title: Developing sustainable seaweed aquaculture of the native kelp Ecklonia radiata in New Zealand

authors: Nepper-Davidsen, Jacob Nicolai

subjects: Seaweed

abstract: The native kelp Ecklonia radiata is a target species for seaweed aquaculture in New Zealand because of its broad distribution and desirable biomass profile (e.g., alginate, fucoidan, and phlorotannins). However, commercial farming practices for E. radiata are not yet developed. The objective of this thesis was therefore to create foundations for sustainable seaweed aquaculture of E. radiata in New Zealand by filling key knowledge gaps regarding patterns of genetic structure (Chapter 2), spatial and temporal variation in biomass composition (Chapter 3), the development of high-throughput methods for biomass grading (Chapter 4), and marine farm design (Chapter 5). 
The development of specialised cultivars is central for optimising key commercial traits for seaweed aquaculture; however, the introduction of genotypes from significantly different genetic sub-populations can reduce genetic diversity and genetic structure of wild populations. Analysis of molecular variance in populations of E. radiata in the North Island of New Zealand revealed significant differences at all three hierarchical levels of genetic structure that were analysed. The highest regional differentiation occurred between Wellington and other regions and was supported by Bayesian and redundancy models showing a high degree of genetic clustering among regions. Furthermore, pairwise Fₛₜ (genetic differentiation) revealed significant differences between most sites showing strong genetic structure and low connectivity also at a local level. These findings indicate that cultivars of E. radiata should not be translocated outside their area of origin, to prevent introducing genotypes from significantly different genetic sub-populations to wild sub-populations.            
Most analysed biomass components of E. radiata showed high spatial variation between sites, including alginate, glucose, and phlorotannins. However, there was no clear pattern in biomass composition among regions, indicating that these differences in biomass content are unlikely to be caused by genetic differences (i.e., Wellington samples did not stand out). Conversely, a strong seasonal pattern was detected with significant temporal variation detected for half of the quantified components. These results indicate that environmental variation is a key driver for the biomass composition of E. radiata and that the high spatial variation was due to do site-specific environmental conditions. In general, the biomass composition of E. radiata was comparable to that of commercially grown northern hemisphere species and could be a suitable southern hemisphere alternative for a wide range of commercial applications. 
The large spatial and temporal variation in biomass composition creates a need for high-throughput grading of raw biomass. Highly accurate models were built for estimating biomass concentration of glucose, alginate, phlorotannins, and carbon using mid-infrared (MIR) and near-infrared (NIR) spectroscopy. NIR models generally demonstrated higher accuracy and lower sensitivity to outliers than MIR models. Furthermore, samples from the Wellington region could consistently be identified based on the NIR data, demonstrating strong phenotypic differences between regions. These results show that NIR and MIR are valuable tools for high-throughput grading of raw seaweed biomass samples and can be used to establish provenance. 
Finally, farming trials quantified the effect of vertical and horizontal line configurations and farming depth on survival and growth of E. radiata at a commercial New Zealand green-lipped mussel (Perna canaliculus) marine farm. Only seaweed growing on vertical lines survived four months after deployment, and juvenile growth by elongation and maximum average individual weight was markedly higher on vertical lines compared to horizontal lines. Survival rates on vertical lines decreased at shallow depths, likely influenced by a combination of light and temperature stress. Similarly, the overall high mortality observed during the experiment was likely correlated to the prolonged marine heatwave of the summer of 2021/22 at the farm location. Conclusively, these results support vertical lines rather than horizontal line for farming of E. radiata.
In summary, this thesis has significant scientific implications for regulatory (i.e., cultivar translocation), commercial (i.e., harvesting timing, biomass grading, and source tracing), and practical farming aspects (i.e., line configuration and a first proof on concept) of aquaculture of E. radiata in New Zealand and provides directions for future research and development.

text: Developing sustainable seaweed aquaculture of the native kelp Ecklonia radiata in New Zealand The native kelp Ecklonia radiata is a target species for seaweed aquaculture in New Zealand because of its broad distribution and desirable biomass profile (e.g., alginate, fucoidan, and phlorotannins). However, commercial farming practices for E. radiata are not yet developed. The objective of this thesis was therefore to create foundations for sustainable seaweed aquaculture of E. radiata in New Zealand by filling key knowledge gaps regarding patterns of genetic structure (Chapter 2), spatial and temporal variation in biomass composition (Chapter 3), the development of high-throughput methods for biomass grading (Chapter 4), and marine farm design (Chapter 5). 
The development of specialised cultivars is central for optimising key commercial traits for seaweed aquaculture; however, the introduction of genotypes from significantly different genetic sub-populations can reduce genetic diversity and genetic structure of wild populations. Analysis of molecular variance in populations of E. radiata in the North Island of New Zealand revealed significant differences at all three hierarchical levels of genetic structure that were analysed. The highest regional differentiation occurred between Wellington and other regions and was supported by Bayesian and redundancy models showing a high degree of genetic clustering among regions. Furthermore, pairwise Fₛₜ (genetic differentiation) revealed significant differences between most sites showing strong genetic structure and low connectivity also at a local level. These findings indicate that cultivars of E. radiata should not be translocated outside their area of origin, to prevent introducing genotypes from significantly different genetic sub-populations to wild sub-populations.            
Most analysed biomass components of E. radiata showed high spatial variation between sites, including alginate, glucose, and phlorotannins. However, there was no clear pattern in biomass composition among regions, indicating that these differences in biomass content are unlikely to be caused by genetic differences (i.e., Wellington samples did not stand out). Conversely, a strong seasonal pattern was detected with significant temporal variation detected for half of the quantified components. These results indicate that environmental variation is a key driver for the biomass composition of E. radiata and that the high spatial variation was due to do site-specific environmental conditions. In general, the biomass composition of E. radiata was comparable to that of commercially grown northern hemisphere species and could be a suitable southern hemisphere alternative for a wide range of commercial applications. 
The large spatial and temporal variation in biomass composition creates a need for high-throughput grading of raw biomass. Highly accurate models were built for estimating biomass concentration of glucose, alginate, phlorotannins, and carbon using mid-infrared (MIR) and near-infrared (NIR) spectroscopy. NIR models generally demonstrated higher accuracy and lower sensitivity to outliers than MIR models. Furthermore, samples from the Wellington region could consistently be identified based on the NIR data, demonstrating strong phenotypic differences between regions. These results show that NIR and MIR are valuable tools for high-throughput grading of raw seaweed biomass samples and can be used to establish provenance. 
Finally, farming trials quantified the effect of vertical and horizontal line configurations and farming depth on survival and growth of E. radiata at a commercial New Zealand green-lipped mussel (Perna canaliculus) marine farm. Only seaweed growing on vertical lines survived four months after deployment, and juvenile growth by elongation and maximum average individual weight was markedly higher on vertical lines compared to horizontal lines. Survival rates on vertical lines decreased at shallow depths, likely influenced by a combination of light and temperature stress. Similarly, the overall high mortality observed during the experiment was likely correlated to the prolonged marine heatwave of the summer of 2021/22 at the farm location. Conclusively, these results support vertical lines rather than horizontal line for farming of E. radiata.
In summary, this thesis has significant scientific implications for regulatory (i.e., cultivar translocation), commercial (i.e., harvesting timing, biomass grading, and source tracing), and practical farming aspects (i.e., line configuration and a first proof on concept) of aquaculture of E. radiata in New Zealand and provides directions for future research and development.

year: 2023

title: A regional model of endogenous growth with creative destruction

authors: Bond-Smith, Steven Craig

subjects: endogenous growth

abstract: We consider a two region growth model with vertical innovations where technical externalities in R&D lead to a technology leading region being the most attractive location for innovative firms. Innovations are produced in the form of quality improvements building on available knowledge and firms choose a technologically advanced location to maximise the productivity of R&D and maintain their niche monopoly. The partial nature of spillovers causes an additional force for agglomeration: the clustering effect. Agglomerated locations have the benefit of local inter-varietal knowledge spillovers for growth while peripheral locations depend on trade and regional knowledge spillovers.

text: A regional model of endogenous growth with creative destruction We consider a two region growth model with vertical innovations where technical externalities in R&D lead to a technology leading region being the most attractive location for innovative firms. Innovations are produced in the form of quality improvements building on available knowledge and firms choose a technologically advanced location to maximise the productivity of R&D and maintain their niche monopoly. The partial nature of spillovers causes an additional force for agglomeration: the clustering effect. Agglomerated locations have the benefit of local inter-varietal knowledge spillovers for growth while peripheral locations depend on trade and regional knowledge spillovers.

year: 2012-04

title: Distributed agent-centric system for indigenous data sovereignty

authors: Noovao, Setephano

subjects: holochain

abstract: The sovereignty of indigenous data is a key issue facing indigenous communities. Holochain, a distributed ledger technology, has the potential to address some of the challenges indigenous communities face with respect to data sovereignty. The purpose of this thesis is to critically evaluate the feasibility of using holochain technology to support indigenous data sovereignty. This paper first explores the literature on holochain technology, examining its underlying architecture and features. The research employs a three-phase design science research methodology, conducting an experiment to explore the integration of a decentralized application, holochain, with a prominent cloud service provider. The first phase concentrates on emulating real data-sharing platforms that may utilize data at its disposal, following the principles of indigenous data sovereignty, where a centralized platform could be hosted on a cloud computing service with multiple services in operation. The second phase involves developing a holochain application guided by the principles of indigenous data sovereignty. The final phase seeks to combine the established centralized platform from the first phase with the outcomes of the holochain application from the second phase to experimentally assess whether both technologies can create a data sovereignty solution that aligns with the needs of indigenous data sovereignty. The results of the experiment will provide a solid foundation for understanding the current state of the field and identifying areas where holochain can potentially offer solutions. Furthermore, the results of our research indicate that holochain shows significant promise in tackling the issue of indigenous data sovereignty, although there are considerable limitations that must be addressed and resolved to achieve improved results.

text: Distributed agent-centric system for indigenous data sovereignty The sovereignty of indigenous data is a key issue facing indigenous communities. Holochain, a distributed ledger technology, has the potential to address some of the challenges indigenous communities face with respect to data sovereignty. The purpose of this thesis is to critically evaluate the feasibility of using holochain technology to support indigenous data sovereignty. This paper first explores the literature on holochain technology, examining its underlying architecture and features. The research employs a three-phase design science research methodology, conducting an experiment to explore the integration of a decentralized application, holochain, with a prominent cloud service provider. The first phase concentrates on emulating real data-sharing platforms that may utilize data at its disposal, following the principles of indigenous data sovereignty, where a centralized platform could be hosted on a cloud computing service with multiple services in operation. The second phase involves developing a holochain application guided by the principles of indigenous data sovereignty. The final phase seeks to combine the established centralized platform from the first phase with the outcomes of the holochain application from the second phase to experimentally assess whether both technologies can create a data sovereignty solution that aligns with the needs of indigenous data sovereignty. The results of the experiment will provide a solid foundation for understanding the current state of the field and identifying areas where holochain can potentially offer solutions. Furthermore, the results of our research indicate that holochain shows significant promise in tackling the issue of indigenous data sovereignty, although there are considerable limitations that must be addressed and resolved to achieve improved results.

year: 2024