The NERC Centre for Doctoral Training in Freshwater Biosciences and Sustainability (GW4 FRESH CDT) provides a world-class doctoral research and training environment, for the next generation of interdisciplinary freshwater scientists equipped to tackle future global water challenges. GW4 FRESH harnesses freshwater scientists from four of the UK’s most research-intensive universities (Bath, Bristol, Cardiff and Exeter) plus world-class research organisations the Centre for Ecology and Hydrology (CEH) and British Geological Survey (BGS).
For an overview of the GW4 FRESH CDT please see website http://www.gw4fresh.co.uk
Full Project Description
Blooms of cyanobacteria are a serious global threat to freshwater habitats and to water security. Bloom incidence is on the rise globally as a result of environmental warming and in response to nutrient loading from agricultural, urban, and industrial sources. Cyanobacteria can impair freshwater habitats and drinking water quality, as a direct result of forming high biomass blooms, and by producing secondary metabolites, such as toxins and persistent taste and odour compounds. Critically, while studies often show correlations between cyanobacteria abundance and environmental factors (e.g. nutrient concentrations and ratios, temperature, rainfall, and sunlight), the association between cellular abundance and concentrations of nuisance metabolites is often weak. Consequently, conservation and management practices are currently constrained by a limited understanding of mechanisms that drive or constrain the presence of nuisance cyanobacteria and metabolites.
Recent studies show that interactions within freshwater microbial communities can strongly influence the abundance of nuisance species and nuisance metabolite production. For example, microbial community composition and dynamics can provide better predictions of bloom outbreaks than environmental data and interactions between strains of the same cyanobacterial species can modify toxin production and species persistence. Consequently, there is growing evidence that understanding inter- and intra-specific interactions within microbial communities is likely to be key to management of nuisance cyanobacteria in freshwater habitats. Here we aim to extend these approaches by combining field monitoring, and in-vitro experiments using simplified microbial communities, to understand the relative importance of inter- and intra-specific interactions within microbial communities for determining cyanobacterial abundance and nuisance metabolite production.
The proposed project will focus on water supply reservoirs within Cornwall with a history of cyanobacterial blooms and will build on an existing study conducted by the supervisory team demonstrating a link between Microcystis sp. diversity and microcystin toxin production. In conjunction with staff at South West Water the student will monitor target reservoirs over one year and characterise standard environmental parameters (e.g. nutrient concentrations, temperature, turbidity), microbial community composition, and common nuisance compounds (i.e. Microcystin – one of the most problematic cyanotoxins, Geosmin and 2-MIB – the major causative chemicals for taste and odour problems in drinking water). The student will receive expert training in each component of the field study - SWW water will provide training in water chemistry analysis, training in metabolite profiling will be provided by Tromas (Montreal) and Perkins (Cardiff), training in microbial community profiling using 16S amplicon sequencing (conduced at the Exeter sequencing service) will be provided by Lowe (Exeter) and Tromas, and training in multivariate data analysis will be provided by Lowe, Buckling (Exeter), and Tromas. The fieldwork will be complemented by experimental studies aimed at isolating the effects of e.g. intraspecific diversity in targeted nuisance species on growth dynamics and secondary metabolite production and on the interactions between concentrations of key nutrients and intraspecific diversity. The experimental studies will be conducted at the University of Exeter, Penryn campus where we have extensive facilities for the isolation, growth, and characterisation of environmental microbial isolates. This component of the project will be guided by Lowe and Buckling who have extensive experience in experimental microbial ecology. The student will also benefit from expertise in the broader research community at Penryn which includes other world leading experts in aquatic microbial ecology (e.g. Yvon-Durocher, Gaze, Vos).
Real Life challenges this project will address
Nuisance chemicals produced by cyanobacteria represent a global challenge to freshwater ecosystems, compromising ecological function and subsequently impacting ecosystem services such as drinking water production. Consequently, strategies to limit or mitigate the abundance of nuisance cyanobacteria or prevent the production of harmful compounds are key for the conservation of freshwater habitats and for water security.
Project specific enquiries should be directed to the lead supervisor, Dr Chris Lowe.