About the Project
• Refining a brand new novel method, developed by the applicants to track and analyse microplastics (Cook et al., 2020)
• Mesocosms studies to track behaviour of microplastics in aquatic flow domains (Rivers, Coastal, Ponds & Wetlands)
• Training in a wide range of ecological methods using state-of-the-art technology
Microplastics (MPs) are an emerging contaminant of increasing concern that are ubiquitous within freshwater and marine ecosystems. Rivers are recognised as a fundamental transport pathway for MPs; connecting terrestrial plastic sources to marine ecosystems, as well as an area where high levels of biological activity and modification can occur. However, there is little consideration as to the sources and fate of plastics within these freshwater ecosystems. Rivers are subject to plastic pollution from both point (i.e. sewage systems) and diffuse (i.e. agricultural and urban runoff) sources. It is expected that riverbed sediments act as a sink for microplastic debris (1). However, the extent to which riverbeds interact with MPs and their entrapment rates will be governed by many physical, biological and chemical factors. Colonisation studies of plastic debris by microbial biofilms have shown to cause buoyant polymers to sink (2,3). Equally, microbial biofilms over riverbed sediment will influence MP infiltration and settling rates. Nevertheless, the relative importance of these processes remains largely unclear with empirical data urgently needed to parametrise models. In this project you will investigate the interactions and feedbacks between riverbed dynamics and MPs. The research will build on a brand new novel tracking methodology developed by the applicants (Cook et al., 2020), which allows real time tracking of microplastics in purpose built experimental flumes.
The main aim will be to determine
the key variables which contribute to the entrapment and resuspension of MPs within this freshwater ecotone. Different types of plastic particles with different size, shape & densities will be considered and analysed using novel state-of the-art technology and innovative methods. The release rate and sources of MPs is vital for a more complete understanding and assessment of the hazards posed by these contaminants. As such, the new insights offered by the project have the potential to contribute directly towards new policies relating to water management and environmental conservation.
We will use our novel mesocosm systems to investigate and isolate the different mechanistic processes governing the interaction between the riverbed and MPs. We will test different plastic polymers, with a range of densities and sizes, across a range of riverbed systems with unique characteristics (i.e. pore size, biofilm coated, bedform shape). Methods will include metagenomics to analyse biofilm community structure and optical spectral imaging to visualise where the biofilm colonises the different plastic polymers. In addition, we will adopt our newly developed method to track the movement of MPs within our laboratory-based system (4) using fluorescence-based technology.
Training and skills:
Training will be provided by the supervisory team in a wide range of environmental science approaches and techniques including environmental river processes, molecular techniques (16S amplicon sequencing), bioinformatics, molecular spectroscopy and multivariate data analysis.
Partners and collaboration:
The student will have a training placement at Thames 21, an environmental NGO operating in London, delivering environmental pollution
management with communities and municipal stakeholders. There will be the opportunity to work closely with the Thames 21 team in their river catchment sites around London; collecting river sediment cores and exploring plastic management solutions.
Year 1: Mesocosm and biofilm community studies to develop process level understanding of the environmental pathways and interactions of
Year 2: Targeted extraction and analysis of microplastics from riverbed cores to investigate their environmental fate and temporal /
Year 3: Integration and ecological interpretation
Jonathan Pearson, School of Engineering, University of Warwick
Gary Bending, School of Life Sciences, University of Warwick
Soroush Abolfathi, School of Engineering, University of Warwick
1. Rillig, M.C., 2012. Microplastic in terrestrial ecosystems and the soil? Environmental Science and Technology 46, 6453-6454.
2. Rummel, C.D., Jahnke, A., Gorokhova, E., Kuhnel, D., Schmitt-Jansen, M, 2017. Impacts of biofilm formation on the fate and potential effects of microplastic in the aquatic environment. Environmental Science & Technology Letters, 4, 258-267.
3. Kaiser, D., Kowalski, N., Waniek, J.J, 2017. Effects of biofouling on the sinking behavior of microplastics. Environmental Research Letters, 12, 124003.
4. Cook, S., Chen, H.L., Abolfathi, S., Bending, G.D, Schäfer, H., Pearson, J.M. Quantifying microplastic transport in aquatic flows using fluorometric techniques, Volume 170, 1 March 2020, 115337 https://doi.org/10.1016/j.watres.2019.115337
5. Merel Kooi* and Albert A. Koelmans,2019. Simplifying Microplastic via Continuous Probability Distributions for Size, Shape, and Density. Environ. Sci. Technol. Lett. 2019, 6, https://doi.org/10.1021/acs.estlett.9b00379