title: International migration in a sea of islands: Challenges and opportunities for insular Pacific spaces

authors: Bedford, Richard

subjects: Pacific Islands

abstract: Our contribution to the International Conference “Connecting Worlds: Emigration, Immigration and Development in Insular Spaces”, held in the Azores between 28 and 30 May 2008, examines contemporary mobility of Pacific peoples in a transnational context with reference to processes of out-migration, return, re-migration and the complex systems of circular mobility between island countries as well as to and from countries on the Pacific rim. There are some significant differences between parts of the Pacific region in terms of the access their peoples have to work and residence opportunities outside their island countries. These are reviewed with reference to some major challenges for development in the region: rapid growth of youthful populations; high levels of unemployment; limited markets for local produce; unsustainable levels of extraction of timber, fish and mineral resources; changing climates; and unstable governance systems in some countries.

text: International migration in a sea of islands: Challenges and opportunities for insular Pacific spaces Our contribution to the International Conference “Connecting Worlds: Emigration, Immigration and Development in Insular Spaces”, held in the Azores between 28 and 30 May 2008, examines contemporary mobility of Pacific peoples in a transnational context with reference to processes of out-migration, return, re-migration and the complex systems of circular mobility between island countries as well as to and from countries on the Pacific rim. There are some significant differences between parts of the Pacific region in terms of the access their peoples have to work and residence opportunities outside their island countries. These are reviewed with reference to some major challenges for development in the region: rapid growth of youthful populations; high levels of unemployment; limited markets for local produce; unsustainable levels of extraction of timber, fish and mineral resources; changing climates; and unstable governance systems in some countries.

year: 2008-07

title: DNA repair enzymes in Prochlorococcus marinus strain MIT9312

authors: Kirby, Bronwyn

abstract: Prochlorococcus marinus, a marine cyanobacterium, is one of the most abundant photosynthetic organisms in the ocean. P. marinus contributes towards approximately 8.5% of global ocean primary productivity. P. marinus is of interest because of the cell’s simple and unique photosynthetic system, efficient carbon concentrating mechanism, and streamlined genome. P. marinus strain MIT9312 is a high-light adapted strain that thrives in the upper euphotic zone where there are minimal nutrients and high levels of UV exposure, which would typically put an organism at risk. Understanding the function of repair proteins is significant for being able to identify the DNA repair pathways used by Prochlorococcus to survive under increasingly more harmful conditions. My research, outlined in this thesis, aimed to characterize DNA repair enzymes in Prochlorococcus marinus strain MIT9312 to further our understanding of cyanobacterial growth, survival, and repair.

LigW is an ATP-dependent ligase that is unique to strain MIT9312. It was found to have low ligase activity on nicked DNA compared to other ligases, making its retention in the small Prochlorococcus genome unusual. It is suspected that LigW could achieve higher ligation rates by interacting with other proteins. LigW is in an operon with other proteins that are predicted to promote LigW activity or have their own DNA modifying activities. The three proteins of interest have been annotated as Pmar3, Pmar4, and Pmar5. The
individual function and relationships between each protein were investigated in this thesis.

This thesis focused on recombinantly producing and biochemically characterizing three of the proteins adjacent to LigW and assessing their activities in vitro. Pmar3 was successfully expressed, purified, and characterized as a potential nuclease. Further mutagenesis work will confirm the proposed function of Pmar3. Attempts were made to characterize Pmar4, with further optimization of expression and purification protocols necessary. Pmar5 has been characterized as a pentameric Mg-dependent topoisomerase-like protein, with an inability to re-join DNA. It is likely that these proteins on the LigW operon work together with LigW in a currently unidentified repair pathway. Once the LigW DNA repair system is characterized, then this can be more easily identified and understood in other organisms where it may not be detected at present.

text: DNA repair enzymes in Prochlorococcus marinus strain MIT9312 Prochlorococcus marinus, a marine cyanobacterium, is one of the most abundant photosynthetic organisms in the ocean. P. marinus contributes towards approximately 8.5% of global ocean primary productivity. P. marinus is of interest because of the cell’s simple and unique photosynthetic system, efficient carbon concentrating mechanism, and streamlined genome. P. marinus strain MIT9312 is a high-light adapted strain that thrives in the upper euphotic zone where there are minimal nutrients and high levels of UV exposure, which would typically put an organism at risk. Understanding the function of repair proteins is significant for being able to identify the DNA repair pathways used by Prochlorococcus to survive under increasingly more harmful conditions. My research, outlined in this thesis, aimed to characterize DNA repair enzymes in Prochlorococcus marinus strain MIT9312 to further our understanding of cyanobacterial growth, survival, and repair.

LigW is an ATP-dependent ligase that is unique to strain MIT9312. It was found to have low ligase activity on nicked DNA compared to other ligases, making its retention in the small Prochlorococcus genome unusual. It is suspected that LigW could achieve higher ligation rates by interacting with other proteins. LigW is in an operon with other proteins that are predicted to promote LigW activity or have their own DNA modifying activities. The three proteins of interest have been annotated as Pmar3, Pmar4, and Pmar5. The
individual function and relationships between each protein were investigated in this thesis.

This thesis focused on recombinantly producing and biochemically characterizing three of the proteins adjacent to LigW and assessing their activities in vitro. Pmar3 was successfully expressed, purified, and characterized as a potential nuclease. Further mutagenesis work will confirm the proposed function of Pmar3. Attempts were made to characterize Pmar4, with further optimization of expression and purification protocols necessary. Pmar5 has been characterized as a pentameric Mg-dependent topoisomerase-like protein, with an inability to re-join DNA. It is likely that these proteins on the LigW operon work together with LigW in a currently unidentified repair pathway. Once the LigW DNA repair system is characterized, then this can be more easily identified and understood in other organisms where it may not be detected at present.

year: 2021

title: Walking into the past to explore the future: Utulizing larval densities to measure the effects of two climate change factors, temperature and salinity on Poorohe (common smelt, Retropinna retropinna) abundance in Te Puuaha o Waikato

authors: Robcke, Sidney

subjects: Common smelt

abstract: Poorohe (common smelt, Retropinna retropinna) are a highly valued kai species in Te Puuaha o Waikato (the lower 66 km of the Waikato River). Fisher whaanau have observed changes in the amount Poorohe that are harvested during annual fish harvests. Since Poorohe are particularly vulnerable to environmental changes, whaanau are particularly concerned about the how climate change might impact Poorohe populations. Climate change vulnerability assessments (CCVA) currently exist for several native New Zealand fish freshwater species; however, one does not yet exist for Poorohe. Previous larval distribution studies in the lower Waikato River only sampled as far downstream as Tuakau bridge (approximately 45km from the river mouth). These studies indicated that important spawning habitats likely existed downstream of Tuakau bridge. Temperature increases and saltwater intrusion have been identified as two climate change factors that will likely impact Poorohe in Te Puuaha o Waikato, because ambient temperatures have increased since the industrial revolution and the proximity of the study area to the ocean. A literature review was used to explore the experiences of fisher whaanau through the past, present and how the experiences will continue to change in a changing climate. The effects of temperature and saltwater intrusion on Poorohe populations were explored through replicating the methods of past research carried out in the 1980s and 2010s. Current river temperatures are in the optimal temperature range (12°C - 18°C) for Poorohe spawning. The saltwater wedge was suppressed by the high river flow during the eight-week sampling period, and it is unclear whether saltwater intrusion has an impact on Poorohe spawning. Larval densities did not significantly increase down river, which suggests large spawning habitat is not found downstream of Tuakau bridge. Furthermore, there were no decreases in larval densities in the two saltwater sites. This study has contributed to the available literature necessary to develop a CCVA for Poorohe and explored the cultural heritage of traditionally significant practices in Te Puuaha o Waikato relating to Poorohe.

text: Walking into the past to explore the future: Utulizing larval densities to measure the effects of two climate change factors, temperature and salinity on Poorohe (common smelt, Retropinna retropinna) abundance in Te Puuaha o Waikato Poorohe (common smelt, Retropinna retropinna) are a highly valued kai species in Te Puuaha o Waikato (the lower 66 km of the Waikato River). Fisher whaanau have observed changes in the amount Poorohe that are harvested during annual fish harvests. Since Poorohe are particularly vulnerable to environmental changes, whaanau are particularly concerned about the how climate change might impact Poorohe populations. Climate change vulnerability assessments (CCVA) currently exist for several native New Zealand fish freshwater species; however, one does not yet exist for Poorohe. Previous larval distribution studies in the lower Waikato River only sampled as far downstream as Tuakau bridge (approximately 45km from the river mouth). These studies indicated that important spawning habitats likely existed downstream of Tuakau bridge. Temperature increases and saltwater intrusion have been identified as two climate change factors that will likely impact Poorohe in Te Puuaha o Waikato, because ambient temperatures have increased since the industrial revolution and the proximity of the study area to the ocean. A literature review was used to explore the experiences of fisher whaanau through the past, present and how the experiences will continue to change in a changing climate. The effects of temperature and saltwater intrusion on Poorohe populations were explored through replicating the methods of past research carried out in the 1980s and 2010s. Current river temperatures are in the optimal temperature range (12°C - 18°C) for Poorohe spawning. The saltwater wedge was suppressed by the high river flow during the eight-week sampling period, and it is unclear whether saltwater intrusion has an impact on Poorohe spawning. Larval densities did not significantly increase down river, which suggests large spawning habitat is not found downstream of Tuakau bridge. Furthermore, there were no decreases in larval densities in the two saltwater sites. This study has contributed to the available literature necessary to develop a CCVA for Poorohe and explored the cultural heritage of traditionally significant practices in Te Puuaha o Waikato relating to Poorohe.

year: 2024-11-23