title: Resilience and recovery of Bratina Island meltwater pond microbial communities to environmental change

authors: Colville, Elizabeth Catherine

abstract: 16S rRNA sequencing of three Bratina Island meltwater ponds has revealed the response of microbial communities within cyanobacterial mats exposed to shading and desiccation as environmental stressors. The resilience of these communities is perhaps not surprising considering the extreme environmental conditions they consistently face in these habitats. It was postulated that cyanobacteria will remain the dominant primary producers across the ponds when exposed to shading and desiccation, because they are known to possess adaptations to these stresses. Similar to research in other studies, it was found that three phyla: Cyanobacteria, Bacteroidota and Proteobacteria make up the majority of the diversity in these communities, but their dominance shifted between shading and desiccation samples. The most obvious changes occurred in desiccation samples, where the abundance of cyanobacteria dropped to less than 10% in some samples. Predicted functional changes in gene sets involved in photosynthesis and methanogenesis were also investigated, and unexpectedly, predicted functional changes in methanogenesis only occurred in one pond.
This thesis describes the microbial ecology of Bratina Island meltwater ponds, and the effect of desiccation and shading as environmental stressors on the diversity. It also addresses potential functional changes within these communities. Although, more extensive research into archaeal and eukaryotic communities alongside changes in physiochemical parameters within each pond is needed to fully understand how shading and desiccation effects the resilience and resistance of microbial communities within meltwater ponds.

text: Resilience and recovery of Bratina Island meltwater pond microbial communities to environmental change 16S rRNA sequencing of three Bratina Island meltwater ponds has revealed the response of microbial communities within cyanobacterial mats exposed to shading and desiccation as environmental stressors. The resilience of these communities is perhaps not surprising considering the extreme environmental conditions they consistently face in these habitats. It was postulated that cyanobacteria will remain the dominant primary producers across the ponds when exposed to shading and desiccation, because they are known to possess adaptations to these stresses. Similar to research in other studies, it was found that three phyla: Cyanobacteria, Bacteroidota and Proteobacteria make up the majority of the diversity in these communities, but their dominance shifted between shading and desiccation samples. The most obvious changes occurred in desiccation samples, where the abundance of cyanobacteria dropped to less than 10% in some samples. Predicted functional changes in gene sets involved in photosynthesis and methanogenesis were also investigated, and unexpectedly, predicted functional changes in methanogenesis only occurred in one pond.
This thesis describes the microbial ecology of Bratina Island meltwater ponds, and the effect of desiccation and shading as environmental stressors on the diversity. It also addresses potential functional changes within these communities. Although, more extensive research into archaeal and eukaryotic communities alongside changes in physiochemical parameters within each pond is needed to fully understand how shading and desiccation effects the resilience and resistance of microbial communities within meltwater ponds.

year: 2020

title: New insights into the role of pH and aeration in the bacterial production of calcium carbonate (CaCO₃)

authors: Seifan, Mostafa

subjects: Science & Technology

abstract: Over recent years, the implementation of microbially produced calcium carbonate (CaCO₃) in different industrial and environmental applications has become an alternative for conventional approaches to induce CaCO₃ precipitation. However, there are many factors affecting the biomineralization of CaCO₃, which may restrict its application. In this study, we investigated the effects of pH and aeration as the main two influential parameters on bacterial precipitation of CaCO₃. The results showed that the aeration had a significant effect on bacterial growth and its rise from 0.5 to 4.5 SLPM could produce 4.2 times higher CaCO₃ precipitation. The increase of pH to 12 resulted in 6.3-fold increase in CaCO₃ precipitation as compared to uncontrolled-pH fermentation. Morphological characterization showed that the pH is an effective parameter on CaCO₃ morphology. Calcite was found to be the predominant precipitate during aeration-controlled fermentations, while vaterite was mainly produced at lower pH (up to 10) over controlled-pH fermentations. Further increase in pH resulted in a morphological transition, and vaterite transformed to calcite at the pH ranges between 10 and 12.

text: New insights into the role of pH and aeration in the bacterial production of calcium carbonate (CaCO₃) Over recent years, the implementation of microbially produced calcium carbonate (CaCO₃) in different industrial and environmental applications has become an alternative for conventional approaches to induce CaCO₃ precipitation. However, there are many factors affecting the biomineralization of CaCO₃, which may restrict its application. In this study, we investigated the effects of pH and aeration as the main two influential parameters on bacterial precipitation of CaCO₃. The results showed that the aeration had a significant effect on bacterial growth and its rise from 0.5 to 4.5 SLPM could produce 4.2 times higher CaCO₃ precipitation. The increase of pH to 12 resulted in 6.3-fold increase in CaCO₃ precipitation as compared to uncontrolled-pH fermentation. Morphological characterization showed that the pH is an effective parameter on CaCO₃ morphology. Calcite was found to be the predominant precipitate during aeration-controlled fermentations, while vaterite was mainly produced at lower pH (up to 10) over controlled-pH fermentations. Further increase in pH resulted in a morphological transition, and vaterite transformed to calcite at the pH ranges between 10 and 12.

year: 2017

title: Local values and the promotion and restoration of wetlands and their ecosystem services in Aotearoa-New Zealand: a case study of Tauranga’s planning regime

authors: Peat, Helen Ann

subjects: Environmental planning

abstract: Aligning wetlands restoration planning mechanisms with public perceptions and values can help gain support for and assistance with restoration. Using Tauranga as a case study, this thesis is an exploratory study that applies the Millennium Ecosystem Assessment (MEA) framework to examine the extent to which New Zealand's planning regime incorporates local values in the promotion and restoration of wetlands and their ecosystem services.

This thesis used multiple qualitative research methods in a two-pronged process. A narrative literature review and systematic statutory analysis in phase one helped identify values associated with wetland ecosystem services and how New Zealand’s, and more specifically Tauranga’s, resource management system promotes and enables the restoration of wetlands and their ecosystem services. A case study approach with analysis of primary and secondary data in phase two helped identify what Tauranga local residents value as important wetland ecosystem services and the extent to which the local policy mechanisms reflect these values. 

Through thematic analysis of semi-structured interviews and summaries of submissions, this thesis identifies six dimensions that represent values towards wetland ecosystem services and their restoration in Tauranga. Other than one dimension that consists of a single value on education from the cultural services category of the MEA framework, the remaining five dimensions comprise services from within and between the framework categories. These dimensions are wetlands as nutrient- and mineral-rich areas that support biodiversity and provide habitat; that regulate water, act as natural flood plains and sequester carbon to help protect against climate change and natural hazards; that maintain Māori cultural practices; that remove nutrients and contaminants in water; and provide recreational and aesthetic experiences. Therefore, identified dimensions could form the basis of educational programmes and toolkits that promote wetlands restoration.

The systematic policy analysis and cross-comparison with the results of the thematic analysis found that Tauranga’s planning regime partially provides for each of the six dimensions. However, the nuances and complexities of the values, including the interconnected nature of wetlands values and services, are not captured. This means Tauranga’s planning regime does not fully incorporate local values in the promotion and restoration of wetlands and their ecosystem services. Bridging the gap between wetlands restoration provisions and wetland ecosystem service values is likely to be supported by enacting the current resource management reforms. Enacting the reforms would help reduce the number of policies and plans, implement regional spatial planning, and develop outcomes-based policy mechanisms that encompass ecological, social, cultural and spiritual values, including those associated with wetlands.

text: Local values and the promotion and restoration of wetlands and their ecosystem services in Aotearoa-New Zealand: a case study of Tauranga’s planning regime Aligning wetlands restoration planning mechanisms with public perceptions and values can help gain support for and assistance with restoration. Using Tauranga as a case study, this thesis is an exploratory study that applies the Millennium Ecosystem Assessment (MEA) framework to examine the extent to which New Zealand's planning regime incorporates local values in the promotion and restoration of wetlands and their ecosystem services.

This thesis used multiple qualitative research methods in a two-pronged process. A narrative literature review and systematic statutory analysis in phase one helped identify values associated with wetland ecosystem services and how New Zealand’s, and more specifically Tauranga’s, resource management system promotes and enables the restoration of wetlands and their ecosystem services. A case study approach with analysis of primary and secondary data in phase two helped identify what Tauranga local residents value as important wetland ecosystem services and the extent to which the local policy mechanisms reflect these values. 

Through thematic analysis of semi-structured interviews and summaries of submissions, this thesis identifies six dimensions that represent values towards wetland ecosystem services and their restoration in Tauranga. Other than one dimension that consists of a single value on education from the cultural services category of the MEA framework, the remaining five dimensions comprise services from within and between the framework categories. These dimensions are wetlands as nutrient- and mineral-rich areas that support biodiversity and provide habitat; that regulate water, act as natural flood plains and sequester carbon to help protect against climate change and natural hazards; that maintain Māori cultural practices; that remove nutrients and contaminants in water; and provide recreational and aesthetic experiences. Therefore, identified dimensions could form the basis of educational programmes and toolkits that promote wetlands restoration.

The systematic policy analysis and cross-comparison with the results of the thematic analysis found that Tauranga’s planning regime partially provides for each of the six dimensions. However, the nuances and complexities of the values, including the interconnected nature of wetlands values and services, are not captured. This means Tauranga’s planning regime does not fully incorporate local values in the promotion and restoration of wetlands and their ecosystem services. Bridging the gap between wetlands restoration provisions and wetland ecosystem service values is likely to be supported by enacting the current resource management reforms. Enacting the reforms would help reduce the number of policies and plans, implement regional spatial planning, and develop outcomes-based policy mechanisms that encompass ecological, social, cultural and spiritual values, including those associated with wetlands.

year: 2022