The genus Microcystis is responsible for many ‘nuisance’ and toxic algal blooms that threaten various fresh water bodies in Australia. Of particular importance is the taxa Microcystis aeruginosa which is highly prevalent and contains a deep pangenome, leading to substantial genomic variability between strains. It has been established that certain cyanobacteria, including hepatotoxic Microcystis species, annually transition between planktonic and benthic forms. Benthic-planktonic coupling has been associated with an increase in the abundance of Microcystis during spring and summer, often resulting in dense surface blooms, followed by the sedimentation of colonies to the benthos during the cooler months. In order to improve industry predictions of the risk, timing and severity of toxic Microcystis blooms, this project aims to investigate the biological mechanisms and environmental triggers that cause bloom development. Through a range of classical isolation techniques and various ‘-omic’ studies this project will study the recruitment of benthic dwelling Microcystis species to surface waters.

PhD Thesis underway by Caitlin Romanis.

Cyanobacterial blooms are a concern for water utilities due to the potential production of cyanotoxins and taste and odours. Current detection methods are slow and may not capture changes in bloom density which can prevent utilities in rapidly adjusting their treatment process. This project investigated using in situ fluorometers as a tool for real-time cyanobacteria monitoring an treatment adjustment.

PhD Thesis completed by Florence Choo in 2019.

This project investigated the relationship between disinfection by-product (DBP) formation in drinking water and the molecular weight distribution of its natural organic matter precursors (NOM) to help increase our understanding of how NOM properties such as size, aromaticity and structure affect DBP formation and toxicity of the formed DBPs.

Honours Thesis completed by Sophie Day in 2012.

Anabaena circinalis, is a commonly occurring cyanobacterial species in Australian source waters. Its presence poses a number of health and aesthetic issues for drinking water quality due to its production of secondary metabolites. This project isolated and characterised a novel toxic fraction from the Anabaena culture.

Honours Thesis completed by Stefania Sotora in November 2012.

Following the discovery of a species of cyanobacteria displaying novel toxicity, Limnothrix as a cause for concern, this project identified the toxin and developed techniques to detect and isolate it.

PhD Thesis completed by Paul Michael Whan in December 2015.

WaterRA is leading a consortium of water industries as part of the future configuration of the “CRC Care” post-June 2021. Water industry leaders (funding partners) of the consortium will determine the key information or research gaps to be addressed in a three-year plan. Topics will include, but not limited to, contamination assessment and remediation thereof in different media as they relate to their core business. Detailed project scopes will be achieved through subsequent co-design with research leads.

The environmental conditions which cause blue-green algae (cyanobacteria) blooms vary according to location, the climate, and other attributes of aquatic ecosystems. This variety has made it difficult to develop one broadly applicable predictive model for cyanobacterial blooms. Water utilities monitor source waters to implement cyanobacterial risk management programmes but there are no standard protocols while limited information transfer between utilities has prevented the identification of management strategies that do or do not work. This research reviewed literature about early warning systems (Almuhtaram et al., 2021) and source control strategies, conducted a survey of 35 utilities in America and Canada (74%) and Australia (Kibuye et al., 2021) and evaluated selected control strategies. These different types of information were synthesised into decision trees within an overarching guidance document. It was concluded that a 3-tier framework to detect algal blooms which monitored biological activity, then confirmed the identification of cyanobacterial genes and associated metabolites gave sufficient early warning, while multi-barrier control strategies gave field-scale efficacy and enabled timely responses.

There are many species of blue-green algae (cyanobacteria), and each species can have a number of genotypes. Water utilities routinely monitor reservoirs and lagoons for the harmful toxin-producing species, and when they find a threshold number of cells, proceed to test for toxins. The problem is that not all genotypes of known toxin-producing species produce toxins. There is already a well-established quantitative PCR method that detects the genes responsible for making toxins, but the relationship between occurrence of these toxic genotypes and the amount of toxin in one water sample is not straightforward.

This project will create a modified version of the existing regulatory protocols for managing toxic blue-green algal blooms by adding the toxic gene qPCR test to the current tests for toxin and species identification. This modified protocol will then be used to assess samples for which there are already results from all three tests. The original management costs will be compared to the desktop analysis of hypothetical costs that would have been incurred if genotoxicity testing had been included in the protocol. Could gene testing reduce overall cyanobacteria management costs and confer operational benefits?

Every day, Australians produce ~5 billion litres of wastewater, which contains a cocktail of chemicals. Industries that discharge wastewater are required to assess chemical risks to the receiving environments by conducting whole animal direct toxicity assessments (DTAs), which are expensive and pose an ethical dilemma. Our preliminary research shows that new in vitro bioassays provide an ethical and cost effective alternative that could be incorporated into DTA programs if their ecological relevance can be demonstrated. This project will develop and validate a new and internationally significant suite of in vitro bioassays for incorporation into DTA programs, leading to more ethical, cost effective and improved environmental protection.

N-nitrosodiumdimethylamine (NDMA) in drinking water is one of many factors – such as a persons’ genes – that cause cancer. Although NDMA is not a sole cause of cancer, the water industry aims to minimise its contribution to illness and disease. This research measured levels of NDMA in drinking and recycled waters and found the majority well below the Australian Drinking Water Guideline values that are considered safe for public consumption. Different sources of NDMA were identified and water monitoring and treatment strategies to optimise NDMA removal from source waters were recommended.