Quantifying the effects of bacteria-phage interactions on daily micronutrient cycling in freshwater ecosystems. NERC FRESH CDT studentship, PhD in Biosciences

Lead Supervisor
Professor Ivana Gudelj, University of Exeter

Additional Supervisors
Dr Craig Barker-Austin, CEFAS
Dr Andrew Singer, CEH

Location: Streatham Campus, University of Exeter, Exeter, Devon.


The NERC Centre for Doctoral Training in Freshwater Biosciences and Sustainability (GW4 FRESH CDT) will provide 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 www.gw4fresh.co.uk

Note, the research projects listed are in competition with 10 other studentship projects available across the GW4 FRESH CDT Partnership. Up to 2 studentships will be awarded to the best applicants.

Project Details
Viruses of bacteria known as phages, are one of the most abundant organisms on Earth. They play critical roles in ecosystem functioning and biogeochemical cycling as well as in regulating densities and community structures of natural bacterial populations. Studies of marine environments reveal the importance of understanding the interactions between phages and their bacterial hosts. Advances in genomics have revealed that marine viruses coevolve with their hosts and, strikingly, kill 20-40% of all surface marine bacteria every day. However, little is known about bacteria-phage interactions in freshwater environments and in particular about the daily effect of phage on bacterial population densities. We hypothesise that such density-dependent co-evolutionary interactions can have a profound impact on water quality, as we explain further.

High-frequency water quality time series conducted by the Centre for Ecology and Hydrology (Neal et al 2012, Neal et al 2013) has identified strong daily cycles in concentrations of a number of micronutrients. However the observed cycles did not have an abiotic explanation suggesting that in-stream biological activity could be asserting significant control over these micronutrients. Given that organic materials can readily be recycled after phage-mediated bacterial cell lysis we postulate that bacteria-phage interactions could influence daily cycles of micronutrient concentrations. To test this hypothesis our project will:

(1) conduct co-evolutionary experiments with freshwater bacteria-phage systems and quantify the effects of phage on bacteria population densities;

(2) carry out whole-genome sequencing of the co-evolved populations and identify patterns of host-phage infection networks; this is important for quantifying the virus host ranges and the effect of viruses on the diversity of bacterial communities;

(3) conduct temporal chemical analysis of the environment during bacteria-phage coevolution focusing in particular temporal measurements of specific micronutrients known to undergo daily cycles in freshwater systems

(4) the outcomes of laboratory studies in (1-3) will be incorporated into a computational model to generate predictions regarding wider range of environmental conditions that promote micronutrient cycling;

(5) obtain time course cultures of bacteria and phage from freshwater habitats and correlate bacteria and phage densities with daily fluctuations in micronutrients from the same sites.

Eligibility:
GW4 FRESH CDT welcomes applications from both UK and EU applicants. For further information regarding the eligibility criteria please see the Student Eligibilty section in the following web page http://www.gw4fresh.co.uk/how-to-apply/doctoral-students/


How to apply
Applications are now open and close at 9:00am on Monday 15 April 2019

You will need to complete an application to the GW4 FRESH CDT for an “offer of funding”.

Please complete the application form at http://www.gw4fresh.co.uk/how-to-apply/doctoral-students/ also sending a copy of your CV and a covering letter to the CDT by 9:00am on Monday 15 April 2019.

After the closing deadline all applications will be forwarded to the lead Supervisor of the project you have selected. They will shortlist their applicants and will contact you if they wish to interview you, and following this interview will submit their preferred candidate for their project to FRESH CDT

Shortlisted candidates will be invited to a panel interview in Bristol on 29 April 2019. Further details will be included in the shortlisting letter

For further details regarding the application process please see the following web page http://www.gw4fresh.co.uk/how-to-apply/doctoral-students/