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 20 of 139 for “"aquatic organisms"”.
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Quantitative structure-activity relationships of comparative toxicity to aquatic organisms.
… toxicities of up to 75 organic chemicals to two aquatic species, Photobacterium phospherum (known as the Microtox test), and the fathead minnow. To model the toxicities 49 physico-chemical and structural parameters were produced including measures of hydrophobicity, molecular size and electronic …
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Functional and pathological responses of selected aquatic organisms to chrysotile asbestos
… 10⁴ fibers/liter in the laboratory suggests that aquatically transmitted asbestos is a potential hazard to these species in the field.
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Influences of Historical and Contemporary Environmental Conditions on Threatened and Endemic Aquatic Organisms
… conditions affect the distribution of aquatic species. The following three chapters seek to assess the degree to which conditions have impacted current distribution and population structure of fishes and mussels. The first chapter assesses genomic hybridization dynamics between the …
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The Influence of Water Quality Characteristics on Vanadium Toxicity to Model Aquatic Organisms
… oil sands region that could present a risk for aquatic organisms. Petroleum coke (PC) has been experimentally used to treat oil sands process-affected water (OSPW) to reduce organic toxicants. However, PC contains up to 1,000 mg of V per kg of PC, and during OSPW treatment V leaches from coke …
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The role of waterbirds in the dispersal of aquatic organisms in southern Africa
… and evolutionary consequences. Not all organisms are capable of dispersing on their own and instead produce propagules that must be transported to new habitat by a vector. Propagule dispersal by frugivorous bird species is well researched, but only very recently has the capacity of …
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The utilization of aquatic organisms for continuous and automatic monitoring of the toxicity of industrial waste effluents
… or the presence of an unsuspected material. Aquatic organisms, on the other hand, respond to their total environment and in this way integrate the effects of all the various chemical and physical waste parameters. The objectives of this study were to evaluate the possibility of using the …
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The use of microcosms to assess the potential impact of underground bunker crude oil on freshwater aquatic organisms
… of the study revealed that the impacts on aquatic ecosystems in a crude oil spill will be devastating. From different trophic levels, organisms (Daphnia magna, Physa spp., Lemna giba and Neocaridina spp) had different responses, but overall, were severely affected by the crude oil …
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Environmental fate and effects of atrazine, metolachlor, carbaryl and chlorothalonil in lotic ecosystems
Pesticides have the potential to affect receiving aquatic ecosystems. These effects are dependent on compound physicochemical characteristics, susceptibility of aquatic organisms, abundance in streams, and stream characteristics. Atrazine, metolachlor, carbaryl, and chlorothalonil have high usage …
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Biological and chemical monitoring of three streams in the area of Blacksburg, Virginia
… several methods of analyzing diversity of the aquatic organisms and attempts to assess water quality in the three streams investigated. The Cairns-Dickson DI<sub>T</sub> diversity index was applied to two trophic levels of aquatic organisms and the results were compared to ascertain whether …
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Fate and effects of triallate in a prairie wetland
… increases the potential for contamination of aquatic ecosystems. Triallate is a widely used herbicide for the control of wild oats and it is frequently detected in aquatic systems. Because triallate is toxic to aquatic organisms and has the potential to persist in sediment, its impact on …
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Assessing Industrial Contamination of Brockport Creek After Removal of Contaminated Sediment
… to 432 µg/kg, below water quality criteria for aquatic organisms and human health. The number of heavy metals detected in sediments after the cleanup decreased from 22 to eight, and their concentrations also decreased. After the cleanup, concentrations of metals ranged from 0.8 to 172 µg/kg; …
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Evaluation of the Development and Effectiveness of Copper Total Maximum Daily Loads (Tmdls) to Achieve Marine Water Quality Criteria
… in surface water are known to be toxic to aquatic organisms (e.g., barnacles, algae, and fish). For a number of these chemicals (e.g., tributyltin [TBT], copper) federal and state water quality standards exist to protect aquatic organisms. As a means to comply with water quality standards, …
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Ecological Magnification of Persistent Organochlorine Pesticides in an Illinois Watershed
… of selected organochlorine pesticides in aquatic organisms of the Lake Decatur watershed in central Illinois were determined in this study. A review of the use of persistent organochlorine pesticides in the United States and the study area is provided. Samples of Pisces, Decapoda, Insecta, …
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Modeling species geographic distributions in aquatic ecosystems using a density-based clustering algorithm
… geographic range of free-living and symbiotic organisms in terrestrial and aquatic ecosystems. More recently, distributional ecology has been used to map disease transmission risk. The implementation of distributional ecology for disease transmission has, however, been erroneous in many cases. …
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The role of stochastic resonance and physical constraints in the evolution of foraging strategy
… Daphnia. While foraging, these small aquatic organisms stochastically choose movement parameters with particular levels of variation, or noise, which are similar across several species. Here, related simulations consistently show that these noise levels may be adjusted to maximize …
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The Toxicity of Ammonia to Atlantic Silverside (Menidia menidia) and Ghost Shrimp (Palaemonetes pugio)
Ammonia is known to be toxic to aquatic organisms. The national water quality criteria for ammonia in the marine environment have been established to protect aquatic organisms from the toxicity of ammonia. Discharge into Chesapeake Bay has not yet been regulated under this criteria. Ammonia limits …
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Evaluation of the relationships between watershed-scale land use and contaminants in aquatic environments and the use of freshwater snails as indicators of impairment
… agricultural land may introduce contaminants to aquatic environments that can negatively affect the health of aquatic organisms. This study utilized a landscape-scale regression-based design to assess the effects of AFOs on contaminant concentrations and resident populations of a pleurocerid …
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