<p> This study explores temporal trends in snowmelt timing, dissolved organic carbon (DOC) concentrations, and DOC fluxes in the large forested Penobscot watershed of Maine. The spatially-distributed process-based Regional Hydro-Ecological Simulation System (RHESSys) model was used to simulate streamflows and DOC fluxes and concentrations from 2004-2013 with peak transport generally associated with snowmelt. Results were evaluated with field measurements (streamflow, DOC concentrations and fluxes) and remotely sensed products (Net Primary Production (NPP) and Leaf Area Index (LAI)). The annual and inter annual variability in the amount of fluvial DOC export was further explored under future climate change scenarios and predicted land cover compositions of the watershed.</p><p>

<p> As urbanization increases, Best Management Practices (BMPs) are used to reduce pollutants otherwise released to streams. Rain gardens are a type of BMPs that are vegetated depressions with highly permeable soil to treat urban runoff. These structures are traditionally assessed using inflow-outflow studies with an emphasis on quantifying removal efficiency. This approach neglects controls on nutrient processing within the rain garden and their role as potential hotspots in urban systems. To bridge this gap, three rain gardens in Charlotte, NC were quantified for soil water nutrient concentrations (ammonium, nitrate, phosphate, DOC) during storms and seasonal potential denitrification rates. The rain gardens were located at Myers Park High School (MP), Park Road Park (PR), and Bruns Academy Elementary School (BR) and vary with vegetation, size, treatment area, and age (4,7, and 15 respectively). The results identified no significant difference in the runoff between site or season which indicated differences within soil water concentrations were caused by structural variances of the rain gardens. Results identified soil water ammonium concentrations were significantly different between sites (<i>p</i>=0.0201). Soil water ammonium concentrations were also found to be significantly lower in the summer compared to the winter when all sites were aggregated together (<i>p</i>=0.0201). Nitrate concentrations were significantly higher (<i>p</i>&lt;0.0001) in soil water across sites, and significantly lower (<i>p</i>&lt;0.0001) in winter soil water compared to summer. These trends were caused by the presence of an underdrain and high infiltration rates that limited favorable denitrification conditions from existing. The potential denitrification rates were 0.39, 0.12, and 0.65 &micro;g/gDM/hr at MP, PR, and BR respectively. Overall, the nitrification process attributed to the decrease in soil water ammonium and the accumulation of soil water nitrate. Without prolonged anoxic conditions present in the rain garden nitrate was stored until subsequent storms exported nitrate to the receiving stream. The sites with the highest soil moisture percent after the storm also had higher denitrification rates. Bruns Academy had very high soil nitrate (2.75 mg/L) compared to the other sites (0.42 and 0.28 mg/L at MP and BR respectively) which may have been caused by a pollutant exposure prior to this study. Phosphate was variable between sites and was likely due to the difference in phosphorus in the original soil media. Between similarly constructed MP and PR, soil water phosphate was higher at MP (0.032 mg/L) than PR (0.007 mg/L). This suggests more adsorption occurred due to an increased ratio of the rain garden area to the treatment area as well as plant assimilation. DOC was different among sites and had an inverse relationship with potential denitrification rates. PR had the lowest denitrification rate and presented the largest soil water DOC concentrations with an average concentration of 14 mg/L. The age gradient of the rain gardens in this study proved rain gardens still have the ability to remove pollutants as the structures age (with the exception of nitrate). The addition of soil water concentrations and potential denitrification rates in this study showed internal processes of rain gardens should be explored further to understand the longevity of these structures, as well as nutrient export as aging occurs.</p><p>

abstract: Peatlands represent 3% of the earth’s surface but have been estimated to contain up to 30% of all terrestrial soil organic carbon and release an estimated 40% of global atmospheric CH4 emissions. Contributors to the production of CH4 are methanogenic Archaea through a coupled metabolic dependency of end products released by heterotrophic bacteria within the soil in the absence of O2. To better understand how neighboring bacterial communities can influence methanogenesis, the isolation and physiological characterization of two novel isolates, one Methanoarchaeal isolate and one Acidobacterium isolate identified as QU12MR and R28S, respectively, were targeted in this present study. Co-culture growth in varying temperatures of the QU12MR isolate paired with an isolated Clostridium species labeled R32Q and the R28S isolate were also investigated for possible influences in CH4 production. Phylogenetic analysis of strain QU12MR was observed as a member of genus Methanobacterium sharing 98% identity similar to M. arcticum strain M2 and 99% identity similar to M. uliginosum strain P2St. Phylogenetic analysis of strain R28S was associated with genus Acidicapsa from the phylum Acidobacteria, sharing 97% identity to A. acidisoli strain SK-11 and 96% identity similarity to Occallatibacter savannae strain A2-1c. Bacterial co-culture growth and archaeal CH4 production was present in the five temperature ranges tested. However, bacterial growth and archaeal CH4 production was less than what was observed in pure culture analysis after 21 days of incubation. / Dissertation/Thesis / Masters Thesis Biology 2018

abstract: Pharmaceutical and Personal Care Products (PPCPs) are a large, diverse group of emerging contaminants comprised of pharmaceuticals, plasticizers, detergents, and insecticides. Studies have shown that PPCPs are entering aquatic environments, wastewaters, and water supplies. The occurrence of these PPCPs has generated concern resulting in proposed federal legislation that could require control, monitoring, and treatment of Pharmaceutical and Personal Care Products by Publicly Owned Treatment Works (POTWs). This study evaluated the potential financial impact this proposed legislation could have on U.S. POTWs using City of Mesa, Arizona as a model POTW. The current laws concerning PPCPs as well as the proposed legislation were described. The proposed federal legislation would create investigational studies about PPCPs. The studies could lead to regulations concerning the control, monitoring, and treatment of PPCPs by POTWs. The potential financial costs of the following strategies were assessed: multiple barriers concept for PPCP control or prevention programs by POTWs, PPCP monitoring of wastewater, and upgrading POTW treatment technology for PPCP removal. Study results found no new wastewater treatment technologies were economically suitable for POTWs, however, community education and programs such as Household Take-back programs could be financially viable. / Dissertation/Thesis / M.S.Tech Technology 2012

Petroleum released to the subsurface may be held in capillary tension above the water table for years, serving as a source of groundwater and soil gas contamination. Soil venting can be used to attack this ongoing source, sometimes in conjunction with biodegradation to permanently destroy the released hydrocarbons vapors. These processes were explored using intact soil cores from the site of an aviation gasoline release. Hydrocarbon vapor concentration profiles were analyzed by gas chromatography and interpreted using mathematical models. In the venting experiment, an intact core was subjected to a horizontal sweep flow of nitrogen. Residual petroleum in the soil volatilized and hydrocarbon vapors diffused upward. Soil venting significantly increased the rate of contaminant removal relative to ambient field conditions. No correlation between hydrocarbon vapor exit flux and sweep flow rate was observed, indicating that flow rates in excess of a minimum value were no more effective. A steady state model balancing volatilization and diffusion successfully predicted the shape of the hydrocarbon concentration profiles. The volatilization source was construed as an LNAPL droplet surrounded by an air water aggregate surrounded by a free air pore, with the aggregate reducing the mass transfer of hydrocarbons from LNAPL to air. Source strength, estimated from a diffusive flux model, decreased with time as LNAPL droplets became smaller. The biodegradation experiment employed an intact core from mid-depth in the unsaturated zone which was subjected to a upward flow of nitrogen, oxygen, water vapor, and hydrocarbon vapors. Significant biodegradation was indicated by reductions in hydrocarbon concentrations with elevation in the core. First order biodegradation rate constants were estimated by calibrating the experimental data to a simple model balancing advection and biodegradation. Agreement with kinetic parameter estimates from microcosm and probe cluster studies was good. For comparison, hydrocarbon vapor profiles due to volatilization, diffusion, and biodegradation were obtained for unvented subsurface conditions by trapping vapor samples on adsorbents in the field, with subsequent laboratory desorption and analysis. The method was effective, and field profiles agreed well with uncalibrated model predictions. Concentrations exhibited considerable scatter at depth, and distillation of the residual was apparent.

An attempt was made to develop an ecosystems approach for the control of the nuisance aquatic plant-Eurasian milfoil, Myriophyllum spicatum L. To this end a cellulolytic fungus, Mycoleptodiscus terrestris (Gerdemann) Ostazeski (M.t.), and a pectinolytic bacterium, Bacillus sp. strain P8 (BSP8), were isolated from the microbial populations naturally resident in the phyllosphere of this plant. These organisms grew compatibly with each other, were able to compete successfully with other microflora on the plant surface and were able to resist the inhibitory action of phenolic compounds produced by the plant. Application of these organisms to the plant, after growth in appropriate media, resulted in plant decline and eventual death. The process of decline included hormone-like stress effects on the plant induced by BSP8 (internodal elongation), increase in strongly pectinolytic microbial populations associated with the plant and penetration into plant tissue by the fungal mycelium. These results were confirmed in a sequence of experiments of increasing volume, conducted in jar, pool and, ultimately, a lake setting. The most rapid decline of the plant, subsequent to inoculation, was observed in jars in the laboratory where high concentration of inoculum and isolation from environmental effects could be maintained. In the pool setting, though the application of M.t. and BSP8 together induced the most significant decline, limits in pool depth and light penetration may also have influenced plant decomposition. Field applications, however, ultimately resulted in the virtual elimination of M. spicatum from a treated plot within 10 weeks. Total numbers of microorganisms isolated from M. spicatum tissues were generally 2-4 orders of magnitude higher than numbers obtained from the adjacent water profile, reflecting the substrate commitment of the microorganisms to the plant. The numbers of organisms were greater on treated than untreated tissues and parallel increases were observed in the water profile. These results were confirmed by observation under the scanning electron microscope. Specificity trials of M.t. infectivity revealed it to be very weakly pathogenic to several aquatic species and terrestrial plants and thereby without potential significant impact outside the area of designated application.

Bibliography: leaves 68-71. / The aim of this dissertation is to is to provide an environmental overview of the water sector in the study area of the Erongo region. Water is a very scarce resource in the study area and has been singled out to be the greatest obstacle to the development of the study area. As such, this study was developed to assist the identification of the various critical issues affecting the water sector. This study was agreed upon by the Ministry of Environment and Tourism of Namibia with the help of funding from DANCED. The study is the follow up of an environmental baseline report on the Erongo region in Namibia. The baseline report was commisioned to gather data on the region which would assist the creation of an Integrated Coastal Zone Management Plan. This baseline report was undertaken by the whole MPhil class as a group exercise. Individual dissertations were then carried out by the members of the Mphil class. The students had to choose topics that were relevant to the study area. This study is one of these dissertations. The study was guided by the principles of Integrated Water Resources Management and the need to be of use in the planning process for water resource utilisation in the study area. To achieve this, the Integrated Environment Management theory is used together with the principles of Integrated Water Resource Management. This will ensure that the study * Uses a broad definition of the environment so as to identify all key opportunities and constraints of the water sector. * Would help towards the creation of a plan to manage the water sector in order to optimise the benefits of the sector while at the same time minimising or mitigating the financial, environmental and social costs. The study aims to identify the critical environmental impacts of the water sector in the study area. These impacts are then assessed but not evaluated.

Includes bibliographical references (leaves 78-108). / By 2005 South Africa was ranked as the 8th largest producer of transgenic crops, with 0.5 million hectares planted to maize, soybean and cotton (James, 2005). A need is recognized for environmental scientists to engage with the technology and understand its place in the agroecosystem and broader environment, and for environmental education to engage agricultural biotechnology so that the benefits and hazards of the new technology are communicated to farmers, regulators and the public. Modern information technology provides a possible means of such communication.

Bibliography: leaves 72-81. / Dryland degradation is widely viewed as a major environmental issue and in many parts of Namibia is perceived to be significant to severe. In recent years, however, following a worldwide trend, there has been a re-evaluation and questioning of the extent, nature and causes of dryland degradation. Too often it seems pronouncements of degradation are based on limited data and a poor understanding of the context and functioning of dryland ecosystems. The aim of this report, therefore, is to demonstrate why an historical perspective of environmental dynamics is valuable in drylands for the identification of degradation and to evaluate the use of such a perspective using northern Damaraland a case study. In order to achieve this aim, several objectives were addressed, these being: to provide a clear and unambiguous definition of the term 'dryland degradation' or 'land degradation'; to review possible indicators and agents of environmental change and land degradation; to provide a conceptual framework that emphasises the importance of an historical; perspective, and the role of arid rangeland dynamics, in evaluating environmental change; to analyse environmental dynamics in northern Damaraland from an historical perspective, utilising aerial photography and archival data in the form of stock numbers; to highlight inherent problems and the utility of an historical perspective.

Bibliography: leaves 130-136. / This dissertation is based on the theoretical assumption that in order for conservation to be achievable it must go hand in hand with development, without undermining development of the environment continuing to degrade. At Independence, Namibia inherited a number of environmental and developmental challenges from previous government systems, including slow and even economic growth, a predominantly rural population dependent on the primary production of natural resources for their survival, human-induced loss of rangelands and croplands and a historical alienation from natural resources of residents from communal lands. As a result, Namibia finds herself confronting a number of development imperatives including the need to address and minimise inherited socio-economic and environmental debts as well as ensure that people are able to meet their basic needs. A further key finding of the REIA was that design, planning and implementation of policies, programmes, plans and projects in Namibia should seek to protect and enhance this sensitive environment, and ill-advised development activities may cause or contribute to additional environmental degradation. Recognising this, and in keeping with international trends, the Namibian conservation authorities, following Independence from South Africa began developing a national community-based natural resource management programme (CBNRM) aimed at addressing some of the key constraints of past conservation approaches and promoting development and conservation. One of the principle means of linking CBNRM and development is through the vehicle of conservancies, a defined geographical area which has been established for the management, conservation and utilisation of its wildlife and other natural resources for the benefit of a specific community. Whilst the conservancy approach was originally designed for application on commercial farms, the intention of communal land conservancies is that a community, within a defined geographical area, jointly manage, conserve and utilise the wildlife and other natural resources within the defined area. In so doing, conservancies aim to help promote sustainable environmental management, rural development and improved income and livelihoods for rural families and communities. The conservancy approach therefore is intended to be simultaneously a vehicle for development and for conservation.