A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. March 2016 / Coastal waterbodies along the east coast of southern Africa evolved from fluvial origins that were slowly drowned by rising sea levels during the Holocene. The accumulation of sediment in these systems is relatively undisturbed, providing ideal sites from which longer term observations of palaeo-climatic variability over most of the Holocene period can be made. Lake St. Lucia, on the north coast of KwaZulu- Natal, is the largest estuarine lagoon in Africa and is widely regarded as one of the most important shallow water systems globally. Despite the importance of this system, little is currently know about the processes driving the long-term evolution of the lake. This study aimed to reconstruct the hydrological changes associated with the Holocene evolution of Lake St. Lucia using fossil diatoms. Analyses were performed on two sediment cores from the North Lake (15.6 m) and False Bay (15.9 m) basins of Lake St. Lucia. Age models, each based on eight radiocarbon dates, revealed continuous sedimentary records covering ~8300 cal. yr BP. A total of 150 samples were examined resulting in a total of 113 species recorded which were used to infer changes in environmental conditions based on their reported ecological preferences. / GR 2016

Avian reproductive success varies depending on environmental conditions, degree of predation, location, and food availability. I examined food availability and nesting habitat of wading birds in South Florida. Evaluating prey availability and prey used by two small heron species demonstrated the ability for small herons to maintain consistent diets through fluctuating environmental conditions, within and across different wetland types. Small herons may be able to cope with environmental changes by altering foraging locations and strategies. Regarding nesting habitat, man-made sites may provide habitat comparable to natural sites, at least in the short-term. The nest’s position can influence its susceptibility to increased temperatures and predators, particularly for. Climatic conditions such as rainfall can also impact nesting success by altering foraging conditions and fish behavior. Understanding the effects of hydrologic regimes on biota can have practical applications since ecosystems around the world share similar problems with competing demands for resources, and there is a concern for how use can affect the quality of the resource. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Lake Tana is a biodiversity and natural reservoir for fresh water supply contributing significantly to the economy of Ethiopia and downstream recipient countries, namely: Sudan and Egypt. The Lake Tana Ecosystem provides a variety of goods and services such as: provisioning, regulating, amenity and supporting services. These services are affected by high human activities which threaten the water quality and biodiversity of the lake. Hence, this study aims to assess the impact of human activities on water quality, biodiversity and livelihood of Lake Tana and its shore sides.To assess the impact of anthropogenic activities of Lake Tana; physicochemical parameters, macroinvertebrates, macrophytes and livelihood of the Lake side communities were collected in the year 2014/2015 during dry and wet seasons for 11 sampling sites as indicated in Figure 1.1 and Table 1.1. The variations of physicochemical, metals and bacterial parameters were investigated. The overall water quality parameters (mean analytical results) of Lake Tana were found to be: Temp (Temperature)23.0OC, pH 7.5, EC (Electrical conductivity)180.1 μS/cm, BOD5 (Biological oxygen demand in 5 days)37.3 mg/l, COD (Chemical oxygen demand)316.5 mg/l, TSS 0.3 mg/l, TDS 93.1 mg/l, SO4 2- 11.0 mg/l, PO4 3- 42.4 mg/l, Cr (0.08 mg/l), (Mn (0.01 mg/l), E. Coli (13.4 Cell/ml), F. Coliform (82.5 Cell/ml), T. Coliform (113.0 Cell/ml), etc. These parameters did not show significant variation among the sites but were significantly different between wet and dry seasons (P<0.05). The highest concentration values were recorded during the wet season. However, most of the parameters under investigation were within the Ethiopian EPA (Environmental protection agency) permissible range except PO4 3-, S2-, E. Coli (Cell/ml), F. Coliform (Cell/ml) and T. Coliform (Cell/ml). Based on the analysis of the water quality index (WQI), Lake Tana water was unfit for drinking purpose and needs treatment. For theMacroinvertebrates analysis, a total number of 629 macroinvertebrate individuals are belonging to 9 orders and 38 families were found. In the study year impacted areas number of identified macroinvertebrates were 478 (76%); of this, 233 (37%) were in the wet season and 245 (39%) in the dry season and the total number of individuals identified in the reference area was 151 (24% of the total) in the wet season 61 (9.7%) and in the dry season 90 (14.3%) individuals. The diversity was more in the dry season. The dominant orders were Odonata (156 individuals), Coleoptera (153 individuals) and Hemiptera (141 individuals). The literature indicated that the presence of more Odonata, Coleptera and Hemipteran larvae is an indication of water quality deterioration due to pollution. From the collected samples, the total number of tolerant individuals was 303 (48.2%) and facultative individuals were 243 (38.7%) while intolerant individuals were 80 (12.7%). Most of the taxa (48.2%) had tolerance scores ranging from 7 to 10. The analysis of different forms of indices showed poor water quality. The water quality of Lake Tana was also determined by developing the LTMI (Lake Tana Metric Index). The index indicated the impairment levels of the study sites. Seven of the sites were in the category of poor (disturbed) and the other three were very poor (highly disturbed). The study on macrophytes recorded 43 species and 18 families during the two seasons (wet and dry), throughout the study year. 2687 individual macrophytes were collected; 1756 in the wet season and 931 in the dry season. Poaceae (15 species) with abundance mean 215.40 ± 421.7 was the most dominant family, followed by Cyperaceae (5 species) 35.40 ± 68.3. Sacciolepis africana was the dominant macrophyte species in Lake Tana. But in the study area Ambobahir, the dominant species was Cyperus papyrus while the Megech study area was invaded by the nuisance exotic weed Eichhornia crassipes. In the present study, the low macrophyte diversity values of Shannon Wiener index (2.90), Simpson Diversity Index (1-D) (0.90), Simpson Dominance Index (D) (0.10), Margalef’s index (M’) richness index (5.32) and Evenness Index (E) (0.77) throughout the study year indicate moderate water quality status while the presence of certain bio-indicator species like Eichhornia, Potamogeton and Cyperus in the lake also confirm pollution. Because of the effect of human activities on water quality and biodiversity, the livelihood of the riparian community is affected indirectly. Hence, to recommend mitigation and remediation actions, this study also focused on the assessment of the change of livelihoods of people living in the study area using qualitative research methods (key informant interview, focus group discussion (FGD), observations, published and unpublished materials and photographes). Lake Tana is a home to different flora and fauna including endemic species. The flora such as macrophytes and forest resources are used mainly for traditional medicine, fuel wood, rope, pole, habitat for birds, animal feed, etc. and the fauna includes fish, hippos, crocodiles, invertebrates, etc. Further, the Lake Tana area is a good habitat for indigenous cattle breeds (Fogera breed) and field crops gene center. The major resources around Lake Tana are land (the major source of livelihood), vegetation resources (macrophytes and forest resources), wildlife resources (fish, the other important source of livelihood) and cultural landscapes (churches and monasteries). Lake Tana is exposed to a set of interrelated environmental problems induced by human influence such as deforestation, erosion, sedimentation, water level reduction, erratic rainfall, flood, and competition for water resources, pollution and introduction of alien species. The causes to these problems were overgrazing, farmland expansion, cultivation of marginal lands (shorelines), encroachment of communal land, pollution and vegetation removal to meet demand for food and fuel wood. It is observed that alteration of Lake Tana and its fringe wetlands has affected the whole dynamics of the Lake’s ecosystem and the livelihood of the surrounding community. Ecosystem components are interlinked; hence correlation analysis was done between physicochemical parameters and macroinvertebrates of Lake Tana. Thus, correlations among many of the physicochemical parameters and macroinvertebrates families have been observed. To mention some of the correlations, the changes in the physical, chemical and biological characteristic of the lake affected the aquatic life forms and significantly affect economic activities that the lake supports. The RDA(Canonical redundency analysis) ordination of the species-environmental variable association indicated that pH, Cd, Pb and SO42- and Velidae, Chironomidae, Physidae, Gerridae, Corixidae, Dytiscidae, Caenidae, Coenogrionidae Simuliidae and Psephenidae were negatively correlated while Mussidae positively correlated with these environmental variables. This study concludes that the main threat to aquatic ecosystems in Lake Tana arises from agricultural activities, urbanization and industrialization that deteriorated water quality and biodiversity. Thus, it is recommended that proper management of Lake Tana should be put in place to prevent further deterioration of water quality and biodiversity of the lake for its sustainable development. / Environmental Sciences / Ph. D. (Environmental Science)

Evidence is presented to support the conclusions that (1) North Lake reservoir is less productive, contains lower standing crops of phytoplankton and total organic carbon than other local reservoirs; (2) that neither the phytoplankton nor their instantaneously-determined primary productivity was detrimentally affected by the power plant entrainment and (3) that the effect of the power plant is to cause nutrient limitation of the phytoplankton primary productivity by long-term, subtle, thermally-linked nutrient precipitation activities.

No description available.

Reliable evaporation data are an essential requirement in any water and/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured using advanced research instruments (Bowen Ratio and Eddy Correlation). Actual over-lake evaporation and weather data measurements were used to understand the mechanism of evaporation in the lake, determine lake-related parameters (such as roughness lengths, heat storage, net radiation, etc.), and examine and evaluate existing lake evaporation methods. This enabled the development of a modified and flexible model incorporating the tested methods for hourly and daily best estimates of lake evaporation using nearby simple land-based weather data and, if available, remotely sensed data. Average evaporation from Bear Lake was about 2 mm/day during the summer season (March-October) of this two-year (1993-1994) study. This value reflects the large amount of energy consumed in heating the water body of the lake. Moreover, evaporation from the lake was not directly related to solar radiation. This observation was clear during nighttime when the evaporation continued with almost the same rate as daytime evaporation. This explains the vital role of heat storage in the lake as the main driving energy for evaporation during nighttime and daytime cloudy sky conditions. When comparing over-lake and nearby land-based weather parameters, land-based wind speed was the only weather parameter that had a significant difference of about 50% lower than over-lake measurements. other weather parameters were quite similar. The study showed that evaporation from the lake can be accurately estimated using Penman-type equations if related parameters such as net radiation, heat storage, and aerodynamic effect are evaluated properly to reflect conditions over the lake. Using other methods may lead to unacceptable errors.

As the railroad and mining industries brought non- Mormon settlers into the territory of Utah, a conflict developed which led to the creation of a separate system of education by the Protestant newcomers. Their purposes were to provide a quality education for their own children free from Harmon influence and to convert children of Mormon families. The Presbyterian Church led in the creation of graded schools from elementary, through secondary, and culminating in the Sheldon Jackson College in Salt Lake City. As public schools were established. the mission schools were closed, except for Wasatch Academy in Mt. Pleasant and Sheldon Jackson College. renamed Westminster in 1902. The First World War forced Westminster to limit its offerings to t he first two years of college. In 1945. a four-year senior college program was introduced and the campus was enlarged. Affiliated with three Protestant denominations, Westminster continues to serve the needs or a changing society, a positive asset to Salt Lake City and its hinterland .

Philosophiae Doctor - PhD / Cichlids are one of the most diverse groups of fishes in the world. The highest concentration of cichlids is found in Lake Malawi, where over 1500 species are recorded to occur, which are dominated by the haplochromine tribe. Several authors proposed that sexual selection has been a major contributor in the high rate of speciation of haplochromine cichlids. However, sexual selection alone may not be sufficient to fully explain high speciation rates among cichlids. Many closely related cichlids in Lake Malawi differ only in coloration, yet occur in sympatry. It is still not fully understood how they remain reproductively isolated. Previous studies suggest that visual cues are primarily used for reproductive isolation and species recognition. In the current study, visual, chemical and acoustic cues were investigated to observe how they may potentially influence species recognition and reproductive isolation between two closely related species, Metriaclima estherae and M. callainos, as well as between alternate colour morphs of M. estherae.

The first of a series of studies of social agencies in Oregon. aimed at collecting and presenting data through the use of a sociological model, this project represents a beginning effort to assess the social welfare resources of the State. Christie School, a small nucleated institution, was examined in terms of its evolution from an orphanage to a treatment-oriented care facility . Particular attention was given to the impact of historical events and analysis of these in terms of the institution’s life cycle. Impetus was given to the study by the crisis of impending closure of the school and events leading to continuance were recounted. The model of institutional development created by Joyce O. Hertzler was selected after examination of a number of other models. Data were collected from a number of original sources and placed in the general categories of the model. The model was found to be generally static and lacking in specificity for the examination of a small nucleated institution. A number of conclusions were drawn from the collection and analysis of the historical data. Among these were the tendency for religion to remain institutionally constant while other institutional factors seemed to vary in light of historical developments. The ability of Christie School to function fairly autonomously within a generally hierarchical structure of the Catholic Church was noted. The force of individual personalities on the shaping of the institution was acknowledged and the communication process was examined in light of the school’s struggle for existence. The impact of secularization was noted as well as the influences of various social movements on the institution throughout its history. Much original material was collected, recorded and preserved by the project.

Eutrophication is one of the primary factors causing harmful cyanobacteria blooms in freshwater lakes; climate change such as warmer temperature can potentially further increase both frequency and intensity of blooms. This study investigated the long-term changes in water quality and summer phytoplankton assemblages in Oswego Lake, OR, in relation to lake management practices (e.g., hypolimnetic aeration and alum treatments), as well as climatic and regional meteorological conditions. Both water quality and phytoplankton assemblages were sampled biweekly during summer seasons between 2001 and 2013. The concentrations of total phosphorus (TP), soluble reactive phosphorus (SRP) and total nitrogen (TN) decreased 66%, 93% and 31%, respectively, in response to the hypolimnetic aeration and alum treatments since 2005. The results of summer phytoplankton assemblages showed a 62% reduction of cyanobacteria biovolume and a switch from cyanobacteria dominance (2001-2005) to diatom and chlorophyte dominance (2006-2013). Cluster analysis identified four statistically different groups of summer phytoplankton assemblages (denoted Groups 1-4). Nonmetric multidimensional scaling analysis indicated that the four groups were associated with different water quality conditions. Group 1 occurred prior to hypolimnetic aeration and was primarily comprised of cyanobacteria, associated with water conditions of high nutrients and high primary production. Group 2, dominated by cyanobacteria and chlorophytes, occurred between hypolimnetic aeration and alum surface application. Group 2 was associated with turbid water conditions. Group 3 was dominated by diatoms, occurring after alum surface application. Group 4 included R-strategist phytoplankton that quickly respond to environmental changes, occurring in the years following alum injection, drawdown and inflow alum treatment. Both Group 3 and 4 were associated with reduced nutrients in the lake. The results demonstrated a strong temporal relationship between the long-term changes in water quality and summer phytoplankton assemblages and the lake management practices. The Pacific Decadal Oscillation (PDO) index, an El-Niño-like pattern of Pacific climate variability, showed a statistically significant correlation with the summer phytoplankton dynamics, while the multivariate ENSO index (MEI) and regional meteorological variables (air temperature, rainfall, wind speed, wind direction and solar radiation) were not significantly related to the changes of phytoplankton communities during the study period. In conclusion, the study results suggest that the lake management practices had strong effects on both production and community compositions of phytoplankton, and suggest the need for a future study on large-scale climate impacts on lake ecosystems and best management practice.