Minerva Elements Records
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ItemQuantifying the impact of climate variability and change on groundwater( 2023-04)Climate change is projected to impact groundwater but the projections are highly uncertain. Quantifying the historic impact allows for an improved understanding of the response of groundwater, but has been rarely examined due to the confounding influence of multiple drivers, such as pumping for agricultural irrigation and land use changes. This thesis aims to contribute to understanding and quantifying the historic impact of climate variability and change on groundwater through three interconnected research questions (RQs): RQ1: How sensitive is the unconfined groundwater level and recharge to climate variations across Australia? RQ2: How much of the observed groundwater level change is attributable to anthropogenic climate change in Australia and when did this impact emerge? RQ3: How has and will the long-term climate variability and change impact the groundwater discharge (low, mean, and high flows) at the large karst catchment (snow-influenced, temperate climate) in central Europe? The RQ1 was examined by quantifying the groundwater level and recharge sensitivity to climate variations in Australia. A total of 4350 sites were first modelled with a time-series groundwater toolbox HydroSight, and 1143 (26%) were identified as climate-dominated sites. A multiple linear regression approach, adapted from streamflow elasticity studies, was then adopted to quantify the groundwater sensitivity. Results show that the groundwater level and recharge are around 8 times more sensitive to precipitation than potential evapotranspiration changes. The inherent properties of the sites, such as climate type and hydrogeology, appear to play an important role in controlling groundwater sensitivity. The RQ2 was examined by detecting and attributing historic groundwater level changes to anthropogenic climate change in Australia. A modelling experiment was performed at the climate-dominated sites to simulate groundwater level changes in both factual and counterfactual (natural) worlds with and without human impact. Results show that 90% of the sites have experienced significant groundwater depletion attributable to anthropogenic climate change at least as early as the 1950s. Southwestern Australia has experienced the most severe depletion which is 4 times higher than the national median rate (-74 cf. -19 mm/yr). These findings are among the first to show that groundwater has already been under the prolonged adverse impact of anthropogenic climate change. The RQ3 was addressed by quantifying the response of groundwater discharge to climate variability and change at a snow-influenced temperate karst catchment (Blautopf) in southern Germany between 1952 and 2100. Statistical measures and conceptual modelling approaches were adopted in this study to quantify the long-term impact. Results show that the changes of annual mean and low discharge were not significant, but the annual peak discharge has shifted towards a low state (< 13.6 m3/s) due to less intense peak snowmelt. Despite non-significant historic changes, all high, low, and mean flows are projected to decline by 2100. These findings may suggest potential water scarcity risks at similar climatic and geologic settings. Quantifying the historic impact of climate variability and change on groundwater contributes to an improved understanding of the groundwater systems and increases confidence in the predictions. Only when we understand the past, may we make better projections for the future.
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ItemThe political economy of international climate finance: Justice, adaptation, and the Green Climate Fund( 2022)In 2010, negotiators at the United Nations climate conference committed to raising $100bn/year for climate action in developing countries, with the intention that much of this be allocated by the newly established Green Climate Fund (GCF). A key goal for the GCF was to advance climate justice, including by allocating its funding evenly between climate change adaptation and mitigation, and by giving greater control over climate finance to developing countries. This thesis investigates the first decade of the GCF’s (adaptation) practices – its design, operation, and financial allocations – to understand the extent to which they advance climate justice. It does this by drawing on interviews with key stakeholders, document analysis, and observations of GCF Board meetings. Three Phases of the GCF’s history are identified and examined in turn: the Design Phase, from late 2010 through to the end of the tenth Board meeting; the Initial Implementation Phase, starting when the Fund began allocating money at the eleventh Board meeting through to the twenty-first meeting; and the Consolidation Phase, which began with the twenty-second Board meeting through to the twenty-sixth meeting in late 2020. This thesis applies a political-economic analytical framework that focuses on the roles of ideas, interests, and institutions (‘3Is’) to each of these Phases to reveal the ideas, interests, and institutions involved in the GCF’s adaptation practices and to trace their influence over the history of the GCF. The justice implications of these practices are then analysed in terms of Nancy Fraser’s trivalent justice model, which includes three interrelated elements: recognition, or (equal) social and cultural standing; redistribution, or the (just) distribution of goods and resources; and representation, or who is included and excluded from discussions of recognition and redistribution. This thesis finds that i) the misrecognition of developing countries and civil society at the GCF leads to the de-prioritisation of the issues of most importance to these groups; ii) the GCF's portfolio has yet to be able to achieve just redistribution; and iii) the equal number of developed and developing country Board members has not led to the equal representation of developed and developing country interests at the GCF, compounding the inadequate recognition of developing countries. These findings reflect the way that key actors (including developed countries and the large development agencies and banks) have been able to influence the Fund’s design and operation such that its portfolio reflects their interests, with significant ramifications for climate justice. Because of the ambiguities built into the Fund’s design, potential exists for the GCF to rectify this course toward a more just set of processes and outcomes. However, given many of the ideas and interests shared by developed countries and international entities have been institutionalised into its practices and processes through its original design and its ongoing operation, it seems unlikely that the GCF will change, and so it seems unlikely that it will be an effective mechanism for advancing climate justice.
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ItemExploring the indirect effects of climate change on fire activity in Australian wet Eucalypt forests( 2022)Understanding the impacts of climate change on future fire activity is critical for assessing the risks posed to biodiversity and communities. However, the mechanisms through which climate change may influence fire activity are varied. In temperate forests, climate change is expected to directly increase fire activity through elevated temperatures and more variable rainfall, resulting in weather conditions conducive to large fire events. However, climate change may indirectly influence fire activity through effects on forest structure and composition. While the direct effects of climate change are well studied, indirect mechanisms are poorly understood. These mechanisms are important because changes to vegetation structure and composition have the potential to amplify or dampen the direct effects of climate change on fire activity through their effects on fuels, particularly dead fuel moisture content (FMC). Forest structure and composition moderate microclimate conditions compared to the open, which is an important factor affecting the moisture content of understorey fuels. FMC is a key determinant of fire activity, particularly in wet Eucalypt forests with high biomass loads. However, our understanding of the magnitude of forest structure and composition effects on microclimate and subsequently FMC dynamics, is a critical knowledge gap in our understanding of climate change effects on future fire activity more broadly. In this thesis, I aimed to quantify the potential for indirect effects of climate change to influence fire activity, through their influence on dead FMC in the wet Eucalypt forests of south-eastern (SE) Australia. In these forests, recurrent high-intensity fire has altered vegetation structure and composition, resulting in a range of alternative forest states to the dominant wet Eucalypt system. To quantify the magnitude of these on potential fire activity, seven alternative forest states and two adjacent open weather stations were instrumented with automated fuel moisture sticks and micrometeorological sensors. FMC and microclimate were measured over a 2-year observation period, and lidar data were used to evaluate the role of forest structure in FMC dynamics. I used a process-based fuel moisture stick model to quantify the relative importance of forest structure effects on microclimate to FMC variability. This model was then used in conjunction with new methods to estimate microclimate from open conditions, and a 48-year climate dataset to model FMC at alternative forest states across the range of climate conditions characteristic to the region. I also evaluated the potential contribution of live species to changes in fuel moisture in a conifer forest and related this to the potential impacts of forest conversion to alternative states. Overall, I found significant differences in dead FMC across alternative forest states, with potentially meaningful implications for fire activity. The sensitivity of FMC to forest structure was examined, with longwave radiation and vapor pressure deficit emerging as key drivers of FMC variability related to structural change. These findings informed the modelling process, where results indicated that differences in FMC related to alternative forest state were greater than the direct effects of climate change (modelled at an open reference site), indicating strong positive and negative feedback processes in this system. Overall, my results suggest that the indirect effects of climate change on potential fire activity are meaningful for fire management, exceeding the role of direct effects in the context of FMC. Consequently, the potential for forests to convert to alternative states is a key issue for land and fire managers.
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ItemThe ‘durability challenge’ for climate change policy: a comparative analysis of carbon pricing in Australia and British Columbia( 2022)While climate change poses a major threat to humanity, policymakers have struggled to enact policy responses capable of addressing it. Some policy instruments have been implemented only to be repealed, creating a ‘durability challenge’ for governments seeking to address climate change. In light of this challenge, this thesis asks: which government strategies are most likely to embed new climate policies so that they can persist long enough to produce the desired effects? Policy durability has received less scholarly attention than policy enactment. Some scholars emphasise the strategic management of stakeholders and interest groups to promote durability (Patashnik 2008), while alternative explanations highlight the importance of securing broad public acceptance for the reform, including by persuasive communication from political leaders. There is not yet enough empirical research to provide clear answers. Accordingly, this thesis presents a comparative study of two carbon pricing reforms, one of which was successful (the policy proved durable), and the other not (the policy was not durable); this approach approximates J. S. Mill’s Most Similar Systems Design. The durable case is the carbon tax implemented in British Columbia (BC), Canada, in 2008, which remains in place, while the non-durable case is Australia’s Carbon Pricing Mechanism, sometimes called ‘the carbon tax’, implemented in 2012 and repealed two years later. The cases are compared to analyse the government strategies that promote policy durability, with BC’s successful trajectory throwing the problems in the Australian case into relief. This study finds that the strategic management of interest groups is not enough to secure policy durability, nor is sophisticated policy design a sufficient condition, particularly if the policymakers stumble on the politics. Instead, the thesis finds that policymakers should focus, above all, on securing broad public acceptance of the reform. These findings challenge the assumption that durability strategies can be activated upon policy implementation (Patashnik 2008), concluding instead that policy durability is highly sensitive to the conditions of enactment. This thesis also challenges the applicability of general studies of policy durability to Westminster-derived jurisdictions, with the political party system, and the ideological orientation of the governing party, proving highly consequential in the two cases here. A key finding of this study is that Right-aligned political parties have a much greater chance of implementing durable climate policies than Left-aligned parties in Westminster political systems.
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ItemDynamics of a flammable species in a forest landscape: A case study on forest wiregrass Tetrarrhena juncea R.Br.( 2022)Species abundance often determines the extent of influence of a species to ecosystem function and processes. Typically, the abundance of a species is constrained by environmental factors within its habitat. However, there are instances where native species becomes prolific and the shift in abundance greatly impacts the ecosystem. Such is the case when a flammable species becomes prolific within its range and alters the flammability of the ecosystem. This is a concern with climate change, as conditions might be tipped in favour of such species. Hence, it is crucial to understand the drivers of abundance to understand how native species can be released from environmental constraints of abundance to become prolific within their own range, and to predict the potential effect of changing environmental conditions on their abundance. Thus, the overarching aim of this thesis was to understand how a flammable native species can become prolific within its own range. This is achieved using a case study species – forest wiregrass Tetrarrhena juncea R.Br. (hereafter wiregrass) – an understorey native species that is of high importance to flammability in the eucalypts forests of south-eastern Australia and grows prolifically under certain conditions. The overarching aim of the thesis was addressed using a mix of research methods to identify the key drivers of wiregrass distribution and abundance. Firstly, a database of the current distribution for wiregrass were analysed using species distribution modelling to identify highly suitable habitat for wiregrass (Chapter 2). Temperature seasonality, precipitation of the driest month, rainfall seasonality, annual mean temperature, the minimum temperature of the coldest month and soil pH were strongly associated with the suitable habitat of wiregrass. The high importance of climatic factors indicates the distribution of wiregrass may be sensitive to climate change. Highly suitable habitats do not necessarily harbor abundant wiregrass because site-specific factors can also control abundance. Hence, Chapter 3 sought to identify the factors most important to wiregrass abundance in the highly suitable habitat of Mountain Ash-dominated forest. Wiregrass cover was assessed in a field survey across a chrono-sequence of 126 sites with contrasting disturbance histories. Canopy cover and net solar radiation were the most important predictors of wiregrass abundance, with wiregrass cover highest in recently disturbed areas with sparse canopy cover, high light levels, and low precipitation. The final component of the thesis used a glasshouse experiment to quantify causal links between resource availability and wiregrass abundance. Wiregrass growth was more sensitive to water availability than light, whereas biomass allocation and leaf morphology were more sensitive to light availability. Collectively, the results showed that, where wiregrass is present (distribution), three key conditions will greatly favour its prolific growth (abundance): (i) non-limiting water resource; (ii) reduced canopy cover and increased light; and (iii) recent disturbance. These key results strongly suggest wiregrass can become prolific when resources are increased, and the vegetation community is substantially disturbed. Under such conditions, increased wiregrass abundance could create a window of increased flammability for the forest ecosystem. Since climate change can alter resource availability and disturbance regime, shifts in wiregrass abundance are likely to occur under future climate scenarios.
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ItemPredicting future fire regimes and the implications for biodiversity in temperate forest ecosystems( 2022)Fire regimes are changing around the world. Fire seasons are lengthening, high severity fires are occurring more often and in unexpected places. Relationships among fire, climate, and vegetation are varied, dynamic, and under-examined in many ecosystems. While some studies have explored links between fire, climate, and vegetation such as species distributions or future fire weather under changing climate, relatively few have considered the dynamic interactions among all three simultaneously. In this thesis, I develop and apply modelling approaches to predict future fire regimes in south-eastern Australia and explore the implications for fire-responsive functional plant types. In the first quantitative chapter of my thesis (Chapter 2), I develop a new fuel model for south-eastern Australia. I use edaphic, climatic, and fire variables to build a predictive fuel model that is independent of vegetation classes and their future distributions. In Chapter 3, I use my fuel model in a landscape fire regime simulator, alongside multiple predictions of future climate, to examine the immaturity risk to an obligate seeder tree species (Eucalyptus delegatensis). My simulations indicate that this species will be under increased immaturity risk under future fire regimes, particularly for those stands located on the periphery of the current distribution, closer to roads or surrounded by a drier landscape at lower elevations. In Chapter 4, I expand the application of the above simulation approach to examine the relative importance of future fuel and future climate to changing fire regimes in six case study areas across temperate south-eastern Australia. My results indicate that the direct influence of climate on fire weather will be the principal driver of changes in future fire regimes (most commonly involving increased extent, decreased intervals, and an earlier start to the fire season). The indirect influence of climate on vegetation and therefore fuel was also important, acting synergistically or antagonistically with weather depending on the area and the fire regime attribute. Finally, in my fifth chapter, I consider future climate and fire impacts on plant persistence by combining the landscape fire regime simulator with spatially explicit population viability analyses. Obligate seeder species were at risk of population extinction or reduction in more simulation scenarios than facultative resprouters. However, my approach highlighted that the resilience of facultative resprouters might also be tested by climate related changes in demographic processes and fire regimes. Overall, my research has provided new methods and scientific insights into the changing nature of fire regimes in temperate south-eastern Australia. Some negative impacts on biodiversity from a changing fire regime, particularly on more vulnerable plant functional types like obligate seeders, appear inevitable. Further understanding of the complex interactions among fire, climate, and vegetation will enable improved integration of risks to people, property, and biodiversity into land and fire management planning.
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ItemFinding the hidden smoke: Exploring the use of digital technologies for assessing grapevine smoke contamination and taint in grapes and wine( 2021)Grapevine smoke contamination and the subsequent development of smoke taint in wine has resulted in significant financial losses for winemakers throughout the world. Unfortunately, the incidence of grapevine smoke exposure is expected to rise as the number and intensity of wildfires increase due to the effects of climate change. Wines produced from smoke affected grapes are characterised by unpleasant smoky aromas, rendering them unpalatable and therefore unprofitable. Traditionally, chromatographic techniques such as gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) have been used for assessing the levels of smoke-derived volatile phenols and their glycoconjugates in grapes and wine. However, these methods are time consuming, expensive and require destructive sample preparation as well as the use of trained personnel. Furthermore, sensory evaluation of wine samples using human panels may be subject to bias due to individual variability of the participants, as well as being expensive and time consuming as large groups of participants must be recruited and trained. In addition to this, a number of methods have been identified for ameliorating smoke taint in wine such as the use of activated carbon and reverse osmosis. While effective at reducing levels of volatile phenols for smoke taint amelioration, they are unable to act on glycoconjugates, and therefore a gradual resurgence of smoky aromas may arise as these glycoconjugates are hydrolysed back into their free active forms over time. This research therefore investigated alternative methods for assessing the degree of grapevine smoke exposure and the level of smoke taint in wine using digital technologies coupled with machine learning (ML) modelling based on artificial neural networks (ANN), and whether the use of a cleaving enzyme prior to the addition of activated carbon could be effective at ameliorating smoke taint in wine. Near-infrared (NIR) spectroscopy was used to obtain a chemical fingerprint of grape berries, leaves, must and wine. These readings were then used as inputs to develop ANN models that showed high accuracy in the classification of berries and leaves according to the level of smoke exposure and degree of taint (97% – 98%), as well as predicting the levels of smoke-derived volatile phenols and their glycoconjugates in grapes, must and wine (R = 0.98 – 0.99). Additionally, models predicting consumer responses towards smoke tainted wines using NIR berry and wine spectral readings were created which displayed high accuracy in their predictive abilities (R = 0.97 – 0.98). The results demonstrated that NIR spectroscopy coupled with ML modelling can provide accurate, rapid and non-destructive tools for assessing grapevine smoke contamination and smoke taint in wine, in addition to predicting the sensory responses of consumers towards smoke tainted wines. Furthermore, the models developed can be used together to form an integrated smoke taint detection system that growers and winemakers can use in-field or in the winery to assess grapes and wine. A low-cost electronic nose (E-nose) was used to assess the aroma potential of smoke-tainted wines. Readings from the e-nose were used as inputs to develop ML models that showed high accuracy in predicting the levels of eight volatile aromatic compounds in wine (R = 0.99), the degree of smoke aroma intensity (R = 0.97). These two models may be used together with previously developed models that predict the levels of smoke-derived volatile phenols and their glycoconjugates and 12 wine descriptors to provide winemakers with a greater picture of the degree of smoke taint and the aroma profiles of smoke-tainted wines. In addition to this, the use of a cleaving enzyme (ZIMAROM, Enologica Vason) prior to treatment with activated carbon was found to be effective in ameliorating smoke taint and may help delay the resurgence of smoky aromas by hydrolysing glycoconjugates into their free volatile phenol forms which can then be removed by the addition of activated carbon. An ANN model displaying high accuracy (98%) was also developed using the readings from the e-nose to classify wine samples according to the type of smoke-taint amelioration treatment applied to assess their effectiveness. The model may offer winemakers a cost-effective, non-destructive, rapid, and accurate tool to assess the effectiveness of smoke taint amelioration treatment by activated carbon with/without the addition of a cleaving enzyme.
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ItemPro-attitudinal advocacy, depolarization, and communicative intentions: The role of self-persuasion( 2020)In the currently fractured attitudinal landscape, many people hold extreme attitudes on important socio-political issues and frequently advocate for their attitudes. As a result of advocating for one’s own attitudes, i.e., engaging in pro-attitudinal advocacy, people may unconsciously persuade themselves (i.e. self-persuade) to polarize further. Moreover, pro- attitudinal advocacy may lead to an unwillingness to engage with those on the opposite side of the attitude spectrum. Such processes may explain polarization in our electorates over time. Given that polarization leads to disrupted social cohesion, a critical question is how we might depolarize attitudes, and encourage open communication. In this thesis, I sought to examine a candidate mechanism of depolarization: self-persuasion. More specifically, this thesis explored self-persuasion occurring during pro-attitudinal advocacy as a way of a) depolarizing attitudes and b) opening up communicative practices in ways that encourage advocates to display open communicative intentions (e.g. willingness to engage with dissimilar others). Across seven studies, participants (N = 1946) were asked to engage in online advocacy to justify their attitudes towards contemporary socio-political and moral issues, such as migration and climate-change. I explored specific factors relevant to pro- attitudinal advocacy, including meta-cognitive confidence (confidence in one’s thoughts and arguments), advocacy framing (moral versus practical framing), and style of advocacy (defending one’s position versus attacking the opposing position). Results indicate that a) low meta-cognitive confidence in one’s advocacy attempt predicts attitude depolarization and greater receptiveness to opposing views, especially if one enjoys effortful cognitive activity (Studies 1 and 2), b) compared to moral justifications, using practical justifications to support one’s attitude predicts attitude depolarization and lower intentions to proselytize, via lower expression of moral language (Studies 3-5), and c) compared to defending one’s position, attacking the opposing position predicts more open communicative practices, such as seeking attitude-inconsistent information, via heightened motivation to hold accurate worldviews (i.e. accuracy motivation; Studies 6 and 7). Interestingly, our findings suggest that although attitudes sometimes depolarize, depolarization is not a necessary pre-requisite for open communicative intentions, such as seeking attitude-inconsistent information. This suggests that pro-attitudinal advocacy may influence behavior, even if attitudes remain unchanged. Further, in addition to self-persuasion, we find other mechanisms, such as, message content and accuracy motivation, which may predict depolarization and increase open communicative practices. We find evidence to suggest that re-framing advocacy attempts, such as encouraging practical as opposed to moral justifications, may depolarize attitudes and encourage more civil discourse between dissimilar others. Overall, our findings have implications for bridging gaps between opposing groups, particularly in online communication environments.
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ItemFeasibility of bacterial probiotics for mitigating coral bleaching( 2020)Given the increasing frequency of climate change driven coral mass bleaching and mass mortality events, intervention strategies aimed at enhancing coral thermal tolerance (assisted evolution) are urgently needed in addition to strong action to reduce carbon emissions. Without such interventions, coral reefs will not survive. The seven chapters in my thesis explore the feasibility of using a host-sourced bacterial probiotic to mitigate bleaching starting with a history of reactive oxygen species (ROS) as a biological explanation for bleaching (Chapter 1). In part because of the difficulty to experimentally manipulate corals post-bleaching, I use Great Barrier Reef (GBR)-sourced Exaiptasia diaphana as a model organism for this system, which I describe in Chapter 2. The comparatively high levels of physiological and genetic variability among GBR anemone genotypes make these animals representatives of global E. diaphana diversity and thus excellent model organisms. The ‘oxidative stress theory for coral bleaching’ provides rationale for the development of a probiotic with a high free radical scavenging ability. In Chapter 3, I construct a probiotic comprised of E. diaphana-associated bacteria able to reduce oxidative stress by neutralizing free radicals such as ROS. I identified six strains with high free radical scavenging ability belonging to the families Alteromonadaceae, Rhodobacteraceae, Flavobacteriaceae, and Micrococcaceae. In parallel, I established a “negative” probiotic consisting of closely related strains with poor free radical scavenging capacities. The application of this probiotic to mitigate the negative impacts of exposure to a simulated heat wave was tested in Chapter 4. There was no evidence for improved thermal tolerance in E. diaphana. Changes in the relative abundance of anemone-sourced Labrenzia provided evidence for its integration in the E. diaphana microbiome. Uptake of other probiotic members was inconsistent and probiotic members did not persist in the anemone microbiome over time. Consequently, the failure of the probiotic inoculation to confer improved thermal tolerance may have been due to the absence of probiotic bacteria for the full duration of the experiment. Importantly, there were no apparent physiological impacts on the holobiont following inoculation, thus showing that shifting the abundance of native anemone microbiome members was not detrimental to holobiont health. Further, I found no evidence for an increase in ROS in the E. diaphana holobiont when it was exposed to heat. Some of the most compelling evidence in support of the ‘oxidative stress theory of coral bleaching’ comes from three published studies that expose corals, cultures of their algal endosymbiont, or E. diaphana to exogenous antioxidants during thermal stress. To confirm that ROS is the main driver behind thermal bleaching in E. diaphana, I replicated these previous experiments with novel methods that allowed a more accurate quantitation of ROS, and found that dosing with exogenous antioxidants (mannitol and ascorbate plus catalase) mitigates bleaching in E. diaphana, with no correlation between bleaching and increased ROS (Chapter 5). A serendipitous finding was that the E. diaphana bacterial community diversity can be rapidly reduced when anemones are reared in sterile seawater, making this model suitable for testing the efficacy of microbial restructuring strategies (Chapter 6). Taken together, the work from my PhD has shown that ROS scavenging varies among anemone-associated bacteria and that a high ROS-scavenging probiotic can be developed. Further, my findings have unveiled several main knowledge gaps that need to be filled before probiotics can be implemented, including administration strategies and choice of probiotic bacteria that maximise the maintenance of probiotic communities over time and a direct measurements of ROS in bleaching corals (Chapter 7).
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ItemModelling the atmospheric influence of coral reef-derived dimethyl sulfide( 2020)Dimethyl sulfide (DMS) is a naturally occurring aerosol precursor gas which plays an important role in the global sulfur budget, aerosol formation and climate. While DMS is produced predominantly by phytoplankton, recent observational literature has suggested that corals and their symbionts produce a significant amount of DMS, which is currently unaccounted for in modelling studies. It has further been hypothesised that the coral reef source of DMS may modulate the climate. In this thesis, two atmospheric models coupled to online chemistry and aerosol schemes were used for the first time to explore the influence of coral reef-derived DMS on atmospheric composition and meteorology across temporal and spatial scales. A simple non-varying representation of coral reef-derived DMS was developed and added to a common DMS surface water climatology. By comparing the differences between simulations with and without coral reef-derived DMS, the role of coral reef-derived DMS was quantified. The Australian Community Climate Earth System Simulator coupled to the United Kingdom Chemistry and Aerosol model (ACCESS-UKCA) was used to quantify the influence of coral reefs at the global scale. ACCESS-UKCA was evaluated against satellite observations and other global climate models and the sensitivity of aerosol, clouds and radiation to large scale perturbations of DMS was tested. ACCESS-UKCA was found to have similar biases and DMS sensitivity compared to other models and it was estimated that marine DMS contributes 0.45K cooling to the present climate. The influence of coral reef-derived DMS on global to regional scale climate was then investigated. In the Maritime Continent-Australian region, where the highest density of coral reefs exist, a small decrease in nucleation and Aitken mode aerosol was found when coral reefs were removed from the system. However, these small responses were found to have no robust effect on global or regional climate. The Weather Research Forecast model coupled to the CBMZ-MOSAIC (Carbon Bond Mechanism Z - Model for Simulating Aerosol Interactions and Chemistry) chemistry-aerosol scheme (WRF-Chem) was then used to study the same question at higher spatial and temporal scales. WRF-Chem was run to coincide with an October 2016 field campaign over the Great Barrier Reef, Australia, against which the model was evaluated. After halving the DMS surface water climatology, the model performed well for DMS and sulfur processes, though aerosol number was overestimated. The inclusion of coral reef-derived DMS resulted in no compositional change in sulfate aerosol mass or total aerosol number. No direct or indirect aerosol effects were detected. Throughout this work, the complexities of the aerosol-climate system have been emphasised and the limitations of current modelling capabilities highlighted. In conclusion, while total marine DMS was found to have an important climatic influence, this thesis has found no robust link between coral reef-derived DMS and climate or weather. Thus, these results do not support hypotheses around the ability of coral reefs to modulate global or regional climate.