title: Variation in nitrate sources and delivery in space and time within the 389 ha Lake Okaro catchment

authors: Eyberg, Claire Elizabeth

subjects: Nitrate

abstract: The eutrophication of surface water is a global issue, with excessive nitrate 
concentrations reducing water quality and affecting water supplies, 
ecosystem health and its recreational use. In New Zealand, the degradation 
of freshwater quality has largely been attributed to nitrate leaching from 
intensive landuse, in particular from intensively grazed pastoral systems.   
As agricultural activity in catchments can contribute a large proportion of the 
nutrient pollution in surface waters, an understanding of nitrogen dynamics 
is therefore vital in managing the downstream effects of diffuse nitrogen 
inputs. Nitrate isotopes (δ¹⁵N, δ¹⁸O) have been increasingly used for 
determining nitrate cycling and source identification. Together with water 
isotopes (δ²H, δ¹⁸O), these conservative tracers can provide the necessary 
tools for determining the transport mechanisms of nitrate.   
    
Lake Okaro has suffered from water quality degradation for several decades, 
and has been the focus of intense lake restoration projects focused on 
nutrient management. The 389 ha agriculture-dominated catchment 
exemplifies New Zealand’s complex physiographic landscape.   

Results from high-resolution monitoring of streamflow during storm events 
demonstrates the potential to capture dynamic shifts in distinct water 
sources, but can be limited by insufficient monitoring of ancillary parameters, 
or a lack of pre-event characterisation of streamflow. Spatial sampling 
indicated characteristic fractionation processes for sites of similar 
environments, likely due to enhanced plant and microbial processing of 
carbon and nitrogen. This spatial sampling demonstrates that even in small 
catchments, there may be a significant degree of heterogeneity in water and 
nitrate flows, in both space and time.   
    
Nitrate contributions were much lower in summer relative to autumn and 
winter during baseflow or non-storm flow. Storm events contributed a 
disproportionate amount of nitrate, but the effect was most notable in winter.   

During baseflow, or non-stormflow, in the main inflow stream in the Lake 
Okaro catchment, nitrate had δ¹⁵N and δ¹⁸O values indicative of a soil 
nitrogen origin (+5.8 ‰ to +7.3 ‰, and -0.5 ‰ to +1.7 ‰, respectively).    

The dominant nitrate sources shifted during rain events, with streamflow in 
the winter event having δ¹⁵N and δ¹⁸O values indicative of urine, whereas 
the summer event observed δ¹⁸O-enriched baseflow signatures. Water 
isotope ratios indicated the winter event was dominated by event water. The 
differing seasonal responses to rainfall suggest nitrate inputs during storms 
in this catchment are strongly linked to seasonal nitrate availability in water 
flow paths.    

Patterns observed in temporal and spatial data collected require more 
investigation around potential reasons or mechanisms of fractionation. 
Further refinement of the Okaro catchment flows and cycling of nitrogen will 
help create more catered management techniques.

text: Variation in nitrate sources and delivery in space and time within the 389 ha Lake Okaro catchment The eutrophication of surface water is a global issue, with excessive nitrate 
concentrations reducing water quality and affecting water supplies, 
ecosystem health and its recreational use. In New Zealand, the degradation 
of freshwater quality has largely been attributed to nitrate leaching from 
intensive landuse, in particular from intensively grazed pastoral systems.   
As agricultural activity in catchments can contribute a large proportion of the 
nutrient pollution in surface waters, an understanding of nitrogen dynamics 
is therefore vital in managing the downstream effects of diffuse nitrogen 
inputs. Nitrate isotopes (δ¹⁵N, δ¹⁸O) have been increasingly used for 
determining nitrate cycling and source identification. Together with water 
isotopes (δ²H, δ¹⁸O), these conservative tracers can provide the necessary 
tools for determining the transport mechanisms of nitrate.   
    
Lake Okaro has suffered from water quality degradation for several decades, 
and has been the focus of intense lake restoration projects focused on 
nutrient management. The 389 ha agriculture-dominated catchment 
exemplifies New Zealand’s complex physiographic landscape.   

Results from high-resolution monitoring of streamflow during storm events 
demonstrates the potential to capture dynamic shifts in distinct water 
sources, but can be limited by insufficient monitoring of ancillary parameters, 
or a lack of pre-event characterisation of streamflow. Spatial sampling 
indicated characteristic fractionation processes for sites of similar 
environments, likely due to enhanced plant and microbial processing of 
carbon and nitrogen. This spatial sampling demonstrates that even in small 
catchments, there may be a significant degree of heterogeneity in water and 
nitrate flows, in both space and time.   
    
Nitrate contributions were much lower in summer relative to autumn and 
winter during baseflow or non-storm flow. Storm events contributed a 
disproportionate amount of nitrate, but the effect was most notable in winter.   

During baseflow, or non-stormflow, in the main inflow stream in the Lake 
Okaro catchment, nitrate had δ¹⁵N and δ¹⁸O values indicative of a soil 
nitrogen origin (+5.8 ‰ to +7.3 ‰, and -0.5 ‰ to +1.7 ‰, respectively).    

The dominant nitrate sources shifted during rain events, with streamflow in 
the winter event having δ¹⁵N and δ¹⁸O values indicative of urine, whereas 
the summer event observed δ¹⁸O-enriched baseflow signatures. Water 
isotope ratios indicated the winter event was dominated by event water. The 
differing seasonal responses to rainfall suggest nitrate inputs during storms 
in this catchment are strongly linked to seasonal nitrate availability in water 
flow paths.    

Patterns observed in temporal and spatial data collected require more 
investigation around potential reasons or mechanisms of fractionation. 
Further refinement of the Okaro catchment flows and cycling of nitrogen will 
help create more catered management techniques.

year: 2020

title: Psychological autonomy and well-being of employees in low-skilled occupations

authors: Yong, Amy Pei Chuin

subjects: low-skilled occupations

abstract: Psychological autonomy and the impact it has on employees’ well-being has seldom been examined for those employed in low-skilled occupations. Using self-determination theory (SDT) as the theoretical grounding, this study aimed to investigate the relationship between supervisors’ support for psychological autonomy and employee outcomes such as well-being, stress, and job performance, for those in low-skilled occupations. SDT proposes that the effect of supervisors’ autonomy support is mediated through the satisfaction and frustration of employees’ needs. Survey data were collected from 171 employees at four different organisations in New Zealand. Regression analysis indicated that supervisors’ autonomy support was positively related to the satisfaction of employees’ autonomy, competence and relatedness needs and negatively related to frustration of employees’ autonomy and relatedness needs. In addition, supervisors’ autonomy support was related to job performance through competence and relatedness satisfaction and to well-being through autonomy satisfaction. Findings highlight the importance of supervisors’ autonomy support for employees’ well-being and job performance, giving organisations ways to improve well-being and job performance.

text: Psychological autonomy and well-being of employees in low-skilled occupations Psychological autonomy and the impact it has on employees’ well-being has seldom been examined for those employed in low-skilled occupations. Using self-determination theory (SDT) as the theoretical grounding, this study aimed to investigate the relationship between supervisors’ support for psychological autonomy and employee outcomes such as well-being, stress, and job performance, for those in low-skilled occupations. SDT proposes that the effect of supervisors’ autonomy support is mediated through the satisfaction and frustration of employees’ needs. Survey data were collected from 171 employees at four different organisations in New Zealand. Regression analysis indicated that supervisors’ autonomy support was positively related to the satisfaction of employees’ autonomy, competence and relatedness needs and negatively related to frustration of employees’ autonomy and relatedness needs. In addition, supervisors’ autonomy support was related to job performance through competence and relatedness satisfaction and to well-being through autonomy satisfaction. Findings highlight the importance of supervisors’ autonomy support for employees’ well-being and job performance, giving organisations ways to improve well-being and job performance.

year: 2019

title: Mana Wahine Geographies: Spiritual, Spatial and Embodied Understandings of Papatūānuku

authors: Simmonds, Naomi Beth

subjects: Mana wahine

abstract: This thesis is a theoretical and empirical exploration of Māori women's knowledges and understandings of Papatūānuku in contemporary Aotearoa. The primary focus of this research is on the complexities, connections, and contradictions of Māori women's embodied relationships with the spaces of Papatūānuku - spaces that are simultaneously material, discursive, symbolic, and spiritual. In doing so, I displace the boundaries between coloniser/colonised, self/other, rational/irrational and scientific/spiritual. I demonstrate that Māori women's colonised realities produce multiple, complex and hybrid understandings of Papatūānuku. 

This thesis has three main strands. The first is theoretical. I offer mana wahine (Māori feminist discourses) as another perspective for geography that engages with the complex intersections of colonisation, race and gender. A mana wahine geography framework is a useful lens through which to explore the complexities of Māori women's relationships to space and place. This framework contributes to, and draws together, feminist geographies and Māori and indigenous academic scholarship.

Autobiographical material is woven with joint and individual semi-structured in-depth interviews conducted with nine Māori women in the Waikato region. The second strand, woven into this thesis, is a critical examination of the colonisation of Māori women's spiritual and embodied relationships to Papatūānuku. The invisibility of Māori women's knowledges in dominant conceptualisations of mythology, tikanga and wairua discourses is not a harmless omission rather it contains a political imperative that maintains the hegemony of colonialism and patriarchy. I argue that to understand further Māori women's relationships to space and place an examination of wairua discourses is necessary.

The third strand reconfigures embodied and spatial conceptualisations of Papatūānuku. Māori women's maternal bodies are intimately tied to Papatūānuku in a way that challenges the oppositional distinctions between mind/body and biology/social inscription. Māori women's maternal bodies (and the representation of them in te reo Māori) are constructed by, and in turn, construct Papatūānuku. Furthermore, women's spatial relationship to tūrangawaewae, home space and wider environmental concerns demonstrates the co-constitution of subjectivities, bodies and space/place. 

My hope is that this thesis will add to geographical literature by addressing previously ignored knowledges and that it will contribute to indigenous scholarship by providing a spatial perspective.

text: Mana Wahine Geographies: Spiritual, Spatial and Embodied Understandings of Papatūānuku This thesis is a theoretical and empirical exploration of Māori women's knowledges and understandings of Papatūānuku in contemporary Aotearoa. The primary focus of this research is on the complexities, connections, and contradictions of Māori women's embodied relationships with the spaces of Papatūānuku - spaces that are simultaneously material, discursive, symbolic, and spiritual. In doing so, I displace the boundaries between coloniser/colonised, self/other, rational/irrational and scientific/spiritual. I demonstrate that Māori women's colonised realities produce multiple, complex and hybrid understandings of Papatūānuku. 

This thesis has three main strands. The first is theoretical. I offer mana wahine (Māori feminist discourses) as another perspective for geography that engages with the complex intersections of colonisation, race and gender. A mana wahine geography framework is a useful lens through which to explore the complexities of Māori women's relationships to space and place. This framework contributes to, and draws together, feminist geographies and Māori and indigenous academic scholarship.

Autobiographical material is woven with joint and individual semi-structured in-depth interviews conducted with nine Māori women in the Waikato region. The second strand, woven into this thesis, is a critical examination of the colonisation of Māori women's spiritual and embodied relationships to Papatūānuku. The invisibility of Māori women's knowledges in dominant conceptualisations of mythology, tikanga and wairua discourses is not a harmless omission rather it contains a political imperative that maintains the hegemony of colonialism and patriarchy. I argue that to understand further Māori women's relationships to space and place an examination of wairua discourses is necessary.

The third strand reconfigures embodied and spatial conceptualisations of Papatūānuku. Māori women's maternal bodies are intimately tied to Papatūānuku in a way that challenges the oppositional distinctions between mind/body and biology/social inscription. Māori women's maternal bodies (and the representation of them in te reo Māori) are constructed by, and in turn, construct Papatūānuku. Furthermore, women's spatial relationship to tūrangawaewae, home space and wider environmental concerns demonstrates the co-constitution of subjectivities, bodies and space/place. 

My hope is that this thesis will add to geographical literature by addressing previously ignored knowledges and that it will contribute to indigenous scholarship by providing a spatial perspective.

year: 2009