This thesis is an investigation into biogenic sulfide oxidation and sulfate reduction associated with hydrothermal systems at oceanic spreading centers. First, the production of sulfur floc and 'snowblower' events due to sulfide oxidizing bacteria is investigated. The effects of sulfur floc on the pososity is shown to be negligible. 'Snowblower' events are shown to be sulfur floc that is stored over long periods of time mixed with a component of sulfur floc being created in a bloom event. Secondly, biogenic sulfate reduction in hydrothermal recharge zones is investigated and the effects on the concentration profiles is considered.

I have compiled digital seismic and well data over a region of approximately 700,000 km² to better improve the correlation of the Mexican sector of the Gulf of Mexico (MGOM) with the better studied and more explored U.S. sector. I have ~25,000 km of regional 2D lines that were collected by the University of Texas in the 1970's. I have digitized data from published PEMEX data from the MGOM using SEG-Y converter software and incorporated these data into my seismic grid. Using these data, I interpreted and correlated 20 surfaces that range in age from Late Jurassic to Recent. The combined shelf-slope-basin dataset from the MGOM allows for correlation of units from the deepwater MGOM, across into the Mexican Ridges passive margin foldbelt, and onto the Mexican shelf. I have also incorporated seismic data from the offshore Chicxulub crater and correlated units in the Yucatan platform area with the deepwater MGOM. This regional data set indicates that normal, growth faulting linked with downdip toe thrusts and folds of the Mexican Ridges initiated in post-Middle Miocene time and are therefore unrelated to the earlier Paleogene Laramide uplift deformation phase. Shelf-slope-deep basin seismic facies of Eocene and Oligocene units show an influx of clastic materials linked with regional uplift and volcanic events affecting central Mexico during this period. I propose that the deepwater folds of the Mexican Ridges accompanied shelf-edge gravity sliding and normal faulting activated during accelerated Oligo-Miocene uplift, regional volcanic activity, and erosion of the Mexican landmass. Downdip sliding occurred on the seaward-dipping top Cretaceous carbonate unit (7° to 13°) along with overlying horizons that range in dip from 1° to 2°. Shelf-slope-deep basin seismic facies of the Paleocene units around the Yucatan peninsula suggest a sediment-starved and slide-free carbonate margin with a current basinward dip of approximately 12° and significantly greater than those dips observed along the present-day eastern Gulf of Mexico. Based on the seismic interpretations and plate reconstructions, I propose four major tectonosequences fill the Gulf of Mexico basin: 1) A Late Jurassic to Late Cretaceous passive margin phase; 2) a Late Cretaceous to Late Eocene Laramide deformational phase; 3) a Late Eocene to Middle Miocene passive margin phase; and 4) a Late Miocene to Recent Neogene deformational phase. / text

In the pursuit of sustainable development, Environmental Impact Assessments (EIA) are acknowledged globally as a tool designed to assist governing authorities by providing the information required to make an informed decision regarding development proposals. South Africa has entrenched this EIA requirement in the presiding environmental legislation: the National Environmental Management Act (Act 107 of 1 998). In the effort to manage the negative impact of development on the rocky ridges of Johannesburg, the Gauteng Department of Agriculture, conservation, Environment and Land Affairs (GDACEL) has introduced a buffer zone requirement in the procedure of the EIA. The Red Data Plant Policy for Environmental Impact Evaluations for GDACEL described a buffer zone as a collar of land that filters out inappropriate influences from surrounding activities. As a tool in the EIA, a buffer zone is a worthwhile concept. However, the determination of the dimension of the buffer zone on rocky ridges, is non-discriminatory between sites, and thus, presents potential contention between decision-making authorities and developers. There is a need for further research to establish a scientifically acceptable method of determining site-specific buffer zones for individual EIA applications. The key objective of this paper is to suggest the possibility of determining a buffer zone that accommodates the unique environmental aspects of each site. This is achieved by determining the distance between the edge of existing developments and the point at which the successional climax community within the adjacent natural vegetation is established. Three suitable study sites, consisting of developed residential estates on ridges adjacent to nature reserves, were identified within the greater Johannesburg metropolis. The three study sites identified for this assessment include Kloofendal (west), Morning Hill (east) and Kliprivier (south). Within each study site field surveys were conducted along transects starting 5m from the development edge and ending 75m within the nature reserve adjacent to each site. Quantitative (species density) and qualitative (Braun-Blanquet cover-abundance values) data analysis was employed to describe and evaluate the identified plant communities. The data in this study provides clear indication that a 25-35m buffer zone would suffice for these specific plant communities to maintain a climax successional status if impacted on by residential development. This paper thus makes a case for permitting the determining of variable buffers zones, based on a gradient analysis of a plant community, as a potential panacea to the problem of resistance and reluctance to accept present standard buffer zones. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2007.

The goal of this thesis was to test the applicability of biomarker analyses to better understand the glacial stratigraphic record of the Hudson Bay Lowlands and Oak Ridges Moraine. A biomarker analysis conducted on three geologic deposits from the Hudson Bay Lowlands showed that they can be differentiated based on organic matter (OM) inputs and stage of diagenesis, relating to paleoclimate and depositional environments. In the second study, a biomarker analysis was applied to samples from ten deposits in the Oak Ridges Moraine. These deposits were differentiated based on OM inputs relating to paleovegetation. Additionally, reincorporation and post-deposition alteration led to sample heterogeneity confirming the current understanding of glacial depositional processes and environments. This thesis shows that biomarker analyses can effectively differentiate and contextualize geologic deposits based on OM inputs and stage of diagenesis. This in turn will provide a more robust understanding of the stratigraphic record.

The goal of this thesis was to test the applicability of biomarker analyses to better understand the glacial stratigraphic record of the Hudson Bay Lowlands and Oak Ridges Moraine. A biomarker analysis conducted on three geologic deposits from the Hudson Bay Lowlands showed that they can be differentiated based on organic matter (OM) inputs and stage of diagenesis, relating to paleoclimate and depositional environments. In the second study, a biomarker analysis was applied to samples from ten deposits in the Oak Ridges Moraine. These deposits were differentiated based on OM inputs relating to paleovegetation. Additionally, reincorporation and post-deposition alteration led to sample heterogeneity confirming the current understanding of glacial depositional processes and environments. This thesis shows that biomarker analyses can effectively differentiate and contextualize geologic deposits based on OM inputs and stage of diagenesis. This in turn will provide a more robust understanding of the stratigraphic record.

The thesis looks at developing a new model for a mental health support program which is integrated into a natural recreational environment. Its starting point is Beginning Again, a registered charity in Richmond Hill, Ontario, Canada, which provides a supportive workplace, called Treasures, to engage psychiatric patients in meaningful and productive work. The intent of the thesis is to develop an architecture that reflects the mission and objectives of the program in order to increase the opportunity for recovery and interaction with the local community. This is done by creating a more general prototype or “parent seed” which can be applicable to many locations and then testing the model by planting it in the Oak Ridges Corridor Park, located in the suburban community of Oak Ridges, Ontario. This thesis builds upon the long history of rehabilitative environments to create a community model of care that regards work as primarily a social and cultural activity.

This thesis discusses the results from the first multi-source and multi-streamer three-dimensional multichannel seismic experiment conducted over a mid-ocean ridge environment. Prestack time migration was applied to the dataset resulting in the most detailed reflection images of a spreading center and its flanks to date. The key products from this work are maps of crustal velocities, crustal thickness, and Moho transition zone (MTZ) reflection character for a section of the fast-spreading East Pacific Rise (EPR) from 9°37.5’N to 9°57’N, excluding the area from 9°40’N to 9°42’N where no data were collected. Moho reflections were imaged within ~92% of the study area. The derived average crustal thickness and average crustal velocity for the investigated ~880 km2 area are 5920±320 m and 6320±290 m/s, respectively. The average crustal thickness varies little from Pacific to Cocos plate suggesting mostly uniform crustal production in the last ~180 Ka. Detailed analysis of the crustal thickness and MTZ reflection character shows that the third-order segmentation is governed by melt extraction processes within the uppermost mantle while the fourth-order ridge segmentation arises from mid- to upper-crustal processes. This analysis also suggests that both the mechanism of lower-crustal accretion and the volume of melt delivered to the crust vary along the investigated section of the EPR. More efficient mantle melt extraction is inferred at latitudes from 9°42’N to 9°51.5’N, with greater proportion of the lower crust accreted from the AML than for the rest of the study area. Larger volume of melt is delivered to the crust from 9°37.5’N to 9°40’N than to the investigated crust further north. At some locations, the Moho reflections are for the first time unambiguously imaged below the AML away from any ridge discontinuity suggesting that the Moho is formed at zero age at least at some sections of the spreading centers. The first study of the melt content of mid-crustal off-axis magma lenses (OAML), done using amplitude variation with offset technique calibrated for a magmatic plumbing system, shows that these magma bodies contain 0 to 20% melt. This suggests that OAMLs likely contribute little to the overall crustal formation.

In the pursuit of sustainable development, Environmental Impact Assessments (EIA) are acknowledged globally as a tool designed to assist governing authorities by providing the information required to make an informed decision regarding development proposals. South Africa has entrenched this EIA requirement in the presiding environmental legislation: the National Environmental Management Act (Act 107 of 1 998). In the effort to manage the negative impact of development on the rocky ridges of Johannesburg, the Gauteng Department of Agriculture, conservation, Environment and Land Affairs (GDACEL) has introduced a buffer zone requirement in the procedure of the EIA. The Red Data Plant Policy for Environmental Impact Evaluations for GDACEL described a buffer zone as a collar of land that filters out inappropriate influences from surrounding activities. As a tool in the EIA, a buffer zone is a worthwhile concept. However, the determination of the dimension of the buffer zone on rocky ridges, is non-discriminatory between sites, and thus, presents potential contention between decision-making authorities and developers. There is a need for further research to establish a scientifically acceptable method of determining site-specific buffer zones for individual EIA applications. The key objective of this paper is to suggest the possibility of determining a buffer zone that accommodates the unique environmental aspects of each site. This is achieved by determining the distance between the edge of existing developments and the point at which the successional climax community within the adjacent natural vegetation is established. Three suitable study sites, consisting of developed residential estates on ridges adjacent to nature reserves, were identified within the greater Johannesburg metropolis. The three study sites identified for this assessment include Kloofendal (west), Morning Hill (east) and Kliprivier (south). Within each study site field surveys were conducted along transects starting 5m from the development edge and ending 75m within the nature reserve adjacent to each site. Quantitative (species density) and qualitative (Braun-Blanquet cover-abundance values) data analysis was employed to describe and evaluate the identified plant communities. The data in this study provides clear indication that a 25-35m buffer zone would suffice for these specific plant communities to maintain a climax successional status if impacted on by residential development. This paper thus makes a case for permitting the determining of variable buffers zones, based on a gradient analysis of a plant community, as a potential panacea to the problem of resistance and reluctance to accept present standard buffer zones. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2007.

Conservation in Canada is increasingly driven by land use planning processes. Approaches to governing nature conservation have shifted dramatically from protecting isolated pristine areas to greater attention to the remaining fragments of greenspace in urban, semi-urban and rural areas. The ways that societies govern and use nature are always changing, and these physical management actions are connected to deeply rooted cultural norms and values about the ideal relationship between humans and nature. In the land use planning approach to conservation, citizens and governments find value and construct meaning for remaining nature rather than beginning with normative considerations of what is most worthy of protection. At the root of this conservation planning trend is a growing appreciation for hybrid nature that is valued as natural in spite of the past or present influences upon it. This represents a dramatic shift from the traditional values involved in North American nature conservation, where nature was most valued for its perceived separation from human influence and protected to maintain its untouched qualities. In light of these ideological shifts in the ways that Canadians value and in turn manage nature, is there a corresponding change in the ways that conservation activists perceive environmental value and evaluate naturalness? An increasing number of studies demonstrate that public valuation of nature is not limited to pristine environments: even highly disturbed environments can be valued as natural and are not perceived as a form of lesser nature. Conceptions of what is natural and what is not are highly subjective and variable; in particular, the body of work on the social dimensions of both invasive species and ecological restoration demonstrates the ways in which people construct naturalness in accord with their values and cultural context. By exploring the extent to which people perceive invasive species as reducing naturalness and how ecological restoration is perceived to restore it, these subjects serve as excellent conceptual lenses for exploring constructions of nature. This study explores the subtle variations in environmental values and perception of naturalness among a study population who self-identify as pursuing the same goal: ensuring the continued protection of the Oak Ridges Moraine. The Moraine is a partly urbanized landform in southern Ontario that is situated within a complex hybrid socio-ecological landscape. It is also the subject of an active and high profile conservation movement that has spanned over 40 years. Using a combination of interviews and Q Method, this study explored how citizens engaged in Oak Ridges Moraine conservation perceive both the current and ideal state of naturalness on the Moraine, with specific emphasis on how the discourses these citizens use to frame the Moraine invoke the concept of naturalness Findings from this study reveal that Moraine activists represent a conservation paradox: they value the natural, non-human qualities of the landform, yet at the same time identify the Moraine as a hybrid landscape with both social and ecological qualities. In particular, respondents indicated a strong interest in naturalness in the context of invasive species and ecological restoration, yet at the same time identified the naturalness of the Moraine to be a lesser priority in the face of urban development pressures. In this way, citizens engaged in Moraine conservation respond to the hybrid quality of the Moraine landscape by moving beyond the binary distinction between nature and society, situating themselves as both apart from and a part of the landscape at the same time. This finding demonstrates how values for conserving nature are affected by hybridity between social and ecological systems, and suggests how embracing the paradox of hybrid nature can contribute to understanding and managing complex socio-ecological systems.

The implementation of UNESCO Biosphere Reserves (BR) in Canada is strongly dependent on grassroots community-based support and understanding. The recent calls for the Oak Ridges Moraine and adjacent Greenbelt lands (ORMGB) to be designated a BR require that a communications strategy be created to garner local support. Taking into consideration complex systems theory, this study looked to build a communications framework that combined higher-scale social organizing literature like social movement and environmental campaigns more detail-focused group dynamics and strategic communications research. Applying this framework to the ORMBG landscape revealed key target audience groups and messaging for the BR communications strategy.