title: Diversity of New Zealand Deep-sea Amphipoda

authors: Knox, Matthew Andrew

subjects: Challenger Plateau

abstract: Biodiversity and the ecological and evolutionary processes which influence faunal distributions are poorly understood in deep-sea habitats. This thesis assesses diversity of deep-sea amphipod crustaceans at three taxonomic levels (family, species, genetic) on continental margins of New Zealand relative to environmental variables. Sampling was undertaken at 20 stations located on Chatham Rise and Challenger Plateau, two major geomorphic features with contrasting environmental conditions.

In Chapter 1, total diversity of the >12,500 amphipods assessed at the family-level revealed high abundance (range: 44 – 2074 individuals 1000 m⁻²) and taxonomic richness (27 families). Amphipod assemblages at all stations were largely dominated by the same families. Chatham Rise stations were mostly similar in family composition to one another and to the two closest Challenger Plateau stations. Overall, amphipod community composition correlated most strongly with surface chlorophyll a, suggesting strong benthic-pelagic coupling.

In Chapter 2, I used molecular methods (COI DNA sequence thresholds of 6%) to estimate species diversity in the dominant amphipod family identified from Chapter 1 - the Phoxocephalidae. Analyses revealed 49 putative species-level taxa, which greatly exceeds the current number (n=17) of formally described New Zealand phoxocephalid species. A cluster of stations with highly similar taxa was identified, broadly distributed over the crest of the Chatham Rise, in association with elevated food availability. Similar to the family-level analyses of Chapter 1 multivariate analysis of phoxocephalid assemblages and environmental parameters revealed a strong correlation with measures of food supply. Analyses of inter-station assemblages revealed a major split between regions, indicating minimal overlap in taxon distributions on eastern and western continental margins.

Chapter 3 examined genetic connectivity among deep-sea habitats. A phylogenetic analyses of three relatively abundant and widespread taxa; cf. Ampelisca chiltoni, cf. Oediceroides apicalis and Phoxocephalidae sp., was combined with available genetic data from a further 61 taxa collected from the same stations, to examine mean levels of inter-station genetic divergences. Nearly identical levels of genetic divergence were found between eastern and western regions for all three taxa. Furthermore, inter-station analysis of the wider amphipod community revealed similar patterns of genetic structure in most taxa. Based on molecular clock estimates, genetic divergences most likely corresponded to isolation following landmass changes during the Pleistocene.

This thesis research has revealed a biodiversity hotspot on New Zealand continental margins. I conclude that Cook Strait and the subtropical front are important structures responsible for shaping benthic communities on New Zealand continental margins and that vicariance is likely to have played an important role in the evolutionary radiation of the New Zealand deep-sea fauna.

text: Diversity of New Zealand Deep-sea Amphipoda Biodiversity and the ecological and evolutionary processes which influence faunal distributions are poorly understood in deep-sea habitats. This thesis assesses diversity of deep-sea amphipod crustaceans at three taxonomic levels (family, species, genetic) on continental margins of New Zealand relative to environmental variables. Sampling was undertaken at 20 stations located on Chatham Rise and Challenger Plateau, two major geomorphic features with contrasting environmental conditions.

In Chapter 1, total diversity of the >12,500 amphipods assessed at the family-level revealed high abundance (range: 44 – 2074 individuals 1000 m⁻²) and taxonomic richness (27 families). Amphipod assemblages at all stations were largely dominated by the same families. Chatham Rise stations were mostly similar in family composition to one another and to the two closest Challenger Plateau stations. Overall, amphipod community composition correlated most strongly with surface chlorophyll a, suggesting strong benthic-pelagic coupling.

In Chapter 2, I used molecular methods (COI DNA sequence thresholds of 6%) to estimate species diversity in the dominant amphipod family identified from Chapter 1 - the Phoxocephalidae. Analyses revealed 49 putative species-level taxa, which greatly exceeds the current number (n=17) of formally described New Zealand phoxocephalid species. A cluster of stations with highly similar taxa was identified, broadly distributed over the crest of the Chatham Rise, in association with elevated food availability. Similar to the family-level analyses of Chapter 1 multivariate analysis of phoxocephalid assemblages and environmental parameters revealed a strong correlation with measures of food supply. Analyses of inter-station assemblages revealed a major split between regions, indicating minimal overlap in taxon distributions on eastern and western continental margins.

Chapter 3 examined genetic connectivity among deep-sea habitats. A phylogenetic analyses of three relatively abundant and widespread taxa; cf. Ampelisca chiltoni, cf. Oediceroides apicalis and Phoxocephalidae sp., was combined with available genetic data from a further 61 taxa collected from the same stations, to examine mean levels of inter-station genetic divergences. Nearly identical levels of genetic divergence were found between eastern and western regions for all three taxa. Furthermore, inter-station analysis of the wider amphipod community revealed similar patterns of genetic structure in most taxa. Based on molecular clock estimates, genetic divergences most likely corresponded to isolation following landmass changes during the Pleistocene.

This thesis research has revealed a biodiversity hotspot on New Zealand continental margins. I conclude that Cook Strait and the subtropical front are important structures responsible for shaping benthic communities on New Zealand continental margins and that vicariance is likely to have played an important role in the evolutionary radiation of the New Zealand deep-sea fauna.

year: 2012

title: Barriers to diabetes self-management in a subset of New Zealand adults with Type 2 diabetes and poor glycaemic control

authors: Chepulis, Lynne Merran

subjects: Science & Technology

abstract: Background. Despite the fact that there is an increasingly effective armoury of medications to treat diabetes, many people continue to have substantially elevated blood glucose levels. The purpose of this study was to explore what the barriers to diabetes management are in a cohort of people with diabetes and poor glycaemic control. Methods. Qualitative semistructured interviews were carried out with 10 people with diabetes who had known diabetes and a recent HbA1c of >11.3% (100 mmol/mol) to explore their experiences of barriers to diabetes self-management and glycaemic control. Results. Barriers to diabetes management were based around two key themes: biopsychosocial factors and knowledge about diabetes. Specifically, financial concerns, social stigma, medication side effects, and cognitive impairment due to hyperglycaemia were commonly reported as barriers to medication use. Other barriers included a lack of knowledge about their own condition, poor relationships with healthcare professionals, and a lack of relevant resources to support diet and weight loss. Conclusion. People with diabetes with poor glycaemic control experience many of the same barriers as those reported elsewhere, but also experience issues specifically related to their severe hyperglycaemia. Management of diabetes could be improved via the increased use of patient education and availability of locally relevant resources.

text: Barriers to diabetes self-management in a subset of New Zealand adults with Type 2 diabetes and poor glycaemic control Background. Despite the fact that there is an increasingly effective armoury of medications to treat diabetes, many people continue to have substantially elevated blood glucose levels. The purpose of this study was to explore what the barriers to diabetes management are in a cohort of people with diabetes and poor glycaemic control. Methods. Qualitative semistructured interviews were carried out with 10 people with diabetes who had known diabetes and a recent HbA1c of >11.3% (100 mmol/mol) to explore their experiences of barriers to diabetes self-management and glycaemic control. Results. Barriers to diabetes management were based around two key themes: biopsychosocial factors and knowledge about diabetes. Specifically, financial concerns, social stigma, medication side effects, and cognitive impairment due to hyperglycaemia were commonly reported as barriers to medication use. Other barriers included a lack of knowledge about their own condition, poor relationships with healthcare professionals, and a lack of relevant resources to support diet and weight loss. Conclusion. People with diabetes with poor glycaemic control experience many of the same barriers as those reported elsewhere, but also experience issues specifically related to their severe hyperglycaemia. Management of diabetes could be improved via the increased use of patient education and availability of locally relevant resources.

year: 2021

title: Understanding the context of hospital transfers and away-from-home hospitalisations for Māori

authors: Cormack, Donna

subjects: Humans

abstract: In Aotearoa New Zealand, people regularly travel away from their home to receive hospital care. While the role of whānau support for patients in hospital is critical for Māori, there is little information about away-from-home hospitalisations. This paper describes the frequency and patterning of away-from-home hospitalisations and inter-hospital transfers for Māori. Data from the National Minimum Dataset (NMDS), for the 6-year period of 1 January 2009-31 December 2014, were analysed. Basic frequencies, means and descriptive statistics were produced using SAS software. We found that more than 10% of all routine hospitalisations constituted an away-from-home hospitalisation for Māori; that is, a hospitalisation that was in a district health board (DHB) other than the DHB of usual residence for the patient. One quarter (25.19%) of transfer hospitalisations were to a DHB other than the patient's DHB of domicile. Away-from-home hospital admissions increase for Māori as deprivation increases for both routine and transfer admissions, with over half of Māori hospital admissions among people who live in areas of high deprivation. This analysis aids in understanding away-from-home hospitalisations for Māori whānau, the characteristics associated with these types of hospitalisations and supports the development and implementation of policies which better meet whānau Māori needs. The cumulative impact of the need to travel to hospital for care, levels of poverty and a primarily reimbursement-based travel assistance system all perpetuate an unequal cost burden placed upon Māori whānau.

text: Understanding the context of hospital transfers and away-from-home hospitalisations for Māori In Aotearoa New Zealand, people regularly travel away from their home to receive hospital care. While the role of whānau support for patients in hospital is critical for Māori, there is little information about away-from-home hospitalisations. This paper describes the frequency and patterning of away-from-home hospitalisations and inter-hospital transfers for Māori. Data from the National Minimum Dataset (NMDS), for the 6-year period of 1 January 2009-31 December 2014, were analysed. Basic frequencies, means and descriptive statistics were produced using SAS software. We found that more than 10% of all routine hospitalisations constituted an away-from-home hospitalisation for Māori; that is, a hospitalisation that was in a district health board (DHB) other than the DHB of usual residence for the patient. One quarter (25.19%) of transfer hospitalisations were to a DHB other than the patient's DHB of domicile. Away-from-home hospital admissions increase for Māori as deprivation increases for both routine and transfer admissions, with over half of Māori hospital admissions among people who live in areas of high deprivation. This analysis aids in understanding away-from-home hospitalisations for Māori whānau, the characteristics associated with these types of hospitalisations and supports the development and implementation of policies which better meet whānau Māori needs. The cumulative impact of the need to travel to hospital for care, levels of poverty and a primarily reimbursement-based travel assistance system all perpetuate an unequal cost burden placed upon Māori whānau.

year: 2022-11-11