85000 research outputs found
Sort by
Managing Integrated Project Delivery
No full textDescribes various relationship based project delivery systems including IPD (integrated project delivery) and Alliancing, the historical perspective of its development and current practice
Vegan Consumption: Insights into the Consumer-driven Emergence of the Vegan Market
No full textVeganism represents an all-encompassing lifestyle movement that impacts the consumer’s ongoing decision-making. Through caring for both the wellbeing of oneself and that of distant others, veganism represents personal agency and empowerment in the marketplace. In its attempt to modify established cultural norms dictating acceptable engagement between humans and animals, veganism continues to grow in terms of its visibility. Through individuals adopting the lifestyle, and through the development of compliant products made available in traditional retail spaces, veganism has become an important part of future consumption discourses. Framed by the theory of Consumer-Driven Market Emergence, this chapter unpacks the organic growth of the vegan market. By delving into the early emergence of the vegan ideology, discussing examples of community entrepreneurs, and presenting market catalysts, the different phases of market emergence offer a clearer understanding of how the vegan market has come to flourish. While it is representative of a bottom-up approach to market development, veganism is suggested to have gained increased acceptance through traditional retailers and brands, which have come to legitimise this lifestyle by both carrying and developing compliant products. Actionable insights are offered to retailers and product developers, and implications for future research are suggested
Bodies and Mobile Media
No full textHave you ever considered how mobile media change what we see, hear and pay attention to, or how they alter our movement through the city? Over the last decade, mobile media and communication technologies have become deeply integral to our perception and bodily experience of the world.
In Bodies and Mobile Media, Ingrid Richardson and Rowan Wilken explore mobile media as a lens through which to understand how embodiment both shapes, and is shaped by, media experience. It offers a unique approach by focusing on specific sensory affordances and body parts – including the eyes, ears, face, hands and feet – to consider the uneven ratios of sensory perception at work in our engagement with mobile devices. Each chapter provides rich and accessible narratives of mobile media practices interwoven with current scholarship in media studies and phenomenology, with a concluding chapter that reflects on mobile media use as a synesthetic experience. By interpreting theoretical insights about the relationship between the body and technology, the book serves as an important work of knowledge translation. This work is crucial, the authors argue, if we are to critically understand how our perception and experience of the world are mediated by technology
A Nanostructured Coating for Improved Corrosion Resistance on Lens-Manufactured and Wrought Biodegradable WE43 Mg Alloy
No full textOver the last few decades, magnesium (Mg) and its alloys, due to their inherent mechanical and biological attributes, have been extensively researched for various biomedical implant applications. Mg is a lightweight and a high specific strength material which makes it suitable as a bone fixing device in orthopaedic implant applications. It degrades naturally in a physiological environment with non-toxic corrosion byproducts that are consumable by the body, demonstrating absolute biocompatibility. The main issue that radically limits its wide clinical use as a biodegradable implant material is its rapid degradation rate in the human electrolytic chloride-rich environment, resulting in dramatic changes in local pH and production of a large volume of hydrogen (H2) gas. Furthermore, the Mg implant may lose its mechanical integrity due to fast degradation, posing the risk of premature implant failure. Thus, there is a pressing need to reduce the degradation rate of Mg-based implants in order for them to function safely to the required extent.
The use of additive manufacturing (AM) technology for biomedical implant manufacture has resulted in innumerable benefits. Customized, complex-shaped, patient-specific implants fabricated in a single step by AM open up a wide range of applications in the artificial implant sector. However, the issue of rapid degradation with 3D printed Mg-based implants must still be addressed.
One of the well-recognized techniques to suppress degradation kinetics of Mg-based implants and to improve their corrosion resistance is surface modification with coating. Surface coating prevents contact with the physiological environment by forming a physical barrier on top of the Mg-based substrate, allowing for a longer healing time.
This project aims to develop the surface coating on 3D-printed, using laser engineered net shaping (LENS), and wrought WE43 Mg alloys, in order to improve their corrosion resistance in the physiological environment. For this purpose, thorough study of the protective coating on the LENS-printed WE43 (LW) and wrought WE43 (WW) was carried out. For coating purposes, ZnO was selected as it is a widely used coating material for Mg-based implants for improving their corrosion resistance. Furthermore, a top layer of Ag was deposited to provide antibacterial benefits which helps in avoiding device associated infections especially in the early stage after implant insertion. Magnetron sputtering (MS) was chosen for deposition of high quality thin dense layers of ZnO and Ag on the WE43 alloy surfaces. To obtain maximum corrosion resistance from the deposited ZnOAg coating, the coating deposition parameters including temperature and time were systematically optimized on both WE43 alloys. Furthermore, the microstructural characteristics, and electrochemical and mechanical properties of the alloys with and without coating were evaluated using SEM, EDX, XRD, FIB-SEM, AFM, PDP, and nano indentation testing.
The research clearly demonstrated the viability and advantages of applying ZnOAg coating for scaling down the degradation rate of the LW and WW Mg alloys. It also uncovered the competence of fabricating load-bearing biodegradable Mg-based implants using LENS technology. MS of ZnO and Ag resulted in formation of crystalline, uniform, dense, and highly compact thin films of deposited materials on LW and WW surfaces as depicted by FIB-SEM and AFM. ZnOAg coating processed by depositing ZnO for 30 min and Ag for 15 min at 80 °C was found to be optimal as it was more effective in terms of improving electrochemical performance of coated samples by showing maximum corrosion resistance in the physiological medium. Thus, for LW, the optimized ZnOAg film shifted the corrosion potential (Ecorr) from -1.616 V to -1.386 V and reduced the corrosion current density (Icorr) from 70.065 µA to 3.016 µA, as compared to uncoated LW. Whereas for WW, Ecorr was shifted from -1.530 V to -1.296 V and Icorr was reduced from 12.759 µA to 0.456 µA, as compared to the uncoated alloy. In this way, the corrosion reduction efficacy of optimized ZnOAg thin film was around 95.7 % for LW and 96.4 % for WW. The amount of H2 evolved after immersion in Hanks’ balanced salt solution (HBSS) was also reduced during the initial 6 days with ZnOAg coating from 18 ml to 3.2 ml for LW and from 0.7 ml to 0.1 ml for WW.
The microstructural investigation of ZnOAg coated and uncoated LW and WW alloys before and after electrochemical corrosion tests provided constructive information regarding the degradation behaviour of substrate materials. Characterization of LW samples revealed spatially varying heterogeneous microstructures with combination of fine equiaxed and columnar grains due to rapid thermo-kinetics of LENS manufacturing process. Evidence of severe evaporation of Mg and increased volume fractions of the alloying contents, intermetallic phases, and oxygen (O) and carbon (C) content was found by EDX. Moreover, 2.5% closed porosity of total volume was also detected using µ-CT scan. On the other hand, WW showed homogeneous, coarse equiaxed grain structure with α-Mg matrix as major constituent of solid solution uniformly distributed throughout the material with minor quantity of secondary phases. The WW was found to be 99.99% dense by µ-CT scan. The average surface roughness of LW was 0.59 µm, while it was 0.04 µm for WW. The surface porosity in LW gave rise to galvanic coupling between Mg and intermetallic phases after immersion in HBSS during electrochemical corrosion testing, resulting in inter-galvanic and localised corrosion. In addition to porosity, the microstructural heterogeneity, elemental segregation, increased concentrations of secondary phases, and zirconium (Zr) precipitates in LW contributed to its corrosion acceleration as compared to WW. The microstructural conditions of LW posed clear effects on ZnOAg coating electrochemical behaviour. The deposited ZnOAg coating could not cover the micro-pores completely, leaving some sites unprotected and open to physiological medium. Moreover, galvanic coupling between Ag, Zn, and Mg speeded up the corrosion process due to simultaneous exposure to the physiological medium, resulting in quick diminishing of ZnOAg protective film as well as corrosion passive byproduct layers of Mg (OH)¬2 and MgO.
The nanohardness (NH) and reduced elastic modulus (EMr) of uncoated LW were 1.10 GPa and 47.73 GPa, respectively, while for uncoated WW, they were 1.66 GPa and 57.8 GPa, respectively. The nano indentation test results concluded indicative effect of deposited ZnOAg coating in terms of improved stiffness of LW and WW surfaces, favourable for the orthopaedic implant applications. The NH and EMr of ZnO film were observed to be 4.45 GPa and 67.26 GPa, respectively. While for ZnOAg coating with Ag film on top, NH and EMr were 2.40 GPa and 79.51 GPa, respectively. Similarly, in nano-wear tests, mean wear volumes for uncoated LW and WW were 62.813 µm3 and 42.076 µm3, respectively. While the mean worn volumes for ZnOAg coated LW and WW were 43.332 µm3 and 30.004 µm3, respectively. In this way, the average material volume removed from uncoated alloy surface at 600 µN was reduced by 31% for ZnOAg coated LW. Whereas for ZnOAg coated WW it was 28.69% lower than the uncoated one, indicating towards improved deformation resistance with coating.
Furthermore, wettability of uncoated and coated WE43 alloys, evaluated by measuring water contact angle (WCA) was found to be 52.4°, 57.3°, 65.7° and 69.8° for LW, WW, ZnOAg coated LW, and ZnOAg coated WW, respectively, which indicates towards hydrophilicity of substrate materials and applied ZnOAg film. Thus, from the accomplished study, it is anticipated that the ZnOAg coating can effectively reduce degradation rate of both LENS-printed and wrought WE43, creating new possibilities for clinical applications of these biodegradable Mg alloys.</p
Biocompatible Ionic Liquids as Designer Solvents for Non-lamellar Lyotropic Liquid Crystalline Nanoparticles
No full textNanomedicine stands as the foremost frontier in drug delivery formulations, and the interest in these systems is continuously increasing. Lipid nanoparticles are heavily investigated due to the capacity of lipids to self-assemble into a variety of structures with distinctive properties. The biocompatibility, cost-effectiveness, and ease of production further accentuate their appeal. Lipid-based lyotropic liquid crystalline nanoparticles (LCNPs) particularly stand out for their ordered structures and high surface to volume ratio, rendering them suitable for delivering a diverse range of therapeutics. However, like all nanoparticles, they confront challenges related to stability post-administration and interaction with blood components, which influence their biological fate. Moreover, these particles are characterised by a structure-function relationship, rendering their preparation by rational design necessary for specific applications. To address these challenges and enhance their function for targeted delivery, manipulating their structures and surface characteristics is often achieved by incorporating surfactants into the main lipid matrix. Ionic liquids (ILs), a versatile class of tailorable solvents composed of ions, emerge as promising solvent additives for this purpose. Biocompatible ILs have demonstrated potential for biological applications owing to their low cytotoxicity and high biodegradability. These ILs have shown remarkable efficacy in optimising nanoparticles, offering improved stability during production and enhanced functions. Moreover, a wide array of biocompatible ILs support the self-assembly of amphiphiles as solvents and co-solvents. Despite these advancements, there remains a gap in research regarding the exploration of biocompatible ILs as solvent additives in LCNP formulations. This gap formed the basis for this project, where the primary objective was to investigate how ILs can be harnessed as additives to modulate the nanostructure of LCNPs. Additionally, the project explored the potential of ILs as functional ingredients, particularly their ability to modify the surface characteristics of LCNPs and potentially enhance their efficacy in hydrophobic drug delivery.
First, a library of 13 choline-based ionic liquids (ILs), commonly described in the literature for biomedical applications, was synthesised. These included 10 choline amino acid ILs, in addition to choline acetate and choline geranate at 2 molar ratios. Their cytotoxicity was examined in 4 cell lines; Human dermal fibroblasts (HDF), epidermoid carcinoma cells (A431), cervical cancer cells (HeLa), and gastric cancer cells (AGS). Their hemolytic activity towards red blood cells was also studied. The results indicated that the toxicity and hemolytic properties of these ILs are mainly influenced by the anion’s hydrophobicity and the pH of the IL solutions. To investigate any correlation between the ILs cytotoxicity and their effects on cell membrane, quartz crystal microbalance with dissipation (QCM-D) and total internal reflection fluorescence (TIRF) microscopy were employed to clarify how selected ILs interact with model lipid membranes made of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). The QCM-D data revealed that ILs with higher toxicity had more significant interactions with the membrane, leading to bigger changes in membrane fluidity and mass. Moreover, TIRF microscopy revealed that choline acetate, the least toxic IL, induced lipid rearrangements and pore formation in the membrane, while choline geranate, a hydrophobic IL amongst the most toxic, disrupted the lipid bilayer. These results highlight the correlation between the cytotoxicity and membrane interactions, and underline the importance of understanding the impact of ILs on cellular membranes in their biocompatibility assessment and design for biomedical applications.
The library of ILs was then explored as solvent additives for Monoolein (MO)-based LCNPs. Dynamic light scattering, small angle X-ray scattering, and cryogenic transmission electron microscopy were used to analyse the physical characteristics of 78 LCNP formulations prepared in ILs aqueous solutions, at six concentrations: 20, 10, 5, 1, 0.33, and 0.16 wt% in H2O. The results revealed the presence of particles with various nanostructures, including cubosomes, hexosomes, and micellar cubosomes. The internal nanostructures of the MO nanoparticles were influenced by the IL anion, IL concentration, but the ILs solution’s pH was the dominant factor.
Phytantriol (PHY)-based LCNP formulations prepared in IL aqueous solutions provided a pH-independent system to investigate the effect of the structure of the IL components on the nanostructure of the particles. The ILs library was extended to 21 choline-based biocompatible ILs, with the addition of 8 choline carboxylic acid ILs composed of anions with various chain lengths. The particles were also incubated with human serum and serum proteins to examine the effect of ILs of the surface characteristics of the particles, and their interactions with the biological media. SAXS analysis revealed that the nanostructure of the LCNPs was dependent on both the concentration of ILs and the hydrophobicity of the anions. Upon incubation with human serum, a transition from the inverse bicontinuous cubic mesophase (Q2) to the inverse hexagonal (H2) mesophase occurred. The rate of this transition was influenced by the specific IL used. Liquid chromatography-mass spectrometry (LC-MS) and proteomics analysis of selected samples were used to identify the protein corona composition of the particles, which was dominated by albumin, apolipoproteins, and serotransferrin. Notably, the abundancy of these proteins in the protein corona varied among the samples. The results obtained from both the MO and PHY-based formulations illustrate the effectiveness of IL additives for tailoring the internal nanostructure of lipid-based LCNPs, and modifying their surface characteristics.
The incorporation of ILs into lipid cubosome formulations to enhance their effectiveness as nanocarriers for hydrophobic drug delivery was then explored. MO cubosomes control sample, and MO cubosomes containing the hydrophilic IL choline glutamate [Cho][Glu] at a 70:30 MO:[Cho][Glu] molar ratio, and the hydrophobic IL choline geranate [Cho][Ge] at a 98:2 MO:[Cho][Ge] molar ratio were prepared to encapsulate the hydrophobic drug paclitaxel (PTX). Our findings indicate that cubosomes with [Cho][Ge] maintained their small size and low size distribution post drug encapsulation. In contrast, both the MO control and MO:[Cho][Glu] samples showed an increase in size and size distribution after drug encapsulation. Additionally, the presence of ILs significantly boosted the PTX encapsulation efficiency of the cubosomes, increasing it from 35% in the MO control to 61% in the MO:[Cho][Glu] sample and 78% in the MO:[Cho][Ge] cubosomes. All cubosome formulations exhibited a two-stage drug release profile (burst and sustained). CellTiter Blue cell toxicity assays demonstrated that all cubosomes effectively inhibited cancer cells growth.
The findings of this project highlight the effectiveness of employing IL additives as a strategy to enhance LCNPs effectiveness for drug delivery purposes.</p
Fabrication of III-Nitride and Metal Chalcogen Heterostructure for Broadband Photodetection
No full textMultispectral photodetection with autonomous light-detection capabilities, without any external voltage bias, holds substantial promise for revolutionizing energy-efficient technologies. Their significance extends to applications in the realms of the future memory devices to optically controlled logic gates. However, the commercial broadband detectors relying on traditional thin-film materials such as silicon, Mercury-cadmium-telluride and Indium-gallium-arsenide have relatively low tolerance against high operation temperature, which hinders their application in specialized domains from space surveillance to combustion monitoring. Therefore, an imperative necessity emerges for a self-bias photodetector endowed with an ultrabroad spectral detection capability, demonstrating robust performance even in elevated temperature conditions. Identifying an appropriate material for broadband photodetection under high-temperature circumstances has proven to be a persistent challenge.
Semiconductors with wider bandgaps become attractive candidates for the thermal stable photodetector; larger bandgaps reduce intrinsic-charge ionization effects due to thermal and radiation. The optical radiation detection range of these materials is confined to visible light. However, this limitation can be overcome by employing a heterostructure comprising a wide bandgap material in conjunction with the narrow bandgap material, thereby extending the detection range. The recent technological advancements have ushered in a significant breakthrough with the introduction of metal chalcogen semiconductors, offering a myriad of promising candidates that span nearly the entire spectrum of interest for photodetector exploration.
Laying a foundation, this study first addresses the quality of gallium-nitride (wide bandgap) thin film materials and explores their optoelectronic properties. On the other side of the coin, we aim for the growth of the different metal-chalcogens for the photodetection application. After these strategies, various heterostructures using metal-chalcogen thin film and gallium-nitride surface have been prepared for self-biased broadband photodetectors, yielding stability under elevated temperature conditions.
Chapter 1 introduces the background, motivations, literature survey and objectives of the research in this thesis. The research scopes of the thesis are defined. The identified research gaps are presented, and research questions are raised. The expected research outcomes/deliverables are demonstrated.
Chapter 2 delineates the methodology of the ongoing research on gallium-nitride (GaN) and metal-chalcogens. The techniques employed for the growth of heterostructure and its bare counterpart material, along with detailed insights into characterizations and optoelectronic parameter assessments, are illustrated.
Chapter 3 is based on the two published works on the growth optimizations of epitaxial GaN thin film for the optoelectronic application. Detailed self-bias photodetection properties of the GaN film under varying temperatures are presented.
Chapter 4 is based on the four published works on the photodetection application of different metal-chalcogens thermal stability is also tested. On the other hand, make a heterostructure of the material that displays the thermally stable behaviour under high-temperature conditions. Besides, theoretical approaches are presented for the heterostructure to support our investigation.
Chapter 5 revolves around four published works; each focus on diverse heterostructures created on the GaN surface by depositing various metal-chalcogen materials. The chapter highlights the performance of these heterostructures in terms of broadband photodetection and thermal stability under the self-bias mode of operation. Additionally, theoretical simulations have been conducted for the final heterostructure-based device to provide robust support for our research findings.
Chapter 6 concludes the thesis and suggests the future direction of the research in the thesis.</p
Designing 3D bio-printed lutein inserts for diabetic retinopathy therapy
No full textAmong posterior eye diseases, diabetes retinopathy (DR) causes 40% of all global retinal blindness.By 2045, 161 million diabetic patients will be affected.Urgent need for DR drug development and delivery.The Age-Related Eye Disease Study (AREDS, 1999) shows benefit of lutein oral supplement for eye disease, but…Lutein supplements and eyedrops are inefficient due to physical/chemical barriers to reach the retina.Currently, lutein ocular injection therapy is an option. But it is not sustainable for DR features improvement.In addition, DR severe cases require invasive/expensive focal laser and replacement surgery.Aims of this projectTo design and print biocompatible 3D insert with luteinAssess the functionality of lutein inserts on UV stressed mice eyesHighlightsNovel non-invasive lutein insertBioactive + reduce DR</p
Blockchain Adoption in the Academic Publishing Ecosystem
No full textThis research explores the potential impact of blockchain technology adoption on the electronic academic publishing ecosystem. One of the major problems within this ecosystem is that academic libraries face yearly increases, well beyond the inflation cost for the electronic resources that they are obliged by their universities and researchers to provide, with consequential inordinate profits for the publishers and continuous high costs for academic libraries.
Blockchain technology is one new technology that has the potential to cause a profound change to practitioners’ current business models, affecting the power imbalance between publishers and academic libraries.
The purpose of this research is to examine the capacity that practitioners have to prepare for the introduction of a potentially disruptive technology such as blockchain technology. The thesis addresses and answers the two research questions:
1)What factors are involved in the potential introduction of blockchain technology in the academic publishing ecosystem?
2)How do practitioners prepare for the possible adoption of blockchain technology within the academic publishing ecosystem?
This study uses a grounded theory method to collect and analyse 30 interviews with practitioners in academic libraries, publishers, and blockchain implementers. This grounded theory method follows a ‘middle road’ approach consisting of open coding, selective coding and a novel method of axial coding using diagrams.
This is one of the first qualitative studies to theorize on the possible introduction of blockchain technology into the academic library and publishing ecosystem.
The research examines the possible future direction of blockchain technology adoption within this ecosystem and the 22 concepts involved in its effects on supply chain networks. These concepts and other findings are compared with the existing academic literature.
The thesis argues that blockchain technology should be seen as infrastructure, that blockchain solutions require solving real business problems, and that a holistic solution which is a cooperative business solution for all stakeholders transforms the ecosystem.
The research finds that as yet there is little uptake of blockchain technology within the academic publishing ecosystem. If blockchain technology is introduced to this ecosystem the most suitable applications for blockchain technology are in the credentialling, identification, metadata distribution, and authentication areas.
There is a general reluctance of academic libraries to develop blockchain applications in-house due to cost and lack of suitable personnel, so they are more likely to take on blockchain from a trusted supplier. Publishers have little need of innovations such as blockchain technology that threaten their already lucrative business model.
The major outcome of this study is the APEBA Framework of blockchain adoption, The framework has five groups: ecosystem, content, blockchain adoption, acceptance, and holistic solution. The relationships between these groups are transforms, influences, enhances, absorbs/incorporates/piecemeal, and produces/provides. Other outcomes are a model comparing acceptance factors with resistance factors, and a model of blockchain knowledge compared with the likelihood of blockchain introduction.
By providing this framework and the two models, this research answers the two research questions and helps to prepare practitioners for possible blockchain adoption, and leads to opportunities for efficiencies in their use, payment, and management of electronic resources.</p
Deep Design For Empathetic Architecture: Negotiating Hyper Complexities During China's Rapid Urbanisation
No full textThis is a practice -based PhD research that seeks to reflect on the 10 Years of work and the evolution of my practice iDEA in parallel with the rapid development of contemporary Chinese architecture. My doctoral research delves into the intellectual and creative foundations of my practice to articulate a new design approach: Deep Design for Empathetic Architecture. This method accentuates the role of design thinking and its corresponding operations, centering on formulating strategies based on inherent propensities, existing events, and fundamental spatial relationships of each project. By embracing this method, innovative design concepts can be carefully cultivated and tailored to effectively address future uncertainties throughout the lifespan of the architecture.
My PhD research is focused on three projects that serve as exemplars illustrating a method of contextualizing contemporary architectural practice in China while also capturing the evolution of architecture reflective of Chinese culture, politics, and changing social dynamics. This study employed RMIT's research methodologies, transitioning from Master's to PhD, involving detailed mappings in Chapter 1 and Appendix 1, critical reflections in Chapter 2, and practical application in Chapter 3 across a curated selection of projects developed in response to the exigencies of China's rapid urbanization. The research promotes Empathetic Architecture, focusing on human interaction, experiential movement, and fostering positive behaviours.
Positioning my practice within the Chinese architects community that I directly engage with, Chapter 4 identifies the values and aspirations derived from diverse experiences, spanning from experimental design in UK, the hands-on knowledge of vernacular architecture in China, to the collaborations with various international and domestic firms (Chapter 5). This exploration culminates with the predication of my future practice in Chapter 6.
The trajectory of my Ph.D. marks a pivotal shift in my design practice, transitioning from implicit design intuition to explicit design thinking, encapsulated within iDEA as interdisciplinary Design for Empathetic Architecture. This research not only nurtures a culture of creativity within my practice but also serves as a catalyst for inspiring colleagues to embrace the profound methodologies of Deep Design.
Finally, the articulation of Deep Design aims to offer a theoretical framework for the seemingly pragmatic design community in China (Appendix 2). It strives to define diversified prototypes (Appendix 3), enabling architects to creatively explore new conceptual and formal possibilities amidst the hyper complexities in China's contemporary architecture.</p
The Hydrology and Biogeochemistry of Australian and African Peatlands
No full textPeatlands cover only 3% of the world’s land area while storing ~30% of the global soil carbon (C) stock. This C stored in peatlands is threatened by climate change and other anthropogenic disturbances such as drainage, land use change, and grazing and trampling by feral animals. Despite the importance of these ecosystems, there remain key knowledge gaps on the biogeochemical and hydrological controls of peatland functioning. The objective of this interdisciplinary study was to contribute new scientific knowledge on peatland functioning by exploring the complex interactions between peat biogeochemistry and hydrology, as well as identifying innovative peatland condition monitoring and assessment techniques.
To examine the link between peat hydrology and biogeochemistry, the movement of the water table depth (WTD) of an Australian Alpine Sphagnum peatland was monitored over four years. WTD was used to identify the boundaries of the peatland ecohydrologic layers: the acrotelm, mesotelm and catotelm. Additionally, the C chemistry, protein content and amino acid composition of peats within each of these ecohydrologic layers were quantified. The results from this study revealed a strong positive correlation between the extent of peat decomposition and protein content, suggesting selective preservation of proteinaceous materials during peat decomposition. Each ecohydrologic layer displayed a distinct amino acid composition and C functional group composition, suggesting differences in microbial activity and decomposition dynamics between these three layers.
Building upon these findings, the links between WTD, C chemistry, and the microbial community composition of degraded and intact Australian Alpine Sphagnum peats were then further examined. To do so, the WTD data was compared with peat samples analysed using High-Throughput Sequencing (HTS) and solid-state 13C Cross Polarisation Magic Angle Spinning Nuclear Magnetic Resonance (13C CP/MAS NMR) spectroscopy from three peat areas (two intact and one degraded). The results of this study demonstrated that the microbial communities of the three peat areas differed significantly, and that WTD, peat chemistry, and depth in the peat profile all influenced microbial community structure. Significant interactions between the microbial communities of these three peat areas and the WTD, as well as with
depth in the profile, were observed. While C content and C:N ratios explained most of the variability in fungal and prokaryotic community structure of the two intact peat areas, the C functional groups explained the variations in these microbial communities in degraded peat areas. These findings imply that disturbance-induced changes to WTD, microbial communities, and/or C chemical composition of peats may affect the ecosystem function and C storage dynamics of these C-rich ecosystems.
The utility of near infrared (NIR) spectroscopy as an innovative technique for monitoring peatland condition was explored by assessing spectra from the intact and degraded Australian Alpine Sphagnum peat areas. The results of this study showed that in situ scanning of fresh peat at the peatland surface was the most effective strategy for using the microNIR spectrometer to measure peatland condition. This study demonstrated the efficacy of the microNIR spectrometer for rapid and cost-effective peatland assessment, which could enable early detection of changes in condition to inform management actions to prevent and/or mitigate further peatland degradation. The further development and application of this technology may foster the preservation of peatlands and the invaluable ecosystem services they provide over broader geographic scales than explored here, including regions where peatland research is currently critically lacking.
Finally, a systematic quantitative literature review and analysis of primary scientific peer-reviewed journal publications on the ‘ecosystem’ (i.e. socio-academic context) of African peatland research revealed a number of research gaps and imbalances in the human dimensions of this field. This systematic quantitative literature review found only 32 primary, peer-reviewed journal articles published between 1992 and 2021 on African peatlands. Although peatlands play a major role in the global C cycle, only nine studies measured the C content of peat, and there were no primary scientific peer-reviewed journal articles reporting peat GHG emissions. This study also revealed the underrepresentation of African peatlands in scholarly research, coupled with a skewed demographic overrepresentation of male and non-African authors. This study highlights the urgent need for increased attention to African peatlands, both in biophysical research and in conservation efforts.
Overall, this thesis advances our understanding of peatlands in Australia and Africa, by providing valuable insights into the key drivers of C storage and peat degradation, as well as identifying a novel technique for effective peatland monitoring. The management implications of this research for Australian Alpine Sphagnum peatlands are discussed. The findings of this thesis contribute new knowledge for policy makers, researchers, and land managers working to preserve these critical C-rich ecosystems for climate change mitigation and environmental conservation.</p