Cardiff University President's Research Scholarship: Significance and response to climate change of new pathways for methanogenesis in marine sediments (Climate Change: confronting the four 'grand challenges') (PhD Studentship)
Reference Number: R934
Key Studentship Information
Project title: Significance and response to climate change of new pathways for methanogenesis in marine sediments
Despite the global significance of biogenic methane as both an important greenhouse gas and as a fossil fuel, surprisingly very few substrates are directly used by methanogens, and they rely on syntrophic associations with bacteria to supply their simple substrates. We have recently indentified two new direct methanogenic substrates (Watkins, et al., 2012), which removes the syntrophic control on their activity. This together with new data showing that the methanogens involved (Methanococcoides sp) are very common in marine sediments, suggest that methanogenesis from methylated organic compounds may be more widespread than previously thought (Oremland, et al., 1982). This project will test this hypothesis and investigate the environmental controls on these novel methanogenic substrates, including those related to climate change.
Sediments from a range of marine sites will be incubated with potential methylated organic compound precursors, such as, lignins, pectin, lipids and other choline sources, creatine, betaine; plus choline and ethanolamines, and change in the prokaryotic community (16S rRNA, methanogen specific and other relevant metabolic genes) and their metabolism and metabolites monitored, including sulphate reduction and methanogenesis. Subsequently, radiotracer experiments (Parkes, et al., 2012) will be conducted to determine the rates and routes (radio-ion chromatography, IC) of methylated compound degradation in sediments under in situ conditions and climate change conditions (e.g. higher temperatures and organic matter loading). In parallel, the detection limit of our current IC analysis of methylated compounds will be improved so that we can quantify concentrations in sediment pore water, and hence, accurately measure in situ rates from radiotracer turnover. The relative contribution of the different methanogenic pathways to total methane production and their relative response to environmental change will be determined.
The student will receive training in geochemical analysis (IC, GC etc), prokaryotic biodiversity assessment using molecular biological techniques, measurement of rates and routes of prokaryotic activity using radiotracers and analysis of organic compounds. Considerable experience of coastal marine sediment sampling using a research vessel, and mud flat sampling will be obtained.
Methanogenesis is an important organic matter degradation process in marine sediments (Cicerone & Oremland, 1988), produces a potent greenhouse gas (~20 x greater than CO2), and may be a potential amplifier of global warming (Dickens, 2003). Hence, it is important that we understand the relative rates of different pathways for methanogenesis in sediments, and how these might respond to climate change. Climate change may also result in changes in productivity and habitats, and thus, the supply of compounds to sediments, such as methylated organic compounds, therefore it is important to know how this might impact on biogenic methane production.
Start date: October 2013
This is a Cardiff University President's Research Scholarship. The award includes full UK/EU tuition fees plus a doctoral stipend matching UK Research Council National Minimum (£13,590 p.a. for 2012/13, updated each year).
Academic Criteria: Applicants must have a First Class Honours degree or a 2.1 plus a postgraduate Masters degree (or their equivalents).
Residency: The award is open to all UK/EU students without further restriction.
How to Apply
Prospective students should submit an application via the University's online application service for the programme in Geomicrobiology, October 2013 start.
A CV and Covering Letter should be submitted to Christine Williams at firstname.lastname@example.org
Application Deadline: 1 February 2013
For further information please contact Christine Williams:
Telephone no: +44 (0)29 208 75772