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Characterising the survival of microbial biofilms in drying river ecosystems

  • School: School of Science and Technology
  • Study mode(s): Full-time / Part-time
  • Starting: 2023
  • Funding: UK student / EU student (non-UK) / International student (non-EU) / Fully-funded


NTU's Fully-funded PhD Studentship Scheme 2023

Project ID: S&T4

Temporary rivers (which sometimes dry out) dominate global river networks and are increasing in extent due to climate change and water resource pressures.  In the UK, rising temperatures, droughts and over-abstraction are contributing to an increase in river drying, including in ‘Winterbourne’ chalk streams which dry seasonally and are valued for their high biodiversity and ecosystem services.  Whilst many of the species inhabiting Winterbourne streams are well-studied, we know little about the microbial communities which underpin the functioning of these ecosystems.

The surfaces of riverbed sediments are coated by biofilms, biodiverse communities of microorganisms including bacteria, fungi and algae.  This project will characterise these communities and how they change in response to drying.  We will achieve this by collecting field samples and undertaking molecular analyses (combining DNA barcodes with high-throughput next generation sequencing).  To complement these field studies, we will conduct laboratory experiments to determine the effects of drying on biofilms.

Microbial biofilms play a key role in shaping river ecosystems.  This is particularly true in temporary rivers—whilst many organisms die when rivers dry, many biofilm species remain metabolically active.  Biofilms thus enable processes such as photosynthesis and nutrient cycling to resume rapidly when flow returns, helping whole ecosystems to recover.  The production of extracellular polymeric substances (EPS) by biofilms intensifies with dryness, providing a protective layer that retains moisture and supports physiological activity.  We will determine the composition of, and measure changes in the concentration of, biofilm EPS under different drying intensities, in both field samples and during laboratory experiments.

Biofilms are a crucial component of nutrient and organic matter cycles in rivers.  The capacity for biofilm microorganisms to rapidly resume metabolic activity is enabled by the pulse of nutrients and organic matter that accompanies the return of flowing water.  We will determine how nutrient and dissolved organic matter concentrations change as rivers experience natural shifts between wet and dry phases and will measure the response of biofilm community composition and physiological activity both in river ecosystems and laboratory-based experimental bioassays.

Supervised by Dr. Erika Whiteford and Prof. Rachel Stubbington, the PhD candidate will join a vibrant, multidisciplinary research team at the forefront of research advancing understanding of ecological responses to river drying.  Co-supervision by Environment Agency colleagues will ensure project findings have considerable real-world impact by informing strategies to assess the health oftemporary rivers as they adapt to global change.

Supervisory Team:

Director of Studies: Dr. Erika Whiteford (School of Science and Technology, NTU)

Second Supervisor: Prof. Rachel Stubbington (School of Science and Technology, NTU)

External Supervisor: Dr. Judy England (Environment Agency)

External Advisor: Kerry Walsh (Environment Agency)

Entry qualifications

For the eligibility criteria, visit our studentship application page.

How to apply

To make an application, please visit our studentship application page.

Fees and funding

This is part of NTU's 2023 fully-funded PhD Studentship Scheme.

Guidance and support

Application guidance can be found on our studentship application page.

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