title: Puarenga Stream alum dosing – Summary of effects on lake biota 2015

authors: Ling, Nicholas

abstract: Continuous alum dosing of the Puarenga Stream commenced in early 2010 to reduce inflows of dissolved reactive phosphorus to Lake Rotorua. Analyses of bioaccumulation in the tissues of macrobiota were undertaken in February 2015 for comparison to comparable samples obtained prior to and since the commencement of alum dosing to satisfy annual resource consent conditions 8.7 and 8.8 of resource consent 65559.
No significant effects of alum dosing could be distinguished. Bioavailable aluminium in the vicinity of Sulphur Bay appears to be primarily influenced by the major geothermal activity of this region. Lake water chemistry in the vicinity of Sulphur Bay is heavily influenced by the direction of geothermal flows emanating from the Bay. No significant differences in aluminium bioaccumulation were observed in any species compared to samples obtained prior to the commencement of alum dosing. Continuous alum dosing of the Puarenga Stream since 2010 apparently has not resulted in adverse effects to Lake Rotorua shoreline biota nor caused any apparent increase in aluminium bioaccumulation in lake biota in the vicinity of Sulphur Bay.

text: Puarenga Stream alum dosing – Summary of effects on lake biota 2015 Continuous alum dosing of the Puarenga Stream commenced in early 2010 to reduce inflows of dissolved reactive phosphorus to Lake Rotorua. Analyses of bioaccumulation in the tissues of macrobiota were undertaken in February 2015 for comparison to comparable samples obtained prior to and since the commencement of alum dosing to satisfy annual resource consent conditions 8.7 and 8.8 of resource consent 65559.
No significant effects of alum dosing could be distinguished. Bioavailable aluminium in the vicinity of Sulphur Bay appears to be primarily influenced by the major geothermal activity of this region. Lake water chemistry in the vicinity of Sulphur Bay is heavily influenced by the direction of geothermal flows emanating from the Bay. No significant differences in aluminium bioaccumulation were observed in any species compared to samples obtained prior to the commencement of alum dosing. Continuous alum dosing of the Puarenga Stream since 2010 apparently has not resulted in adverse effects to Lake Rotorua shoreline biota nor caused any apparent increase in aluminium bioaccumulation in lake biota in the vicinity of Sulphur Bay.

year: 2016

title: Redox cycling of colloidal macro- and micro-nutrients in a monomictic lake

authors: Saeed, Huma

subjects: Anoxia

abstract: Lakes are more than just water bodies as they play an essential role in the cycling of nutrients and carbon, with impacts at the local and global scale. This study selected Lake Ngapouri, a small monomictic lake in the Waikiti Valley, Taupo Volcanic Zone, New Zealand, which receives a considerable amount of nutrients and organic carbon input from the surrounding pastures. The study was designed to investigate the cycling of nutrients and dissolved organic carbon in lake Ngapouri, with a focus on processes occurring at the colloidal size level under varying thermal and redox conditions. 
To achieve the objectives of the study, a year-long sampling campaign was designed involving field and laboratory measurements of the lake's water column. The lake's physicochemical characteristics were determined via high-resolution depth profiles and paried  with a detailed set of depth-resolved geochemical measurements. Analysis for reduced Fe (II) was used to control for oxidative loss during transportation and storage of samples, and generally demonstrated very good protocols and minimal sample alteration. 
This work comprises a comparison of components in colloidal and dissolved size ranges, determined by ultrafiltration under a zero grade N2 atmosphere, and in situ measurements by diffusive gradients in thin films (DGT). Colloids from the lake were additionally analyzed using transmission electron microscopy (TEM), atomic force microscopy (AFM), fluorescence spectroscopy, and a suite of complementary methods. 
Results show considerable changes in the physicochemical properties of the lake over the hydrological year. Isothermal conditions prevailed through the water column during austral autumn and winter, with thermal stratification becoming established as the summer progressed. Dissolved oxygen concentration followed the thermal pattern, and thus vertically divided the water column into three distinct zones during summer. These zones are referred to as 1) Epilimnion (0-5m measuring from the surface) with uniform thermal and dissolved oxygen concentration, 2) transition zone with varying temperature and dissolved oxygen concentration referred to as metalimnion (6-13m), and 3) hypolimnion (15-20m) marked with cold water and reduced oxygen concentration in comparison to the upper two compartments. The pH of the water column stayed circumneutral during this study. The implications of the lake's variation in thermal and redox status on the cycling of macro and micronutrients are discussed in data chapters.  
The third chapter of this thesis addresses the role of suspended iron hydroxides in phosphorus cycling. The spatial and temporal distribution of iron and phosphorus was clearly coupled and was strongly influenced by sediment releases of both elements in anaerobic bed sediments. Both iron and phosphorus were predominantly colloidal and displayed an increasing degree of lability (to DGT) as hypolimnetic anoxia deepened. The implications of this finding are that iron-based colloids can mediate phosphorus cycling even under anaerobic conditions, and might therefore influence iron and phosphorus bioavailability within the water column. 
The fourth chapter of this thesis explores the evolution, seasonal production, and consumption of dissolved organic matter (DOM) in the water column of Lake Ngapouri. Both the quality and quantity of DOM influence the turnover of DOM in the lake system, and this influence was explored using the constituent molecules' fluorescent properties. The resulting excitation-emission matrices (EEM's) were analyzed using parallel factor analysis (PARAFAC), identifying two humic-like fluorophores and one protein-like fluorophore in both colloidal and dissolved size fractions. DOM in the lake showed marked seasonality with greater production and turnover during the summer season. This study shows that the concentration of humic-like DOM was ~3.5 times lower and less variable than protein-like DOM. The proteinaceous material in the low molecular weight fraction cycled actively in the anaerobic hypolimnetic water during summer, consistent with the contemporaneous dissimilatory reduction of manganese, iron, and sulphur. 
Chapter 5 of this thesis examines the spatial and temporal distribution of trace elements (iron (Fe), manganese (Mn), zinc (Zn), copper(Cu), chromium (Cr), cobalt (Co), nickel (Ni), and cadmium (Cd)) in Lake Ngapouri, and the degree to which binding to colloidal surfaces and DOM influence trace element bioavailability. DGT-lability was thus used as a proxy the available metal for biological uptake. In general, the DGT-labile fraction was much lower than a total load of respective trace metal, indicating the significance of adsorption, precipitation, and complexation reactions for trace metal availability for biological uptake. Broadly, the study groups trace metals into two distinct categories: strongly redox cycled, and controlled by organic complexation. This work shows that colloidal association is often, but not always a predictor of lower bioavailability with important implications for our understanding of metal micronutrients in aquatic systems. 
The contributions from this study are significant for studies of the bioavailability of macro and micronutrients which exhibit strong adsorption behavior. The redox state of lakes affects the formation, complexation character, and stability of various mineral colloids. Colloids clearly should be considered as an important intermediary phase with the potential to affect nutrient availability and with implications for lake restoration and management initiatives.

text: Redox cycling of colloidal macro- and micro-nutrients in a monomictic lake Lakes are more than just water bodies as they play an essential role in the cycling of nutrients and carbon, with impacts at the local and global scale. This study selected Lake Ngapouri, a small monomictic lake in the Waikiti Valley, Taupo Volcanic Zone, New Zealand, which receives a considerable amount of nutrients and organic carbon input from the surrounding pastures. The study was designed to investigate the cycling of nutrients and dissolved organic carbon in lake Ngapouri, with a focus on processes occurring at the colloidal size level under varying thermal and redox conditions. 
To achieve the objectives of the study, a year-long sampling campaign was designed involving field and laboratory measurements of the lake's water column. The lake's physicochemical characteristics were determined via high-resolution depth profiles and paried  with a detailed set of depth-resolved geochemical measurements. Analysis for reduced Fe (II) was used to control for oxidative loss during transportation and storage of samples, and generally demonstrated very good protocols and minimal sample alteration. 
This work comprises a comparison of components in colloidal and dissolved size ranges, determined by ultrafiltration under a zero grade N2 atmosphere, and in situ measurements by diffusive gradients in thin films (DGT). Colloids from the lake were additionally analyzed using transmission electron microscopy (TEM), atomic force microscopy (AFM), fluorescence spectroscopy, and a suite of complementary methods. 
Results show considerable changes in the physicochemical properties of the lake over the hydrological year. Isothermal conditions prevailed through the water column during austral autumn and winter, with thermal stratification becoming established as the summer progressed. Dissolved oxygen concentration followed the thermal pattern, and thus vertically divided the water column into three distinct zones during summer. These zones are referred to as 1) Epilimnion (0-5m measuring from the surface) with uniform thermal and dissolved oxygen concentration, 2) transition zone with varying temperature and dissolved oxygen concentration referred to as metalimnion (6-13m), and 3) hypolimnion (15-20m) marked with cold water and reduced oxygen concentration in comparison to the upper two compartments. The pH of the water column stayed circumneutral during this study. The implications of the lake's variation in thermal and redox status on the cycling of macro and micronutrients are discussed in data chapters.  
The third chapter of this thesis addresses the role of suspended iron hydroxides in phosphorus cycling. The spatial and temporal distribution of iron and phosphorus was clearly coupled and was strongly influenced by sediment releases of both elements in anaerobic bed sediments. Both iron and phosphorus were predominantly colloidal and displayed an increasing degree of lability (to DGT) as hypolimnetic anoxia deepened. The implications of this finding are that iron-based colloids can mediate phosphorus cycling even under anaerobic conditions, and might therefore influence iron and phosphorus bioavailability within the water column. 
The fourth chapter of this thesis explores the evolution, seasonal production, and consumption of dissolved organic matter (DOM) in the water column of Lake Ngapouri. Both the quality and quantity of DOM influence the turnover of DOM in the lake system, and this influence was explored using the constituent molecules' fluorescent properties. The resulting excitation-emission matrices (EEM's) were analyzed using parallel factor analysis (PARAFAC), identifying two humic-like fluorophores and one protein-like fluorophore in both colloidal and dissolved size fractions. DOM in the lake showed marked seasonality with greater production and turnover during the summer season. This study shows that the concentration of humic-like DOM was ~3.5 times lower and less variable than protein-like DOM. The proteinaceous material in the low molecular weight fraction cycled actively in the anaerobic hypolimnetic water during summer, consistent with the contemporaneous dissimilatory reduction of manganese, iron, and sulphur. 
Chapter 5 of this thesis examines the spatial and temporal distribution of trace elements (iron (Fe), manganese (Mn), zinc (Zn), copper(Cu), chromium (Cr), cobalt (Co), nickel (Ni), and cadmium (Cd)) in Lake Ngapouri, and the degree to which binding to colloidal surfaces and DOM influence trace element bioavailability. DGT-lability was thus used as a proxy the available metal for biological uptake. In general, the DGT-labile fraction was much lower than a total load of respective trace metal, indicating the significance of adsorption, precipitation, and complexation reactions for trace metal availability for biological uptake. Broadly, the study groups trace metals into two distinct categories: strongly redox cycled, and controlled by organic complexation. This work shows that colloidal association is often, but not always a predictor of lower bioavailability with important implications for our understanding of metal micronutrients in aquatic systems. 
The contributions from this study are significant for studies of the bioavailability of macro and micronutrients which exhibit strong adsorption behavior. The redox state of lakes affects the formation, complexation character, and stability of various mineral colloids. Colloids clearly should be considered as an important intermediary phase with the potential to affect nutrient availability and with implications for lake restoration and management initiatives.

year: 2022

title: Haumanu Hauora: refining public health institution policy to include Māori and climate change

authors: Masters-Awatere, Bridgette

abstract: The deepening climate crisis generates specific impacts that will exacerbate the already disproportionately negative health outcomes experienced by Indigenous people. Disparate health outcomes have not spontaneously emerged, but rather have been foreshadowed by existing inequities. This article summarizes a sample of the work from a two-year research project in Aotearoa New Zealand to understand existing policy processes and ascertain the extent to which health institutions give serious consideration to climate change impacts on Māori (Indigenous people) with health vulnerabilities. Speaking to tāngata whenua (Indigenous Māori), District Health Board (DHB) employees, and subject matter experts (SMEs), it was clear that policy processes were ad hoc and problematically silenced consistent Māori input. While research participants expressed their experiences of, and aspirations for, dealing with climate change, their voices were not evident in DHB policy development processes. The deficit within existing policy process reflects a lack of preparedness in the face of climate change. Despite clear resilience and adaptation strategies, structural change is needed to address identified disadvantages. Through a co-designed policy framework (“Haumanu Hauora”), we guide policy formation to mitigate climate change risk to Māori (and others). Central to the revised policy framework is the creation of space for both internal and external Māori voices to ensure consistent Māori input throughout the policy process. We also introduce a commissioning, refining, and monitoring stage (that includes evaluation). Haumanu Hauora considers whānau-centered healthcare knowledge, needs, resources, and aspirations, to contribute to a transformed and responsive health system. Above all, we believe that strengthening health institution responsiveness to Māori health needs is essential.

text: Haumanu Hauora: refining public health institution policy to include Māori and climate change The deepening climate crisis generates specific impacts that will exacerbate the already disproportionately negative health outcomes experienced by Indigenous people. Disparate health outcomes have not spontaneously emerged, but rather have been foreshadowed by existing inequities. This article summarizes a sample of the work from a two-year research project in Aotearoa New Zealand to understand existing policy processes and ascertain the extent to which health institutions give serious consideration to climate change impacts on Māori (Indigenous people) with health vulnerabilities. Speaking to tāngata whenua (Indigenous Māori), District Health Board (DHB) employees, and subject matter experts (SMEs), it was clear that policy processes were ad hoc and problematically silenced consistent Māori input. While research participants expressed their experiences of, and aspirations for, dealing with climate change, their voices were not evident in DHB policy development processes. The deficit within existing policy process reflects a lack of preparedness in the face of climate change. Despite clear resilience and adaptation strategies, structural change is needed to address identified disadvantages. Through a co-designed policy framework (“Haumanu Hauora”), we guide policy formation to mitigate climate change risk to Māori (and others). Central to the revised policy framework is the creation of space for both internal and external Māori voices to ensure consistent Māori input throughout the policy process. We also introduce a commissioning, refining, and monitoring stage (that includes evaluation). Haumanu Hauora considers whānau-centered healthcare knowledge, needs, resources, and aspirations, to contribute to a transformed and responsive health system. Above all, we believe that strengthening health institution responsiveness to Māori health needs is essential.

year: 2023-05-05