From carbon cycling to microstructure: echinoderms as a control on global climate and ocean biogeochemistry

There is evidence to suggest that echinoderms, including the sea urchins, produce a similar amount of calcium carbonate as coral reefs [1] and are thus a globally important component of the carbon cycle. However, echinoderm calcification is extremely poorly studied compared to corals, such that we do not have good constraints on how much of this carbon is buried and how and why echinoderms may be sensitive to environmental change. Therefore, while the response of echinoderms to (e.g.) ongoing ocean acidification may be an important carbon cycle feedback process, we do not know the potential these small creatures have, on aggregate, to drive environmental change. In this project, you will apply cutting-edge techniques used in the field of biomineralisation and combine these results with experimental laboratory culturing [2], isotope geochemistry [3], and comparative data collected from field trips and unique museum collections. Specifically, you will:  

1. Determine the mechanism of echinoderm biomineralisation and its sensitivity to environmental change using diverse techniques including confocal microscopy, isotope geochemistry, and (cryo) light and X-ray fluorescence, the latter using the cutting-edge capabilities of the UK’s national synchrotron facility, Diamond Light Source.  
2. Use existing surveys and datasets to produce accurate estimates for the present-day echinoid carbon flux, thus determining the precise importance of these organisms to the global carbon cycle.  
3. Couple the above data with both existing (from museum collections) and new geological samples (collected via field work as part of this project) with a biogeochemical model to assess the contribution of echinoderm calcification to the global carbon cycle through geologic time.  

As well as supervisors based at the University of Southampton, you will also be supervised by Jessica Walker from Diamond Light Source/STFC.