UWB Crest

School of Ocean Sciences

PhD Topics 2010-11

Image of underwater life

Applications are invited for NERC Quota Ph.D. studentships on the topics listed below. Applicants should send:

  • a curriculum vitae (including the name and contact details of TWO referees) and
  • a letter, stating clearly the applicant’s name, the project title and first-named supervisor.  Applicants should explain their inspiration behind their application and the particular choice of project.

These should be e-mailed, in electronic form (PDF, MS Word or text format), to: Phdapplications@cns.bangor.ac.uk

Title your documents in the following format:

Supervisor Surname_your surname_your initial_cv or letter

For example, if your name was John Smith and you were applying for Dr Andrew Davies’ project on biological mediators of wave energy, you should name the covering letter file: Davies_Smith_J_letter.

Deadline: 15 March, 2010.

These projects are subject to NERC rules for funding. Applicants must visit the NERC eligibility webpage to check their eligibility before making an application. 

Applications will be scored on the basis of academic qualification and background, previous employment (if relevant), quality of references and the contents of the covering letter.  Short-listed candidates will be invited to the School of Ocean Sciences for interview.

Studentship Topics

Project Descriptions

Biological mediators of wave energy in coastal landscapes

Dr Andrew Davies, Professor Steve Hawkins, Dr Martin Skov

Many structure-forming benthic organisms interact with and influence the surrounding water flow, relying upon this for a variety of ecological processes including the supply of particulate matter, sediment stability and the recruitment of conspecifics. One effect of this interaction is that structure-formers can attenuate wave energy transmission and reduce flooding throughout coastal areas. Unfortunately, there is little quantitative evidence on reduction of wave energy in mussel beds, salt marshes and rocky intertidal habitats. No study has compared the relative importance of systems with different intertidal position, physiological tolerances and different successional states. The proposed project will use a combination of experimental, taxonomical and modelling approaches to assess how structural species in a range of coastal environments attenuate wave energy, identify the main traits that mediate this function and how the combination of structural habitat and attenuation impacts biodiversity on a range of spatial scales (centimetres, metres and kilometres).

Microbial pathogen transfer from Catchment to Coast

Professor Colin Jago, Professor Davey Jones, Professor Hilary Lappin-Scott, Dr Shelagh Malham

Microbial pollution affects all aspects of river, estuarine and coastal environments and pathogen transfer is likely to increase with increasing temperature and precipitation events. This project is concerned with microbiological hazards in estuarine waters and the risks of pathogen infection to ecosystem and human health. Many pathogens are transferred from land to ocean via particulate matter whose biophysical properties change as it traverses the freshwater/saltwater interface; the project focuses on the dynamics and fate of particulate pathogens as they are transported from fresh to salt water environments. Little is known about transformations that undoubtedly occur in the river-estuary transition zone: these are important because they determine whether particulate pathogens are stored in, or flushed out of, the estuary which in turn determines the risk to ecosystem and human health. The research will be linked to an ongoing NERC-funded field project on the transfer of particulate organic matter from rivers to estuaries and is part of a larger £1.8 million programme on land-ocean interaction within the Centre for Catchment and Coastal Research. The project will include: observations in the Conwy and Dyfi river-estuary systems; studies to assess microbial activity and virulence; and laboratory experiments to elucidate pathogen activity under different predicted climate change scenarios of increased temperature and increased freshwater flow. The project will suit graduates in either physical or biological sciences who are interested in the challenges of interdisciplinary research. Training will include the use of DNA fingerprinting, qPCR and general microbial techniques as well as the coupling of microbiological processes with hydrodynamic models of the river-estuary system (depending on the expertise of the chosen candidate which will also influence the specific direction of the evolving project).

Tidal amplification of sea bed light and implications for primary production in tidal seas

Dr David Bowers

Sea bed light, in sufficient quantity, is an essential requirement for the growth of benthic macro- and micro-algae, both of which make significant contributions to the productivity of shallow waters. Evidence for the importance of sea bed light in these ecosystems is provided by studies showing that the maximum depth at which algae are found is proportional to the water clarity. In a non-tidal sea, or lake, the irradiance arriving at the algal surface depends only on the sunlight arriving at the water surface, the depth of water and the water clarity. However, in tidal waters the tide produces fluctuations in sea bed light which depend on the tidal range and the time of low water. Recently it has been discovered that these tidal fluctuations amplify the light reaching the sea bed, compared to non-tidal water of the same mean depth and clarity. This happens because light decays exponentially with depth in the sea; in consequence the gain in light at low tide is greater than the loss at high tide, leading to a net gain when averaged over a tidal cycle. Models of the biological productivity of coastal waters that have not included this effect will have under-estimated algal growth rates and carbon uptake. The implication is that macro-algae should be more productive and be able to live deeper in tidal waters than in similar, but non-tidal, waters. The aim of this project is first to confirm the physical ideas by making more measurements in locations with different tidal conditions (including lakes with no tide) and secondly to assess the impact on benthic productivity by making simple measurements of algal growth. The project will appeal to students who want to work at the interface between the physical and biological aspects of the coastal ocean and who are keen to carry out experimental work as well as developing theoretical ideas.

Carbon fluxes in polar oceans: the role of sea ice growth and decay

Dr Hilary Kennedy, Professor David Thomas

Large salinity and temperature shifts are the major physical-chemical transformations within sea ice during its seasonal cycle of growth and decay. The freezing of seawater results in the expulsion of dissolved salts from the ice crystal matrix, leading to increased concentration of dissolved constituents during brine formation. Cumulatively, the chemical and thermodynamic changes, and resulting gradients in the brines of sea ice, give rise to fluxes from the growing ice sheet of a) dissolved inorganic carbon across the ice-seawater interface, and b) gaseous carbon dioxide across the ice-seawater and ice-air interfaces. However, our knowledge of carbon fluxes in sea ice is rudimentary in comparison with what we know about them in open ocean waters and marine sediments. As yet carbon fluxes in sea ice remain a poorly quantified component of the polar carbon cycle. The focus of this study will be to characterise the major carbon fluxes associated with physical-chemical changes during sea ice growth and decay, using chemical and stable isotope techniques. Laboratory studies will be used a) to develop analytical methods appropriate for the measurement of carbon fluxes in sea ice and b) to determine the changes that these fluxes confer on the stable isotopic composition of carbon in seawater, brine and gas. The study will enable a better understanding of the role of sea ice in the mediation of carbon fluxes between the atmosphere and ocean and, hence, its contribution to the carbon cycle in the polar oceans. The student will receive training in marine chemistry and chemical thermodynamics, a range of laboratory techniques and geochemical methods relevant to applications for saline and hyper-saline systems at sub-zero temperatures. The student will also receive training in data analysis and interpretation. The PhD will contribute to current research being undertaken by an international team of sea ice biogeochemists and is ideally suited for an individual with an interest in chemistry and environmental change.

Impact of past and future sea-level rise on shelf sea sediment dynamics

Dr Simon Neill, Professor James Scourse

The repeated flooding and emersion of the continental shelves driven by Quaternary glacio-eustatic sea level cycles of up to 115–135 m means that the areal extent of the shelf seas (< 200 m deep) is now 425% greater than during the Last Glacial Maximum (21 ka, LGM), some 7% of the total global sea-surface. The evolution of the shelf seas had important feedbacks on marine productivity and atmospheric pCO2, tidal energy budgets for driving the Atlantic meridional overturning circulation (MOC) and shelf sea sediment transport and resuspension. These feedbacks can be explored using palaeotidal and palaeowave models but such simulations require constraining and testing via observational data. Such constraints are potentially provided by the sedimentary record. In this studentship, state-of-the-art palaeotidal and palaeowave models will be applied to time slices of the NW European shelf seas from the LGM until the present. The hydrodynamic output from these models will be used to predict changes in sediment grain size through time, and therefore to generate synthetic stratigraphies for discrete locations around the shelf seas. These stratigraphies will be validated with well-dated core records from these contrasting sites. After validation with past sea-level rise, the methodology will be extrapolated to predict, with confidence, the evolution of the shelf seas over the next century as a consequence of predicted sea-level rise. If strong relationships between model simulations and geological data on sedimentary changes can be established, the same simulations will be used to predict changes in tidal amplitudes, tidal current velocity fields and changes in seasonal stratification dynamics for specified rises in sea level. The successful candidate will become proficient in tidal and wave modelling software for the shelf seas with diverse environmental applications. There is a shortage of competence in this field nationally and internationally; with the reality of rising sea levels into the future such expertise is likely to be in very short supply. Hence the future scientific/vocational prospects for research in this field are excellent. The candidate will be trained in and have access to the high performance computing resources of the College of Natural Sciences, necessary for running such state-of-the-art numerical models.