title: The effects of terrestrial sediment inputs on ecosystem functions in seagrass meadows and unvegetated sediments

authors: Flowers, Georgina

subjects: seagrass

abstract: Ecological functions in estuarine seagrass and unvegetated soft sediment habitats underpin many valuable ecosystem services. However, changing land-use and climate are accelerating inputs of fine terrestrial sediments, threatening these habitats. The prolonged suspension of fine sediments can reduce seafloor light availability and long-term accumulations increase sediment mud content (particles < 63 µm), both of which could have significant consequences on ecosystem functioning. Understanding how ecosystem functioning may respond to environmental change is vital to estuary management. In this thesis, I investigated the short- and long-term effects of elevated terrestrial sediment inputs on benthic primary production and nutrient cycling in intertidal seagrass meadows (Zostera muelleri) and microphytobenthos-dominated unvegetated habitats. 
To investigate the effects of reduced seafloor light availability and prolonged submergence periods resulting from global heating induced sea-level rise, I conducted a two-year seasonal in situ assessment of photosynthesis-irradiance relationships during submerged and emerged conditions in an adjacent seagrass meadow and unvegetated sandflat. Submerged gross primary production (GPP) in both habitats and emerged GPP in the seagrass habitat were strongly controlled by light availability. Higher rates of light-saturated GPP were found during submerged periods compared to emerged periods in both habitats, but this difference was most pronounced in the unvegetated habitat. If the water-column remains clear, sea-level rise could therefore increase daily GPP in soft sediment habitats. However, declines in submerged GPP with increased water-column turbidity will be exacerbated with sea-level rise. 
Across a natural mud content gradient, I measured primary production in seagrass and unvegetated habitats to address the long-term implications of elevated sediment inputs. In sediments with ≤ 35 % mud content, net primary production (NPP) and GPP was independent of mud content in both habitats. However, extending the mud gradient in unvegetated habitats to 49 % (seagrass habitats restricted to ≤ 35 % mud content) resulted in NPP and GPP declining with increasing mud content. These results highlight that loss of seagrass meadows resulting in expansion of unvegetated habitats could lead to reductions in intertidal production; seen most acutely in areas with high mud content (≥ 39 %).
I also investigated the spatial and temporal variability in nutrient cycling in seagrass and unvegetated habitats to examine how environmental gradients affected sediment nutrient fluxes and denitrification rates. Ammonium effluxes were lower in the seagrass compared to the unvegetated habitats and were lower in both habitats during light compared to dark conditions. Denitrification rates were similar in both habitats but were found to decrease with increasing mud content. Overall, denitrification efficiency was highest in the seagrass habitat. These results indicate that future seagrass decline and/or increased mud content in soft sediment habitats will reduce resilience to eutrophication. 
This thesis demonstrates that future seagrass decline and elevated terrestrial sediment inputs are likely to have serious implications on the high rates of primary production and nutrient cycling of intertidal seagrass meadows and unvegetated habitats. Furthermore, it highlights the value of measuring ecosystem functions in different soft sediment habitat types across multiple spatial and temporal scales to inform future management against anthropogenic stressors.

text: The effects of terrestrial sediment inputs on ecosystem functions in seagrass meadows and unvegetated sediments Ecological functions in estuarine seagrass and unvegetated soft sediment habitats underpin many valuable ecosystem services. However, changing land-use and climate are accelerating inputs of fine terrestrial sediments, threatening these habitats. The prolonged suspension of fine sediments can reduce seafloor light availability and long-term accumulations increase sediment mud content (particles < 63 µm), both of which could have significant consequences on ecosystem functioning. Understanding how ecosystem functioning may respond to environmental change is vital to estuary management. In this thesis, I investigated the short- and long-term effects of elevated terrestrial sediment inputs on benthic primary production and nutrient cycling in intertidal seagrass meadows (Zostera muelleri) and microphytobenthos-dominated unvegetated habitats. 
To investigate the effects of reduced seafloor light availability and prolonged submergence periods resulting from global heating induced sea-level rise, I conducted a two-year seasonal in situ assessment of photosynthesis-irradiance relationships during submerged and emerged conditions in an adjacent seagrass meadow and unvegetated sandflat. Submerged gross primary production (GPP) in both habitats and emerged GPP in the seagrass habitat were strongly controlled by light availability. Higher rates of light-saturated GPP were found during submerged periods compared to emerged periods in both habitats, but this difference was most pronounced in the unvegetated habitat. If the water-column remains clear, sea-level rise could therefore increase daily GPP in soft sediment habitats. However, declines in submerged GPP with increased water-column turbidity will be exacerbated with sea-level rise. 
Across a natural mud content gradient, I measured primary production in seagrass and unvegetated habitats to address the long-term implications of elevated sediment inputs. In sediments with ≤ 35 % mud content, net primary production (NPP) and GPP was independent of mud content in both habitats. However, extending the mud gradient in unvegetated habitats to 49 % (seagrass habitats restricted to ≤ 35 % mud content) resulted in NPP and GPP declining with increasing mud content. These results highlight that loss of seagrass meadows resulting in expansion of unvegetated habitats could lead to reductions in intertidal production; seen most acutely in areas with high mud content (≥ 39 %).
I also investigated the spatial and temporal variability in nutrient cycling in seagrass and unvegetated habitats to examine how environmental gradients affected sediment nutrient fluxes and denitrification rates. Ammonium effluxes were lower in the seagrass compared to the unvegetated habitats and were lower in both habitats during light compared to dark conditions. Denitrification rates were similar in both habitats but were found to decrease with increasing mud content. Overall, denitrification efficiency was highest in the seagrass habitat. These results indicate that future seagrass decline and/or increased mud content in soft sediment habitats will reduce resilience to eutrophication. 
This thesis demonstrates that future seagrass decline and elevated terrestrial sediment inputs are likely to have serious implications on the high rates of primary production and nutrient cycling of intertidal seagrass meadows and unvegetated habitats. Furthermore, it highlights the value of measuring ecosystem functions in different soft sediment habitat types across multiple spatial and temporal scales to inform future management against anthropogenic stressors.

year: 2024-04-15

title: Childfree couples' experiences of stereotyping, harassment and pressure

authors: Riley, Theresa Mary

subjects: childfree

abstract: This qualitative study is about New Zealand couples who, by choice, do not have children. Strong social norms exist for couples to have children, and those who express a desire to do otherwise have been disbelieved, pressured, and stereotyped. Womanhood has continued to be associated with motherhood, and a maternal instinct is expected to drive women to have children. The aim of this research was to add to knowledge and awareness of how childfree people have experienced being stereotyped, pressured and harassed for being childfree. For this research, I conjointly interviewed ten heterosexual, childfree couples residing in the city of Hamilton. Participants self-identified as childfree, and ranged in age from 23 to 56 years old. Five of the couples also participated in a focus group. Participants related the ways in which they perceived that the wider social context played a role in the negative responses they experienced. Participants revealed how they felt less socially valued through: an idealization of parenthood, exclusion from work benefits, and an expectation that women should manage both employment and motherhood. Stereotyping was found to still occur, with participants reporting that they were labelled as selfish, immature, and anti-children. Stereotypes of being destined for loneliness in later life, and of their pets being substitutes for children were common. Some evidence was found in participants' comments that there were elements of truth in stereotypes of the childfree. The negative stereotyping appeared to have little, if any, impact on how participants viewed or felt about themselves. Participants reported feeling harassed by other people's disbelief in their choice, and assumptions, that despite what they said, everybody wanted children. The pressures experienced by participants took various forms, such as persistent questioning, and came from various sources, including siblings and acquaintances. Participants' reports of feeling pressured or harassed seem to reflect minor and fleeting feelings, rather than a continuing concern. How pressuring comments were perceived by the recipient was very context-dependent. Participants tolerated and coped with people's negative responses by various methods, such as confronting, ignoring, and avoiding the topic of children with certain people. I recommend that further research be done, and that work is needed to promote both acceptance of the childfree option, and freedom of women's identification from association with childbearing.

text: Childfree couples' experiences of stereotyping, harassment and pressure This qualitative study is about New Zealand couples who, by choice, do not have children. Strong social norms exist for couples to have children, and those who express a desire to do otherwise have been disbelieved, pressured, and stereotyped. Womanhood has continued to be associated with motherhood, and a maternal instinct is expected to drive women to have children. The aim of this research was to add to knowledge and awareness of how childfree people have experienced being stereotyped, pressured and harassed for being childfree. For this research, I conjointly interviewed ten heterosexual, childfree couples residing in the city of Hamilton. Participants self-identified as childfree, and ranged in age from 23 to 56 years old. Five of the couples also participated in a focus group. Participants related the ways in which they perceived that the wider social context played a role in the negative responses they experienced. Participants revealed how they felt less socially valued through: an idealization of parenthood, exclusion from work benefits, and an expectation that women should manage both employment and motherhood. Stereotyping was found to still occur, with participants reporting that they were labelled as selfish, immature, and anti-children. Stereotypes of being destined for loneliness in later life, and of their pets being substitutes for children were common. Some evidence was found in participants' comments that there were elements of truth in stereotypes of the childfree. The negative stereotyping appeared to have little, if any, impact on how participants viewed or felt about themselves. Participants reported feeling harassed by other people's disbelief in their choice, and assumptions, that despite what they said, everybody wanted children. The pressures experienced by participants took various forms, such as persistent questioning, and came from various sources, including siblings and acquaintances. Participants' reports of feeling pressured or harassed seem to reflect minor and fleeting feelings, rather than a continuing concern. How pressuring comments were perceived by the recipient was very context-dependent. Participants tolerated and coped with people's negative responses by various methods, such as confronting, ignoring, and avoiding the topic of children with certain people. I recommend that further research be done, and that work is needed to promote both acceptance of the childfree option, and freedom of women's identification from association with childbearing.

year: 2008

title: He oranga tō te wai: Māori Pedagogies - A Culturally Responsive View of Aquatic Education and Drowning Prevention in Aotearoa

authors: Haimona, Mark Waihape

abstract: Drowning is a leading cause of accidental death and hospitalisation among Māori in Aotearoa. Drowning reports (Water Safety New Zealand, 2010, 2016, 2019) indicate Māori are over-represented in drowning compared to non-Māori, and on average account for up to a quarter of all drowning fatalities each year. Māori male aged 15-44 years and Māori children under five are most at risk of drowning (WSNZ, 2018, 2). A recent Aotearoa study on children’s water survival skills suggest changes are needed to improve how children develop fundamental aquatic skills and how teachers can best teach those skills (Button et al., 2017). In particular, the teaching of water safety skills for broader use in the open water environments of Aotearoa. 
Māori pedagogies within physical education, health, and education in the outdoors (Hemara, 2000; Jackson et al, 2016; Phillips, 2018) have demonstrated the benefits of Māori teaching methods that foster positive learning outcomes for Māori. (Bishop & Berryman, 2006, 2009). As such, this research investigated core components of Māori pedagogies that can improve aquatic education for Māori. It sought to validate traditional and contemporary aquatic teachings and water safety practices that Māori exercise as an expression of ira tangata (human development) and their relationship with te ao tūroa (the long-standing world). By means of kaupapa Māori research and the development of a new framework - Tāne Whānau Mārama, this thesis offers valuable insights into the importance of culturally responsive pedagogies in aquatic education that will enhance the health, educational achievements, and well-being of Māori whānau and communities.

text: He oranga tō te wai: Māori Pedagogies - A Culturally Responsive View of Aquatic Education and Drowning Prevention in Aotearoa Drowning is a leading cause of accidental death and hospitalisation among Māori in Aotearoa. Drowning reports (Water Safety New Zealand, 2010, 2016, 2019) indicate Māori are over-represented in drowning compared to non-Māori, and on average account for up to a quarter of all drowning fatalities each year. Māori male aged 15-44 years and Māori children under five are most at risk of drowning (WSNZ, 2018, 2). A recent Aotearoa study on children’s water survival skills suggest changes are needed to improve how children develop fundamental aquatic skills and how teachers can best teach those skills (Button et al., 2017). In particular, the teaching of water safety skills for broader use in the open water environments of Aotearoa. 
Māori pedagogies within physical education, health, and education in the outdoors (Hemara, 2000; Jackson et al, 2016; Phillips, 2018) have demonstrated the benefits of Māori teaching methods that foster positive learning outcomes for Māori. (Bishop & Berryman, 2006, 2009). As such, this research investigated core components of Māori pedagogies that can improve aquatic education for Māori. It sought to validate traditional and contemporary aquatic teachings and water safety practices that Māori exercise as an expression of ira tangata (human development) and their relationship with te ao tūroa (the long-standing world). By means of kaupapa Māori research and the development of a new framework - Tāne Whānau Mārama, this thesis offers valuable insights into the importance of culturally responsive pedagogies in aquatic education that will enhance the health, educational achievements, and well-being of Māori whānau and communities.

year: 2023