The role that aquatic actinomycetes play, in the production of tastes and odors in water supplies has been investigated since 1948. The ability of these organisms to produce by-products in lakes and streams, which renders the water unpalatable, is of considerable public health importance. It is desirable that the waterworks industry has as much information as possible concerning the factors that contribute to the growth of these organisms. Since it appears that the aquatic actinomycetes may be isolated from most fresh-water sources, the problem of diversified environments and nutritional requirements offers an excellent field of investigation. The fresh-waters of the world contain variable quantities of electrolytes that may determine in part the biological activity of these organisms. The unsolved questions in this instance are concerned with the electrolytes present and their quantitative effects on the growth and development of these forms.

A suite of biomarkers was developed using the crab Carcinus maenas and the mussel Mytilus edulis as test organisms. The ability of the biomarkers to differentiate amongst the major toxic components and to indicate the concentration of chemical mixtures was evaluated in the laboratory. Biomarkers were also applied in a field trial and their potential to monitor environmental water quality in a chemically contaminated estuary investigated. The results from the biomarker assays were compared with and validated against two commonly used toxicity tests (Tisbe battagliai LC-50, and Microtox®). Novel methods for recognising patterns of biomarker responses were developed and assessed. The most sensitive and reliable biomarker assays investigated were neutral red retention time in crabs and mussels and heart rate and glutathione-S-transferase activity in crabs. Effects were observed at environmentally realistic concentrations; for example lysosomal enlargement was observed in mussels exposed to a complex mixture containing chemicals at environmental quality standard concentrations. Exposure concentrations required to illicit biomarker responses were similar to toxicity test EC-50 values. The ease of interpretation and clarity of the results was enhanced when data from suites of biomarkers were pooled and analysed using multivariate statistical techniques (multidimensional scaling and cluster analysis). Multivariate analysis differentiated amongst mixtures containing solely organic chemicals, metals and metal and organic chemical mixtures. Exposure response relationships to complex mixtures were established for some of the individual biomarkers tested (crab heart rate and gill metallothionein) and also for suites of biomarkers when multivariate analysis was carried out. In the field biomarkers, in both transplanted and indigenous animals, were able to differentiate between clean and contaminated sites and indicate a pollution gradient along the Tees Estuary. This was not achieved using toxicity tests. The results were displayed clearly using multivariate analysis, enhancing the power of biomarkers as monitoring tools.

<p> Government agencies assess the biological integrity of streams and the chemistry of groundwater to monitor anthropogenic impacts on freshwater ecosystems. Some of the impacted streams lack obvious stressors that can be linked to the impacts. In the case of elevated nutrients and ionic concentrations found in impacted stream sites within the Malibu Creek Watershed, research from the Las Virgenes Municipal Water District pointed towards the naturally occurring leachate from the Modelo formation, which contests previous studies suggesting an influence from anthropogenic activity. Differentiating between natural sources of trace element concentrations and point/non-point source contamination could aid in resolving water quality issues since monitoring occurs near anthropogenic development. Water, bedrock, and diatoms were sampled from spring, seep, and stream sites underlain by Tertiary sedimentary bedrock throughout the study area. Multivariate analyses revealed an association of groups driven by salinity along with a correlation between geochemistry and diatom assemblages. Mixing models and radar charts identified potential rock types as sources for analyte concentrations. Sites that were underlain by the Modelo formation presented brackish water conditions and high nutrient concentrations, which potentially influenced the diatom species compositions found at the spring/seep sites as a result of weathering.</p>

<p> Eulachon smelt <i>Thaleichthys pacificus</i> are anadromous forage fish of the North Pacific Ocean that annually spawn in coastal rivers of North America in late winter and early spring. These spawning runs range from northern California to southwestern Alaska and provide important resources to nearby communities, indigenous cultures, and wildlife predators. However, eulachon life history is not well understood or documented throughout their range. In recent years, concerns for eulachon population abundances in the southern portions of their range have led to federal protection. Though there are no federal listings in Alaska, there have been local concerns documented for eulachon runs of the Chilkat and Chilkoot rivers since approximately 1990. However, eulachon run timing and abundance trends are difficult to detect due to limited available data and variability in eulachon runs. To document baseline information and explore patterns of eulachon runs of the Chilkat and Chilkoot rivers, we sought local and traditional knowledge from residents of nearby communities to document information about local uses, run timing, abundance, and wildlife observations related to eulachon runs. Observations of eulachon runs were integrated with historical records from newspaper articles and scientific reports to construct temporal trends in eulachon run timing and abundance. </p><p> Based on the findings of this study, annual eulachon runs of the Chilkat and Chilkoot rivers generally occur for about a week or two between mid-April and mid-May. The arrival dates of eulachon runs often vary from year to year, but the timing appears to have shifted earlier, from mid-May to mid-April, over the past couple of decades. Abundance records were not sufficient to quantify trends. However, qualitative information regarding abundance did not suggest any clear trends in eulachon abundances of the Chilkat and Chilkoot rivers over the years, nor did there appear to be prominent local concerns about abundance declines. Many respondents suggested that eulachon populations were naturally too variable to be able to describe trends in abundance. Interviews also provided insight into local perspectives on eulachon life history and ecology. These results suggest that variability in eulachon run timing and abundance could be related to environmental conditions, including tidal height, river habitat, and water temperature. For a data-limited species like eulachon, integrating local observations and historical records offers a promising approach to documenting baseline information and improving the scientific understanding of eulachon runs and other environmental phenomena.</p>

Ph.D, Faculty of Science, University of the Witwatersrand, 2011 / Abstract Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) (water hyacinth), a neotropic noxious weed of South American origin, is counted among the “big five” aquatic weeds in South Africa. The weed causes dramatic ecological and economic losses in infested areas. Its control is facilitated by the release of biocontrol agents, mainly Neochetina eichhorniae (Warner) and Neochetina bruchi Hustache (Coleoptera: Curculionidae). Control efforts via biocontrol are hampered, mainly by the climate incompatibility of the agents, aggravated further by the indiscriminate use of lethal doses of glyphosate based herbicides. The lethal doses interfere with the successful establishment and persistence of the biocontrol agents, thus undermining their impact. Continued use of herbicide kills the water hyacinth mat and as a result, the immature stages of the agents are killed. If biocontrol is to succeed as a control strategy, then low doses of the herbicide need to be advocated. It was hypothesized that a low dose will constrain the vegetative and reproductive capacity of the weed, while maintaining the habitat for the biocontrol agents. Consequently, this study was conducted to identify a retardant dose of glyphosate herbicide and test its effect on the Neochetina weevils. A concentration of 0.8% (0.11g m-² or 2880mg a.i /L) glyphosate based herbicide, sprayed at 150 L ha-1 was proved to retard the vegetative and the reproductive growth of the weed, in terms of leaf and ramet production. Further, the retardant dose did not have any detrimental effects on the adult weevils and its larval stages. Weevil herbivory was also enhanced by the retardant dose. Furthermore, the retardant dose did not have any detrimental effects on ‘plant quality’ as evidenced by % nitrogen level in plant tissues such as crown and leaves. Contrary to expectation however, the combined effects of the retardant dose and Neochetina herbivory (0.8%+Ne) did not result in the production of lower number of ramets or leaves than water hyacinth plants dosed with 0.8% herbicide alone. Water hyacinth biocontrol agents in South Africa are subjected to frosty winters with low temperatures which cause the biocontrol agents to decline to an overwintering larval population that fails to catch up with the weed as it rebounds from the frost in spring. This hypothesis was tested in this study at 12 water hyacinth infested sites, which were grouped as temperate and sub-tropical sites. At both the temperate and subtropical sites, water hyacinth plants produced ramets (daughter plants) through autumn and increased biomass during summer. However, weevil numbers were very low at these sites, as evidenced by adult counts and feeding scars, indicating a marked seasonal asynchrony between the phenologies of the weevils and water hyacinth. Hence, intervention by seasonal applications of the herbicide is crucial to constrain weed growth. Herbicidal applications during autumn and spring inhibited the growth of the weed without adversely affecting the adult weevils or immature, immobile stages. Continued use of herbicides raises concerns of effect on non-target species, such as amphibians. Results from this study indicate that a direct application of a retardant dose of glyphosate did not kill or affect the growth of the Xenopus larvae, as determined by survival and body lengths. However, under laboratory conditions, this study has shown for the first time that an invasive aquatic weed (water hyacinth) was more lethal to an aquatic vertebrate (Xenopus larvae) than a herbicide advocated for its control. This study conclusively shows that retardant dose of glyphosate herbicide can be integrated with biocontrol to provide a sustainable and eco-friendly technique with which to combat water hyacinth infestations in South Africa.

Resumo: O objetivo deste trabalho foi avaliar o ganho de biomassa de Eichhornia crassipes cultivada em microcosmo em diferentes épocas do ano. O experimento teve duração de 189 dias e ocorreu entre abril e outubro de 2006. Indivíduos de E. crassipes foram cultivados em um sistema de recirculação de água composto por 3 unidades experimentais. O fluxo de água foi contínuo (vazão de 0,25 L min-1) e nutrientes foram adicionados semanalmente. Valores de nitrito, nitrato, ortofosfato, oxigênio dissolvido, condutividade elétrica, turbidez, pH e temperatura da água foram obtidos semanalmente. Os valores médios semanais de temperatura mínima absoluta atmosférica foram calculados através dos dados obtidos pela Estação Meteorológica CEAPLA/UNESP, localizado a aproximadamente 500 metros do local do experimento. Semanalmente as plantas foram pesadas e posteriormente devolvidas as respectivas unidades experimentais. Variações de temperatura atmosférica foram verificadas. O período com os menores valores de temperatura mínima atmosférica (junho e julho) coincidem com o período de menores valores de ganho de biomassa do vegetal. Após este período, os valores de temperatura aumentaram favorecendo o crescimento do vegetal, ocorrendo os maiores valores de ganho de biomassa. / Orientador: Antonio Fernando Monteiro Camargo / Coorientador: Gustavo Henrique Gonzaga da Silva / Banca: Luis Mauricio Bini / Banca: Ciro césar Zanini Branco / Mestre

<p> An aquaculture production system was constructed at the Waik&imacr;k&imacr; Aquarium in the fall of 2016 that produces mysid shrimp zooplankton (<i> Americamysis bahia</i>). From November 2017 to February 2018, the Waik?k? Aquarium (WAq) required an average of 5,751 live mysids per week that were imported as feed with current import rates of $0.08 per animal or$24,000 annually. Fixed and variable budgets were used to evaluate the economics for the mysid culture system. Sensitivity analyses of labor costs, the sale of excess mysid production, and the discount rate were also conducted using stochastic modeling of in-house domestic yields to estimate the expected the net present values (NPV) of domestic production in comparison with imports. The indirect benefits of domestic production were qualitatively evaluated. Results showed that WAq had a greater (> 0) NPV across a variety of cost and benefit scenarios and a less expensive $.05 mysid versus the imported $.08 mysid.</p><p>

Environmental issues from oil production have left inestimable environmental degradation and impacts to the lives of people in the Nigerian oil-producing region (NOPR). Research to date has suggested the importance of stakeholders’ collaboration in managing environmental issues. However, little research has been conducted to understand roles of stakeholders in developing a framework for stakeholders’ collaboration in the NOPR. This research produces a framework for stakeholders’ collaboration to expand knowledge in the development of a collaborative environmental management in the NOPR. The research aim was achieved based on four objectives; 1) identified recommended practices for stakeholders’ collaboration in managing environmental issues and established how they could be applied in the NOPR; 2) investigated stakeholders’ perception of collaborative roles in managing environmental issues in the NOPR; 3) designed a framework for stakeholders’ collaboration for managing environmental issues in the NOPR through the synthesis of outcomes of 1) and 2); and 4) validated the designed framework by identifying the critical success factors for its application. In achieving these objectives, interpretive research was applied, and it was underpinned by stakeholder analysis methodology to provide a coherent research design. Furthermore, the Ostrom’s institutional analysis and development (IAD) framework and the theory of common pool resource were extended to inform the interpretation of collaborative roles of stakeholders in managing environmental issues in the NOPR. Adhering to the theoretical suggestions of stakeholder analysis / IAD framework and to allow a robust investigation of stakeholders’ collaboration, this research focused on the qualitative investigation of roles of the key stakeholders–i.e., Nigerian government agencies, multinational oil companies and host communities. While analysis of selected documents of the key stakeholders was conducted to explore the roles of stakeholders, semi-structured interviews were conducted with a select heads of departments and managers to examine their perception regarding their collaborative roles and critical success factor for stakeholders’ collaboration. While selective manual coding was used for the document analysis, narrative analysis assisted with NVivo 11 was used for the semi-structured interview analysis. The findings from both the document analysis and the review of recommended environmental management practices were synthesized to develop the framework for stakeholders’ collaboration. Policy review and development; strategic environmental management, systematic implementation of environmental management strategies and periodic review of management practices and policies were identified as key components of the framework for stakeholders’ collaboration. Findings from the framework validation derived from the semi-structured interviews show that critical success factors of stakeholders’ collaboration in managing environmental issues in the NOPR are primarily driven by socio-economic interests and political will as well as compliance to environmental management policies. Furthermore, it was found that ignorance and lack of commitment, among other barriers, can hinder stakeholders’ collaboration in managing environmental issues in the NOPR. This research suggests that due to the diversity of stakeholders’ roles regarding their institutional interests and complexity of environmental issues in the NOPR, successful stakeholders’ collaboration would depend on the concerted commitment and genuine collaboration across stakeholders.

<p> Bighead Carp <i>Hypophthalmichthys nobilis</i> and Silver Carp <i> H. molitrix</i> (collectively referred to as bigheaded carp) were introduced to the United States in the 1970s and escaped into the Mississippi River from aquaculture ponds. Since their escape, bigheaded carp have become established in the Mississippi River Basin, including the Ohio River and its tributaries. More recently, bigheaded carp have invaded the Tennessee and Cumberland rivers. Little research has been conducted on bigheaded carp in Tennessee waters, with preliminary studies investigating the distribution and characteristics of established bigheaded carp populations, including growth rates and recruitment. My study represents the first systematic sampling of bigheaded carp in the Tennessee and Cumberland rivers, both tributaries to the Ohio River, and in large reservoirs in the southeast U. S. Standardized, multi-gear sampling methods were used to sample bigheaded carp in Kentucky Lake and Pickwick Lake on the Tennessee River and Lake Barkley and Cheatham Lake on the Cumberland River in 2017 and 2018. Overnight gill nets were the most effective gear, capturing an average of 17 Silver Carp per gill net gang. Short-set gill nets captured an average of one Silver Carp per gill net gang, and electrofishing captured an average of one Silver Carp per 10-minute electrofishing transect. Maximum total length (TL) was 1,390 mm for Bighead Carp and 1,111 mm for Silver Carp, and the maximum age for both species was 11 years. Average age and condition of Silver Carp was higher in upstream impoundments than downstream, and thus suggested an early invasion period from Ohio River movements. Gonadosomatic index (GSI; egg mass weight to body weight ratio) was also higher in upstream impoundments than downstream impoundments. Higher GSI values were observed in the spring and summer, when bigheaded carp may begin to spawn in response to high flows. Length-at-age estimates for the four reservoirs suggested bigheaded carp growth rates in the Tennessee and Cumberland rivers are similar to other populations in the US, indicating populations may be experiencing density effects in southeastern impoundments. No young of year (YOY) bigheaded carp were captured during the study, but weak and missing year classes due to erratic recruitment patterns are common in bigheaded carp, and monitoring for YOY fish should continue. Mean catch-per-unit-effort (CPUE) was not significantly different among reservoirs for the three gear types, and no significant seasonal variation in mean CPUE was observed for overnight gill nets. A lack of differences in CPUE across sampling seasons suggested population densities could be assessed as agencies could fit into their schedules. Overall, the results represent the first large-scale standardized sampling effort for bigheaded carp across four southeastern states and provide integral population information for natural resource managers. Future monitoring efforts should continue to track characteristics of bigheaded carp populations in the Tennessee and Cumberland rivers and determine effective control and management strategies for populations in large impoundments. </p><p>

Purpose: The purpose of this investigation was to identify a deep-water running (DWR) style that most closely approximates terrestrial running. Methods: Twenty healthy male and female intercollegiate (NCAA III) distance runners were videotaped from the right sagittal view while running on a treadmill (TR) and in deep water at 55-60% of their TR VO₂[subscript max] using each of four DWR styles: shod cross-country (SCC), barefoot cross-country (BCC), shod high-knee (SHK), and barefoot high-knee (BHK). All biomechanical data were digitized and analyzed using the Peak Motus® system. Physiological variables of interest were oxygen consumption (V0₂), heart rate (HR), and rating of perceived exertion (RPE). Biomechanical variables of interest were horizontal (X) and vertical (Y) displacement of the knee and ankle, and stride rate (SR). An ANOVA with repeated measures was utilized to ascertain the differences across styles. The alpha significance level was set at .05, and a post hoc pairwise analysis was conducted with a Bonferonni adjustment of the alpha level. Results: Omnibus significant differences were found for all physiological variables: VO₂ (p<.025), HR (p<.042), RPE (p<.000). However, the post hoc pairwise comparisons revealed that only TR vs. SHK V0₂ (p<.005), and the RPE responses for treadmill vs. all DWR styles exhibited significant differences (p<.000-.002). Omnibus tests for biomechanical variables exhibited statistical significance. The post hoc pairwise comparisons revealed significant differences in SR (p<.000) between TR (1.25 ± .08 Hz) and all DWR styles and also between the CC and HK styles of DWR (SCC: 0.78 ± .08 Hz, BCC: 0.81 ± .08 Hz, SHK: 1.13 ± .10 Hz, BHK: 1.14 ± .10 Hz). The CC style of DWR was found to be similar to TR with respect to linear ankle displacement, whereas the HK style was significantly different from TR in all but two of the 16 comparisons made for ankle and knee displacement. Conclusion: The CC style of DWR is recommended as an adjunct to distance running training if the goal is to mimic the ankle linear horizontal displacement of land-based running. However, if the goal is to mimic SR, the HK style is a closer approximation than the CC style. / Graduation date: 2004