Biology Ph.D. Dissertations


Wet wall algal community response to in-field nutrient manipulation of nitrogen and phosphorus, and the taxonomy, ecology, and distribution patterns of the acidophilic diatom genus Eunotia Ehrenberg (Bacillariophyta) of the Great Smoky Mountains Na

Date of Award


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Biological Sciences

First Advisor

Dr. Rex Lowe

Second Advisor

Dr. Alexander Izzo

Third Advisor

Dr. Jeffrey Johansen (Committee Member)

Fourth Advisor

Dr. Karen Root (Committee Member)

Fifth Advisor

Dr. Dan Wiegmann (Committee Member)


The basic ecology of wet wall algal assemblages and the ecology, distribution patterns, and taxonomy of the acidophilic diatom genus Eunotia Ehrenberg were explored from the Great Smoky Mountains National Park (GSMNP), U.S.A. First, the structural response of wet wall algal assemblages were studied through an in-field experimental manipulation of nutrients (nitrogen and phosphorus) at high and low altitudes. Subaerial algal assemblages are understudied communities and the factors that drive community dynamics in these environments are poorly understood. Algal assemblages were not as nitrogen or phosphorus limited as initially anticipated. Although not directly tested in this study, results suggested that other factors, such as ultraviolet radiation, pH, moisture levels, or microhabitat differences, are influential in shaping wet wall, algal community structure. Second, diatoms from high elevation springs and headwater streams were examined and found to be dominated by a couple of Eunotia taxa, including a new species, E. macroglossa sp. nov. The presence of morphological deformities at some of the spring sites was documented with both light and scanning electron microscopy and the malformations suggest that acid precipitation may directly be harming the aquatic ecosystems in the park. Third, the distribution patterns of Eunotia species from sites throughout the park were explored in relation to environmental factors such as elevation, pH, geology, and water chemistry. As expected higher altitude streams generally had lower pH levels and a greater relative abundance of Eunotia relative to other diatom genera, especially species in the E. exigua complex. The results highlighted how vulnerable high elevation areas in the GSMNP may be to acid precipitation. Finally, an image rich documentation and inventory of the Eunotia taxa in the GSMNP was provided, including species descriptions, morphological measurements and a discussion of taxonomic challenges. The Eunotia were very diverse with over 65 subgeneric taxa being documented, many of which were new park records, new records for North American and/or were undescribed species. This dissertation explored a new algal frontier (wet walls) and provided further taxonomic documentation and ecological description of an understudied group of diatoms, the genus Eunotia.