Project title: Chemical signalling and cycling in a changing ocean. Will environmental shifts alter the microbial-scale interactions that control marine sulphur cycling?
Supervisors: Prof. Justin Seymour, Dr Katherina Petrou and Dr Bonnie Laverock
Project title: A significant marine sulphur compound is dimethylsulphoniopropionate (DMSP), a metabolite that represents up to 10% of the organic molecules produced by phytoplankton. This molecule is a climatically relevant compound, as phytoplankton and bacteria transform DMSP into dimethylsulphide (DMS), a gas that is the major vehicle for oceanic sulphur to reach the atmosphere. DMS has been proposed to regulate regional climate by indirectly promoting cloud condensation in the atmosphere, but is subject to competing bacterial processes that degrade both DMS and its precursor DMSP in order to lock sulphur into the marine food web.
Interactions between DMSP and marine microbes, therefore, represent a key link between the base of the marine food-web and global climate, whereby the behaviour and composition of the microbial community dictate the fate of organosulphur compounds in marine surface waters. The extent to which these microbial processes and interactions influence ocean-scale sulphur cycling is still poorly characterised and how these interactions will be impacted by environmental change remains unknown.
This project investigates how DMSP-mediated interactions between marine microbes are affected by environmental shifts over space and time, and in turn, how these changes in microbial community composition and behaviour influence DMSP cycling. Using a suite of biochemical, molecular and bioinformatic approaches, this project will identify key microbes involved in marine sulphur cycling and will highlight spatial and temporal patterns in the abundance of the regulatory genes that drive sulphur transformations within the ocean environment.