Department of Earth Sciences, University of Bristol
Aqueous and Environmental Geochemistry
Prof. D. M. Sherman

Current Postdoctoral and Studentship Openings

There are always several projects going on that could lead to a Ph.D thesis. If you would like to explore doing aPh.D with us on a topic not listed here, please send us an e-mail. For UK Nationals, support can be obtainedfrom NERC. For those outside the UK, we need to look for alternative ways to fund the project.
  • Trace element uptake in marine minerals: from crystal chemistry to global geochemical cycles (Ph.D Studentship)

    Trace metals such as Co, Ni Cu and Zn are important biologically limiting micronutrients in the oceans. These metals are strongly sorbed by nanocrystalline minerals such as iron and manganese oxides. However, we have a poor understanding of these processes. Consequently, we cannot determine how past changes in ocean pH, hydrothermal activity and riverine inputs have affected the trace metal chemistry of the oceans and the evolution of life. Of more pressing concern, we cannot predict how ocean acidification (due to increased atmospheric CO2 and the proposed sequestration of CO2 in the deep oceans) will affect the trace metal biogeochemistry of the oceans in the next few centuries. The goal of this studentship is develop thermodynamic and kinetic models of trace metal uptake by marine minerals. From this work we will test the grand hypothesis that the trace metal concentration in the deep ocean are close to chemical equilibrium. We will then use our thermodynamic/kinetic models to predict the changes in marine chemistry that will result from ocean acidification. During the research project, we will determine the crystal chemical mechanism of trace metal sorption by nanocrystalline Fe-Mn (hydr)oxides using synchrotron-based EXAFS spectroscopy and atomistic simulations. The sorption of trace metals by Fe-Mn minerals will be measured as a function of pH and temperature in a series of laboratory experiments. From those experiments we will determine equilibrium constants for sorption equilibria to develop a thermodynamic model that can be applied to the deep oceans. This project links the atomic-scale problems of crystal chemistry to the global-scale problems of biogeochemistry. This work also develops our understanding the fate of heavy metals in soil and groundwater. There will be opportunities to develop skills in several experimental and theoretical techniques that would provide an outstanding foundation for a research career in geochemistry. Students from any science background are welcome but need to have had A-Level Chemistry or equivalent for this project. The project will also be done under close supervision and extra training in chemical methods will be provided as necessary.

EXAFS Spectroscopy

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