Marine stressor and receptor interactions: A new approach to incorporate multiple stressor impacts into marine spatial management

Soft sediment benthic ecosystems are highly productive habitats which provide humans with a variety of valued resources and ecosystem services globally. However, coastal environments are subject to ongoing and increasing levels of anthropogenic stress which urgently needs to be quantified and strategically managed to balance socioeconomic resource interests. To support a more holistic approach to Marine Spatial Planning and better inform management decisions, spatial assessment approaches are needed which quantify the accumulating impact of multiple stressors on coastal species and habitats. This thesis investigates stressor-induced change in the density and distribution of subtidal benthic invertebrates from two globally pervasive stressors (sedimentation and bottom fishing), to develop spatial assessment tools useful to inform marine spatial management decisions. For many benthic species, their functional capacity is inherently density-dependent, and environmental stressors can impact population density, hence limiting the functional capacity of species and their ability to contribute to ecosystem processes and overall ecosystem health. A holistic approach to MSP needs to address the ways in which humans can cumulatively use, and also impact the environment, but it is difficult to measure the impact an environmental stressor can cause without first quantifying the current density and distribution of key species that they effect. Furthermore, it can often be challenging to obtain species records measuring abundance, density, or species richness within certain geographical locations, due to data scarcity, even if more data is available over a broader spatial scale. Probability of occurrence, abundance, and density was predicted using Species Distribution Models (SDMs) for seven functionally distinct benthic invertebrates, over two different spatial scales to compare the difference in model performance and usefulness of predictions made using data-rich national scale models compared to data limited regional scale models. Results indicated that neither occurrence nor abundance SDMs performed consistently better at either scale across all taxa models, demonstrating the challenge of working in-data limited environments. Models which achieved the more optimal predictive performance across spatial scales were selected to be combined into a regionally useful density model (i.e., regional data-derived occurrence model * national data-derived abundance model) highlighting the utility of a multi-scalar approach. Knowledge of how multiple stressors impact marine species and modify habitats over time is critical, to support management and mitigation of anthropogenic stressors. Bottom fishing and sedimentation stress are two globally pervasive coastal stressors. The transportation of terrestrially sourced silt, mud, and clay into the coastal environment from inadequate land management can alter sediment biogeochemistry, and alter macrofaunal community composition, which can lead to the smothering of seafloor communities. Bottom fishing can directly damage and disturb seabed habitats, reducing the abundance of macrofaunal communities, and can lead to homogenisation of the seascape. A spatially explicit model including correlative stressor-response relationships were applied to simulate single and multi-stressor impact scenarios over a temporal period of four-years to predict the change in density, distribution, and recovery for different stressor combinations and magnitudes. Models focussed on three functionally distinct coastal seafloor invertebrates that varied in stressor response and recovery time. All taxa exhibited different stressor responses in terms of density change, and the spatial distribution pattern of density values was affected, informed through empirically derived stressor-receptor response curves. The greatest modification to taxa density occurred across the shallow coastal environment, near shore, for habitats that were predicted to have high density to begin with. Fishing was the more dominant stressor and overlapping fishing impact year on year resulted in little to no recovery. For sensitive emergent epifauna (Callyspongia), sedimentation stress was almost as impactful as fishing, highlighting that greater management consideration should be given to the compound effect of slow-acting, accumulating stressors, even in scenarios where a single stressor is more dominant. Failure to adequately identify and mitigate the effects of multiple stressors increases the risk of focussing conservation efforts on areas that could become ecologically diminished in the future. To ensure that global biodiversity conservation targets are upheld under ongoing anthropogenic conditions, practitioners must identify robust and ecologically resilient habitats that will persist over time as part of a systematic prioritization approach. A comparative spatial prioritization assessment was performed to test the utility of using density SDMs that had been modified by stressor impacts (stressor-impacted predictions) to drive a spatial prioritization using Zonation, as opposed to using unimpacted density SDMs (the conventional method). Utilising stressor-impacted predictions within the prioritisation assessment increased conservation efficiency, and thus spatial accuracy, to help prioritise high-density areas that showed resilience to stressor impacts over time (from 4 years of successive stress). This analysis highlighted that conventional prioritization approaches may no longer be sufficient and may prioritise habitats that experience density loss under stressed conditions, undermining conservation effectiveness. Incorporating multiple stressor effects that have accrued over time can help identify areas that are likely to retain a higher total density into the future, to support long-term conservation objectives. Incorporation of spatially explicit stressor effects using taxa stressor impacted density predictions helps identify ecologically rich and resilient habitat areas that persist within the broad footprints of stressors, instead of avoidance, which is often promoted by conventional approaches to minimise conservation cost. Collectively, this thesis demonstrated the utility of novel modelling approaches which integrate the combined and accumulating effects of anthropogenic stressors on coastal species and habitats to help inform MSP decision-making. It also highlighted the range of possible implications to benthic species and coastal ecosystems if anthropogenic stressors are not adequately identified and managed

Scale locality of the energy cascade in magnetohydrodynamics

Turbulence behaves differently in electrically charged fluids, such as plasmas, due to the turbulent motions being accompanied by magnetic field influences. This thesis looks at how the magnetic field in these fluids impacts energy transferred from large scales to small scales—the energy cascade—by analyzing data from numerical simulations of turbulence. We will be following Doan et al's approach of decomposing the fluctuations into large-scale and small-scale contributions using bandpass filtering, then plotting the flux of the energy and enstrophy in 2D and 3D magnetohydrodynamics. This will help quantify various aspects of the energy cascade, including the degree of scale-locality. The results will be compared to those from Doan et al's analysis of non-electrically charged fluids

Eighteenth-century solo soprano cantatas: A study of Christoph Graupner’s (1683-1760) style and contribution to this genre

The Baroque composer Christoph Graupner (1683-1760) worked as the Kapellmeister for the Hesse-Darmstadt court from 1709 to his death in 1760. A prolific composer of several genres of music, including operas, concertos, sinfonias and many other instrumental works, Graupner wrote over 1,400 sacred cantatas for use in the court chapel’s weekly services. In this study I will examine a small, but significant, segment of Graupner’s cantata oeuvre; the forty-eight solo soprano cantatas. The purpose of this study is to examine Graupner’s compositional techniques for these cantatas and to report on his progressive style, particularly in regards to stile galant. Using John White’s methodology, a detailed musical analysis of thirteen solo soprano cantatas is given in chapters two and three, along with broader structural and stylistic analysis of all forty-eight solo soprano cantatas. Chapter three also highlights the instrumentation of several solo soprano arias within selected SATB chorus cantatas. Chapter four considers the six sopranos employed during Graupner’s tenure and examines the tessitura and range of a selection of cantatas. Chapter four also investigates the role of the basso continuo in solo soprano cantatas and the influence of opera on Graupner’s cantata compositional style. Chapter five details the performative considerations for the thirteen solo soprano cantatas presented over four public recitals during this study. Performance methodology by Sarah Fuller, Brad Haseman, and Margaret Kartomi is employed in order to reflect on the aspects of both listening and performing the music of Graupner, in a modern twenty-first century setting

Role of Seasonal Melt Streams in Heavy Metal and Nutrient Transport from an Antarctic Penguin Colony

Despite the perception that Antarctica is pristine, concentrations of heavy metals and persistent organic pollutants have been recorded at increasing levels. Heavy metals may be present within the Antarctic terrestrial environment through natural geologic processes, long-range atmospheric transport, anthropogenic point sources, and biological transport. While the biological transport of contaminants remains frequently overlooked, in the Arctic, it has been shown to rival atmospheric fluxes of contaminants. Adélie penguins are known vectors for transporting heavy metals and nutrients from within the marine environment and depositing them on the land through guano, feathers, eggshells, and whole carcasses. The incorporation of this material in deep ornithogenic soils has resulted in Adélie penguin colonies being identified as sites of heavy metal and nutrient accumulation. Despite seasonal glacial melt streams that erode these colony soils, their role in heavy metal and nutrient transport is largely under-researched. Therefore, this study evaluated the redistribution of heavy metals and nutrients via melt streams. Stream discharge and load, in addition to soil heavy metal and nutrient content, were also assessed. Five sites along two streams, one flowing through an Adélie penguin colony (P1 to P5) and a control stream with no penguin influence (C1 to C5), were compared throughout this research. Melt water within the Adélie penguin colony had elevated arsenic, cadmium, and lead (p<0.05), with total heavy metal concentrations exceeding New Zealand freshwater guidelines for ecological health up to 37, eight, and two times, respectively. Cadmium and lead were found mostly in particulate form (dissolved cadmium <22 % and dissolved lead <11 %), however, there was a relatively higher portion of arsenic (up to 72 %) that was dissolved (<45 m). This indicates increased bioavailability and concern for toxicity of arsenic. Nutrient anions (ammonium, nitrate, and phosphate) were also elevated in penguin-influenced water compared to the control stream (p<0.05), surpassing water quality guidelines up to 1038, 1017, and 551 times. When accounting for differences in discharge, stream loads of heavy metals and nutrients were significantly higher within the Adélie penguin colony (p<0.05), with nitrate and phosphate exhibiting the most prominent differences (p<0.01). In both streams, discharge exhibited large fluctuations on both diurnal and daily time scales (P3 16.7 L s-1 to 53.3 L s-1; C3 10.8 L s-1 to 14.7 L s-1) and was correlated strongly with air temperature (P3 R=0.88, C3 R=0.81). The pH of all stream sites was circumneutral to basic (6.86 to 8.07). This research suggests that seasonal melt streams play a critical role in redistributing potentially toxic levels of heavy metals and nutrients from penguin colonies into the Southern Ocean. Ornithogenic soil samples from the penguin colony had up to 27, 71, and six times higher arsenic, cadmium, and lead compared to two sampled control soils (p<0.05). Ammonium, total nitrogen, and total carbon were also significantly more enriched with up to 5727, 2454, and 484 times higher concentrations than the control soils (p<0.05). These enrichments were particularly significant with the upper 44 cm. Concentrations of arsenic in the topsoil (0 - 2 cm) and cadmium at soil depths 0 – 44 cm were present in concentrations that exceeded the Canadian ecological quality guidelines for soil. The pH of all soils was neutral to basic (7.78 to 9.86) reflecting the basic basalt parent material. These findings support previous research that ornithogenic soils are sites of heavy metal and nutrient accumulation. Given the fluctuating nature of melt streams, both daily and seasonally, results are likely to be variable over longer time scales and therefore, more research is suggested to quantify this. Moreover, climate change disproportionately affects polar regions with expected temperature rises. Thus, understanding how melt streams intensify in flow, duration, and transport capacity is an essential area of investigation, to which this research provides important baseline data

Self-decolonisation in Aotearoa: Pushing through programmatic Pākehā paralysis

Te reo, tīkanga, mātauranga, te Ao, and kaupapa Māori are finally seeing a resurgence in Aotearoa. This revitalisation is occurring in the tertiary education sector, but staff and skill deficits are holding back many academic disciplines. This chapter documents the challenges facing a traditionally colonial tertiary programme—philosophy— attempting to de-colonise itself. The overlapping nature of the challenges can make decolonising appear to be so difficult that some programmes may feel paralysed. This chapter argues that the importance of decolonisation requires that programmes push through any paralysis they may be experiencing by prioritising decolonisation above other goals

Exploring the symbiosis and tensions between vocational practices and the aspirations for vocational education and training in Aotearoa New Zealand

Vocational Education and Training (VET) is recognised as a key to social, ecological and economic transformation, pertinent given the urgency for societies to transition to more socially just and environmentally sustainable forms of human development, what has been termed a “just transition”. As such, a key policy aspiration is to improve the relevance of VET to support individuals and communities and meet the anticipated demands of diverse stakeholder groups through these transitions. In the Aotearoa New Zealand VET context, these principles have been reflected in the recent Reform of Vocational Education (RoVE) and signalled in the Government’s social development and climate response policies. Yet VET research is replete with enduring examples of VET’s failures based on a narrow conception of training people for skills for work rather than how VET contributes to the full range of human capabilities and flourishing. Therefore, a reimagining of VET is required however what this might look like is theoretically under development while the narrow conceptions endure. Contributing to this reimagining, this investigation argued a practice-theoretical approach to VET research using the Theory of Practice Architectures provides opportunities to explore the conditions of possibility inherent in vocational practices as the sites where transformations occur. To achieve this, a qualitative, ethnographic case study of the vocation of beekeeping in a workand study-based context was undertaken. Using a hybrid approach to participant observation/observant participation, unstructured interviews and a review of historical materials on beekeeping, a complex array of beekeeping practices was generated and thematised. This provided the empirical resources to explore the rich complexity of beekeeping practices, to identify notions of relevance from these perspectives of practice, and analyse the symbiosis or tensions between them against a review of New Zealand’s current suite of apiculture qualifications and programmes as a part of New Zealand’s recent reforms and aspirations to meet just transitions objectives through a relevant VET system. The findings located tensions between the strategic industry focuses and projects of production in the qualifications against the affective dimensions and projects of productivity for care that describes the unique beekeeping practice traditions of human-bee relations. This further implicated how the qualifications and programmes were relevant to the needs of learners and employers and illuminated why disparate experiences between training and work manifest. Further, these tensions highlighted how VET can change the practice landscape of beekeeping practices in ways that consolidate this industry focus. However, by making these tensions visible, transformative possibilities inherent in new meanings of VET and the traditions of vocational practices themselves were identified. This supports the use of a practice-theoretical approach to contribute to a range of theoretical, strategic and practical endeavours in VET research, policy and practice, further backgrounding opportunities for practice-based research to define transformational trajectories for vocational practices and VET moving forward

Debate on ultra-processed foods shouldn’t derail good dietary advice

Evidence is mounting linking ultra-processed foods (UPF) to risk of chronic disease. Typically, UPF are foods that are energy-dense, high in fat, sugar and salt, low in fibre and with a long shelf life. Examples include biscuits, chips, candy, instant noodles, mass-produced bread, sweetened breakfast cereals, ready-to-eat meals and reconstituted meats. Dietary recommendations encourage people to eat foods that are ‘whole’ or less processed. This can be a challenge when our food environments and food supply systems are dominated by UPF. Categorising foods according to the type and extent of processing can help us understand the healthfulness of individual foods, diets and the food supply system. However, we must still consider the nutritional value, affordability, accessibility, sustainability and cultural acceptability of foods. And in some cases, foods classified as UFP may still be a component of a well-balanced dietary intake —for example, wholegrain bread. While acknowledging this tension on the margins, there remains a strong case for promoting the consumption of fruits, vegetables, wholegrain and minimally processed foods

Consequences of shellfish die-offs on seafloor biodiversity

Coastal soft sediment habitats contain highly productive benthic communities that provide numerous ecological services. Many of these functions, processes and services are underpinned by the behaviour, density and diversity of the resident macrofaunal community. Climate change has caused heat waves to become more regular and extreme, causing die-off’s of functionally important shellfish beds, potentially generating large shifts in benthic community structure and functioning. Recent studies of the New Zealand intertidal cockle (Austrovenus stutchburyi) dieoff events have focused on cockle population recovery, but there is very little understanding of how the rest of the macrofaunal community responds. To understand how the macrofaunal communities respond to cockle-die offs, a manipulative experiment was undertaken at 23 sites in four estuaries on the northeast coast of the North Island. In late summer, at each site we established a 9m2 control and 9m2 exclusion plot. One year later, we sampled all plots for macrofauna and sediment properties. Results indicate a strong relationship between treatment type and community composition, with none of the exclusion treatments returning to predisturbance community compositions. Furthermore, that recovery was largely estuary specific and community composition following disturbance was highly variable within exclusion treatments. Statistical analysis highlighted that exposure to high intensity wind-wave activity and polychaete dominance within estuaries could explain the relatively improved recovery of Ongare sites within Tauranga harbour. Additionally, there are observable variations in cockle recruitment between sites for both adults and juveniles. This experiment explores whether the removal of cockles, as key habitat forming species, selects for a different macrofaunal community type. The observed changes in community structure can be linked to shifts in ecosystem functioning in these soft sediment habitats

The evolution of tidal coastal landscapes and the controls on pathways to equilibrium

The evolution of tidal basins is fundamental to understanding the drivers of our vulnerable estuarine and lagoon environments, ultimately determining key ecological parameters such as intertidal area, inundation regime, connectivity and accommodation space. This thesis uses multiple methods including idealized modelling, field observation of an estuarine shoal covered with mangroves, and a calibrated and validated model with field data in order to explore how different components of tidal environments influence the short and long-term dynamics of tidal lagoons. The idealised modelling specifically focused on the roles of initial bathymetry, bed sediment and mud concentration at open boundaries on shaping equilibrium profile development of tidal basins. The results of the model showed that geomorphological development (long-term evolution) is similar in sandy environments with different initial bathymetries and without a mud supply. This was concluded because the equilibrium profiles and tidal asymmetries evolved similarly at the end of simulations. However, residence time, development of channels and energy dissipation were observed to be different. In the case of available incoming mud from open boundaries, equilibrium bathymetry was dominated by the mud supply and sediments accreted all over the domain, forming a mudflat and a deeply incised ebb-dominated channel, with several minor side channels of which their size and number were dependent on mud concentration. The response of tidal environments to sea-level rise has been previously studied often by neglecting the importance of initial configuration in the model. In such process-based modelling, different initial bathymetries are only considered to influence the time to reach a stable equilibrium condition but will always lead to identical equilibrium bathymetry. Here we demonstrated that initial profile not only affects some aspects of tidal basins such as channel formation, residence time and energy dissipation in equilibrium condition, but also impacts their geomorphological development under sea-level rise. In the northern North Island of Aotearoa New Zealand, tidal environment evolution is mediated by mangroves. The governing dynamics on a recently evolving estuarine, mangrove-covered channel-shoal system in Whitianga Estuary, Aotearoa New Zealand. Observations of water level, flow velocity, suspended sediment concentration and bed sediment characteristics were used to infer flow asymmetry and sediment transport pathways around the shoal. The impact of mangrove colonization on channel dynamics, sediment texture of upper layer and mud layer thickness was studied by a one-week field campaign. Due to changes in land use, the estuary was subjected to an increase in sediment supply, causing the tidal flats to elevate and provided suitable conditions for the expansion of mangroves in 1940s. By the use of historical images, the expansion of mangroves in Whitianga Estuary was captured and the results were combined with the measured data of water level, current and sediment dynamics in order to explore the short-term dynamics around the shoal and the role of vegetation as eco-engineers in inter-tidal environments. The shoal expanded laterally independent of mangrove colonization. However, observed mud layer thickness was larger around mangroves compared to un-vegetated parts of the shoal. The mangrove creek (which was a shoal channel before expansion of mangroves) was consistently ebb-dominated and the shoal channel located outside the forest on the edge of the shoal was flood-dominated. The results suggested that mangroves impose a control on their surrounding environment and can ultimately lead to a regime shift in channels and changes in sediment texture. The understanding provided by the field observations was confirmed with a 2-D numerical model, developed in the Delft3D modelling system, which was calibrated and validated with the data collected from the field. This model was used to study the short-term influence of mangroves and tidal creeks on tidal circulation and large-scale tidal asymmetry. The results showed that the effect of vegetation on tidal asymmetry and flow routing was larger compared that of the tidal creeks. However, the small impact of the channels may be due to the small size of the creeks compared to the size of the forest. When vegetation was removed, tidal velocity asymmetry changed substantially whereas channel infilling caused a shift in tidal asymmetry inside the creeks and around the head of the creeks mostly (from being ebb-dominated to flood-dominated). Removing vegetation led to an increase in speed all over the forest except inside the creeks and elevated parts of the forest where velocity decreased. In a scenario in which channels were filled in, currents became weaker in the location of the creeks and velocity increased around the creeks and on the edge of the forest. Furthermore, a scenario was designed in which morphology of the shoal in the 1940s prior to expansion of mangroves was simulated, aiming to quantify the hypothesis posed by field measurement with numerical models. The results of the model demonstrated that mangrove colonization caused a regime shift in the channels, showing that as mangroves colonize inter-tidal areas, they play a critical role in shaping the geomorphology. In Whitianga Estuary, expansion of mangroves around changed a flood-dominated pre-existing shoal channel to an ebb-dominated mangrove creek, suggesting that mangroves are likely to be eco-engineers of the estuarine system. The idealized modelling experiments helped identifying the parameters and elements that govern the long-term morphology and equilibrium of coastal tide-dominated environments and the way they respond to sea-level rise force. Results of this theoretical exploration showed that processes localised, and timescales for equilibrium development vary vastly across the landscape. Elucidating local changing to asymmetry became the focus of subsequent chapters, firstly with a field exploration, and then supported by numerical modelling. The fieldwork presented here elucidated the short-term hydrodynamics and suspended sediment dynamics in an estuarine shoal covered with mangroves. Moreover, observation of aerial images in a multi-decadal timescale combined with hydrodynamics inside a mangrove creek and a shoal channel highlighted the complex non-linear interactions of hydrodynamics and vegetation that lead to a regime shift of a channels in the mangrove forest in Whitianga Estuary, Aotearoa New Zealand. Finally, the results of the numerical model developed and validated by utilizing field data presented here provided insights into the detailed short-term hydrodynamics. Moreover, the scenarios designed by removing channels, vegetation and reconstructing the condition prior to mangrove expansion showed that the effect of vegetation extends beyond the footprint of the vegetation to the surrounding environment with implications for hydrodynamics, morphological evolution and channel dynamics