Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"artificial stream"”.
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Simulation models for assessing the effects of power plant cooling systems upon protozoans
… determine the effects upon colonization of downstream communities. For preliminary tests an apparatus consisting of a test cell constructed of acrylic plastic with a small resistance heater controlled by a variable transformer was developed to deliver a heat shock to protozoans while they were …
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Alternative approaches for monitoring aquatic ecosystems: a study on the effects of municipal sewage effluent on biota in the South Saskatchewan River
… Saskatchewan River through field monitoring and artificial stream experimentation. Field studies indicated that primary productivity was stimulated by nutrient enrichment, however, standing crop measurements were strongly influenced by increased abundance of invertebrates (i.e., chironomids). …
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Impact zone delineation for biological assessment of power plant effluent effects on snail populations in the Clinch River
… were measured below plant discharges and upstream, and compared with water column Cu, snail tissue Cu and aufwuchs Cu measurements. Habitat selection was strongly influenced by effluent but the role of waterborne metals concentration and habitat alterations (e.g. periphyton changes and …
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Effects of turbidity on the foraging abilities of brook trout (Salvelinus fontinalis) and smallmouth bass (Micropterus dolomieu)
… sedimentation has focussed on its effects on stream habitat and its ramification on the reproductive potential of fish. Although relatively large sediment loads may be necessary to alter stream habitat, only small loads are needed to raise mean stream turbidity levels. Turbidity may be an …
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The Role of Streambed Biofilms in The Removal of Biodegradable Contaminants From Shallow Streams
Previous research has demonstrated that streambed biofilms are important in contaminant removal in shallow streams. However, the ability to predict the rate at which this removal occurs did not exist. To develop a model describing streambed biofilm activity, experiments were conducted in an 8-meter …
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Techniques for Evaluating Power Plant Discharges Using In-Situ Breakdown and Flow Though Laboratory Sediment Bioassays
… of Boxelder leaves (Acer negundo) in insitu and artificial stream studies. In both studies the rates for the decline in penetrance values decreased significantly in the thermally influenced treatments. Reduction in mass-loss rate coefficients was significant in the in-situ study, but not in the …
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Validation of laboratory versus field avoidance behavior of schooling fathead minnows to heavy metal blends relative to acute toxicity during long term exposure
… in a laboratory avoidance chamber, an artificial stream and in a natural stream setting on a seasonal basis during continuous exposure to low levels of the metal blend for up to 9 months. Laboratory avoidance responses were determined seasonally during 12 months of laboratory holding …
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Sensitivity of early life stages of freshwater mussels (Bivalvia: Unionidae) to copper
… on glochidia was detected following 30- day artificial stream exposures of gravid adults to 19.1 ug Cu/L and an effluent containing an average of 23.9 ug Cu/L. Isolated glochidia were killed by copper concentrations ranging from 20-80 ug/L in 24-hour exposures, with sensitivity increasing …
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An assessment of the environmental effects of coal ash effluents using structural and functional parameters of aufwuchs communities
A site-specific artificial stream system receiving selected levels of fly ash, heavy metals, or sulfates was compared to a natural stream (Adair Run) influenced by effluent from the fly ash settling basin at Glen Lyn, Virginia. Aufwuchs communities colonizing glass microscope slides were monitored …
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Bacterial and Sediment Transport in an Artificial Sand Bed Stream During Unsteady Flow
… fecal indicator bacteria (FIB) concentrations in stream water. Causes for this concentration increase include FIB-laden stormwater runoff and the release of bacteria from stream-bottom sediments. Studies were carried out to quantify this second cause of water quality impairment. Coliform bacteria …
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The Effects of Multiple Predator Species on the Prey's Risk of Predation
… face from six different pairings of common stream predator species (represented by two insect and two fish species) and compared the observed risk to that predicted by a null model. Using controlled, replicated experiments in both artificial stream tanks and enclosures in a natural stream, I …
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The Effect of Dieoffs of Asian Clams (Corbicula fluminea) on Native Freshwater Mussels (Unionidae)
… mussel recruitment may be greater. Two miniature artificial stream tests were used to determine the effect of clam density on dieoff rate, ammonia production and dissolved oxygen levels. Only clams at the highest density of 10,000/m2 experienced 100% mortality. Unionized ammonia levels exceeded …
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Microhabitat use and its effect on growth of age-0 smallmouth bass in the North Anna River, Virginia
… profitable microhabitats. In experiments in an artificial stream, juvenile smallmouth bass assessed the potential profitability of an area by the foraging rate they achieved there. They usually did not remain in an area unless they foraged well at the time they searched it, and did not appear to …
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Multispecies toxicity tests using indigenous organisms: predicting the effects of hazardous materials in streams
… 1 was to determine which of the following artificial stream designs would be most logistically simple yet effective in maintaining riffle insects during a 30-d bioassay: 1) static and no current (S-NC); 2) flow-through and no current (FT-NC); 3) static with current (S-C); or 4) flow-through …
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An Ecotoxicological Recovery Assessment of the Clinch River Following Coal Industry-related Disturbances in Carbo, Virginia (USA): 1967-2002
… Asian clams (Corbicula fluminea) at sites downstream of the CRP. More importantly, these results indicated renewed toxicity in CRP effluent. Additional transplant studies using two enclosure types were conducted to isolate effects attributable to CRP effluent from the potentially confounding …
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Toxicological, physiological, and behavioral responses of the Asiatic clam, Corbicula sp., to biocidal and copper perturbations
… activity) of clams during 30-day laboratory artificial stream studies. Studies also were conducted comparing sublethal responses (e.g., glycogen, tissue water, soluble protein, and siphoning activity) of clams to copper, a component of power plant effluents, during 30-day laboratory, …
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Effects of discharge and substrate characteristics on FPOM retention
I released chloride and corn pollen into artificial streams to study the effects of discharge, substrate size, leaf packs, and pools on the retention and transport of fine particulate organic matter (FPOM). I found that doubling discharge significantly decreased both hydraulic and FPOM retention …