Microbial Hazards in Changing Coastal Environments
- Publication Type:
- Thesis
- Issue Date:
- 2022
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Coastal environments deliver many crucial ecosystem services, such as the maintenance of biodiversity, and are used widely for recreation by human populations. While microbial communities within these environments underpin ecosystem services, they often incorporate pathogenic microbes that can proliferate under beneficial environmental conditions. Furthermore, pathogens and antimicrobial-resistant bacteria (ARB), enter coastal environments via sewage contamination or animal faeces. Many processes which underpin the dynamics of endemic microbial hazards and anthropogenically introduced microbial hazards are not well defined, which hinders remediation efforts. Therefore, I aimed to increase our understanding of these processes. In Chapter 1, I introduce coastal environments, their microbial ecology, and their associated microbial hazards. In Chapter 2, I analysed the latitudinal dynamics of Vibrio along the eastern coast of Australia, where I defined their patterns in abundance and diversity to reveal new insights into the distribution of potential human pathogens within a region experiencing significant ecological shifts due to climate change. In Chapter 3, I used Microbial Source Tracking (MST) to specify sources of faecal pollution and their impact on an urban beach, which helped to identify remediation targets. In this chapter, I applied the Bayesian statistical package Source Tracker to both track the spatiotemporal dynamics of specific bacterial signatures for individual stormwater drains and to quantify the relative strength of the microbial signature from different stormwater drains. In Chapter 4, I investigated how rainfall leads to elevated levels of ARB at a recreationally used coastal beach. To do this, I applied the indicspecies statistical R package to 16S amplicon data and ran a correlation analysis between the bacteria which were indicators of sewage, with both faecal markers and ARB. In Chapter 5, I aimed to define the relative importance of natural environmental perturbations and anthropogenic impacts on bacterial assemblages within intermittently opened and closed lagoons (ICOLLs). In this study, I observed that sewage was a principal driver of shifts in the microbiology of ICOLLs exposed to stormwater, while natural seasonal shifts in the physio-chemical parameters controlled microbial communities at other times. Finally, in Chapter 6, I synthesise the results and conclusions of this thesis. Overall, the findings of this project have brought a new understanding of how microbial hazards can proliferate in, and enter, coastal environments. This project has informed the water quality strategies of government agencies, and in some cases highlighted significant health risks to recreational users of coastal environments.
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