Supervisors and Institutions
Marine phytoplankton grow via photosynthesis by fixing carbon from CO2 in the atmosphere. Carbon (C) in these tiny organisms serves as the base of the food chain. The balance between the C returned to the atmosphere upon death and decay of these algae (and their consumers) and that sequestered and buried in sediments controls much of the Earth’s C-cycle. Disruptions of this complex C balance may have triggered changes in the planet’s climate, glaciation, and sea level that can be linked with mass extinctions. Carbon isotope compositions have been an essential tool in evaluating the balance of C stored in atmosphere/ocean and sequestered in sediments. Yet, the inability to measure C isotopes of individual species of the tiny, marine, organic-walled plankton has obscured a full understanding of this complex cycle. For much of the Palaeozoic, organic-walled microfossils (palynomorphs) are our only record of these vital processes at the base of the food web. Previous analytical limitations necessitated analyses of “bulk samples” that are complex organic mixtures. We are developing new analytical tools, capable of routinely and accurately measuring the C isotopes of single planktic palynomorph specimens, which will provide a more complete view of the C-cycle in deep time.
The successful candidate will help develop these methods for C-isotope analyses of organic walled microfossils (palynomorphs), and will eventually apply this new tool to carefully selected biogeochemical events in the Ordovician or Silurian, to unravel the processes that led to these dramatic, but poorly understood, perturbations of the C-cycle in deep time. The student will be trained in key analytical techniques including optical microscopy, scanning electron microscopy (SEM), and isotopic analyses. In addition to analytical research skills, the successful candidate will have opportunities to undertake training in transferable skills, to gain experience in mentorship, and to participate in fieldwork. The PhD Researcher will work closely with the PIs and other members of the wider team.
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