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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Evaluating microbial indicators of environmental condition in Oregon rivers

Pennington, Alan Travis 29 July 1999 (has links)
Traditional public health bacterial indicators of water quality and the Biolog�� system were evaluated to compare their response to other indicators of stream condition with the state of Oregon and between ecoregions (Coast Range, Willamette Valley, Cascades, and Eastern Oregon). Forty-three randomly selected Oregon rivers were sampled during the summer low flow period in 1997 and 1998. Testing included heterotrophic plate counts (HPC), total coliforms, fecal coliforms, E. coli, and Biolog�� GN plates. Statewide, HPC correlated strongly with physical habitat and chemistry indicators while fecal coliforms and E. coli were highly correlated only with the river chemistry indicators. Total coliform bacteria did not correlate with either of the above environmental indicators. Dividing the sites by ecoregion, Eastern Oregon was characterized by high HPC, fecal coliforms, E. coli, nutrient loads, and indices of human disturbance, whereas the Cascades ecoregion had correspondingly low counts of these indicators. The Coast Range reflected statewide results and the Willamette Valley presented no consistent indicator pattern. Attempts to separate ecoregions with the Biolog system were not successful nor did a statistical pattern emerge between the first five principle components and the other environmental indicators. Our research has shown that traditional public health microbial indicators may, however, be useful in measuring the effects of anthropogenic stress over large spatial scales. / Graduation date: 2000
52

Preliminary investigation of microbial indicators in the assessment of Oregon streams

Campbell, Heidi M. K. 29 September 1998 (has links)
The Environmental Monitoring and Assessment Program (EMAP) site selection protocol was used to generate a random sample of streams throughout the state of Oregon. One hundred and forty-six selected streams were sampled during the summer, low-flow period of 1997. Traditional microbial public health indicators, including heterotrophic plate counts (HPC), total coliforms (TC), fecal coliforms (FC) and E. coli, were enumerated using the membrane filtration technique. Nearly 17% (3.4-23.6%, 95% C.I.) of streams exceeded the current state of Oregon standard for water-contact recreation. Levels of bacteria were also shown to differ significantly by ecoregion. The Cascades ecoregion had low levels of all types of bacteria. The Willamette Valley, Columbia Plateau and Snake River Basin had high levels of one or more groups of bacteria measured. Twenty-six sites were resampled and FC and E. coli estimates were not significantly different for the different sampling dates. Biolog GN plates were used to provide a measure of the functional diversity of microbial communities for the same streams as above. Two groups were formed based on inoculum density and Biolog GN plates were analyzed using principal component analysis (PCA). The first few principal components explained nearly half of the variation of the data in both groups. Principal components were correlated with the average carbon source utilization, levels of coliform bacteria, and ecoregions. These results indicate that patterns produced by Biolog GN plates may be useful in the assessment of ecological condition of freshwater streams. Subsequent publications will explore the relationships between the pattern of substrate utilization of Biolog GN plates with other indicators of ecological function. / Graduation date: 1999
53

Detection of human-induced stress in streams : comparison of bioassessment approaches using macroinvertebrates /

Dahl, Joakim. Johnson, Richard K. Sandin, Leonard. January 2004 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2004. / Thesis documentation sheet inserted. Appendix reproduces three papers and manuscripts co-authored with R.K. Johnson and two papers co-authored with R.K. Johnson and L. Sandin. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.
54

Photopigments as descriptors of phytoplankton assemblages for biotic assessment of Illinois lakes and reservoirs : an HPLC aided analysis /

Krenz, Robert J., January 2009 (has links) (PDF)
Thesis (M.S.)--Eastern Illinois University, 2009. / Includes bibliographical references (leaves [117]-125).
55

Optimisation and validation of methods used to detect amoebae resistant bacteria in water distribution systems.

Muchesa, Petros. January 2011 (has links)
M. Tech. Water care / Free-living amoebae are important predators that feed on bacteria, fungi and algae by phagocytosis. However, a number of bacteria have become resistant to, and are able to survive, grow and exit Free-living amoebae. Free-living amoebae are ubiquitous organisms that have been isolated from various man-made and environmental water systems. Some of these free-living amoebae host amoeba-resistant bacteria such as Legionella spp. Vibrio cholerae and Mycobacterium species which are regarded as human pathogens. The objective of this study was to establish amoebal enrichment and co-culture techniques in order to isolate and identify amoebae and amoeba-resistant bacteria from seeded and environmental water samples. The aim of the study was to introduce and establish amoebal co-culture and amoebal enrichment techniques in South Africa, to provides South African laboratories with baseline information on the efficiency of culture-based methods as well as analytical requirements like incubation temperature, media preparation and storage conditions for amoebal enrichment and co-culture techniques for the detection and isolation of amoebae and amoeba-resistant bacteria from environmental water systems.
56

The use of microphytobenthos (benthic microalgae) as an environmental indicator of past and present environmental conditions : a comparative study of Mnweni Catchment and the St. Lucia Estuary.

January 2006 (has links)
Diatoms are a large and diverse group of algae which are distributed throughout the world in all types of aquatic systems and are one of the most important food resources in freshwater ecosystems. The need to sample diatoms arises from the necessity to know the history of the water quality. Diatom communities reflect the overall ecological integrity by integrating various stressors and as result provides a broad measure of their impacts. They are recognized as valuable organisms for bio assessment, due to their ease of identification, rapid life cycle and their visibility to the naked eye. Diatom communities provide interpretable indications of specific changes in the water quality Environmental gradients and assemblage composition in the Mnweni River catchment revealed that water chemistry, habitat structure, flow type and land use were the most important environmental factors for diatom assemblage composition in the Mnweni River. The results indicates that the diatom diversity and assemblage composition in the Mnweni River shows that changes in the water chemistry as well as organic pollution, but also indicate changes in the habitat character which is related to the water flow, river bank character and catchment land use. The diatom assemblages that were found at the sites are typical of clean or mildly enriched water conditions. The changing salinity in St. Lucia is the main physical factor that is driving the constant change in ecological conditions within the estuary. The changes in the diatom community structure in the estuarine system indicate the variable nature of the benthic communities under different salinity conditions. Contrary to the drought conditions that are being experienced, the diatom biomass did not show any significant changes or differences. This may be due to the rapid recovery ability that diatom communities exhibit in response to changes that are occurring in their environment. / Thesis (M.A.)-University of KwaZulu-Natal, 2006.
57

Comparison of macroinvertebrate assemblages in a first- and second-order stream in Wilber Wright State Fish and Wildlife Area, Henry County, Indiana in 2000

Conrad, Richard C. January 2003 (has links)
Macroinvertebrate assemblages were semi-quantitatively sampled from the Little Blue River and an isolated headwater stream in Wilbur Wright Fish and Wildlife Area from March through November of 2000. Physicochemical conditions and qualitative habitat characteristics were recorded at each site. Each stream contained unique community assemblages based on taxa richness, composition, functional feeding groups, behavioral groups, reproductive habits, and drought tolerance/avoidance. Collections from the first-order stream contained fewer taxa and a greater proportion of non-insects and tolerant taxa than those from the Little Blue River. Taxa from the Little Blue River were adapted for filtering/collecting and for swimming or clinging, while taxa from the first-order stream were primarily gathering/collecting and swimming or sprawling. The proportion of taxa with adaptations for drought resistance or avoidance was significantly higher in the first-order stream than in the Little Blue River (p<0.001). / Department of Biology
58

A comparison of SAAS and chemical monitoring of the rivers of the Lesotho Highlands Water Project.

Rajele, Molefi Joseph January 2004 (has links)
The Lesotho Highlands Development Authority routinely uses the South African Scoring System version 4 (SASS4) in conjunction with water chemistry to monitor water quality of rivers in the Lesotho Highlands Water Project areas. The objective of this study was to test the efficiency of SASS4 in these areas.
59

Assessment of aquatic invertebrate communities of tributaries of the Buffalo River, Arkansas, and evaluation of indices of community integrity /

Mixon-Hinsey, Janice Arlene, January 1900 (has links)
Thesis (M.S.)--Missouri State University, 2008. / "December 2008." Includes bibliographical references (leaves 63-74). Also available online.
60

Physiological responses of a bloom-forming macroalga to eutrophic conditions implications for use as a bioindicator of freshwater and nutrient influx to estuarine areas /

Cohen, Risa A., January 2003 (has links)
Thesis (Ph. D.)--University of California, Los Angeles, 2003. / Vita. Includes bibliographical references.

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