REE carbonates, and allanite) of the host rocks were characterized to identify the potential sources of REE. The REE chemical composition highlights a local re-incorporation of the REE released from the alteration processes in the APS minerals of

  17. Geographic Analysis of Alaska Lake Districts

    Science.gov (United States)

    Arp, C. D.; Jones, B. M.; Zimmerman, C. E.

    2007-12-01

    The state of Alaska has over 400,000 lakes greater than 0.01 km2 in surface area covering approximately 3.3% of the landscape. As in most lake-rich regions, these lakes are unevenly distributed on the landscape. So in order to better understand how lakes are organized on the landscape and relate this geographic organization to other climatologic, geologic, and biogeographic characteristics, we analyzed the spatial distribution of Alaska lakes. Using a combination of numerical abundance and surface-area extent of lakes, we selected lake density thresholds to identify and delineate 22 lake districts in Alaska. The total area of these 22 lakes districts occupy 16% of Alaska, yet encompass 64% of lakes and 76% of lake surface-area. The three largest lake districts are associated with the Yukon-Kuskokwin Delta, the Northern Arctic Coastal Plain, and the mountain front of the Alaskan Range on the Alaska Peninsula. Interestingly, these largest lake districts are covered by >17% lakes, while most of the smaller lake districts we identified have Parks (NP) and National Wildlife Refuges (NWR). Not surprisingly, 12 of these lake districts occur partly or wholly within NWRs, and all but two are associated with other state or federally managed parks or wildlife refuges. Analysis of lake districts in Alaska, or other regions on Earth, may prove to be useful for better understanding lake change, aquatic and terrestrial habitats, and regional hydrologic budgets and regimes. Such fresh views of the landscape may become increasingly important for improving natural resource science and management in Alaska, where future climate change is predicted to be very rapid.

  18. A multiple lines of evidence approach for the ecological risk assessment of an accidental bitumen release from a steam assisted gravity drainage (SAGD) well in the Athabasca oil sands region.

    Science.gov (United States)

    Berger, Robert G; Aslund, Melissa Whitfield; Sanders, Greg; Charlebois, Michael; Knopper, Loren D; Bresee, Karl E

    2016-01-15

    To assess the ecological impacts of two independent accidental bitumen releases from two steam assisted gravity drainage (SAGD) wells in the Athabasca oil sands region, a multiple lines of evidence (LOE) approach was developed. Following the release in 2010, action was taken to minimize environmental impact, including the selective removal of the most highly impacted vegetation and the use of oil socks to minimize possible runoff. An ecological risk assessment (ERA) was then conducted based on reported concentrations of bitumen related contaminants in soil, vegetation, and water. Results of biological assessments conducted at the site were also included in the risk characterization. Overall, the conclusion of the ERA was that the likelihood of long-term adverse health effects to ecological receptors in the area was negligible. To provide evidence for this conclusion, a small mammal sampling plan targeting Southern red-back voles (Myodes gapperi) was carried out at two sites and two relevant reference areas. Voles were readily collected at all locations and no statistically significant differences in morphometric measurements (i.e., body mass, length, foot length, and adjusted liver weight) were found between animals collected from impact zones of varying levels of coverage. Additionally, no trends corresponding with bitumen coverage were observed with respect to metal body burden in voles for metals that were previously identified in the source bitumen. Hepatic ethoxyresorufin-O-deethylase (EROD) activity was statistically significantly elevated in voles collected from the high impact zones of sites compared to those collected from the reference areas, a finding that is indicative of continued exposure to contaminants. However, this increase in EROD was not correlated with any observable adverse population-wide biological outcomes. Therefore the biological sampling program supported the conclusion of the initial ERA and supported the hypothesis of no significant

  19. FISH FAUNA OF THE HWAJINPO LAKE,KOREA

    Institute of Scientific and Technical Information of China (English)

    JUNKIL; Choi; OSAMU; Mitamura; YASUSHI; Seike; KAORU; Fujinaga

    2006-01-01

    There are sevenlagoons onthe east coast of Korea,including Kyeongpo Lake,Hyang Lake,Mae Lake,Chung-cho Lake,Yeoungrang Lake,Songji Lake and HwajinpoLake.They are all originally natural and brackish waterlakes.Therefore,these lakes are not only historically veryimportant but also have high values for geological,andecological sciences.Natural lakes like lagoons are different from man-made lakes.That is,water level in natural lakes is almostconstant,cline by waterside is not much,and wet landvegetation is well...

  20. Caohai Dianchi Lake Water Pollution Control Plan

    OpenAIRE

    Wang, Zhe

    2010-01-01

    Caohai is located in the lowest of Lake Dian area, and is in this region the only wastewater containing water body. Lake Dian is in the natural succession process and has entered a period of aging and eutrofication. The lake is shallow lake, and therefore the lake water self-purification ability is weaker and weaker. The major rivers into Lake DIan run through some urban areas, villages, farms, industrial areas; therefore a large number of hazardous substances and nutrients are carried from t...

  1. Bear Lake Basin : History, geology, biology, people

    OpenAIRE

    Palacios, Patsy; Luecke, Chris; Robinson, Justin

    2007-01-01

    Bear Lake is a large, deep lake located on the border of Utah and Idaho in Rich County Utah and Bear Lake County Idaho. It was formed through seismic activity along a fault on the eastern side of the lake. Tectonic shifts of the plates along this fault resulted in a lake basin that is over 200 ft deep along the eastern shore with a gradual slope to the western shore. The lake water has high concentrations of calcium carbonate because of high levels of evaporation typical of this semi-arid ...

  2. Heihu (黑湖 - Black Lake)

    OpenAIRE

    Elosua, Miguel

    2011-01-01

    This photo was taken in October 2011. Heihu is located in the Altai Mountains, in the northern tip of Xinjiang, bordering Mongolia and Kazakhstan. The lake is adjacent to the larger Lake Kanas, China's deepest alpine lake, a popular destination among Chinese tourists, some of whom come to the lake in search of a mysterious lake creature that according to legend feeds on horse and cattle. Kazakh nomads inhabit the area, camping around the lake during the summer and descending to the cities as ...

  3. Lake water quality mapping from Landsat

    Science.gov (United States)

    Scherz, J. P.

    1977-01-01

    In the project described remote sensing was used to check the quality of lake waters. The lakes of three Landsat scenes were mapped with the Bendix MDAS multispectral analysis system. From the MDAS color coded maps, the lake with the worst algae problem was easily located. The lake was closely checked, and the presence of 100 cows in the springs which fed the lake could be identified as the pollution source. The laboratory and field work involved in the lake classification project is described.

  4. Investigation of the dramatic changes in lake level of the Bosten Lake in northwestern China

    Science.gov (United States)

    Guo, Mengjing; Wu, Wei; Zhou, Xiaode; Chen, Yongmin; Li, Jing

    2015-01-01

    Bosten Lake, located in the arid region of northwest China, is the largest inland freshwater lake in China. Water resources in Bosten Lake are of great importance for the regional drinking water supply, agricultural irrigation, and economic development of Xinjiang province. In this study, the dynamics of the lake level in Bosten Lake were investigated from 1956 to 2010. We found that the lake level experienced three different periods of change due to the combined influences of climate variation and human activities. Generally, the lake level has shown a significant downward trend since the first observation started in 1956 and dropped to its lowest level in 1987. Thereafter, the lake level presented a continuous upward trend and rose to its highest value in 2002. Then, the level decreased dramatically from 2002 to 2010. A water balance model and the climate elasticity method were used to estimate the reasons for the lake level changes of Bosten Lake. The results showed that an increase in lake evaporation led to the continuous decrease in lake level from 1958 to 1987. Then, human-controlled lake outflow and increasing lake inflow together led to the increase in lake level from 1988 to 2002. During 2003 to 2010, the emergency project of transferring water to Tarim River led to the increase in lake outflow, while the lake inflow obviously decreased because of a decrease in precipitation. These factors resulted in a sharp decrease in the lake level from 2003 to 2010. The changes in lake level indicate changes in available water resources from Bosten Lake. This reason for the analysis of the change in lake level in this study is to support the water resources management of Bosten Lake.

  5. Analysis of eutrophication state and trend for lakes in China

    OpenAIRE

    JIN XIANGCAN

    2003-01-01

    The article analyzes the present state and trend of eutrophication of lakes in China and concludes that lakes throughout the country are commonly undergoing the process of eutrophication: most of urban lakes are facing hypertrophication, many mediumsized lakes are of eutrophic state, some lakes even approaching to hypertrophic level. The five large freshwater lakes are in the condition of eutrophication, especially Lake Caohu and Lake Taihu are already in the state of eutrophication, water qu...

  6. A census of colonially breeding waterbirds on Lake Louise and Skilak Lake, Alaska, 21-22 July 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report presents a census of colonial waterbird sites at Lake Louise and Slikak lake on 21 and 22 July 1981 respectively. Both Lake Louise and Skilak Lake are...

  7. Lake Naivasha, Kenya

    Science.gov (United States)

    2008-01-01

    If you live in Europe and buy roses, there is a good chance that they were grown in Kenya specifically, in one of the colossal greenhouses that blot out the once wild shores of Lake Naivasha, 90km north-west of Nairobi. Some 25% of Europe's cut flowers come from Kenya. After a tentative start in the 1980s the industry is now the country's third-largest foreign-currency earner, bringing in $120m a year. But the recent violence in Kenya is having a major impact on the flower growers. A local trade union says 3,000 of the 30,000 workers employed in Naivasha's flower farms have abandoned their jobs. Kenya emerged as a flower power when Israel scaled down its own industry. It has since lost business to neighboring Ethiopia, which offers tax breaks and better security, but Naivasha's perfect intensity of sunlight and days of near-constant length should keep it on top. The ASTER image was acquired February 2, 2008, covers an area of 25 x 26.6 km, and is located near 0.8 degrees south latitude, 36.4 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  8. 14 CFR 93.69 - Special requirements, Lake Campbell and Sixmile Lake Airports.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Special requirements, Lake Campbell and Sixmile Lake Airports. 93.69 Section 93.69 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Anchorage, Alaska, Terminal Area § 93.69 Special requirements, Lake Campbell and Sixmile Lake Airports....

  9. 77 FR 65574 - Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Draft Comprehensive Conservation...

    Science.gov (United States)

    2012-10-29

    ... Complex. We started this process through a notice in the Federal Register (72 FR 27328; May, 15, 2007... Fish and Wildlife Service Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Draft... assessment (EA) for the Lake Andes National Wildlife Refuge Complex (Complex), which includes Lake Andes...

  10. 33 CFR 110.127 - Lake Mohave and Lake Mead, Nevada and Arizona.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lake Mohave and Lake Mead, Nevada and Arizona. 110.127 Section 110.127 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.127 Lake Mohave and Lake Mead, Nevada and Arizona. (a) Willow...

  11. Acoustic estimates of abundance and distribution of spawning lake trout on Sheboygan Reef in Lake Michigan

    Science.gov (United States)

    Warner, D.M.; Claramunt, R.M.; Janssen, J.; Jude, D.J.; Wattrus, N.

    2009-01-01

    Efforts to restore self-sustaining lake trout (Salvelinus namaycush) populations in the Laurentian Great Lakes have had widespread success in Lake Superior; but in other Great Lakes, populations of lake trout are maintained by stocking. Recruitment bottlenecks may be present at a number of stages of the reproduction process. To study eggs and fry, it is necessary to identify spawning locations, which is difficult in deep water. Acoustic sampling can be used to rapidly locate aggregations of fish (like spawning lake trout), describe their distribution, and estimate their abundance. To assess these capabilities for application to lake trout, we conducted an acoustic survey covering 22 km2 at Sheboygan Reef, a deep reef (trout, that lake trout were 1–2 m above bottom, and that spawning took place over specific habitat. Lake trout density exhibited a high degree of spatial structure (autocorrelation) up to a range of ~190 m, and highest lake trout and egg densities occurred over rough substrates (rubble and cobble) at the shallowest depths sampled (36–42 m). Mean lake trout density in the area surveyed (~2190 ha) was 5.8 fish/ha and the area surveyed contained an estimated 9500–16,000 large lake trout. Spatial aggregation in lake trout densities, similarity of depths and substrates at which high lake trout and egg densities occurred, and relatively low uncertainty in the lake trout density estimate indicate that acoustic sampling can be a useful complement to other sampling tools used in lake trout restoration research.

  12. Exploring trends, causes, and consequences of declining lipids in Lake Superior lake trout

    Science.gov (United States)

    The ability of lake trout to forage in deepwater habitats is facilitated by high lipid content, which affords buoyancy. In Lake Superior, lean lake trout historically occupied depths < 80 m, and siscowet lake trout occupied depths > 80 m. Siscowets have been known f...

  13. 76 FR 2579 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

    Science.gov (United States)

    2011-01-14

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead... establishing a safety zone on the navigable waters of Lake Mead in support of the construction project for Lake... the timing of the construction. Immediate action is necessary to ensure the safety of commercial...

  14. 75 FR 13232 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

    Science.gov (United States)

    2010-03-19

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead... establishing a safety zone on the navigable waters of Lake Mead in support of the construction project for Lake... ensure the public's safety. Background and Purpose Vegas Tunnel Construction will be...

  15. Global Lake and River Ice Phenology Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Lake and River Ice Phenology Database contains freeze and thaw/breakup dates as well as other descriptive ice cover data for 865 lakes and rivers in the...

  16. Biota - 2011 Vegetation Inventory - Marsh Lake, MN

    Data.gov (United States)

    Army Corps of Engineers, Department of the Army, Department of Defense — 2011 Vegetation Classification for Marsh Lake, MN Vegetation Project Report, OMBIL Environmental Stewardship - Level 1 Inventory. Marsh Lake is located on the...

  17. Togiak National Wildlife Refuge lake surveys, 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Preliminary review of the data reveals that all lakes surveyed can be classified as having low conductibility, ranging from the low 20s for the Goodnews Lakes to...

  18. Medicine Lake NWR Water Use Report- 1944

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Medicine Lake NWR for 1944. The document provides tabulated data for each area of Medicine Lake NWR, including the...

  19. Karluk Lake sockeye salmon studies 1984: Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the findings of a study on Karluk Lake sockeye salmon. The objectives of the study were to: collect sediment core samples from Karluk Lake...

  20. Lake evaporation estimates in tropical Africa (Lake Ziway, Ethiopia)

    Science.gov (United States)

    Vallet-Coulomb, Christine; Legesse, Dagnachew; Gasse, Françoise; Travi, Yves; Chernet, Tesfaye

    2001-05-01

    Estimates of evaporation from an open shallow lake in tropical Africa (Lake Ziway, Main Ethiopian Rift) are made by using monthly hydrometeorological data available for the past three decades. On the one hand, annual average estimates are inferred from three climatic approaches, which can be applied in areas with limited meteorological data. The lake energy balance yields an evaporation rate of 1780 mm yr -1, assuming a Bowen ratio of 0.15 (that of Lake Victoria). The Penman method gives an annual evaporation rate of 1870 mm. The complementary relationship lake evaporation model (CRLE) applied on monthly averaged values of air temperature, air humidity and sunshine duration gives 1730 mm yr -1. The sensitivity of each method to changes in input variables is analyzed in order to test the stability of the resulting estimates. This helps discuss uncertainties and possible inter-annual variations of the evaporation rate. On the other hand, the monthly lake level records together with precipitation and river discharge data between 1969 and 1990, allow us to estimate the water balance, providing an annual rate of 1937 mm for the combined evaporation and groundwater losses. The chloride budget is used to discriminate the groundwater from the evaporation loss. It gives us an annual evaporation rate of 1740 mm and a corresponding groundwater loss of 200 mm yr -1. The groundwater loss estimate is of the same order of magnitude as the surface outflow, but the associated error in the former is significant because the result is sensitive to the poorly known chloride content of river inflows. Our results can be used to forecast the impact of increased water consumption in the basin.

  1. Long Lake National Wildlife Refuge : Easement District No. 1 : May to August 1944

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report cover activities during May to August 1944 for Long Lake, Wildfang Lake, Lost Lake, Florence Lake, Moraine Lake, Canfield Lake, Hutchinson...

  2. The most acidified Austrian lake in comparison to a neutralized mining lake

    OpenAIRE

    Moser, Michael; Weisse, Thomas

    2011-01-01

    This study investigated two mining lakes located in the north of Lower Austria. These lakes arose 45 years ago when open cast lignite mining ceased. The lakes are separated by a 7-m wide dam. Due to the oxidation of pyrite, both lakes have been acidified and exhibit iron, sulphate, and heavy metal concentrations several orders of magnitude higher than in circumneutral lakes. The water column of both lakes is divided into two layers by a pronounced chemocline. The smaller mining lake (AML), wi...

  3. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    Directory of Open Access Journals (Sweden)

    Gerhard MAIER

    2005-08-01

    Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

  4. Profundal oligochaete assemblages in Palaearctic lakes

    OpenAIRE

    Timm, Tarmo

    2012-01-01

    The profundal oligochaete fauna is mostly formed of species present also in shallower waters. Endemic taxa have developed only in ancient rift lakes like Lake Baikal. "Common" lakes, mostly of glacial or volcanic origin, are too ephemeral for speciation. In the profundal of larger European oligotrophic lakes, there can occur about 10 tubificid and lumbriculid species. With a decline in dissolved oxygen in water, only 1-2 of them will remain, Tubifex tubifex often being the last surv...

  5. Monitoring change in Great Salt Lake

    Science.gov (United States)

    Naftz, David L.; Angeroth, Cory E.; Freeman, Michael L.; Rowland, Ryan C.; Carling, Gregory

    2013-01-01

    Despite the ecological and economic importance of Great Salt Lake, only limited water quality monitoring has occurred historically. To change this, new monitoring stations and networks—gauges of lake level height and rate of inflow, moored buoys, and multiple lake-bottom sensors—will provide important information that can be used to make informed decisions regarding future management of the Great Salt Lake ecosystem.

  6. Bathythermal habitat use by strains of Great Lakes- and Finger Lakes-origin lake trout in Lake Huron after a change in prey fish abundance and composition

    Science.gov (United States)

    Bergstedt, Roger A.; Argyle, Ray L.; Krueger, Charles C.; Taylor, William W.

    2012-01-01

    A study conducted in Lake Huron during October 1998–June 2001 found that strains of Great Lakes-origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes-origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002–2005. Based on those data, we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002–2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998–2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002–2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998–2001. Aside from the sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002–2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both.

  7. Preliminary isotope studies in Poyang Lake

    International Nuclear Information System (INIS)

    Poyang Lake is the largest fresh water lake in China, and the largest wetland protection area in Asia. The lake serves as the largest buffer for the Yangtze River as well. In order to make better understanding of the water dynamics, water balance, water chemistry, and the relations between lake, rivers and groundwater, isotope investigation has been carried out systematically for one and a half hydrological years. The paper reports the preliminary results of the study. (author)

  8. Preliminary isotope studies of Poyang Lake, China

    International Nuclear Information System (INIS)

    Poyang Lake is the largest fresh water lake in China, and the largest wetland protection area in Asia. The lake serves as the largest buffer for the Yangtze River as well. In order to make better understanding of the water dynamics, water balance, water chemistry, and the relations between lake, rivers and groundwater, isotope investigation has been carried out systematically for one and a half hydrological years. The paper will report the preliminary results from this program. (author)

  9. The Tomb Statues beside Dongqian Lake

    Institute of Scientific and Technical Information of China (English)

    RaoRao

    2005-01-01

    Located 17 kilometers to the City of Ningbo, Dongqian Lake covers an area of 20 square kilometers, which is four only the biggest freshwater lake in Zhejiang Province but atso renowned for its gorgeous scenery. Recently, this beautiful lake once again caught people's eye because a large number of Southern Song Dynasty (1127-1279) gravestone statues were discovered among the mountains beside the lake area.

  10. Seasonal dynamics of phytoplankton community in the bitter lakes and temsah lake

    OpenAIRE

    Nassar, M.Z.; Shams El-Din, N.G.

    2006-01-01

    Water and phytoplankton samples were sampled on a seasonally basis, from autumn 2002 to summer 2003 at five stations located in Bitter Lakes and four at Temsah Lake. A total of 116 taxa were identified, among which 72 taxa of diatoms, 16 dinoflagellates, 14 chlorphytes, 11 cyanophytes, two euglenophytes and one silicoflagellate species. Bitter Lakes were more diversified than Temsah Lake, although the highest population density was recorded at Temsah Lake. A total of 108 taxa were identified ...

  11. The role of satellite lakes in conservation of fish species diversity in the Lake Kyoga basin

    OpenAIRE

    Ogutu-Ohwayo, R.; Wandera, S.B.; Namulemo, G.; Mbabazi, D.

    1999-01-01

    Lakes Victoria and Kyoga had, a diverse fish fauna, which was important as food for local population and valuable in scientific studies. Over the past twenty years, the diversity of fish in these lakes had declined due to over-exploitation, introduction of new fish species including the piscivorous Nile perch and degradation of fish habitat. Studies of satellite lakes in the Victoria and Kyoga lake basins suggested that some of these lakes harboured species which had been lost from the mai...

  12. The influence of load and lake morfology on lake water quality

    OpenAIRE

    Skubic, Jana

    2006-01-01

    In this graduation thesis, the Imboden model is used as a basis for the prediction of the limiting nutrient concentrations in the lake. The Imboden model is a simplified phosphorous model, based on the phosphorus balance in a lake, presuming phospherous is the only limiting factor of lake eutrophication. The model separately describes the processes in the epilimnion and in the hypolimnion. The limiting nutrient concentrations in the lake are strongly influenced by lake morphology and water in...

  13. A Synoptic Climatology of Heavy Rain Events in the Lake Eyre and Lake Frome Catchments

    OpenAIRE

    Michael John Pook; James eRisbey; Caroline eUmmenhofer; Timothy eCohen; Peter eBriggs

    2014-01-01

    The rare occasions when Lake Eyre in central, southern Australia fills with water excite great interest and produce major ecological responses. The filling of other smaller lakes such as Lake Frome, have less impact but can contribute important information about the current and past climates of these arid regions. Here, the dominant synoptic systems responsible for heavy rainfall over the catchments of Lake Eyre and Lake Frome since 1950 are identified and compared. Heavy rain events are defi...

  14. A synoptic climatology of heavy rain events in the Lake Eyre and Lake Frome catchments

    OpenAIRE

    Pook, Michael J.; Risbey, James S.; Ummenhofer, Caroline C.; BRIGGS Peter R.; Cohen, Timothy J.

    2014-01-01

    The rare occasions when Lake Eyre in central, southern Australia fills with water excite great interest and produce major ecological responses. The filling of other smaller lakes such as Lake Frome have less impact but can contribute important information about the current and past climates of these arid regions. Here, the dominant synoptic systems responsible for heavy rainfall over the catchments of Lake Eyre and Lake Frome since 1950 are identified and compared. Heavy rain events are defin...

  15. Eutrophication of Shallow Lakes: Modeling and Management. The Lake Balaton Case Study

    OpenAIRE

    Somlyody, L.; Herodek, S.; Fischer, J

    1983-01-01

    The phenomenon of eutrophication is more irregular in character and less satisfactorily understood for shallow water bodies than for deep lakes. Research, initiated by IIASA, focussed of Lake Balaton, Hungary, as the subject of a case study. Three main considerations promoted the selection of Lake Balaton: 1) a large amount of data was available, due to Hungarian research activities; 2) the lake possesses the "typical" properties of shallow lakes; and 3) serious economic interests are associ...

  16. 27 CFR 9.83 - Lake Erie.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Lake Erie. 9.83 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.83 Lake Erie. (a) Name. The name of the viticultural area described in this section is “Lake Erie.” (b) Approved...

  17. 27 CFR 9.128 - Seneca Lake.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Seneca Lake. 9.128 Section... Lake. (a) Name. The name of the viticultural area described in this section is “Seneca Lake”. (b) Approved Maps. The appropriate maps for determining the boundary of the Seneca Lake viticultural area...

  18. 36 CFR 13.1208 - Lake Camp.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Lake Camp. 13.1208 Section 13... § 13.1208 Lake Camp. Leaving a boat, trailer, or vehicle unattended for more than 72 hours at the facilities associated with the Lake Camp launching ramp is prohibited without authorization from...

  19. 27 CFR 9.99 - Clear Lake.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Clear Lake. 9.99 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.99 Clear Lake. (a) Name. The name of the viticultural area described in this section is “Clear Lake.” (b) Approved...

  20. Salt Lake in Chaidamu Basin

    Institute of Scientific and Technical Information of China (English)

    王良华

    2007-01-01

    Chaidamu Basin(柴达木盆地) is in the west of China. It covers an area(地区) of 220,000 square kilometres(平方公里). The number of salt lakes(盐湖) is more than twenty in it. Chaerhan(察尔汗) Salt Lake is the largest in this area. If you get here, you will find that in the lake there is no water but a thick layer(层) of salt. You can walk in it without difficulty, and cars can come and go across it. The thickest layer of salt in this basin is about fifty metres thick. People tried their best to use the salt to build house...

  1. Periodic structures of Great Lakes levels using wavelet analysis

    OpenAIRE

    Cengiz, Taner M.

    2011-01-01

    The recently advanced approach of wavelet transforms is applied to the analysis of lake levels. The aim of this study is to investigate the variability of lake levels in four lakes in the Great Lakes region where the method of continuous wavelet transform and global spectra are used. The analysis of lake-level variations in the time-scale domain incorporates the method of continuous wavelet transform and the global spectrum. Four lake levels, Lake Erie, Lake Michigan, Lake Ontario, and Lake S...

  2. Lake Volume Monitoring from Space

    Science.gov (United States)

    Crétaux, J.-F.; Abarca-del-Río, R.; Bergé-Nguyen, M.; Arsen, A.; Drolon, V.; Clos, G.; Maisongrande, P.

    2016-03-01

    Lakes are integrators of environmental change occurring at both the regional and global scale. They present a wide range of behavior on a variety of timescales (cyclic and secular) depending on their morphology and climate conditions. Lakes play a crucial role in retaining and stocking water, and because of the significant global environmental changes occurring at several anthropocentric levels, the necessity to monitor all morphodynamic characteristics [e.g., water level, surface (water contour) and volume] has increased substantially. Satellite altimetry and imagery are now widely used together to calculate lake and reservoir water storage changes worldwide. However, strategies and algorithms to calculate these characteristics are not straightforward, and specific approaches need to be developed. We present a review of some of these methodologies by using lakes over the Tibetan Plateau to illustrate some critical aspects and issues (technical and scientific) linked to the observation of climate change impact on surface waters from remote sensing data. Many authors have measured water variation using the limited remote sensing measurements available over short time periods, even though the time series are probably too short to directly link these results with climate change. Indeed, there are many processes and factors, like the influence of lake morphology, that are beyond observation and are still uncertain. The time response for lakes to reach a new state of equilibrium is a key aspect that is often neglected in current literature. Observations over a long period of time, including maintaining a constellation of comprehensive and complementary satellite missions with service continuity over decades, are therefore necessary especially when the ground gauge network is too limited. In addition, the design of future satellite missions with new instrumental concepts (e.g., SAR, SARin, Ka band altimetry, Ka interferometry) will also be suitable for complete

  3. Mechanism and control of lake eutrophication

    Institute of Scientific and Technical Information of China (English)

    QIN Boqiang; YANG Liuyan; CHEN Feizhou; ZHU Guangwei; ZHANG Lu; CHEN Yiyu

    2006-01-01

    A review about lake naturally eutrophi- cating, the internal loading of nutrients from lake sediment as well as the mechanism of algal blooms and the control practices was made, especially the eutrophication problem of shallow lakes since sev- enty percent of fresh water lakes in China are shallow lakes. It was found that shallow lakes are apt toward eutrophication than deep lakes. Without any influ- ences of human activity, shallow lakes in the middle and lower reaches of Yangtze River are still easily eutrophicated, which may be owing to the effects of flood in this area. In shallow lakes, sediments are frequently disturbed by wind-wave and resuspended, which result in huge nutrients release to overlying water. This may be the major reason for higher in- ternal loading of nutrients in shallow lakes than in deep lakes. Algal bloom is an extreme response of lake ecosystem to the eutrophication. Appearance of algal blooms is related to physical condition of lakes, such as underwater radiation (or transparency), temperature, and hydrodynamic conditions, or related to geochemical conditions of lakes, like concentra- tions of nutrients and ratio of nitrogen to phosphorus, as well as the physiological advantage of cyanobac- teria such as vacuole for moving towards the radiant energy-rich zone and the mycosporine-like amino acids (MAAs) for resisting the harm of ultraviolet ra- diation. In shallow lakes, these advantages of cyanobacteria are favorable in the competition than in deep lakes. Also being the shallowness, it is more difficult to reduce nutrient loading and to control algae blooms in shallow lakes. For the control of eutrophi- cation, people should follow the sequence from pollution sources control, ecological restoration to catchment management. To control the internal nu- trient release, physical, chemical, biological tech- niques, and even bionic techniques could be selected. The idea of ecological restoration for a eutrophic lake is to shift the ecosystem

  4. Lava Lakes in Io's Paterae

    Science.gov (United States)

    Radebaugh, J.; McEwen, A. S.; Milazzo, M.; Davies, A. G.; Keszthelyi, L. P.; Geissler, P.

    2002-05-01

    New Galileo images and Galileo and Cassini temperature data lend credence to previous proposals that some of the paterae on Io contain lava lakes, similar in some ways to those observed on Earth. Galileo's October 2001 I32 flyby produced spectacular new high resolution observations of Io's paterae, their margins, and floors. Images reveal where lavas have filled Emakong Patera and overtopped its margins. Landslides from the peaks of Tohil Mons are not present on the adjacent floor of a dark patera, perhaps because they have slumped into a molten lava pit. Dark lavas have filled and drained back from colorful Tupan Patera, leaving a ring of material on its walls. This patera also shows evidence of interaction between molten sulfur and silicate lavas, a relationship observed at the terrestrial Poas Volcano (Francis et al., 1980, Nature 283, 754-756; Oppenheimer and Stevenson, 1990, La Recherche 21,1088-1090). The extremely uniformly dark materials in many other paterae could also be lava lakes. Pele Volcano on Io, in particular, has previously been considered a lava lake based on several characteristics (Davies et al., 2001, JGR 106,33,079-33,103). Recent analyses of eclipse images of Pele from Cassini reveal average temperatures of 1375 K, with variations on short (~10 minute) timescales, consistent with active fountaining in a lava lake. Similar oscillations around high temperatures over these time scales are seen in terrestrial lava lakes, such as at Kupaianaha (Flynn et al., GRL, 19,6461-6476, 1993) and Erta Ale (Bessard, Caillet and others, in progress). Nightside high resolution (60 m/pixel) images from Galileo I32 reveal a region of overturning and convection, with some areas reaching in excess of 1800 K, verifying very high-temperature components identified in high-resolution NIMS data (Lopes et al., 2001, JGR, 106, 33,053-33,078). This region is ringed with small hotspots, comparable to locations of breakup and fountaining at the margins of many terrestrial

  5. Physical Limnology in Lake Banyoles

    OpenAIRE

    Casamitjana, Xavier; Colomer, Jordi; Roget, Elena; Serra Putellas, Teresa

    2006-01-01

    The main physical long-scale processes occurring in Lake Banyoles are reviewed as a tribute to Prof. Margalef. These processes include the water fluxes below the surface of the lake, the behavior of the sediment in suspension in the basins, the heat fluxes at the surface and at the bottom layers, the internal seiching, the formation of a baroclinic current due to differences in cooling between the two lobes, the mixing dynamics, the meromictic behavior of some of the basins and the f...

  6. Noble gases in Tagish Lake

    OpenAIRE

    Grady, Monica; Verchovsky, Sasha; Franchi, Ian; Wright, Ian; Pillinger, Colin

    2001-01-01

    From the introduction: Tagish Lake has been classified as a CI2 chondrite [1] with an interstellar grain abundance enhanced over that of CI1 and CM2 chondrites [2]. Noble gases have been used as markers for the presence of exotic, presolar grains in chondritic meteorites: Xe-HL (nanodiamonds) and Xe-s/Ne-E (SiC). We have measured 4He, Ne, Ar and Xe in whole-rock Tagish Lake, and an orthophosphoric acid-resistant residue, in an effort to define more precisely the...

  7. Gas hydrates of Lake Baikal

    OpenAIRE

    Khlystov, O.; De Batist, M.; Shoji, H; Nishio, S.; L. Naudts; J. Poort

    2011-01-01

    This paper reviews some of the results of recent gas-hydrate studies in Lake Baikal, the only fresh-water lake in the world containing gas hydrates in its sedimentary infill. We give a historical overview of the different investigations and discoveries and highlight some recent breakthroughs in our understanding of the Baikal hydrate system. The importance of mapping mud volcanoes and gas seeps is stressed, as these are currently the only locations where gas hydrates at or very close to the f...

  8. Protecting the endangered lake salmon

    Energy Technology Data Exchange (ETDEWEB)

    Soimakallio, H.; Oesch, P. [ed.

    1997-11-01

    In addition to the Ringed Seal, the labyrinthine Saimaa lake system created after the Ice Age also trapped a species of salmon, whose entire life cycle became adapted to fresh water. In order to improve the living conditions of this lake salmon which - like the ringed seal - is today classified as an endangered species, an intensive research programme has been launched. The partners include the Finnish Game and Fisheries Research Institute, fishing and environmental authorities and - in collaboration with UPM-Kymmene Oy and Kuurnan Voima Oy - the IVO subsidiary Pamilo Oy

  9. Managing Lakes and Lake Basins for Sustainable Use

    OpenAIRE

    World Bank

    2009-01-01

    Lakes and reservoirs are the world's major repository of accessible freshwater. They are central to the livelihoods and economies of a large fraction of the world's population, as well as being centers of aquatic biodiversity. They play a central role in integrated water resources management. Yet in spite of their importance and the growing threats to them, they have not received sufficien...

  10. Post Audit of Lake Michigan Lake Trout PCB Model Forecasts

    Science.gov (United States)

    The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

  11. Feeding ecology of lake whitefish larvae in eastern Lake Ontario

    Science.gov (United States)

    Johnson, James H.; McKenna, James E.; Chalupnicki, Marc A.; Wallbridge, Tim; Chiavelli, Rich

    2009-01-01

    We examined the feeding ecology of larval lake whitefish (Coregonus clupeaformis) in Chaumont Bay, Lake Ontario, during April and May 2004-2006. Larvae were collected with towed ichthyoplankton nets offshore and with larval seines along the shoreline. Larval feeding periodicity was examined from collections made at 4-h intervals over one 24-h period in 2005. Inter-annual variation in diet composition (% dry weight) was low, as was spatial variation among collection sites within the bay. Copepods (81.4%), primarily cyclopoids (59.1%), were the primary prey of larvae over the 3-year period. Cladocerans (8.1%; mainly daphnids, 6.7%) and chironomids (7.3%) were the other major prey consumed. Larvae did not exhibit a preference for any specific prey taxa. Food consumption of lake whitefish larvae was significantly lower at night (i.e., 2400 and 0400 h). Substantial variation in diet composition occurred over the 24-h diel study. For the 24-h period, copepods were the major prey consumed (50.4%) and their contribution in the diet ranged from 29.3% (0400 h) to 85.9% (1200 h). Chironomids made up 33.4% of the diel diet, ranging from 8.0% (0800 h) to 69.9% (0400 h). Diel variation in the diet composition of lake whitefish larvae may require samples taken at several intervals over a 24-h period to gain adequate representation of their feeding ecology.

  12. Isotope techniques in lake water studies

    International Nuclear Information System (INIS)

    Freshwater lakes are among the most easily exploitable freshwater resources. Lakes are also recognized as major sedimentological features in which stored material can be used to study recent climate and pollution evolution. To adequately preserve these important landscape features, and to use them as climatic archives, an improved understanding of processes controlling their hydrologic and bio-geochemical environments if necessary. This article briefly describes the IAEA activities related to the study of lakes in such areas as lake budget, lake dynamics, water contamination, and paleolimnological investigations

  13. Evaluation of offshore stocking of Lake Trout in Lake Ontario

    Science.gov (United States)

    Lantry, B.F.; O'Gorman, R.; Strang, T.G.; Lantry, J.R.; Connerton, M.J.; Schanger, T.

    2011-01-01

    Restoration stocking of hatchery-reared lake trout Salvelinus namaycush has occurred in Lake Ontario since 1973. In U.S. waters, fish stocked through 1990 survived well and built a large adult population. Survival of yearlings stocked from shore declined during 1990–1995, and adult numbers fell during 1998–2005. Offshore stocking of lake trout was initiated in the late 1990s in response to its successful mitigation of predation losses to double-crested cormorants Phalacrocorax auritus and the results of earlier studies that suggested it would enhance survival in some cases. The current study was designed to test the relative effectiveness of three stocking methods at a time when poststocking survival for lake trout was quite low and losses due to fish predators was a suspected factor. The stocking methods tested during 2000–2002 included May offshore, May onshore, and June onshore. Visual observations during nearshore stockings and hydroacoustic observations of offshore stockings indicated that release methods were not a direct cause of fish mortality. Experimental stockings were replicated for 3 years at one site in the southwest and for 2 years at one site in the southeast. Offshore releases used a landing craft to transport hatchery trucks from 3 to 6 km offshore out to 55–60-m-deep water. For the southwest site, offshore stocking significantly enhanced poststocking survival. Among the three methods, survival ratios were 1.74 : 1.00 : 1.02 (May offshore : May onshore : June onshore). Although not statistically significant owing to the small samples, the trends were similar for the southeast site, with survival ratios of 1.67 : 1.00 : 0.72. Consistent trends across years and sites indicated that offshore stocking of yearling lake trout during 2000–2002 provided nearly a twofold enhancement in survival; however, this increase does not appear to be great enough to achieve the 12-fold enhancement necessary to return population abundance to restoration

  14. The lakes of the Jordan Rift Valley

    International Nuclear Information System (INIS)

    This paper presents a summary of the proceedings of a workshop on the Lakes of the Jordan Rift Valley that was held in conjunction with the CRP on The Use of Isotope Techniques in Lake Dynamics Investigations. The paper presents a review of the geological, hydrogeological and physical limnological setting of the lakes in the Jordan Rift Valley, Lake Hula, Lake Kinneret and the Dead Sea. This is complemented by a description of the isotope hydrology of the system that includes the use of a wide range of isotopes: oxygen-18, deuterium, tritium, carbon-14, carbon-13, chlorine isotopes, boron-11 and helium-3/4. Environmental isotope aspects of the salt balances of the lakes, their palaeolimnology and biogeochemical tracers are also presented. The scope of application of isotopic tracers is very broad and provides a clear insight into many aspects of the physical, chemical and biological limnology of the Rift Valley Lakes. (author)

  15. Glacial lakes Buni and Jezerce: Albania

    Directory of Open Access Journals (Sweden)

    Milivojević Milovan

    2005-01-01

    Full Text Available The paper presents glacial lakes and glacial relief forms at the foothill of the peak Maja Jezerce in Mt. Prokletije in Albania, near the border with Montenegro. The group of lakes Buni and Jezerce, which consists of six lakes and which genetically belongs to glacial-erosional lakes, is analyzed. Lakes are situated at the cirque bottom, between the moraines and limestone ridges. Except presented morphometric characteristics of lake basins, data about cirque are given, as well as the reconstruction of the glacier which was formed here. Recent erosion processes are intensive in this area and have considerably changed post-Pleistocene morphology of the lake, as well as the cirque bottom.

  16. Seasonal Reversals of Groundwater Flow Around Lakes and the Relevance to Stagnation Points and Lake Budgets

    Science.gov (United States)

    Anderson, Mary P.; Munter, James A.

    1981-08-01

    Several researchers have observed seasonal reversals in the direction of groundwater flow around lakes. If these reversals are prolonged and are accompanied by the formation of a stagnation point, they may have a significant effect on a lake's water and nutrient budgets. The formation of a stagnation point at a flow-through lake (i.e., a lake that receives groundwater through part of the lake basin and recharges the groundwater system over the rest of the lake basin) is accomplished by the formation of a groundwater mound on the downgradient side of the lake. In this paper the seasonal formation of a stagnation point at Snake Lake, Wisconsin, is investigated with the aid of two-dimensional transient computer models applied in cross section and areally. The analysis demonstrates the potential for the seasonal formation of a stagnation point at a flow-through lake and provides some insight into the transient development of the stagnation point.

  17. CHED Events: Salt Lake City

    Science.gov (United States)

    Wink, Donald J.

    2009-03-01

    The Division of Chemical Education (CHED) Committee meetings planned for the Spring 2009 ACS Meeting in Salt Lake City will be in the Marriott City Center Hotel. Check the location of other CHED events, the CHED Social Event, the Undergraduate Program, Sci-Mix, etc. because many will be in the Salt Palace Convention Center.

  18. Beijing Star Lake Ecology Park

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Beijing Star Lake Ecology Park is a Five-star hotel which has developed multi-functions of restaurant, lodge, bath, landscape seeing, leisure,body exercise, recreation, Ecology agriculture,etc. Occupying an area of 500 mu, the park is an environmental friendly five-star hotel.

  19. Eutrophication of lakes and rivers

    Science.gov (United States)

    Eutrophication is an ecological process, akin to aging, in which a water body is increasingly enriched with organic matter. While the most obvious signs of eutrophication in lakes and rivers involve algal blooms and fish kills, the systemic of eutrophication, although profound, are often not as noti...

  20. Salt Lake 2002 mascot story

    OpenAIRE

    2014-01-01

    The story of the Salt Lake 2002 Olympic Winter Games Mascots is inspired from our culture. Centuries ago, the first inhabitants etched in stone the images of animals that shared their world. These simple pictograms became the foundation for cultural legends — oral stories that inspired generations to respect and admire the natural world of Utah..

  1. Lake Baikal Bibliography, 1989- 1999

    OpenAIRE

    Limnological Institute of RAS SB

    1999-01-01

    This is a bibliography of 839 papers published in English in 1989- 1999 by members of Limnological Institute of RAS SB and by their partners within the framework of the Baikal International Center for Ecological Research. Some of the titles are accompanied by abstracts. Coverage is on different aspects of Lake Baikal.

  2. The Lake Poets in Romanticism

    Institute of Scientific and Technical Information of China (English)

    李陈晶

    2015-01-01

    Romanticism is an essential part in English literature.In this new trend,the group of poets,also called the Lake Poets,used their finest poems to show respect to nature and life,to advocate human instincts and emotions and to look forward to new world.

  3. Schistosomiasis in Lake Malawi villages

    DEFF Research Database (Denmark)

    Madsen, Henry; Bloch, Paul; Makaula, Peter;

    2011-01-01

    Historically, open shorelines of Lake Malawi were free from schistosome, Schistosoma haematobium, transmission, but this changed in the mid-1980s, possibly as a result of over-fishing reducing density of molluscivore fishes. Very little information is available on schistosome infections among...

  4. BACTERIAL INHIBITORS IN LAKE WATER

    Science.gov (United States)

    The populations of six bacterial genera fell rapidly after their addition to sterile lake water but not after their addition to buffer. The decline in numbers of two species that were studied further, Klebsiella pneumoniae and Micrococcus flavus, occurred even when the buffer was...

  5. Stable isotope composition of Earth's large lakes

    Science.gov (United States)

    Jasechko, S.; Gibson, J. J.; YI, Y.; Birks, S. J.; Sharp, Z. D.

    2011-12-01

    Lakes cover about three percent of Earth's continental area. Large lakes can significantly influence lake shore and regional climates by increasing specific humidity during evaporation and by moderating air temperatures. Stable isotopes of oxygen and hydrogen can be used to quantify lake evaporation, providing a supplementary and often cost-advantageous alternative to conventional hydrologic approaches that require over lake monitoring. Further, stable isotopes in lake sediments are an established tool in paleolimnology; however, interpreting changes to a lake's past isotope composition requires a comprehensive understanding of contemporary controls. Here, δ18O and δ2H values of water in modern lakes exceeding roughly five hundred square kilometres are compiled (n > 35). Voluminous and seasonally mixed lakes - such as the North American Great Lakes - have the most homogenous stable isotope compositions, while perennially-stratified and shallow lakes show greater variability. A rudimentary stable isotope mass balance is used to assess evaporation fluxes from large lakes on Earth. The approach taken simultaneously constrains evaporation outputs for both oxygen and hydrogen stable isotopes by accounting for lake effects on the overlying atmosphere. Model development highlights important considerations such as isotopic stratification (Tanganyika), disequilibrium isotopic mass balances (Baikal), and non-steady hydrologic balances. Further, the isotope composition of Earth's continental surface water reservoir is calculated. This value - weighted to volume - is δ18O = -7.5±1.7 per mille relative to standard mean ocean water. The compiled data may be a useful tracer of continental evaporate in global atmospheric water cycle studies and could be coupled to climate models capable of incorporating oxygen-18 and deuterium tracers to improve or validate calculations of lake effects on regional water cycling.

  6. Contaminant Monitoring Strategy for Henrys Lake, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    John S. Irving; R. P. Breckenridge

    1992-12-01

    Henrys Lake, located in southeastern Idaho, is a large, shallow lake (6,600 acres, {approx} 17.1 feet maximum depth) located at 6,472 feet elevation in Fremont Co., Idaho at the headwaters of the Henrys Fork of the Snake River. The upper watershed is comprised of high mountains of the Targhee National Forest and the lakeshore is surrounded by extensive flats and wetlands, which are mostly privately owned. The lake has been dammed since 1922, and the upper 12 feet of the lake waters are allocated for downriver use. Henrys Lake is a naturally productive lake supporting a nationally recognized ''Blue Ribbon'' trout fishery. There is concern that increasing housing development and cattle grazing may accelerate eutrophication and result in winter and early spring fish kills. There has not been a recent thorough assessment of lake water quality. However, the Department of Environmental Quality (DEQ) is currently conducting a study of water quality on Henrys Lake and tributary streams. Septic systems and lawn runoff from housing developments on the north, west, and southwest shores could potentially contribute to the nutrient enrichment of the lake. Many houses are on steep hillsides where runoff from lawns, driveways, etc. drain into wetland flats along the lake or directly into the lake. In addition, seepage from septic systems (drainfields) drain directly into the wetlands enter groundwater areas that seep into the lake. Cattle grazing along the lake margin, riparian areas, and uplands is likely accelerating erosion and nutrient enrichment. Also, cattle grazing along riparian areas likely adds to nutrient enrichment of the lake through subsurface flow and direct runoff. Stream bank and lakeshore erosion may also accelerate eutrophication by increasing the sedimentation of the lake. Approximately nine streams feed the lake (see map), but flows are often severely reduced or completely eliminated due to irrigation diversion. In addition, subsurface

  7. Development of indicators for assessment of Lake Malawi Basin in an Integrated Lake Basin Management (ILBM) framework

    OpenAIRE

    Clara Limbitso Chidammodzi; Victor Shiholo Muhandiki

    2015-01-01

    This paper sought to understand the current state of the management environment of Lake Malawi Basin, deduce a lake vision and develop indicators for assessing Integrated Lake Basin Management (ILBM) in the lake basin. The premise of the study was that targeted indicators are necessary to effectively monitor the lake basin and manage it sustainably. The study focused on the Malawian side of the lake. Interviews, field observations and review of existing lake management and indicator developme...

  8. Lake volume monitoring from space

    Science.gov (United States)

    Crétaux, Jean-Francois; Abarca Del Rio, Rodrigo; Berge-Nguyen, Muriel; Arsen, Adalbert; Drolon, Vanessa; Maisongrande, Philippe

    2016-04-01

    Lakes are integrator of environmental changes occurring at regional to global scale and present a high variety of behaviors on a variety of time scales (cyclic and secular) depending on the climate conditions and their morphology. In addition their crucial importance as water stocks and retaining, given the significant environment changes occurring worldwide at many anthropocentric levels, has increased the necessity of monitoring all its morphodynamics characteristics, say water level, surface (water contour) and volume. The satellite altimetry and satellite imagery together are now widely used for the calculation of lakes and reservoirs water storage changes worldwide. However strategies and algorithms to calculate these characteristics are not straightforward and need development of specific approaches. We intend to present a review of some of these methodologies by using the lakes over the Tibetan Plateau to illustrate some critical aspects and issues (technical and scientific) linked with the survey of climate changes impacts on surface waters from remote sensing data. Many authors have measured water variations using the short period of remote sensing measurements available, although time series are probably too short to lead to definitive conclusions to link these results directly with the framework of climate changes. Indeed, many processes beyond the observations are still uncertain, for example the influence of morphology of the lakes. The time response for a lake to reach new state of equilibrium is one of the key aspects often neglected in the current literature. Observations over long period of time, therein maintaining a constellation of comprehensive and complementary satellite missions with a continuity of services over decades, especially when ground gauges network is too limited is therefore a necessity. In addition, the design of future satellite missions with new instrumental concepts (e.g. SAR, SARin, Ka band altimetry, Ka interferometry) is

  9. Life history of lake herring of Green Bay, Lake Michigan

    Science.gov (United States)

    Smith, Stanford H.

    1956-01-01

    Although the lake herring has been an important contributor to the commercial fish production of Green Bay, little has been known about it. This study is based on field observations and data from about 6,500 lake herring collected over the period 1948 to 1952. Relatively nonselective commercial pound nets were a primary source of material for the study of age and growth. Commercial and experimental gill nets were used to obtain data on gear selectivity and vertical distribution. Scales were employed to investigate age and growth. Age group IV normally dominated commercial catches during the first half of the calendar year and age group III the last half. At these ages the fish averaged about 10.5 inches in length. The season's growth started in May, was most rapid in July, and terminated near the end of October. The sexes grew at the same rate. Selectivity of fishing gear was found to influence the estimation of growth. Geographical and annual differences in growth are shown. Factors that might contribute to discrepancies in calculated growth are evaluated. Possible real and apparent causes of growth compensation are given. The relation between length and weight is shown to vary with sex, season, year, and method of capture. Females were relatively more plentiful in commercial catches in February than in May through December. The percentage of females decreased with increase in age in pound-net catches but increased with age in gill-net samples. Within a year class the percentage of females decreased with increase in age. Most Green Bay lake herring mature during their second or third year of life. They are pelagic spawners with most intensive spawning over shallow areas. Spawning takes place between mid-November and mid-December, and eggs hatch in April and May. Lake herring ovaries contained from 3,500 to 11,200 eggs (averaged 6,375). Progress of spawning by age, sex, and length is given. Lake herring were distributed at all depths in Green Bay in early May, were

  10. 40 CFR 35.1605-3 - Publicly owned freshwater lake.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Publicly owned freshwater lake. 35.1605... Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public access to the lake through publicly owned contiguous land so that any person has the same opportunity...

  11. Cultural Eutrophication of Lonar Lake, Maharashtra, India

    Directory of Open Access Journals (Sweden)

    Vyankatesh B. Yannawar

    2013-06-01

    Full Text Available Lonar is one of the youngest Lake and is unique in the world for its alkalinity and salinity of the water. But its alkalinity, pH and salinity go on decrease day by day. An attempt has been made to examine environmental analysis of Lonar Lake. Objective: This papers aims at improving the water quality in the lakes from hyper-eutrophic to minor eutrophic conditions. Methods: The physical and chemical parameters were analyzed as per APHA. Results: It is found that major Spirulina species of algae was found in lake water. This species Spirulina having medicinal value for human body. This species occupied the Lonar lake water phytoplankton about 90.0% and above. Rests of 10 % are other members of Chlorophyceae, Cynophyceae and Bacillariophyceae also found in this lake. Lonar lake water was found to be very rich in mineral nutrient contents. No fish species was recorded in the same water body. Conclusions: Hence this World heritage lake should be preserved for its alkalinity and salinity. Use of agrochemicals on crater floor; nuisance of tourists; sewage disposal in the lake; constructions on the crater rim; etc. are some of the problems requiring attention. The lake urgently needs to take immediate protection from pollution and save and preserve for future generations.

  12. Lake ice cover and its influence on lake ecology in a Finnish lake district

    Science.gov (United States)

    Leppäranta, Matti; Arvola, Lauri

    2014-05-01

    A wintertime research program on the physics and biology of lakes in Häme lake district in Finland has been performed in the last five years. The set of study lakes contains a wide spectrum in size, depth and trophic status. In this region the lakes freeze over annually for 4-6 months and the mean ice thickness is around 0.5 m. The ice sheet consists of congelation ice and snow-ice. The snow-ice fraction ranges from 0 to 90 per cent depending on the snow fall history and its magnitude makes a major contribution to the ice properties and conditions in the water body beneath the ice, in particular the mechanical strength and optical thickness are much less than for congelation ice. The e-folding depth of light intensity was 50-100 cm for congelation ice and 5-10 cm for snow. A numerical model has been developed to simulate the annual cycle of ice stratigraphy, temperature and thickness. The water bodies had a 1-4 m thick upper mixed layer thick thermocline, and in deeper lakes a lower homogeneous layer. Fall cooling process was crucial to determine the temperature of the lower layer at freeze-up, anything within 0-4°C. Oxygen concentration decreased in winter, especially close to the bottom sediments, and carbon dioxide concentration increased due to respiration activity. Phytoplankton production and biomass level were low or very low and, therefore, heterotrophic and mixotrophic species were abundant. Oxygen depletion in the hypolimnium had several chemical and ecological consequences, such as release of phosphorus from the bottom sediments. In spring, just before the ice-out, photosynthesis was at a high level beneath the ice due to improved light conditions and started to elevate the oxygen concentration in the topmost water layer. Primary production under the ice is limited or prohibited by low level of available light.

  13. Fat content of the flesh of siscowets and lake trout from Lake Superior

    Science.gov (United States)

    Eschmeyer, Paul H.; Phillips, Arthur M., Jr.

    1965-01-01

    Samples of flesh were excised from the middorsal region of 67 siscowets (Salvelinus namaycush siscowet) and 46 lake trout (Salvelinus n. namaycush) collected from Lake Superior. Chemical analysis of the samples revealed a range in fat content (dry weight) of 32.5 to 88.8 per cent in siscowets and 6.6 to 52.3 per cent in lake trout. Percentage fat increased progressively with increase in length of fish in both forms, but the average rate of increase was far greater for siscowets than for lake trout at lengths between 12 and 20 inches. Despite substantial individual variation, the percentage fat in the two forms was widely different and without overlap at all comparable lengths. The range in iodine number of the fat was 100 to 160 for siscowets and 103 to 161 for lake trout; average values were generally lower for siscowets than for lake trout among fish of comparable length. Percentage fat and relative weight were not correlated significantly in either subspecies. The fat content of flesh samples from a distinctive subpopulation of Lake Superior lake trout known as 'humpers' was more closely similar to that of typical lean lake trout than to siscowets, but the rate of increase in fat with increasing length was greater than for lean lake trout. Flesh samples from hatchery-reared stocks of lake trout, hybrid lake trout X siscowets, and siscowets tended to support the view that the wide difference in fat content between siscowets and lake trout is genetically determined.

  14. MORPHOMETRY OF LAKE SFANTA ANA, ROMANIA (LAKE SAINT ANN)

    OpenAIRE

    Gavril PANDI

    2008-01-01

    Lake Sfanta Ana is one of the most emblematic lacustrine complexes of our country. In this context, its monitoring is not only necessary but also compulsory. The study of its evolution and the forecasts are done easier because we have had hydrotopometric highs for about 100 years, even if the frequency of evaluations has not been periodical. The morphometric elements have had a normal evolution, of continuous diminution, specific to lacustrine complexes. The modification rates of the morphome...

  15. Geological nature of subglacial Lake Vostok

    Science.gov (United States)

    Leitchenkov, G. L.; Masolov, V. N.; Lukin, V. V.; Bulat, S. A.; Kurinin, R. G.; Lipenkov, V. Ya.

    2003-04-01

    Lake Vostok is located at the edge of vast upland of East Antarctic (Precambrian) Crystalline Shield and represents a typical extensionally-induced intracontinental rift zone. Type indicators of rift nature are: width (60-80 km) and length (about 300 km) of the lake depression; several (3-5) kilometers of sediments (modeled from gravity data) infilling the lake graben, considerable amplitudes of faults bounding the lake (up to 2 km in bedrock relief and in excess of 5 km in basement topography), half-graben-like structures (rotated crustal blocks) at flanks of the lake traceable to crustal extension; along-strike segmentation of the depression (the presence of two isolated basins, recognized from seismic and gravity data); knee-shaped spatial configuration of the lake and existence of diagonal fractures (displayed in bedrock topography) normally nascent in conditions of tensional stress. The rift graben of Lake Vostok is considered to be a part (branch) of more spacious rift system, main arm of which stretched from the Prydz Bay trough the Lambert Glacier and the eastern foot of Gamburtsev Mts. to, at least, 110E. This rift system is a result of large-scale extensional event, which occurred in East Antarctica in Late Jurassic - Early Cretaceous prior to East Gondwana break-up. Sedimentary infill of this age is proposed to dominate in Vostok Lake, although postrift, preglacial (Cretaceous - Paleogene) strata can also forms significant part of depositional section. Helium isotopes data give evidence that the Lake Vostok rift is not active. On the other hand, thermophilic bacteria found in accretion ice suggest the possibility of hydrothermal activity in lake bottom. The conduits for warm underwater can be provided by deep crustal faults bordering rift graben. Microseismicity recorded in the area of Lake Vostok suggests the possibility of crustal deformations (likely during more dramatic earthquakes) providing a necessary fault permeability for water seepage from

  16. Expanding Models of Lake Trophic State to Predict Cyanobacteria in Lakes: A Data Mining Approach

    Science.gov (United States)

    Background/Question/Methods: Cyanobacteria are a primary taxonomic group associated with harmful algal blooms in lakes. Understanding the drivers of cyanobacteria presence has important implications for lake management and for the protection of human and ecosystem health. Chloro...

  17. Great Lakes Restoration Initiative Great Lakes Mussel Watch(2009-2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Following the inception of the Great Lakes Restoration Initiative (GLRI) to address the significant environmental issues plaguing the Great Lakes region, the...

  18. Lake Morphometry for NHD Lakes in Lower Colorado Region 15 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  19. Lake Morphometry for NHD Lakes in North East Region 1 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  20. Lake Morphometry for NHD Lakes in Arkansas White Red Region 11 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  1. Lake Morphometry for NHD Lakes in Great Basin Region 16 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  2. Lake Morphometry for NHD Lakes in Souris Red Rainy Region 9 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  3. Lake Morphometry for NHD Lakes in Texas-Gulf Region 12 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  4. Lake Morphometry for NHD Lakes in Mid-Atlantic Region 2 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  5. Lake Morphometry for NHD Lakes in Pacific Northwest Region 17 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  6. Lake Morphometry for NHD Lakes in Upper Colorado Region 14 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  7. Lake Morphometry for NHD Lakes in the Upper Portion of the Missouri Region 10 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  8. Lake Morphometry for NHD Lakes in Rio Grande Region 13 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  9. Lake Morphometry for NHD Lakes in Lower Mississippi Region 8 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  10. Lake Morphometry for NHD Lakes in the Lower Portion of the Missouri Region 10 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  11. Ardoch Lake, Kellys Slough, Devils Lake National Wildlife Range : Narrative Report : Calendar Year 1965

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Ardoch Lake, Kellys Slough, Devils Lake National Wildlife Refuge outlines Refuge accomplishments during the 1965 calendar year. The...

  12. Lake Morphometry for NHD Lakes in Upper Mississippi Region 7 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  13. Environmental Assessment: Submerged Aquatic Plant Management of Banks Lake, Banks Lake NWR, Lakeland, Georgia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment is an analysis of five alternatives developed to address themanagement of the submerged aquatic plants of Banks Lake on Banks Lake...

  14. Radiocarbon concentration of lake sediment cellulose from Lake Erhai in southwest China

    International Nuclear Information System (INIS)

    To improve age models for lake sediment cores without suitable 14C dating materials such as terrestrial plant fossils, we investigated the radiocarbon dating of lake sediment cellulose. The cellulose fraction in the sediments was obtained by a sequential decomposition of other organic matter, and subsequently dated by AMS. In general, 14C ages of the lake sediment cellulose obtained from a 10-m sediment core from Lake Erhai on the Yunnan-Guizhou Plateau are in agreement with 14C dates from terrestrial plant fossils. For the early Holocene, however, differences of up to 1000 14C years are observed between lake sediment cellulose and terrestrial plant fossils. This disagreement is probably caused by the contribution of 14C-depleted cellulose synthesized by aquatic plants/algae in the lake. To obtain a precise and accurate chronology based on 14C ages of lake sediment cellulose, the origin of lake sediment cellulose needs to be established

  15. Long Lake National Wildlife Refuge, Long Lake Wetland Management District: Annual narrative report: Calendar year 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, and the easement refuges outlines Refuge accomplishments during the 1985 calendar year. The report...

  16. Hydrology of Malheur Lake, Hydrology of Malheur Lake, Harney County, southeastern Oregon

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The various components of inflow and outflow to and from the lake and their relative magnitudes were identified. In 1972 water year the total inflow to the lake was...

  17. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    OpenAIRE

    Gerhard MAIER; Pfeiffer, Martin; Hans Bernd STICH

    2005-01-01

    The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than ...

  18. Lake trout spawning habitat in the Six Fathom Bank-Yankee Reef lake trout sanctuary, Lake Huron

    Science.gov (United States)

    Edsall, Thomas A.; Brown, Charles L.; Kennedy, Gregory W.; Poe, Thomas P.

    1992-01-01

    Attempts to reestablish self-sustaining stocks of lake trout (Salvelinus namaycush) in the lower four Great Lakes, where the species was extinguished in the 1950s and 1960s, have been largely unsuccessful. To avoid many of the problems believed to be contributing to this failure, the fishery management community recently established several sanctuaries in the offshore waters of the Great Lakes where the development and protection of self-sustaining stocks of lake trout would be a primary management objective. One of these, the Six Fathom Bank-Yankee Reef sanctuary, was created in the south-central portion of Lake Huron. This sanctuary covers 168,000 ha and includes the shallower portions of the Six Fathom and Ipperwash scarps, which are major bathymetric features in the southern half of the lake. Historical accounts describe Six Fathom Bank as the most important lake trout spawning ground in the lake. Here we present the results of lake bed surveys conducted in the sanctuary with side-scan sonar, underwater videocamera systems, and a small research submarine. Our observations of the lake bed are consistent with what is known of the bedrock stratigraphy, glacial history, and karst geomorphology of the Lake Huron basin. Most of the loose rock we found seemed to be derived from local carbonate bedrock formations, although non-carbonate rock probably from Precambrian sources to the north was also present in some areas. Much of the bedrock and loose rock displayed karst solution features described for the Bruce Peninsula on the Ontario shoreline. Our surveys revealed substantial areas of lake bed at water depths of 20–36 m that resembled suitable spawning and fry production habitat for the shallow-water strains of lake trout that are the focus of the rehabilitation effort. Low mid-lake nutrient levels documented recently by others and the extremely high abundance of Mysis relicta (an important item in the diet of young lake trout) that we documented on Yankee Reef

  19. Bottom sediments of Ypacarai Lake

    International Nuclear Information System (INIS)

    Bottom sediments of Ypacarai Lake was investigated with XRF and Mossbauer techniques. The lake of about 120 Km2, is a shallow one, medium deep of about 1.8m. In addition to its use for recreation, its basin has a wide area of influence and of economical significance. Bottom sediments play an important role in the overall distribution of trace elements in the aquatic system and act as a sink for metals. Bottom samples were taken from 5 different sampling stations, selected according to the morphology and population sites in the shore. The concentration of toxic metals was found to be low and no negative ecological impact should be expected. The main metallic ion component is iron (1.69%). Mossbauer studies showed this element appears as Fe+3 and no Fe+2 was detected. It is here suggested that Fe+3 acts as the limiting element which controls eutrophication process

  20. Monitoring and Modelling Lakes and Coastal Environments

    Science.gov (United States)

    Odada, Eric

    2009-01-01

    The monitoring and modeling of lakes and coastal environments is becoming ever more important, particularly because these environments bear heavy loads in terms of human population, and their resources are critical to the livelihoods and well-being of coastal inhabitants and ecosystems. Monitoring and Modelling Lakes and Coastal Environments is a collection of 18 papers arising from the Lake 2004 International Conference on Conservation, Restoration and Management of Lakes and Coastal Wetlands, held in Bhubaneswar, Orissa, India, 9-13 December 2004. Consequently, 15 of the papers are concerned with studies on the Indian subcontinent, and many of the papers focus on India's Lake Chilika, the site of a special session during the conference. Two papers concern Japan, and one focuses on North America's Great Lakes region. Although the book has a regional bias, the replication of best practices that can be drawn from these studies may be useful for an international audience.

  1. A blood chemistry profile for lake trout

    Science.gov (United States)

    Edsall, Carol Cotant

    1999-01-01

    A blood chemistry profile for lake trout Salvelinus namaycush was developed by establishing baseline ranges for several clinical chemistry tests (glucose, total protein, amylase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, calcium, and magnesium). Measurements were made accurately and rapidly with a Kodak Ektachem DT60 Analyzer and the Ektachem DTSC Module. Blood serum was collected from both laboratory-reared lake trout (1978 and 1986 year-classes) and feral spawning trout from Lake Michigan and then analyzed in the laboratory. No clinically significant differences were found between samples analyzed fresh and those frozen for 1 or 6 weeks. The ranges in chemistry variables for feral lake trout were generally wider than those for laboratory-reared lake trout, and significant differences existed between male and female feral lake trout for several tests. Blood chemistry profiles also varied seasonally on fish sampled repeatedly.

  2. Molecular analyses of ostracod flocks from Lake Baikal and Lake Tanganyika

    OpenAIRE

    SCHON, Isa; Martens, Koen

    2012-01-01

    Ancient lakes are excellent laboratories for evolutionary research, where species can be studied in the cradle where they originated. In this article, we investigate two endemic ostracod species flocks from the two oldest lakes in the world, Lake Baikal (LB) (ca. 28 myr) and Lake Tanganyika (LT) (ca. 12 myr), with DNA sequence data. Nuclear ITS1 failed to resolve the phylogeny of both flocks. Whilst most phylogenetic relationships of the Tanganyika flock are resolved with mitochondrial COI, t...

  3. Environmental control of methanotrophsin lakes

    OpenAIRE

    Suarez Rodriguez, Marco

    2011-01-01

    Aerobic methanotrophs (MOB) are a functional group of proteobacteria that use methane as their only energy and carbon source. Phylogenetically, such methanotrophs are affiliated with present alpha and gamma proteobacteria. Methanotrophic microorganisms play an essential role in the methane cycle, since they to a great extent reduce potential methane emissions to the atmosphere. In stratified lakes the aerobic methanotrophs are commonly present at the oxic-anoxic interfaces. This study aims to...

  4. Lake Nasser evaporation reduction study

    Directory of Open Access Journals (Sweden)

    Hala M.I. Ebaid

    2010-10-01

    Full Text Available This study aims to evaluate the reduction of evaporation of Lake Nasser’s water caused by disconnecting (fully or partially some of its secondary channels (khors. This evaluation integrates remote sensing, Geographic Information System (GIS techniques, aerodynamic principles, and Landsat7 ETM+ images. Three main procedures were carried out in this study; the first derived the surface temperature from Landsat thermal band; the second derived evaporation depth and approximate evaporation volume for the entire lake, and quantified evaporation loss to the secondary channels’ level over one month (March by applied aerodynamic principles on surface temperature of the raster data; the third procedure applied GIS suitability analysis to determine which of these secondary channels (khors should be disconnected. The results showed evaporation depth ranging from 2.73 mm/day at the middle of the lake to 9.58 mm/day at the edge. The evaporated water-loss value throughout the entire lake was about 0.86 billion m3/month (March. The analysis suggests that it is possible to save an approximate total evaporation volume loss of 19.7 million m3/month (March, and thus 2.4 billion m3/year, by disconnecting two khors with approximate construction heights of 8 m and 15 m. In conclusion, remote sensing and GIS are useful for applications in remote locations where field-based information is not readily available and thus recommended for decision makers remotely planning in water conservation and management.

  5. Carbon cycling in Lake Superior

    Science.gov (United States)

    Urban, N. R.; Auer, M. T.; Green, S. A.; Lu, X.; Apul, D. S.; Powell, K. D.; Bub, L.

    2005-06-01

    Carbon (C) cycling in Lake Superior was studied within the Keweenaw Interdisciplinary Transport Experiment in Superior (KITES) project to assess (1) whether the lake is net heterotrophic, (2) sources, sinks and residence time for dissolved organic carbon (DOC), (3) importance of terrigenous organic C subsidies, and (4) factors limiting C flow through bacteria. During 3 years of fieldwork, measurements were made of spatial and temporal distributions of C pools and rates of photosynthesis, community respiration, and bacterial production. Measurements were made of the composition of dissolved organic matter (DOM), rates of DOM photolysis, lability of DOM toward microbial consumption, and river inputs of DOM. All measurements suggest the lake is net heterotrophic. The C:N ratios of DOM suggest that it is primarily of terrigenous origin, but other characteristics (size distribution, UV absorption) point to the presence of autochthonous DOM and to alteration of terrigenous material. The lake mass balance indicates that the residence time (˜8 years) of the DOC pool (17 Tg) is short relative to the hydrologic residence time (170 years). The known flux of terrigenous DOC (˜1 Tg/yr) is too low to support annual bacterial carbon demand (6-38 Tg/yr), but microbial respiration is the major sink for terrigenous DOC. A rapidly cycling, autochthonous DOC pool must exist. Microbial activity was correlated with temperature, phosphorus availability, and DOC concentration but not with photosynthesis rates. Measurements of respiration (˜40 Tg/yr), photosynthesis (2-7 Tg/yr), and bacterial production (0.5-2 Tg/yr) are not all mutually compatible and result in a discrepancy in the organic carbon budget.

  6. Microbial Ecology of Lake Kivu

    OpenAIRE

    Llirós, Marc; Descy, Jean-Pierre; Libert, Xavier; Morana, Cédric; Schmitz, Mélodie; Wimba, Louisette; Nzavuga-Izere, Angélique; García-Armisen, Tamara; Borrego, Carles; Servais, Pierre; Darchambeau, François

    2012-01-01

    We review available data on archaea, bacteria and small eukaryotes in an attempt to provide a general picture of microbial diversity, abundances and microbe-driven processes in Lake Kivu surface and intermediate waters (ca. 0–100 m). The various water layers present contrasting physical and chemical properties and harbour very different microbial communities supported by the vertical redox structure. For instance, we found a clear vertical segregation of archaeal and bacterial assemblages bet...

  7. Fisheries Management Plan: Rice Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Rice Lake National Wildlife Refuge provides a sport fishery on three of the four refuge lakes. Fishing is restricted to designated areas. Rice Lake, though not open...

  8. 76 FR 24505 - Great Lakes Pilotage Advisory Committee

    Science.gov (United States)

    2011-05-02

    ... SECURITY Coast Guard Great Lakes Pilotage Advisory Committee AGENCY: Coast Guard, DHS. ACTION: Committee Management; Notice of Federal Advisory Committee Meeting. SUMMARY: The Great Lakes Pilotage Advisory... Great Lakes pilot registration, operating requirements, training policies, and pilotage rates and...

  9. Refuge Land Acquisition Biological Reconnaissance Report Lake Umbagog 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report describes a 15,600-acre area called Lake Umbagog. The focus of the report is on the lake shore, marsh, swamp, and uplands, predominately on the lake's...

  10. Recreational Fishery Management Plan for Lake Andes National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Current condition of lake Andes (1996) and highlights potential problems and recommendations for improving the lake as a hatchery. Lake Andes was a much larger body...

  11. Potential flood volume of Himalayan glacial lakes

    Directory of Open Access Journals (Sweden)

    K. Fujita

    2013-07-01

    Full Text Available Glacial lakes are potentially dangerous sources of glacial lake outburst floods (GLOFs, and represent a serious natural hazard in Himalayan countries. Despite the development of various indices aimed at determining the outburst probability, an objective evaluation of the thousands of Himalayan glacial lakes has yet to be completed. In this study we propose a single index, based on the depression angle from the lakeshore, which allows the lakes to be assessed using remotely sensed digital elevation models (DEMs. We test our approach on five lakes in Nepal, Bhutan, and Tibet using images taken by the declassified Hexagon KH-9 satellite before these lakes experienced an outburst flood. All five lakes had a steep lakefront area (SLA, on which a depression angle was steeper than our proposed threshold of 10° before the GLOF event, but the SLA was no longer evident after the events. We further calculated the potential flood volume (PFV; i.e., the maximum volume of floodwater that could be released if the lake surface was lowered sufficiently to eradicate the SLA. This approach guarantees repeatability to assess the possibility of GLOF hazards because it requires no particular expertise to carry out, though the PFV does not quantify the GLOF risk. We calculated PFVs for more than 2000 Himalayan glacial lakes using visible band images and DEMs of ASTER data. The PFV distribution follows a power-law function. We found that 794 lakes did not have an SLA, and consequently had a PFV of zero, while we also identified 49 lakes with PFVs of over 10 million m3, which is a comparable volume to that of recorded major GLOFs. This PFV approach allows us to preliminarily identify and prioritize those Himalayan glacial lakes that require further detailed investigation on GLOF hazards and risk.

  12. Estimated Optical Constants of Tagish Lake Meteorite

    Science.gov (United States)

    Roush, Ted L.; Fonda, Mark (Technical Monitor)

    2002-01-01

    The visible, near-infrared, and mid-infrared (0.3-25 micron) real and imaginary indices of refraction are derived from reflectance measurements of the Tagish Lake meteorite. These are compared to some real and imaginary indices of refraction of the individual minerals composing the Tagish Lake meteorite. From this comparison it is clear that the imaginary indices of several individual minerals contribute to the estimated imaginary index of the Tagish Lake.

  13. 1997 fisheries statistics, Lake Kariba - Zimbabwe shore

    OpenAIRE

    Songore, N.; Mugwagwa, M.; Moyo, A.

    1998-01-01

    The report provides catch records for the kapenta (Limnothrissa miodon) and inshore fisheries in the Zimbabwean waters of Lake Kariba for the year 1997. Kapenta usually constitute about 94% of the total catch from Lake Kariba; for statistical purposes catches are recorded for the 5 hydrological basins - Mlibizi, Binga, Sengwa, Bumi and Kariba. The kapenta, which occupy the open pelagic waters of the lake, represent a unit stock which is harvested by both Zimbabwe and Zambia; the artisanal fis...

  14. Seismicity of southern Lake Tanganyika

    Science.gov (United States)

    Lavayssiere, A.; Gallacher, R. J.; Keir, D.; Ebinger, C. J.; Drooff, C.; Khalfan, M.; Bull, J. M.

    2015-12-01

    Global seismic networks document frequent and unusually deep earthquakes in East African rift sectors lacking central volcanoes. The deep seismicity means that we can use earthquakes to probe the geometry and kinematics of fault systems throughout the crust, and to understand the distribution of strain between large offset border fault systems and intrabasinal faults. The southern Tanganyika rift zone has the highest seismicity rate within East Africa during the period 1973-present, yet earlier temporary seismometer networks have been too sparse in space and time to relocate earthquakes with location and depth errors of Lake Tanganyika since June 2014 using a network at 12 broadband seismic stations. The distribution of earthquakes shows that deformation primarily occurs on large offset border faults beneath the lake. Subsidiary earthquake activity occurs along the subparrallel Rukwa graben, and beneath the NE-SW striking Mweru rift. The distribution of earthquakes suggests the southern end of lake Tanganyika is characterized by a network of intersecting NNW and NE striking faults. The depths of earthquakes are distributed throughout the crust, consistent with the relatively strong lithosphere.

  15. 78 FR 72706 - Notice of Inventory Completion: Michigan State Police, Houghton Lake Post, Houghton Lake, MI

    Science.gov (United States)

    2013-12-03

    ... National Park Service Notice of Inventory Completion: Michigan State Police, Houghton Lake Post, Houghton Lake, MI AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The Michigan State Police, Houghton Lake Post has completed an inventory of human remains, in consultation with the appropriate...

  16. 78 FR 24228 - Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final Comprehensive Conservation Plan

    Science.gov (United States)

    2013-04-24

    ... review and comment following the announcement in the Federal Register on October 29, 2012 ] (77 FR 65574... Fish and Wildlife Service Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final... conservation plan and finding of no significant impact (FONSI) for the Lake Andes National Wildlife...

  17. 76 FR 13508 - Ninth Coast Guard District Sector Realignment; Northern Lake Michigan and Lake Huron

    Science.gov (United States)

    2011-03-14

    ... Lake Michigan and Lake Huron AGENCY: Coast Guard, DHS. ACTION: Final Rule. SUMMARY: This rule makes... Sector Lake Michigan, Sector Detroit, and Sector Sault Ste. Marie. This action is taken to rebalance... the reassignment of Station Charlevoix and Station Alpena from Group Sault Ste. Marie to Sectors...

  18. Hydrogeologic controls on the groundwater interactions with an acidic lake in karst terrain, Lake Barco, Florida

    Science.gov (United States)

    Lee, T.M.

    1996-01-01

    Transient groundwater interactions and lake stage were simulated for Lake Barco, an acidic seepage lake in the mantled karst of north central Florida. Karst subsidence features affected groundwater flow patterns in the basin and groundwater fluxes to and from the lake. Subsidence features peripheral to the lake intercepted potential groundwater inflow and increased leakage from the shallow perimeter of the lake bed. Simulated groundwater fluxes were checked against net groundwater flow derived from a detailed lake hydrologic budget with short-term lake evaporation computed by the energy budget method. Discrepancies between modeled and budget- derived net groundwater flows indicated that the model underestimated groundwater inflow, possibly contributed to by transient water table mounding near the lake. Recharge from rainfall reduced lake leakage by 10 to 15 times more than it increased groundwater inflow. As a result of the karst setting, the contributing groundwater basin to the lake was 2.4 ha for simulated average rainfall conditions, compared to the topographically derived drainage basin area of 81 ha. Short groundwater inflow path lines and rapid travel times limit the contribution of acid-neutralizing solutes from the basin, making Lake Barco susceptible to increased acidification by acid rain.

  19. 33 CFR 162.138 - Connecting waters from Lake Huron to Lake Erie; speed rules.

    Science.gov (United States)

    2010-07-01

    ... to Lake Erie; speed rules. 162.138 Section 162.138 Navigation and Navigable Waters COAST GUARD... REGULATIONS § 162.138 Connecting waters from Lake Huron to Lake Erie; speed rules. (a) Maximum speed limit for... speed not greater than— (i) 12 statute miles per hour (10.4 knots) between Fort Gratiot Light and...

  20. Diet of lake trout and burbot in northern Lake Michigan during spring: Evidence of ecological interaction

    Science.gov (United States)

    Jacobs, Gregory R.; Madenjian, Charles P.; Bunnell, David B.; Holuszko, Jeffrey D.

    2010-01-01

    We used analyses of burbot (Lota lota) and lake trout (Salvelinus namaycush) diets taken during spring gill-net surveys in northern Lake Michigan in 2006-2008 to investigate the potential for competition and predator-prey interactions between these two species. We also compared our results to historical data from 1932. During 2006-2008, lake trout diet consisted mainly of alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), whereas burbot utilized a much wider prey base including round goby (Neogobius melanostomus), rainbow smelt, alewives, and sculpins. Using the Schoener's diet overlap index, we found a higher potential for interspecific competition in 1932 than in 2006-2008, though diet overlap was not significant in either time period. No evidence of cannibalism by lake trout or lake trout predation on burbot was found in either time period. In 2006-2008, however, lake trout composed 5.4% (by weight) of burbot diet. To determine whether this predation could be having an impact on lake trout rehabilitation efforts in northern Lake Michigan, we developed a bioenergetic-based consumption estimate for burbot on Boulder Reef (a representative reef within the Northern Refuge) and found that burbot alone can consume a considerable proportion of the yearling lake trout stocked annually, depending on burbot density. Overall, we conclude that predation, rather than competition, is the more important ecological interaction between burbot and lake trout, and burbot predation may be contributing to the failed lake trout rehabilitation efforts in Lake Michigan.

  1. Aquatic macrophyte richness in Danish lakes in relation to alkalinity, transparency, and lake area

    DEFF Research Database (Denmark)

    Vestergaard, Ole Skafte; Sand-Jensen, Kaj

    2000-01-01

    We examined the relationship between environmental factors and the richness of submerged macrophytes species in 73 Danish lakes, which are mainly small, shallow, and have mesotrophic to hypertrophic conditions. We found that mean species richness per lake was only 4.5 in acid lakes of low...

  2. Lake Michigan lake trout PCB model forecast post audit (oral presentation)

    Science.gov (United States)

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents an...

  3. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, McLean National Wildlife Refuge, Camp Lake Easement Refuge, Hiddenwood Easement Refuge, Lake Otis Easement Refuge, Lost Lake Easement Refuge, Sheyenne Lake Easement Refuge : Narrative report : 1971

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, McLean National Wildlife Refuge, Camp Lake...

  4. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, McLean National Wildlife Refuge, Camp Lake Easement Refuge, Hiddenwood Easement Refuge, Lake Otis Easement Refuge, Lost Lake Easement Refuge, Sheyenne Lake Easement Refuge: Narrative report: 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, McLean National Wildlife Refuge, Camp Lake...

  5. Heavy Metal Contents of Lake Sapanca

    OpenAIRE

    YALÇIN, Nevin; SEVİNÇ, Vahdettin

    2001-01-01

    The heavy metal pollution of Lake Sapanca located in the Marmara region (Turkey), was investigated over time. The lake is the drinking water source of the city of Adapazarı and its environs. The D-80 (TEM) motorway passes about 5 km along the lake's zero point in the Sapanca district. The motorway's wastewater drainages have been connected to the lake without having been subjected to any wastewater treatment. The motorway was opened to service in October 1990. Analyses w...

  6. THE LAKES FROM ROŞIA MONTANĂ

    OpenAIRE

    Răzvan-Horaţiu BĂTINAŞ

    2009-01-01

    The mining industry related to the gold-silver ores has created some particular category of lakes, rare at national level. These small lakes have been used for processing the raw material extracted from the open pits or mine galleries. In the past at Roşia Montană were more than 100 lakes with this type of use, but now only few have remained. The paper will analyze the morphometrical and qualitative water features of the lakes and also the will emphasize the touristic potential of these water...

  7. /sup 210/Pb fluxes in acidified lakes

    International Nuclear Information System (INIS)

    The acidification of softwater lakes by atmospheric deposition of strong acids has occurred in several regions of the world; however, the rate of acidification of freshwater systems is generally unknown. The authors have tested the hypothesis that the /sup 210/Pb technique can be used to establish the chronologies of sediments in acidified lakes, with the purpose of establishing the rate of change of the chemical and perhaps biological composition of the water. Sediment cores were collected from four lakes near Sudbury, Ontario, Canada, that either were acidic (pH 4.2 to 4.4) or had been acidic, but were recently neutralized by the addition of calcium carbonate/calcium hydroxide. /sup 210/Pb flux was measured at five sites per lake. The whole lake fluxes in the Sudbury lakes were significantly lower than those of 11 nonacidic lakes -- 250 km to the southeast. Because it is unlikely that lead (Pb) is leached from the sediments, it is hypothesized that acidification results in alteration of the sedimentation mechanism, leading to reduced /sup 210/Pb (and stable Pb) retention in acidic lakes. Therefore, the /sup 210/Pb method is not suitable for establishing sediment chronologies in recently acidified lakes using existing models

  8. Global patterns in lake surface temperature trends

    Science.gov (United States)

    O'Reilly, C.; Sharma, S.; Gray, D.; Hampton, S. E.; Read, J. S.; Rowley, R.; McIntyre, P. B.; Lenters, J. D.; Schneider, P.; Hook, S. J.

    2014-12-01

    Temperature profoundly affects dynamics in the water bodieson which human societies depend worldwide. Even relatively small water temperature changes can alter lake thermal structure with implications for water level, nutrient cycling, ecosystem productivity, and food web dynamics. As air temperature increases with climate change and human land use transforms watersheds, rising water temperatures have been reported for individual lakes or regions, but a global synthesis is lacking; such a synthesis is foundational for understanding the state of freshwater resources. We investigated global patterns in lake surface water temperatures between 1985 and 2009 using in-situ and satellite data from 236 lakes. We demonstrate that lakes are warming significantly around the globe, at an average rate of 0.34 °C per decade. The breadth of lakes in this study allowed examination of the diversity of drivers across global lakes, and highlighted the importance of ice cover in determining the suite of morphological and climate drivers for lake temperature dynamics. These empirical results are consistent with modeled predictions of climate change, taking into account the extent to which water warming can be modulated by local environmental conditions and thus defy simple correlations with air temperature. The water temperature changes we report have fundamental importance for thermal structure and ecosystem functioning in global water resources; recognition of the extent to which lakes are currently in transition should have broad implications for regional and global models as well as for management.

  9. The pollution of East Lake,Wuhan

    Institute of Scientific and Technical Information of China (English)

    Yi xiGu; Mialy Rakotondravah

    2009-01-01

    @@ 1.The history East Lake was an open lake:she connected Yangtze River through Qlngshan Channel.The water level was controlled by Yangtze River:rising in summer,and decreasing in winter.After building Wufeng Gate in 1957,changing the Qingshan harbor as water supply channel,the East Lake is completely isolated from Yangtze River and then East Lake changes from a natural lake to a closed lake by human control.The watar level is related with rainfall,evaporation,surface runoff,pumping off by the factories along the lake,agricultural and domestic sewage water.East Lake is a typical shallow lake in the northeast of Wuhan city.When the water level is 20.5m,the area is 28km2, volume is 62 million m3,and catchment area is 186 km2.The deepest position:4.75m,average depth is 2.21m2,And also it is a multi-function:water-sport entertainments.drinking water source,fishing,industrial water and famous scene.

  10. Residence time and physical processes in lakes

    Directory of Open Access Journals (Sweden)

    Nicoletta SALA

    2003-09-01

    Full Text Available The residence time of a lake is highly dependent on internal physical processes in the water mass conditioning its hydrodynamics; early attempts to evaluate this physical parameter emphasize the complexity of the problem, which depends on very different natural phenomena with widespread synergies. The aim of this study is to analyse the agents involved in these processes and arrive at a more realistic definition of water residence time which takes account of these agents, and how they influence internal hydrodynamics. With particular reference to temperate lakes, the following characteristics are analysed: 1 the set of the lake's caloric components which, along with summer heating, determine the stabilizing effect of the surface layers, and the consequent thermal stratification, as well as the winter destabilizing effect; 2 the wind force, which transfers part of its momentum to the water mass, generating a complex of movements (turbulence, waves, currents with the production of active kinetic energy; 3 the water flowing into the lake from the tributaries, and flowing out through the outflow, from the standpoint of hydrology and of the kinetic effect generated by the introduction of these water masses into the lake. These factors were studied in the context of the general geographical properties of the lake basin and the watershed (latitude, longitude, morphology, also taking account of the local and regional climatic situation. Also analysed is the impact of ongoing climatic change on the renewal of the lake water, which is currently changing the equilibrium between lake and atmosphere, river and lake, and relationships

  11. Lake Titicaca: History and current studies

    International Nuclear Information System (INIS)

    This article summarizes results of Titicaca lake water balance studies including the findings of the IAEA Technical Cooperation Project RLA/08/022. Direct precipitation over the lake accounts for about 55% of the water inflow and rivers and streams provide about 45% of the water inflow. Diffuse groundwater leakage into the lake from coastal aquifers is believed to represent a negligible term of water balance. Evaporation from the lake is strong and accounts for more than 95% of the water losses. The isotopic and chemical composition data obtained within the frameworks of the IAEA Technical Cooperation Project RLA/08/022 are discussed

  12. Paleolimnological assessment of riverine and atmospheric pathways and sources of metal deposition at a floodplain lake (Slave River Delta, Northwest Territories, Canada).

    Science.gov (United States)

    MacDonald, Lauren A; Wiklund, Johan A; Elmes, Matthew C; Wolfe, Brent B; Hall, Roland I

    2016-02-15

    Growth of natural resource development in northern Canada has raised concerns about the effects on downstream aquatic ecosystems, but insufficient knowledge of pre-industrial baseline conditions continues to undermine ability of monitoring programs to distinguish industrial-derived contaminants from those supplied by natural processes. Here, we apply a novel paleolimnological approach to define pre-industrial baseline concentrations of 13 priority pollutant metals and vanadium and assess temporal changes, pathways and sources of these metals at a flood-prone lake (SD2) in the Slave River Delta (NWT, Canada) located ~500 km north of Alberta's oil sands development and ~140 km south of a former gold mine at Yellowknife, NWT. Results identify that metal concentrations, normalized to lithium concentration, are not elevated in sediments deposited during intervals of high flood influence or low flood influence since onset of oil sands development (post-1967) relative to the 1920-1967 baseline established at SD2. When compared to a previously defined baseline for the upstream Athabasca River, several metal-Li relations (Cd, Cr, Ni, Zn, V) in post-1967 sediments delivered by floodwaters appear to plot along a different trajectory, suggesting that the Peace and Slave River watersheds are important natural sources of metal deposition at the Slave River Delta. However, analysis revealed unusually high concentrations of As deposited during the 1950s, an interval of very low flood influence at SD2, which corresponded closely with emission history of the Giant Mine gold smelter indicating a legacy of far-field atmospheric pollution. Our study demonstrates the potential for paleolimnological characterization of baseline conditions and detection of pollution from multiple pathways in floodplain ecosystems, but that knowledge of paleohydrological conditions is essential for interpretation of contaminant profiles. PMID:26688053

  13. The Diatom Stratigraphy of Rawapening Lake, Implying Eutrophication History

    OpenAIRE

    Tri Retnaningsih Soeprobowati; Suwarno Hadisusanto; Peter Gell; Atun Zawadski

    2012-01-01

    Problem statement: The use of diatoms to reconstruct past ecological conditions in lakes is well established. Diatoms are microscopic algae that forms siliceous frustules which allow them to preserve well in sediments. Rawapening Lake is one of 15 Indonesian lakes identified as 2010-2014 National Priority Lakes. Naturally, Rawapening is a tectono-volcanic lake. In the early 1900s, the sole outlet of the lake, Tuntang River, was impounded for hydroelectricity, irrigation and fisheries. Since t...

  14. Long Lake National Wildlife Refuge and Long Lake Wetland Management District: Annual narrative report: Calendar year 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, Slade NWR, Florence Lake NWR, and the easement refuges outlines Refuge accomplishments during the...

  15. Long Lake National Wildlife Refuge and Long Lake Wetland Management District: Annual narrative report: Calendar year 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, Slade NWR, Florence Lake NWR, and the easement refuges outlines Refuge accomplishments during the...

  16. Long Lake National Wildlife Refuge and Long Lake Wetland Management District: Annual narrative report: Calendar year 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, Slade NWR, Florence Lake NWR, and the easement refuges outlines Refuge accomplishments during the...

  17. Long Lake National Wildlife Refuge and Long Lake Wetland Management District: Annual narrative report: Calendar year 1996

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, Slade NWR, Florence Lake NWR, and the easement refuges outlines Refuge accomplishments during the...

  18. Long Lake National Wildlife Refuge and Long Lake Wetland Management District: Annual narrative report: Calendar year 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, Slade NWR, Florence Lake NWR, and the easement refuges outlines Refuge accomplishments during the...

  19. Long Lake National Wildlife Refuge and Long Lake Wetland Management District: Annual narrative report: Calendar year 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, Slade NWR, Florence Lake NWR, and the easement refuges outlines Refuge accomplishments during the...

  20. Long Lake National Wildlife Refuge and Long Lake Wetland Management District: Annual narrative report: Calendar year 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Long Lake NWR, Long Lake WMD, Slade NWR, Florence Lake NWR, and the easement refuges outlines Refuge accomplishments during the...

  1. Holocene Lake Records on Kamchatka

    Science.gov (United States)

    Diekmann, Bernhard; Biskaborn, Boris; Chapligin, Bernhard; Dirksen, Oleg; Dirksen, Veronika; Hoff, Ulrike; Meyer, Hanno; Nazarova, Larisa

    2014-05-01

    The availibility of terrestrial records of Holocene palaeoenvironmental changes in eastern Siberia still is quite limited, compared to other regions on the northern hemisphere. In particular, the Kamchatka Peninsula as an important climate-sensitive region is very underrepresented. Situated at the border of northeastern Eurasia, the maritime-influenced terrestrial setting of Kamchatka offers the potential to pinpoint connections of environmental changes between the periglacial and highly continental landmasses of eastern Siberia and the sub-Arctic Pacific Ocean and Sea of Okhotsk. The study region lies at the eastern end-loop of the global thermohaline ocean conveyor belt and is strongly affected by atmospheric teleconnections. Volcanic, tectonic, and glacial processes overprint palaeoenvironmental changes in addition to primary climate forcing. In order to widen our understanding of plaeoclimate dynamics on Kamchatka, sediment cores from different lake systems and peat sections were recovered and analysed by a multi-proxy approach, using sedimentological and geochemical data as well as fossil bioindicators, such as diatoms, pollen, and chironomids. Chronostratigraphy of the studied records was achieved through radiocarbon dating and tephrostratigraphy. Sediment cores with complete Holocene sedimentary sequences were retrieved from Lake Sokoch, an up to six metre deep lake of proglacial origin, situated at the treeline in the Ganalsky Ridge of southern central Kamchatka (53°15,13'N, 157°45.49' E, 495 m a.s.l.). Lacustrine sediment records of mid- to late Holocene age were also recovered from the up to 30 m deep Two-Yurts Lake, which occupies a former proglacial basin at the eastern flank of the Central Kamchatka Mountain Chain, the Sredinny Ridge (56°49.6'N, 160°06.9'E, 275 m a.s.l.). In addition to sediment coring in the open and deep Two-Yurts Lake, sediment records were also recovered from peat sections and small isolated forest lakes to compare

  2. Environmental isotope signatures of the largest freshwater lake in Kerala

    International Nuclear Information System (INIS)

    Sasthamkotta lake, the largest freshwater lake in Kerala, serves as a source for drinking water for more than half a million people. Environmental 137Cs analysis done on undisturbed sediment core samples reveals that the recent rate of sedimentation is not uniform in the lake. The useful life of lake is estimated as about 800 years. The δD and δ18O values of the lake waters indicate that the lake is well mixed with a slight variation horizontally. The stable isotope studies on well waters from the catchment indicate hydraulic communication with the lake and lake groundwater system is flow-through type. Analytical model also supports this view. (author)

  3. The decreasing level of Toshka Lakes seen from space

    CERN Document Server

    Sparavigna, Amelia Carolina

    2011-01-01

    Toshka Lakes are lakes recently formed in the Sahara Desert of Egypt, by the water of the Nile, conveyed from the Nasser Lake through a canal in the Toshka Depression. From space, astronauts noticed the growing of a first lake, the easternmost one, in 1998. Then additional lakes grew in succession due west, the westernmost one between 2000 and 2001. In fact, sources of precious information on Toshka Lakes are the pictures takes by the crews of space missions and the satellite imagery. They show that, from 2006, the lakes started shrinking. A set of recent images displays that the surface of the easternmost lake is strongly reduced.

  4. Planning Interventions for Lake Conservation: A Case of Shahpura Lake, Bhopal, India

    Science.gov (United States)

    Munoth, Navneet; Nagaich, Anugrah Anilkumar

    2015-09-01

    With due increment in the development process of India, the problems related to environment are under constant increment and its contamination has now became a great threat for the rich ecology of the country. Particularly, the problems regarding the water quality are now becoming more acute and complicated due to increasing urbanization, industrialization, siltation, agricultural run-off and discharge of untreated sewage water. The city Bhopal in India having named as the city of lakes, is also experiencing similar issues. The famous characteristic lakes of Bhopal are under great environmental stress due to pollution from various sources. The Shahpura lake is one such lake, situated well within the city. A number of wards and colonies surrounding the lake boundary discharge their sewage and silage into the existing drainage network of the area, which ultimately finds its way into the lake through open drains. The main source of contamination in the lake is sewage fed drains, which are dumped into the lake during the summers. Besides this, other activities like bathing, cloth washing, cattle bathing and religious activities like idol immersion etc. also paves the way for high concentration of harmful chemicals in the lake. This work mainly discusses the existing situation and causes of water pollution in the Shahpura lake of Bhopal. It also brings into light the constitutional safeguards related to Lake Conservation in India and reviews their practical implications. In the end, it focuses on recommending the lake conservation strategies for the case of Shahpura lake; and suggests measures that could be adopted elsewhere to prevent the issue of lake pollution from various sources, emphasizing the importance of lakes.

  5. Determining lake surface water temperatures (LSWTs) worldwide using a tuned 1-dimensional lake model (FLake, v1)

    OpenAIRE

    Layden, A.; S. MacCallum; Merchant, C.

    2015-01-01

    FLake, a 1-dimensional freshwater lake model, is tuned for 244 globally distributed large lakes using lake surface water temperatures (LSWTs) derived from Along-Track Scanning Radiometers (ATSRs). The model, tuned using only 3 lake properties; lake depth, albedo (snow and ice) and light extinction co-efficient, substantially improves the measured biases in various features of the LSWT annual cycle, including the LSWTs of saline and high altitude lakes. The daily ...

  6. 78 FR 53675 - Safety Zone; Lake Erie Heritage Foundation, Battle of Lake Erie Reenactment; Lake Erie, Put-in...

    Science.gov (United States)

    2013-08-30

    ... for each Battle of Lake Erie Reenactment support vessel. In a separate temporary rule (78 FR 44014...-366-9826. SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Erie Heritage Foundation, Battle...

  7. Late Quaternary lake-level changes of Lake El'gygytgyn, NE Siberia

    OpenAIRE

    Juschus, O.; Pavlov, M.; G. Schwamborn; Preusser, F.; Fedorov, G.; Melles, M.

    2011-01-01

    Lake El'gygytgyn is situated in a 3.6 Ma old impact crater in northeastern Siberia. Presented here is a reconstruction of the Quaternary lake-level history as derived from sediment cores from the southern lake shelf. There, a cliff-like bench 10 m below the modern water level has been investigated. Deep-water sediments on the shelf indicate high lake levels during a warm Mid-Pleistocene period. One period with low lake level prior to Marine Oxygen Isotope Stage (MIS) 3 has been identified, fo...

  8. Effects of storm-water runoff on an urban lake, Lake Ellyn at Glen Ellyn, Illinois

    Science.gov (United States)

    Striegl, R.G.

    1985-01-01

    Detention of urban runoff was observed to have physical, chemical, and biological effects on a small lake located near Chicago, Illinois. Accumulated bottom sediments reduce lake storage and have comparatively high concentrations of metals and organic compounds. Concentrations of many constituents dissolved in the lake water are seasonally cyclic, with annual concentration peaks occurring during the winter. Maintenance of desirable benthic invertebrate and fish communities, and development of undesirable phytoplankton blooms appear to be inhibited by sediments deposited on the lake bottom and suspended in the lake water. (USGS)

  9. Spatial distribution of seepage at a flow-through lake: Lake Hampen, Western Denmark

    DEFF Research Database (Denmark)

    Kidmose, Jacob Baarstrøm; Engesgaard, Peter Knudegaard; Nilsson, Bertel; Laier, Troels; Looms, Majken Caroline

    2011-01-01

    The spatial distribution of seepage at a flow-through lake in western Denmark was investigated at multiple scales with integrated use of a seepage meter, lake–groundwater gradients, stable isotope fractionation (d18O), chlorofl uorocarbon (CFC) apparent ages, land-based and off -shore geophysical...... recharge patiern of the lake and relating these to the geologic history of the lake. Recharge of the surrounding aquifer by lake water occurs off shore in a narrow zone, as measured from lake–groundwater gradients. A 33-m-deep d18O profi le at the recharge side shows a lake d18O plume at depths that...

  10. Radioactivity of lakes in the urbanized territories

    International Nuclear Information System (INIS)

    Full text: The lakes contain the same radioactive elements as rivers and seas. Main radioactive elements in natural waters are uranium, radium, radon and potassium. To study radioactivity of the lakes in the Absheron peninsula in 1998 and in 2000 we took specimens of water and bottom sediments from 20 typical lakes. Selection site of bottom specimens is: coast-centre of the lake, from the surface of the floor as deep as 0,5 m. There was determined amount of thorium, radium, potassium, radon-220, radon-222 in Bq/l and in the bottom sediments there was determined amount of uranium (in compliance with radium), thorium, potassium in Bq/kg. All these analyses were made in Geology Institute of Azerbaijan National Academy of Sciences. Results of the analyses to verify amount of radionuclides in the water of the investigated lakes demonstrate their absence in the water. Only one analysis revealed a small amount of radium, in the water of the lake Khodjagasa. Radioactivity of some lake waters in the Absheron peninsula is determined by potassium. Amount of potassium varies in a wide range - from 0 to 1,4 g/l. In most of the lakes amount of potassium is not more than 0,2-9,3 g/l. 0,56 g/l of potassium in the lake Pirshagi and 1,2-1,4 g/l of potassium in the lake Gyrmyzy are abnormal and demonstrate high concentration of salts in the waters of these lakes. Probably potassium is delivered to the lakes with coastal drainage. However one can suppose that the lake Gyrmyzy is a relict of marine waters and it is a basin of a lagoon origin. In the oceanic water amount of potassium varies about 0,39 g/l, i.e. it is rather high to create anomaly in the waters of the relict lakes during the evaporation. In the lakes like Beyuk Shor, Masazyr, Duzly etc. amount of potassium is somewhat lower than in the oceanic water but many times it exceeds its amount in the river water

  11. Cooling and eutrophication of southern Chilean lakes.

    Science.gov (United States)

    Pizarro, Jaime; Vergara, Pablo M; Cerda, Sergio; Briones, Daniela

    2016-01-15

    Understanding the impacts of global warming and human-disturbances on lakes is required for implementing management strategies aimed at mitigating the decline of the quality and availability of water for humans. We assessed temporal trends in water parameters, and the contribution of land use to the eutrophication of the largest lakes of central-southern Chile. The mean values of water parameters varied seasonally, with lakes Chapo and Caburgua exhibiting lower pH, temperature, and N/P ratio values. Over the assessed period (19 years), we found a temporal reduction in water conductivity and temperature of the lakes. The concentration of NO3(-)-N, PO4(3-)-P and dissolved oxygen increased in all the lakes, but pH increased in eight out of the ten lakes. The negative temporal trend in temperature was more pronounced as the depth level increased. Lakes whose basins had a higher percentage of forest plantation and urban areas had larger values of Chlorophyll a and pH, as well as, smaller values of dissolved oxygen. Lakes whose basins included larger percentages of native forest had smaller nutrient (NO3(-)-N, PO4(3-)-P) concentrations. Our findings suggest that decreased rainfall in central-southern Chile due to climate change may cause a decrease of particulate material that is carried by tributaries into the lakes. The observed temporal decrease in temperature, especially at the deeper levels, may be explained by the rapid melting of glaciers. Although the studied lakes are classified as oligotrophic, deforestation and expansion of urban areas around the lakes have led to increased nutrient input, thus accelerating their eutrophication. PMID:26437345

  12. Evaluation of a lake whitefish bioenergetics model

    Science.gov (United States)

    Madenjian, Charles P.; O'Connor, Daniel V.; Pothoven, Steven A.; Schneeberger, Philip J.; Rediske, Richard R.; O'Keefe, James P.; Bergstedt, Roger A.; Argyle, Ray L.; Brandt, Stephen B.

    2006-01-01

    We evaluated the Wisconsin bioenergetics model for lake whitefish Coregonus clupeaformis in the laboratory and in the field. For the laboratory evaluation, lake whitefish were fed rainbow smelt Osmerus mordax in four laboratory tanks during a 133-d experiment. Based on a comparison of bioenergetics model predictions of lake whitefish food consumption and growth with observed consumption and growth, we concluded that the bioenergetics model furnished significantly biased estimates of both food consumption and growth. On average, the model overestimated consumption by 61% and underestimated growth by 16%. The source of the bias was probably an overestimation of the respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit of the model to the observed consumption and growth in our laboratory tanks. Based on the adjusted model, predictions of food consumption over the 133-d period fell within 5% of observed consumption in three of the four tanks and within 9% of observed consumption in the remaining tank. We used polychlorinated biphenyls (PCBs) as a tracer to evaluate model performance in the field. Based on our laboratory experiment, the efficiency with which lake whitefish retained PCBs from their food (I?) was estimated at 0.45. We applied the bioenergetics model to Lake Michigan lake whitefish and then used PCB determinations of both lake whitefish and their prey from Lake Michigan to estimate p in the field. Application of the original model to Lake Michigan lake whitefish yielded a field estimate of 0.28, implying that the original formulation of the model overestimated consumption in Lake Michigan by 61%. Application of the bioenergetics model with the adjusted respiration component resulted in a field I? estimate of 0.56, implying that this revised model underestimated consumption by 20%.

  13. Anaerobic psychrophiles from Lake Zub and Lake Untersee, Antarctica

    Science.gov (United States)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Stahl, Sarah; Hoover, Richard B.

    2009-08-01

    The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology of this unique ecosystem. Also, the astrobiological significance for the study of these ecosystems is based on new findings of ice covered water systems on other bodies of our solar system. Anaerobic psychrotolerant strain LZ-22 was isolated from a frozen sample of green moss with soils around the rhizosphere collected near Lake Zub in Antarctica. Morphology of strain LZ-22 was observed to be motile, rod shaped and spore-forming cells with sizes 1 x 5-10 μm. This new isolate is a mesophile with the maximum temperature of growth at 40°C. Strain LZ-22 is able to live on media without NaCl and in media with up to 7 % (w/v) NaCl. It is catalase negative and grows only on sugars with the best growth rate being on lactose. The strain is a neutrophile and grows between pH 5 and 9.0 with the optimum at 7.8. Another two strains UL7-96mG and LU-96m7P were isolated from deep water samples of Lake Untersee. Proteolytic strain LU-96m7P had a truly psychrophilic nature and refused to grow at room temperature. Sugarlytic strain UL7-96mG was found to be psychrotolerant, but its rate of growth at 3°C was very high compared with other mesophiles. Two homoacetogenic psychrophilic strains A7AC-96m and AC-DS7 were isolated and purified from samples of Lake Untersee; both of them are able to grow chemolithotrophically on H2+CO2. In the presence of lactate, these strains are able to grow only at 0-18 °C, and growth at 22 °C was observed only with yeast extract stimulation. In this paper, physiological and morphological characteristics of novel psychrophilic and psychrotolerant isolates

  14. Anaerobic Psychrophiles from Lake Zub and Lake Untersee, Antarctica

    Science.gov (United States)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Stahl, Sarah; Hoover, Richard B.

    2009-01-01

    The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology of this unique ecosystem. Also, the astrobiological significance for the study of these ecosystems is based on new findings of ice covered water systems on other bodies of our solar system. Anaerobic psychrotolerant strain LZ-22 was isolated from a frozen sample of green moss with soils around the rhizosphere collected near Lake Zub in Antarctica. Morphology of strain LZ-22 was observed to be motile, rod shaped and spore-forming cells with sizes 1 x 5-10 micron. This new isolate is a mesophile with the maximum temperature of growth at 40C. Strain LZ-22 is able to live on media without NaCl and in media with up to 7% (w/v) NaCl. It is catalase negative and grows only on sugars with the best growth rate being on lactose. The strain is a neutrophile and grows between pH 5 and 9.0 with the optimum at 7.8. Another two strains UL7-96mG and LU-96m7P were isolated from deep water samples of Lake Untersee. Proteolytic strain LU-96m7P had a truly psychrophilic nature and refused to grow at room temperature. Sugarlytic strain UL7-96mG was found to be psychrotolerant, but its rate of growth at 3C was very high compared with other mesophiles. Two homoacetogenic psychrophilic strains A7AC-96m and AC-DS7 were isolated and purified from samples of Lake Untersee; both of them are able to grow chemolithotrophically on H2+CO2. In the presence of lactate, these strains are able to grow only at 0-18C, and growth at 22C was observed only with yeast extract stimulation. In this paper, physiological and morphological characteristics of novel psychrophilic and psychrotolerant isolates from

  15. Diversity of extremophilic purple phototrophic bacteria in Soap Lake, a Central Washington (USA) Soda Lake.

    Science.gov (United States)

    Asao, Marie; Pinkart, Holly C; Madigan, Michael T

    2011-08-01

    Culture-based and culture-independent methods were used to explore the diversity of phototrophic purple bacteria in Soap Lake, a small meromictic soda lake in the western USA. Among soda lakes, Soap Lake is unusual because it consists of distinct upper and lower water bodies of vastly different salinities, and its deep waters contain up to 175 mM sulfide. From Soap Lake water new alkaliphilic purple sulfur bacteria of the families Chromatiaceae and Ectothiorhodospiraceae were cultured, and one purple non-sulfur bacterium was isolated. Comparative sequence analysis of pufM, a gene that encodes a key photosynthetic reaction centre protein universally found in purple bacteria, was used to measure the diversity of purple bacteria in Soap Lake. Denaturing gradient gel electrophoresis and subsequent phylogenetic analyses of pufMs amplified from Soap Lake water revealed that a significant diversity of purple bacteria inhabit this soda lake. Although close relatives of several of the pufM phylotypes obtained from cultured species could also be detected in Soap Lake water, several other more divergent pufM phylotypes were also detected. It is possible that Soap Lake purple bacteria are major contributors of organic matter into the ecosystem of this lake, especially in its extensive anoxic and sulfidic deep waters. PMID:21410624

  16. Lake Fluctuation Effectively Regulates Wetland Evapotranspiration: A Case Study of the Largest Freshwater Lake in China

    Directory of Open Access Journals (Sweden)

    Xiaosong Zhao

    2014-08-01

    Full Text Available Lakes and wetlands provide valuable water resources. Wetland evapotranspiration (ET is a key hydrologic component; however, the effects of lake fluctuation on wetland ET remain unclear. The Poyang Lake is the largest freshwater lake in China and experiences a dramatic fluctuation in water level and inundated area. This study used remote sensing data to estimate the wetland ET for Poyang Lake and to illustrate the distribution of wetland ET and its response to lake fluctuations. Our results showed that wetland ET was related to lake fluctuation both spatially and temporally. Within the same year, the difference between annual water evaporation (Ewater and wetland ET (ETwetland was primarily attributed to lake fluctuation through its effects on inundated area and exposure days. A 1% increase in inundated area would result in a 7.87 ± 1.13 mm a−1 reduction in annual Ewater-to-ETwetland differences, and a 10-day elongation of exposure could lead to an 11.1 ± 1.6 mm a−1 increase in annual Ewater-to-ETwetland differences, on average. Inter-annually, the Ewater-to-ETwetland differences were attributed to the combined effects of atmospheric and environmental variables and lake fluctuation. The lake fluctuation contributed 73% to the inter-annual ET difference, followed by relative humidity (19%, net radiation (5%, and wind speed (4%. Overall, lake fluctuation effectively regulates wetland ET, and its effect should receive careful consideration in hydrological and water resources studies under the current changing climate.

  17. Focused groundwater discharge of phosphorus to a eutrophic seepage lake (Lake Væng, Denmark)

    DEFF Research Database (Denmark)

    Kidmose, Jacob Baarstrøm; Nilsson, Bertel; Engesgaard, Peter Knudegaard;

    2013-01-01

    A study on Lake Væng in Denmark demonstrates a high potential for loading of phosphorous via groundwater to seepage lakes. Groundwater discharges are displayed as an important source of phosphorous to a lake due to: (1) high concentrations in the aquifer just below the lake, and (2) the main flow...... paths through the aquifer–lakebed interface either being overland flow through a seepage face, or focused in zones with very high discharge rates. In-lake springs have measured discharge of up to 7.45 m3 per m2 of lakebed per day. These findings were based on seepage meter measurements at 18 locations......, stable isotope (δ18O) analyses, temperature profiles and mapping of ice cover distribution. Groundwater–lake interaction was modelled with a 2D conceptual flow model (MODFLOW) with hydrogeology interpreted from catchment multi electrode profiling, on-lake ground-penetrating radar, well logging and...

  18. Have Titan's North-Polar Lakes Changed?

    Science.gov (United States)

    Wall, Stephen D.; Hayes, A.; Elachi, C.; Stofan, E.; Paillou, P.; Formico, T.; Mitchell, K.; Casarano, D.; Notarnicola, C.

    2012-10-01

    Cassini's RADAR instrument acquired a SAR swath over Titan's north polar lakes on May 22, 2012 , providing repeat images of a number of the smaller lakes. Previous coverage of these lakes was obtained on various passes in 2006 and 2007. Among the principal objectives of the Cassini mission is to monitor the liquid in the lakes with the approach of northern summer. Evidence of change in the lakes' levels might consist of shoreline changes, changes in radar backscatter (e.g. as penetration increases or dry spots appear), or combinations of these. We have chosen ten lakes and lake complexes for study, ranging from -4 to -100 km largest dimension. Visual comparison of repeat images is complicated by the dissimilar imaging geometry and (in some cases) resolution, and by SAR speckle. There are ambiguous cases that require further study, but at this writing we cannot identify certain changes. Ambiguous cases will be analyzed by using electromagnetic models, which can also take into account different acquisition geometry. Further analysis will be carried out exploiting electromagnetic scattering models and inversion approaches (e.g., Bayesian) to provide estimate of the lake parameters and any related changes. Parts of the research described in this paper were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  19. 33 CFR 117.979 - Sabine Lake.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Sabine Lake. 117.979 Section 117.979 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Texas § 117.979 Sabine Lake. The draw of the S82 bridge, mile...

  20. Lake Erie phosphorus loading and Cladophora updates

    Science.gov (United States)

    The presentation will focus on updates or progress being made on each Phosphorus Loadings and Cladophora for Lake Erie. The format will give a brief summary of data, findings, and results that were used by the Great Lakes Water Quality Agreement (GLWQA) Annex 4 Nutrients Modeli...

  1. 33 CFR 117.434 - Caddo Lake.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Caddo Lake. 117.434 Section 117.434 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.434 Caddo Lake. The draw of the Kansas...

  2. Current and temperature structure of Rihand Lake

    Digital Repository Service at National Institute of Oceanography (India)

    Suryanarayana, A.; Swamy, G.N.; Sadhuram, Y.

    The environmental parameters such as wind, water and air temperatures, and currents were measured in Rihand Lake, Madhya Pradesh, India during the hotest months, May-June of 1983. Rihand is an artificial lake having an area of 300 km super(2...

  3. 27 CFR 9.184 - Trinity Lakes.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Trinity Lakes. 9.184... Trinity Lakes. (a) Name. The name of the viticultural area described in this section is “Trinity Lakes”. (b) Approved Maps. The appropriate maps for determining the boundary of the Trinity...

  4. 27 CFR 9.177 - Alexandria Lakes.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Alexandria Lakes. 9.177... Alexandria Lakes. (a) Name. The name of the viticultural area described in this section is “Alexandria Lakes”. (b) Approved maps. The appropriate maps for determining the boundary of the Alexandria...

  5. Estimation of radiation flux on Lake Ikeda

    International Nuclear Information System (INIS)

    Lake Ikeda is a valuable source of fresh water for various industries. Proper management of such freshwater resources is indispensable for the successful conservation of lake environments. The objective of this study is to examine the estimation method of radiation flux on the lake, which will be a fundamental factor for evaluating the hydrologic and thermal budget of the lake basin. Meteorological data for temperature and sunshine duration at Ibusuki weather station, which is located about 7.5 km east of the lake, and relative humidity, cloud cover ratio and atmospheric pressure measurements from Makurazaki local meteorological observatory, which is located about 27 km west of the lake, are used as the input data for the estimation method. The estimated shortwave and longwave radiation based on the meteorological data in the vicinity of Lake Ikeda are in good agreement with the measured radiation flux besides the lake. The root mean square differences between estimated and measured radiation are about 25 W m-2 for the shortwave radiation and about 15 W m sup-2 for the longwave radiation

  6. Modern Pollen Study in Lake Qinghai Valley

    Science.gov (United States)

    Shang, X.; Li, X.; An, Z.; Ji, M.; Zhang, H.

    2008-12-01

    This study shows results of modern pollen in Lake Qinghai valley in the northeastern Tibetan Plateau. The records suggest that most pollen assemblages are dominated by shrub and herb pollen (mostly>84%). Seventeen taxa of indicator pollen are significantly correlated with the vegetation types of this area. In the pollen spectra, Artemisia is over-represented, while Poaceae, Cyperaceae and Polygonaceae are low- represented. Artermisia/Chenopodiaceae (A/C) radios with the regional vegetation characteristic can be used as a proper index to reconstruct the history of vegetation and climate in Lake Qinghai valley. Modern pollen in the lake mainly comes from the nearby vegetation. The pollen spectra is controlled by the directions and velocity of the wind and influenced by rivers. The distribution of modern pollen in Lake Qinghai tends to be similar in most part of the lake. The difference of pollen sedimentation process in the lake can be potentially influenced by the focusing function of the lake, river streams, and lake current.

  7. Preparation of aluminium lakes by electrocoagulation

    Directory of Open Access Journals (Sweden)

    Prapai Pradabkham

    2008-07-01

    Full Text Available Aluminium lakes have been prepared by electrocoagulation employing aluminium as electrodes. The electrocoagulation is conducted in an aqueous alcoholic solution and is completed within one hour. The dye content in the lake ranges approximately between 4-32%.

  8. Cryptanalysis of the LAKE Hash Family

    DEFF Research Database (Denmark)

    Biryukov, Alex; Gauravaram, Praveen; Guo, Jian; Khovratovich, Dmitry; Ling, San; Matusiewicz, Krystian; Nikolić, Ivica; Pieprzyk, Josef; Wang, Huaxiong

    We analyse the security of the cryptographic hash function LAKE-256 proposed at FSE 2008 by Aumasson, Meier and Phan. By exploiting non-injectivity of some of the building primitives of LAKE, we show three different collision and near-collision attacks on the compression function. The first attack...

  9. Lake Chapala change detection using time series

    Science.gov (United States)

    López-Caloca, Alejandra; Tapia-Silva, Felipe-Omar; Escalante-Ramírez, Boris

    2008-10-01

    The Lake Chapala is the largest natural lake in Mexico. It presents a hydrological imbalance problem caused by diminishing intakes from the Lerma River, pollution from said volumes, native vegetation and solid waste. This article presents a study that allows us to determine with high precision the extent of the affectation in both extension and volume reduction of the Lake Chapala in the period going from 1990 to 2007. Through satellite images this above-mentioned period was monitored. Image segmentation was achieved through a Markov Random Field model, extending the application towards edge detection. This allows adequately defining the lake's limits as well as determining new zones within the lake, both changes pertaining the Lake Chapala. Detected changes are related to a hydrological balance study based on measuring variables such as storage volumes, evapotranspiration and water balance. Results show that the changes in the Lake Chapala establish frail conditions which pose a future risk situation. Rehabilitation of the lake requires a hydrologic balance in its banks and aquifers.

  10. The Lake Charles CCS Project

    Energy Technology Data Exchange (ETDEWEB)

    Doug Cathro

    2010-06-30

    The Lake Charles CCS Project is a large-scale industrial carbon capture and sequestration (CCS) project which will demonstrate advanced technologies that capture and sequester carbon dioxide (CO{sub 2}) emissions from industrial sources into underground formations. Specifically the Lake Charles CCS Project will accelerate commercialization of large-scale CO{sub 2} storage from industrial sources by leveraging synergy between a proposed petroleum coke to chemicals plant (the LCC Gasification Project) and the largest integrated anthropogenic CO{sub 2} capture, transport, and monitored sequestration program in the U.S. Gulf Coast Region. The Lake Charles CCS Project will promote the expansion of EOR in Texas and Louisiana and supply greater energy security by expanding domestic energy supplies. The capture, compression, pipeline, injection, and monitoring infrastructure will continue to sequester CO{sub 2} for many years after the completion of the term of the DOE agreement. The objectives of this project are expected to be fulfilled by working through two distinct phases. The overall objective of Phase 1 was to develop a fully definitive project basis for a competitive Renewal Application process to proceed into Phase 2 - Design, Construction and Operations. Phase 1 includes the studies attached hereto that will establish: the engineering design basis for the capture, compression and transportation of CO{sub 2} from the LCC Gasification Project, and the criteria and specifications for a monitoring, verification and accounting (MVA) plan at the Hastings oil field in Texas. The overall objective of Phase 2, provided a successful competitive down-selection, is to execute design, construction and operations of three capital projects: (1) the CO{sub 2} capture and compression equipment, (2) a Connector Pipeline from the LLC Gasification Project to the Green Pipeline owned by Denbury and an affiliate of Denbury, and (3) a comprehensive MVA system at the Hastings oil field.

  11. Salt transport in Songkhla Lake

    OpenAIRE

    Pornpinatepong, S.

    2005-01-01

    Salinity surveys in 1997 revealed that in the dry season salinity in Thale Sap Songkhla, Thale Sap and Thale Luang reached the maximum values of 30, 11 and 5 ppt, respectively. Among the complex system of the lake, Khlong Pak Ro showed a complicate seawater transport with a maximal salinity of 20 ppt. Incomplete mixing with a stratification at a depth of 2-3 m occured. The difference in salinity between the surface and the bottom was about 3 ppt. A vertically-averaged salt transport model was...

  12. Stennis visits Lake Cormorant school

    Science.gov (United States)

    2010-01-01

    Alexis Harry, assistant director of Astro Camp at NASA's John C. Stennis Space Center, talks with students at Lake Cormorant (Miss.) Elementary School during a 'Living and Working in Space' presentation March 30. Stennis hosted the school presentation during a visit to the Oxford area. Harry, who also is a high school biology teacher in Slidell, La., spent time discussing space travel with students and answering questions they had about the experience, including queries about how astronauts eat, sleep and drink in space. The presentation was sponsored by the NASA Office of External Affairs and Education at Stennis. For more information about NASA education initiatives, visit: http://education.ssc.nasa.gov/.

  13. Crenarchaeota in Lake Michigan sediment.

    OpenAIRE

    MacGregor, B.J.; Moser, D. P.; Alm, E W; Nealson, K. H.; Stahl, D. A.

    1997-01-01

    RNA from Lake Michigan sediment was hybridized with a DNA probe for archaeal 16S rRNA. There was a peak of archaeal rRNA abundance in the oxic zone and another immediately below it. Six contributing species were identified by PCR amplification of extracted DNA with primers specific for archaeal rDNA: two related to Methanosarcina acetivorans and four related to marine crenarchaeotal sequences. rRNA quantification using a DNA probe specific for this crenarchaeotal assemblage showed it is most ...

  14. Mono Lake's Radiocarbon Budget: An unsolved enigma

    Science.gov (United States)

    Broecker, Wallace; Stine, Scott

    Mono Lake occupies a semiarid basin just east of the central Sierra Nevada in California. During the past 4 decades, diversion of the lake's tributary streams by the Los Angeles Department of Water and Power (LADWP) has caused the lake to shrink dramatically. This shrinkage has concentrated the salts that occur naturally in the lake, forcing the salinity to rise toward levels that will cause the extinction of the resident brine shrimp and brine flies that provide food for many hundreds of thousands of migratory waterfowl. The lake is now the focus of a pitched battle between conservationists who want to curtail diversions before serious ecological consequences occur and the LADWP, whose responsibility is to supply the city with water.

  15. Search for ancient microorganisms in Lake Baikal

    Energy Technology Data Exchange (ETDEWEB)

    Hunter-Cevera, Jennie C.; Repin, Vladimir E.; Torok, Tamas

    2000-06-14

    Lake Baikal in Russia, the world's oldest and deepest continental lake lies in south central Siberia, near the border to Mongolia. The lake is 1,643 m deep and has an area of about 46,000 km2. It holds one-fifth of all the terrestrial fresh water on Earth. Lake Baikal occupies the deepest portion of the Baikal Rift Zone. It was formed some 30-45 million years ago. The isolated Lake Baikal ecosystem represents a unique niche in nature based on its historical formation. The microbial diversity present in this environment has not yet been fully harvested or examined for products and processes of commercial interest and value. Thus, the collection of water, soil, and sub-bottom sediment samples was decided to characterize the microbial diversity of the isolated strains and to screen the isolates for their biotechnological value.

  16. Amino acids in the Tagish Lake Meteorite

    Science.gov (United States)

    Kminek, G.; Botta, O.; Glavin, D. P.; Bada, J. L.

    2002-01-01

    High-performance liquid chromatography (HPLC) based amino acid analysis of a Tagish Lake meteorite sample recovered 3 months after the meteorite fell to Earth have revealed that the amino acid composition of Tagish Lake is strikingly different from that of the CM and CI carbonaceous chondrites. We found that the Tagish Lake meteorite contains only trace levels of amino acids (total abundance = 880 ppb), which is much lower than the total abundance of amino acids in the CI Orgueil (4100 ppb) and the CM Murchison (16 900 ppb). Because most of the same amino acids found in the Tagish Lake meteorite are also present in the Tagish Lake ice melt water, we conclude that the amino acids detected in the meteorite are terrestrial contamination. We found that the exposure of a sample of Murchison to cold water lead to a substantial reduction over a period of several weeks in the amount of amino acids that are not strongly bound to the meteorite matrix. However, strongly bound amino acids that are extracted by direct HCl hydrolysis are not affected by the leaching process. Thus even if there had been leaching of amino acids from our Tagish Lake meteorite sample during its 3 month residence in Tagish Lake ice and melt water, a Murchison type abundance of endogenous amino acids in the meteorite would have still been readily detectable. The low amino acid content of Tagish Lake indicates that this meteorite originated fiom a different type of parent body than the CM and CI chondrites. The parent body was apparently devoid of the reagents such as aldehyldes/ketones, HCN and ammonia needed for the effective abiotic synthesis of amino acids. Based on reflectance spectral measurements, Tagish Lake has been associated with P- or D-type asteroids. If the Tagish Lake meteorite was indeed derived fiom these types of parent bodies, our understanding of these primitive asteroids needs to be reevaluated with respect to their potential inventory of biologically important organic compounds.

  17. Simulation of Heavy Lake-Effect Snowstorms across the Great Lakes Basin by RegCM4

    Science.gov (United States)

    Notaro, M.; Zarrin, A.; Vavrus, S. J.; Bennington, V.

    2013-12-01

    A historical simulation (1976-2002) of the Abdus Salam International Centre for Theoretical Physics Regional Climate Model Version 4 (ICTP RegCM4), coupled to a one-dimensional lake model, is validated against observed lake ice cover and snowfall across the Great Lakes Basin. The model reproduces the broad temporal and spatial features of both variables in terms of spatial distribution, seasonal cycle, and interannual variability, including climatological characteristics of lake-effect snowfall, although the simulated ice cover is overly extensive largely due to the absence of lake circulations. A definition is introduced for identifying heavy lake-effect snowstorms in regional climate model output for all grid cells in the Great Lakes Basin, using criteria based on location, wind direction, lake ice cover, and snowfall. Simulated heavy lake-effect snowstorms occur most frequently downwind of the Great Lakes, particularly to the east of Lake Ontario and to the east and south of Lake Superior, and are most frequent in December-January. The mechanism for these events is attributed to an anticyclone over the central United States and related cold air outbreak for areas downwind of Lakes Ontario and Erie, in contrast to a nearby cyclone over the Great Lakes Basin and associated cold front for areas downwind of Lakes Superior, Huron, and Michigan. Projections of mid- and late-21st century lake-effect snowstorms in the Great Lakes Basin will be summarized, based on dynamically downscaled CMIP5 (Coupled Model Intercomparison Project Phase Five) simulations.

  18. A coupled lake-atmosphere model (CLAM) and its application to Lake Kinneret

    Science.gov (United States)

    Pan, Hai

    1999-08-01

    Kinneret is a 166-km2 lake located in Northern Israel, in the central part of the Jordan Valley, a corridor running from north to south, between the Galilee hills in the west and the Golan Heights in the east. Both the Galilee hills and the Golan Heights reach an elevation of about 400 m above mean sea level (MSL), and the lake is about -210 m (MSL). North of the lake is the mountainous area of the Hermon, culminating at about 2800 m (MSL). About 120 km south of it is the Dead Sea, which is about -410 m (MSL), and about 45 km west of it is the Mediterranean Sea. The complexity of the terrain, combined with relatively arid soil and various ground covers surrounding the lake, results in a very complicated system of atmospheric and lake processes. To understand this system, especially the processes affecting the atmosphere and lake dynamics and thermodynamics, and their effects on Lake Kinneret evaporation, a coupled lake-atmosphere model (CLAM) was developed and applied to the lake region. The CLAM is based on the Regional Atmospheric Modeling System (RAMS) and the oceanic S-coordinate Rutgers University Model (SCRUM). Energy, mass, and momentum are conserved at the interface between the atmosphere and the lake, and appropriate balance equations are applied there. In the atmospheric module, two nested grids are employed to simulate Northern Israel at a resolution of 4 x 4 km2, and the near-lake region at a resolution of 1 x 1 km 2. Synoptic conditions obtained from the National Meteorological Center (NMC) reanalysis are assimilated by the model. Soil moisture, which appears to have a significant impact on atmospheric circulation in this region, was transformed from the normalized difference vegetation index (NDVI). Observations collected during two summers above and inside the lake emphasize the good capability of CLAM to simulate surface fluxes and other microclimatic conditions, as well as lake temperature and currents. Although the lake is small (about 12-km wide

  19. Sedimentary Feature in Lake Terkhiin Tsagaan and Lake Ugii, Central Mongolia

    Science.gov (United States)

    Orkhonselenge, Alexander; Davaagatan, Tuyagerel

    2016-04-01

    We present characteristics of lacustrine sediments recorded from Lake Terkhiin Tsagaan and Lake Ugii at near latitudes in Central Mongolia. Physical-chemical properties of eight core sediments collected from these lakes show impact of different montane and prairie landscapes on the lacustrine sediments. Lake Terkhiin Tsagaan indicating a montane landscape with higher contents of organic matter and biogenic silica, and finer sediments differs from Lake Ugii reflecting a prairie landscape with higher contents of carbonates and minerals, and coarser sediments. Stratigraphical sequences of the lacustrine sediments recommend that these two lakes have experienced a numerous of environmental conditions during the arid mid Holocene and humid late Holocene reconstructed from the adjacent lakes in Central Mongolia. These Holocene climatic changes inferred from dramatic fluctuations in temperature and precipitation might have been responsible for the identical environmental conditions, resulting in the sedimentary feature in Lake Terkhiin Tsagaan and Lake Ugii. More investigations with precise dating are thus needed from the both lakes for determining lacustrine sedimentations and reconstructing paleoenvironmental changes in Central Mongolia.

  20. Lake Roosevelt fisheries monitoring program

    International Nuclear Information System (INIS)

    The purpose of this study was to provide baseline data that could be used to evaluate the effectiveness of two kokanee salmon hatcheries that will produce 8 million kokanee salmon (Oncorhynchus nerka) fry or 3.2 million adults for stocking into Lake Roosevelt. The hatcheries will also produce 500,000 rainbow trout (Oncorhynchus mykiss) fingerlings to support the Lake Roosevelt net-pen programs. The baseline data will also be used to evaluate the effectiveness of the habitat improvement projects ongoing on a separate contract. At the present time, the principle sport fish in the reservoir are net-pen rainbow trout and walleye (Stizostedion vitreum). The objectives of the second year of the monitoring program were: (1) to determine angling pressure, catch per unit effort, total harvest and the economic value; (2) to determine relative abundance of fish species in the reservoir by conducting electrofishing and gillnet surveys at nine index stations during May, August, and October; (3) to determine growth rates of kokanee, rainbow trout, and walleye based upon backcalculations from scales collected during May, August and October and creel surveys; (4) to determine density, size, and biomass of zooplankton and how reservoir operations affect their population dynamics; (5) to determine feeding habits of kokanee, rainbow trout, and walleye and their preferred prey densities; and (6) to determine migration patterns of tagged walleye and net-pen rainbow trout. 118 refs., 20 figs., 98 tabs