This project seeks to understand the modes of environmental change in the subpolar North Pacific and North Atlantic, by creating records of past changes in ocean pH, CO2, temperature, circulation, and biological productivity. This will involve new sediment core material, analysed using novel geochemical methods, and synthesis of results with a variety of modelling approaches.
Material is made available through ongoing collaboration with the Alfred-Wegner Institute for Polar Research, Woods Hole Oceanographic Institute, Oregon State University, and the International Ocean Drilling Project. The student will undertake sampling trips to these institutes, and may also partake in a research cruise.
The project will take advantage of cutting edge geochemical techniques available in the new St Andrews Isotope Geochemistry labs (STAiG). These include boron isotopes, which have seen recent development as a tracer of the ocean CO2 system (Rae et al., 2011), and are now well-poised to answer exciting questions about the nature of CO2 change in the past (e.g. Martinez-Boti et al., 2015). These boron measurements will be paired, for the first time, with silicon isotope measurements on diatoms and sponge spicules, respectively tracing the usage and abundance of this key nutrient. To examine changes in physical circulation and climate, we will produce records of sea surface temperature and salinity change, using paired 18O-Mg/Ca in planktic foraminifera along with organic SST proxy measurements at Durham University.
Depending on interest of the student, interpretation of the data may be accompanied by experiments with numerical models, including box models, the GENIE earth system model, and analysis of General Circulation Model output.
The student will also benefit from ongoing collaborations on this topic with Dr David Thornalley at UCL and Dr Kate Hendry at the British Antarctic Survery.