Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 931 - 960 of 1060

Full-Text Articles in Entire DC Network

Spatial And Temporal Patterns Of Fluvial Suspended Sediment Yield From Eastern North America, Catherine Treena Conrad Jan 2000

Spatial And Temporal Patterns Of Fluvial Suspended Sediment Yield From Eastern North America, Catherine Treena Conrad

Theses and Dissertations (Comprehensive)

A knowledge of spatial and temporal patterns of sediment yields and an understanding of the factors that determine those patterns have theoretical, environmental and socio-economic significance. To assess the change in sediment yields (in both space and time) a data base of 193 river gauging sites spanning the eastern provinces of Canada and eastern United States was compiled. The original source of the data was the United States Geological Survey data base (obtained from a Hydrosphere Data Inc. cd-rom) and Environment Canada (HYDAT) data base, which included stream discharge, sediment loads and basin areas, with record lengths of one year …


The Use Of Stable Isotopic Signatures Of Marine Biota To Map Sewage Effluent Disposed Into The Marine Environment, Adam Gartner Jan 2000

The Use Of Stable Isotopic Signatures Of Marine Biota To Map Sewage Effluent Disposed Into The Marine Environment, Adam Gartner

Theses : Honours

Recent work indicates that nitrogen stable isotopic signatures of aquatic biota can be used to link nutrient inputs in the marine environment to terrestrial sources. While this technique of tracing nutrients has been shown to be effective in environments that are not nutrient limited, it has not been proved that this method is effective in oligotrophic environments. This study examined whether nitrogen stable isotopic signatures of marine biota can be used to trace the distribution of sewage effluent in highly mixed, nitrogen limited waters, by examining the δ15N values of marine biota situated close to and distant from …


The Effect Of Rock Creep On The Morphology Of Steep-Sloped Sections Of The Niagara Escarpment (Ontario), John Barlow Jan 2000

The Effect Of Rock Creep On The Morphology Of Steep-Sloped Sections Of The Niagara Escarpment (Ontario), John Barlow

Theses and Dissertations (Comprehensive)

The thesis addresses the post-glacial development of the Niagara Cuesta between Hamilton and Collingwood. Conventional thinking on the escarpment during the Holocene suggests that the present morphology developed rapidly following deglaciation due to periglacial processes (Straw, 1966/Tovell 1992). The disruption of the preglacial drainage pattern by drift has meant the escarpment has not been subject to extensive fluvial action along its base, resulting in an extremely slow rate of retreat (Bird, 1980). The concept that the escarpment is a relict feature therefore pervades the modem literature. The apparent motion of the blocks at the face of the escarpment (Hintz, I997) …


Intelligent Visualization And Automated Processing For Large Scale Geographic Information Systems, Yu Jiang Dec 1999

Intelligent Visualization And Automated Processing For Large Scale Geographic Information Systems, Yu Jiang

All-Inclusive List of Electronic Theses and Dissertations

This research focuses on developing a new output system that compacts maps in multiple projections into a single Geographic Information System (GIS) without visual errors, through constructing a discrete GIS database that is managed by a Relational Data Base Management System (RDBMS). Unlike in a traditional large GIS database, the data are "physically discrete but logically continuous." In a new discrete GIS database, every map keeps its individuality without a relationship to any other map, and the relationships among the maps are centrally managed by a RDBMS. A study site was chosen at the boundary of the state of Indiana …


The Effect Of Divalent Cations On The Prophenoloxidase Enzyme Cascade Activity In The Freshwater Crayfish Cambarus Latimanus, Hans Skailand Eikaas Dec 1999

The Effect Of Divalent Cations On The Prophenoloxidase Enzyme Cascade Activity In The Freshwater Crayfish Cambarus Latimanus, Hans Skailand Eikaas

Theses and Dissertations

The effect of divalent cations such as cadmium, calcium, copper, lead and magnesium upon the prophenoloxidase system (proPO) was studied in hemocytes of the crayfish Cambarus latimanus. It was demonstrated that cadmium, calcium, copper and lead increased proPO activity significantly, whereas magnesium had no statistically significant effect on the system. Also, the molecular weight of the proPO enzyme was estimated using SDS-PAGE and found to be approximately 76 kDa.


Calibration, Installation Techniques, And Initial Measurements For Vertical Resistivity Probes Used In Hydrogeologic Investigations, Jeffrey Mark Groncki Dec 1999

Calibration, Installation Techniques, And Initial Measurements For Vertical Resistivity Probes Used In Hydrogeologic Investigations, Jeffrey Mark Groncki

Masters Theses

Vertical Resistivity Probes (VRPs) are being increasingly used in a variety of applications where detailed vertical resistivity information in both the vadose and saturated zones is needed. All the different possible array types and spacings must be calibrated for the effect of the 2" (outer diameter) insulating PVC cylinder on which the electrodes are mounted. Apparent resistivities must be corrected by calibration factors. Varying the installation parameters greatly influences the measured apparent resistivity because of the disturbed annulus and the composition of the backfill materials. Bentonite slurry is necessary for the installations to keep the electrodes in good contact with …


The Effects Of Phosphorus Enrichment On The Dominant Phytoplankton Communities Of Chaney Lake, Kathy Tehrani Aug 1999

The Effects Of Phosphorus Enrichment On The Dominant Phytoplankton Communities Of Chaney Lake, Kathy Tehrani

Masters Theses & Specialist Projects

Chaney Lake is a temporary karst wetland located in southern Warren County, Kentucky. Because of an impermeable chert layer between the surface and the porous limestone, Chaney Lake fills with water over the winter and spring and then gradually drains over the summer. Three experiments were conducted over the course of the 1998 flooding season to assess the effects of phosphorus addition on the phytoplankton community in Chaney Lake. Ten plastic-sided mesocosms were constructed and placed in the marsh area of the wetland at three different periods: early spring, early summer, and late summer. Phosphorus in the form of K2HPO4 …


Molecular Characterization Of Soil Ammonia-Oxidizing Bacteria Based On The Genes Encoding Ammonia Monooxygenase, Jose Javier Alzerreca May 1999

Molecular Characterization Of Soil Ammonia-Oxidizing Bacteria Based On The Genes Encoding Ammonia Monooxygenase, Jose Javier Alzerreca

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ammonia-oxidizing bacteria (AOB) are chemolithotrophs that oxidize ammonia/ammonium to nitrite in a two-step process to obtain energy for survival. AOB are difficult to isolate from the environment and iso lated strains may not represent the diversity in soil. A genetic database and molecular tools were developed based on the ammonia monooxygenase (AMO) encoding genes that can be used to assess the diversity of AOB that exist in soil and aquatic environments without the isolation of pure cultures. The amo genes have excellent potential as molecular markers; since AMO is only found in the AOB and is essential for their metabolism, …


A Geomorphology Of Megaliths: Neolithic Landscapes In The Alto Alentejo, Portugal, Gregory A. Pope, Vera C. Miranda Jan 1999

A Geomorphology Of Megaliths: Neolithic Landscapes In The Alto Alentejo, Portugal, Gregory A. Pope, Vera C. Miranda

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The Alentejo region of Portugal is known for a high concentration of Neolithic-aged megalithic monuments: tombs (dolmens or antas) and ceremonial features such as standing stones (menhirs) and stone circles (cromleques). Concentrations of these monuments tend to be found on or near weathered granite terrains. Unloading slabs and remnant corestones appear to be the stones of preference for megalith makers in the Alentejo district of Portugal. Some of the stones may have been imported from distant sources, but most appear to be of local origin. In general, most stones do not appear to have been altered much from their original …


Environmental Vulnerability And Agriculture In The Karstic Domain: Landscape Indicators And Cases In The Atlas Highlands, Morocco, Brahim Akdim, Mohammed Amyay Jan 1999

Environmental Vulnerability And Agriculture In The Karstic Domain: Landscape Indicators And Cases In The Atlas Highlands, Morocco, Brahim Akdim, Mohammed Amyay

International Journal of Speleology

After the brief presentation of the major karstic areas in Morocco, the article focused essentially on the Atlas mountains to investigate the impact of the agriculture on the natural systems equilibrium. Socio-economic changes (demographic pressure, escalation of the landscape use, utilisation of new techniques in water harvesting, etc...) have sometimes fathered mechanisms of degradation. Many indicators seem to reflect these mechanisms. The pedologic indicators, soil erosion, the hydrologic and geomorphic indicators, are apprehended to demonstrate existent correlation between different variables and the often negative impacts of land over-use in the karstic domain of the Middle Atlas.


Nitrate Attenuation In A Narrow Non-Forested Riparian Buffer Zone In An Agricultural Watershed In Southern Ontario, Mark David Harris Jan 1999

Nitrate Attenuation In A Narrow Non-Forested Riparian Buffer Zone In An Agricultural Watershed In Southern Ontario, Mark David Harris

Theses and Dissertations (Comprehensive)

Riparian buffer zones are defined as strips of natural vegetation separating streams or lakes from surrounding upland landscapes. These zones may effectively reduce the nitrate-N load in shallow ground water draining intensively fertilized agricultural regions. Contemporary research has tended to focus on wide, forested riparian zones situated on poorly drained lowland sites. In addition, research has typically focused on the growing season, when the ecosystem is biologically active, with relatively day hydrological conditions. This field study monitored spatial and temporal patterns of nitrate-N in a comparatively narrow, non-forested buffer zone situated in an upland agricultural watershed in southern Ontario. Results …


Evolution Of Quaternary Intraplate Mafic Lavas Detailed Using Helium-3 Surface Exposure And Argon-40/Argon-39 Dating, And Elemental And Helium, Strontium, Neodymium And Lead Isotopic Signatures: Potrillo Volcanic Field, New Mexico, United States Of America And San Quintin Volcanic Field, Baja California Norte, Mexico, Wendi Joan Whitehead Williams Jan 1999

Evolution Of Quaternary Intraplate Mafic Lavas Detailed Using Helium-3 Surface Exposure And Argon-40/Argon-39 Dating, And Elemental And Helium, Strontium, Neodymium And Lead Isotopic Signatures: Potrillo Volcanic Field, New Mexico, United States Of America And San Quintin Volcanic Field, Baja California Norte, Mexico, Wendi Joan Whitehead Williams

Open Access Theses & Dissertations

The Pleistocene Potrillo volcanic field (PVF) resides within the southern axis of the Rio Grande Rift, New Mexico, U.S.A., near the eastern extent of the Basin and Range Province. Its alkalic mafic volcanism has resulted in several hundred cones, flows and maars distributed over approximately 4,600 km2. Alignments are segregated into two halves relative to the East Robledo fault system that dissects this field. Three of the five maars have brought peridotitic and lower to upper crustal xenoliths to the surface; several older, non maar-related flows from the west half of the field host ultramafic clots. Stratigraphic relationships, 3He surface …


Uncertainty In Recharge From Subsidence Craters At Frenchman Flat, Nevada Test Site: Impacts Of Initial And Boundary Conditions And Media Properties, David Matthew Ely Dec 1998

Uncertainty In Recharge From Subsidence Craters At Frenchman Flat, Nevada Test Site: Impacts Of Initial And Boundary Conditions And Media Properties, David Matthew Ely

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Nevada Test Site has over 400 subsidence craters formed by the collapse of overlying rock following underground nuclear tests. Under natural conditions, infiltration and recharge would not be considered likely due to infrequent precipitation events and extreme evapotranspiration. Crater U5a in Frenchman Flat was chosen for study because it intercepts significantly more drainage than surrounding craters. Vadose zone modeling was conducted to test the sensitivity of water movement to boundary and initial conditions. The effects of ponding depth was negligible but depth of wetting front movement was highly dependent on the lateral extent of the ponds. The model was …


Modelling Direct Episodic Recharge In The Western Australian Wheatbelt, F Lewis, Cooperative Research Centre For Catchment Hydrology (Australia) Nov 1998

Modelling Direct Episodic Recharge In The Western Australian Wheatbelt, F Lewis, Cooperative Research Centre For Catchment Hydrology (Australia)

Resource management technical reports

In agricultural regions of Western Australia, salinity is spreading. This is because the area taken up by groundwater discharge is increasing as a result of increased groundwater recharge following the replacement of native vegetation systems by annual crops and pasture species. Attempts to reduce groundwater recharge are now being made as it is hoped that this will decrease the rate of land salinisation. At several sites, average recharge rates have been estimated to be from 2% to 13% of the average annu ter hydrographs from the agricultural regions indicate that at some sites recharge does not occur as small amounts …


Seismic Reflection Imaging Of A Geothermal Aquifer In An Urban Setting, Lee Liberty Jul 1998

Seismic Reflection Imaging Of A Geothermal Aquifer In An Urban Setting, Lee Liberty

CGISS Publications and Presentations

A seismic reflection survey that was conducted in downtown Boise, Idaho, to help city planners site a new well for injection of spent geothermal water illustrates some methods to safely and successfully employ a seismic reflection survey in an urban setting. The objective of the seismic survey was to estimate the depth and continuity of a basalt and rhyolite volcanic sequence. Well siting was based on geothermal aquifer depth, location of interpreted faults, projected thermal impact of injection on existing wells, surface pipe extension costs, and public land availability. Seismic acquisition tests and careful processing were used to ensure high-quality …


A Generic Multi-Electrode Automated/Semi-Automated Field Resistivity System, Douglas D. Werkema Apr 1998

A Generic Multi-Electrode Automated/Semi-Automated Field Resistivity System, Douglas D. Werkema

Masters Theses

Geophysical field exploration using electrical resistivity typically employs the use of four electrodes which are progressively relocated to positions that differ from a few meters to hundreds of meters. Consequently, field operations are tiresome and often lead to imprecise locations of electrodes and poor data quality. This project develops an automated field resistivity system.

This automation of resistivity measurements is accomplished by using multiple sets of field electrodes, a programmable switch box, remotely controlling the acquisition instrument and digitally storing the results. Controlling the process is the Acquisition Control©software, for Windows 95© .The prototype switch box has …


A Molecular Evaluation Of Contaminants And Natural Organic Matter In Surface Sediments From Western Lake Ontario, Michael A. Kruge, Prasanta K. Mukhopadhyay, C.F. Michael Lewis Jan 1998

A Molecular Evaluation Of Contaminants And Natural Organic Matter In Surface Sediments From Western Lake Ontario, Michael A. Kruge, Prasanta K. Mukhopadhyay, C.F. Michael Lewis

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) analysis of bottom sediment from Lake Ontario was shown to be effective in assessing organic contaminants, especially attractive as it is a rapid technique requiring little sample preparation. Pyrolyzates of samples richer in organic matter (OM) were relatively enriched in aliphatic hydrocarbons and pyrrolic nitrogen compounds, while leaner samples were more aromatic and pyridinic. Alkylbenzene and alkylphenol distributions in the pyrolyzates were most compatible with derivation from aquatic (algal, bacterial) OM. The organonitrogen compounds indicated the presence of degraded proteinaceous material from aquatic sources and/or sewage. Normal and polycyclic aromatic hydrocarbon distributions indicate, at least in …


Resource Use In The Trinational Sangha River Region Of Equatorial Africa: Histories, Knowledge Forms, And Institutions, Heather E. Eves, Rebecca Hardin, Stephanie Rupp Jan 1998

Resource Use In The Trinational Sangha River Region Of Equatorial Africa: Histories, Knowledge Forms, And Institutions, Heather E. Eves, Rebecca Hardin, Stephanie Rupp

Yale School of the Environment Bulletin Series

This volume is based on an international conference, “Natural Resource Use Relations in the Trinational Sangha River Region of the Northwest Congo Basin,” held at Yale University in September 1997. In recognition of the bilingual context in which conservation occurs in the three countries of the Sangha region — Cameroon, Central African Republic, and Congo — all sessions of the conference were conducted simultaneously in French and English. This publication, which is a complete rendering of the conference papers and discussion sessions, is available in its entirety in both French and English.


The Use Of Spectrofluorimetry And Capillary Electrophoresis/Laser-Induced Fluorescence For The Detection Of Fluorescent Dyes In Groundwater Migration Studies, Patrick Ferguson Oct 1997

The Use Of Spectrofluorimetry And Capillary Electrophoresis/Laser-Induced Fluorescence For The Detection Of Fluorescent Dyes In Groundwater Migration Studies, Patrick Ferguson

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis involves work that was accomplished during a two-year internship at the Environmental Protection Agency's (EPA), Environmental Chemistry Branch. The research is an application of trace level determination of fluorescein dyes used as groundwater tracers. The work was performed to determine whether groundwater could migrate from a Resource Conservation Recovery Act (RCRA) site to an adjacent Superfund site. The research involved using Spectrofluorimetry and a new technique called capillary electrophoresis/laser induced fluorescence (CE/LIF) to determine tracer dyes that were injected at the RCRA site and monitored at the Superfund site. Results from Spectrofluorimetry were compared to those of CE/LIF. …


Systematics Of Stable Isotopes And Radionuclides In Precipitation At Kalamazoo, Michigan, Usa, Madhav V. Machavaram Aug 1997

Systematics Of Stable Isotopes And Radionuclides In Precipitation At Kalamazoo, Michigan, Usa, Madhav V. Machavaram

Dissertations

Precipitation samples were collected at Kalamazoo from June 1992 to March 1995. The samples were analyzed for their 8D and 8lgO values. The 5D - 5I80 relationship is comparable to that of Meteoric Water Line (MWL). The monthly mean isotopic values in precipitation exhibited strong seasonality, being higher in summer and lower in winter months. This behavior is apparently a direct consequence of the temperature effect on isotope fractionation.

The summer precipitation at Kalamazoo is derived predominantly from the water vapor originated in the Gulf of Mexico. A box model calculation showed that a Rayleigh type distillation with Gulf moisture …


River Management In The Twenty-First Century: The Vision Thing, A. Dan Tarlock Jun 1997

River Management In The Twenty-First Century: The Vision Thing, A. Dan Tarlock

Dams: Water and Power in the New West (Summer Conference, June 2-4)

12 pages.

Contains references.


Glen Canyon Dam: Flood Flows And Adaptive Management In The Lower Colorado River Basin: Response, Joe Hunter Jun 1997

Glen Canyon Dam: Flood Flows And Adaptive Management In The Lower Colorado River Basin: Response, Joe Hunter

Dams: Water and Power in the New West (Summer Conference, June 2-4)

9 pages.

Contains references.


Glen Canyon Dam: Flood Flows And Adaptive Management In The Lower Colorado River Basin, Edmund D. Andrews Jun 1997

Glen Canyon Dam: Flood Flows And Adaptive Management In The Lower Colorado River Basin, Edmund D. Andrews

Dams: Water and Power in the New West (Summer Conference, June 2-4)

11 pages.

Contains 2 pages of references.


Agenda: Dams: Water And Power In The New West, University Of Colorado Boulder. Natural Resources Law Center Jun 1997

Agenda: Dams: Water And Power In The New West, University Of Colorado Boulder. Natural Resources Law Center

Dams: Water and Power in the New West (Summer Conference, June 2-4)

Conference organizers and/or speakers included University of Colorado School of Law professors David H. Getches, Douglas S. Kenney, Kathryn M. Mutz, Elizabeth Ann (Betsy) Rieke, Charles F. Wilkinson and Lawrence J. MacDonnell.

The keynote address by Charles F. Wilkinson is titled Coming to Grips with Growth in the West: Traditional Communities, Free Rivers and the New Megalopoli, and it will be held on Monday, June 2, at 12:30 p.m. in the Lindsley Memorial Courtroom of the law school. Wilkinson is a noted law professor, writer and authority on Western issues.

The conference will begin by providing historical context for the …


The Pacific Northwest Governors’ Comprehensive Energy Review: How Comprehensive?, Angus Duncan Jun 1997

The Pacific Northwest Governors’ Comprehensive Energy Review: How Comprehensive?, Angus Duncan

Dams: Water and Power in the New West (Summer Conference, June 2-4)

43 pages (includes illustrations).

Contains footnotes and 1 page of references.


The Columbia Slough, Scott A. Wells Mar 1997

The Columbia Slough, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

This report was written in an attempt to provide the public and Bureau of Environmental Services Staff with a summary of work accomplished on the Columbia Slough system by Portland State University and other consultants working on the Slough over the last 6 years. An attempt was made to create an easy-to-read report with important overviews of the "big picture", glossary of definitions, index, and further details to assist in technology transfer.


Two-Dimensional Seismic Image Of The San Andreas Fault In The Northern Gabilan Range, Central California Evidence For Fluids In The Fault Zone, C. Thurber, S. Roecker, W. Ellsworth, Y. Chen, W. Lutter, R. Sessions Jan 1997

Two-Dimensional Seismic Image Of The San Andreas Fault In The Northern Gabilan Range, Central California Evidence For Fluids In The Fault Zone, C. Thurber, S. Roecker, W. Ellsworth, Y. Chen, W. Lutter, R. Sessions

United States Geological Survey: Staff Publications

A joint inversion for two-dimensional P-wave velocity (Vp), P-to-S velocity ratio (Vp/Vs), and earthquake locations along the San Andreas fault (SAF) in central California reveals a complex relationship among seismicity, fault zone structure, and the surface fault trace. A zone of low Vp andh ighV p/Vs lies beneatht he SAF surfacetr ace( SAFST), extending to a depth of about 6 km. Most of the seismic
activity along the SAF occurs at depths of 3 to 7 km in a southwest-dippingz one that roughly intersectst he SAFST, and lies near the southweset dgeo f the low Vp and high Vp/Vs zones. …


Application Of Environmental Organic Petrology And Geochemistry To Fingerprint Organic Pollutants In The Recent Sediments Of Lake Ontario, Prasanta K. Mukhopadhyay, Michael A. Kruge, C.F. Michael Lewis Jan 1997

Application Of Environmental Organic Petrology And Geochemistry To Fingerprint Organic Pollutants In The Recent Sediments Of Lake Ontario, Prasanta K. Mukhopadhyay, Michael A. Kruge, C.F. Michael Lewis

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Selected surface sediment samples (sediment depth 0-10 cm) collected in the Niagara basin (western Lake Ontario) were chosen for organic matter characterization using organic petrological and geochemical techniques normally reserved for the study of coal, petroleum source rock and crude oil. The study was performed to assess the effectiveness of these techniques in discriminating between natural and anthropogenic organic matter and to determine the extent of organic pollution of the lake sediments. The organic carbon contents of the samples vary from 1.5 to 3.5%, with upper layer (0-5 cm) samples have higher TOC values than those from the lower layer …


The Impact Of Glacier Recession Upon The Discharge Of The Bow River Above Banff, Alberta, 1951-1993, Christopher Dennis Hopkinson Jan 1997

The Impact Of Glacier Recession Upon The Discharge Of The Bow River Above Banff, Alberta, 1951-1993, Christopher Dennis Hopkinson

Theses and Dissertations (Comprehensive)

Three methods have been used to explore the volumetric change of glaciers in the Bow Basin above Banff for the years 1951 to 1993. Using aerial photography, the extent of glacier covers for the two years were mapped at a scale of 1:50,000. The first volumetric calculation of glacier loss was based on inventory criteria; the second a hyposgraphic curve method based on Young’s investigations in Mistaya Basin (1991) and the third stereo air photogrammetry and DEM comparisons using computer software. These methods were applied to the highly glacierized Hector Lake catchment within the Bow Valley and then extrapolated up …


Reexamination Of Scarp Development Along The Niagara Escarpment, Ontario, Canada, David Walter Hintz Jan 1997

Reexamination Of Scarp Development Along The Niagara Escarpment, Ontario, Canada, David Walter Hintz

Theses and Dissertations (Comprehensive)

The Niagara Escarpment is generally viewed as a relict landform which shows ancient structural features and the effects of glaciation. Since it was realized that the Escarpment was not a fault, but instead a feature of erosional origin, little interest has been paid to development of the steep cliffed section of the Niagara Escarpment. This research project has several objectives. The first is an examination of the relationship between the morphology of the Escarpment and its geological units. This will include analysis of the structure and lithology of each and the geochemistry, especially, of the Queeston Formation. Associated with the …