PhD Title: The biomineralogy of marine calcifying organisms and ocean acidification.

Supervisors: Harry Elderfield, Simon Redfern and Jean-Pierre Gattuso (Laboratoire d'Océanographie, Villefranche-sur-Mer)

Description: My project aims to provide a mineralogical assessment of the effects of ocean acidification on calcium carbonate shells.  Anthropogenic CO2 emissions are altering the carbon chemistry of our surface ocean ("ocean acidification"), creating an environment that should be hostile to shell-producing organisms.  At present, we know that this "acidification" effects marine calcifyers (see links below), but the effects are complex and vary dramatically between and within groups of organisms.  Several major research programs are investigating this complex problem, studying live organisms and ancient fossils to try and predict the response of these important organisms to ocean acidification.

I am investigating the mineral microstructure of biologically produced calcite and aragonite, and how this microstructure varies with environmental conditions.  The fine-scale mineral-organic structure of shells determines their physical characteristics (e.g. strength, flexibility) and their susceptibility to dissolution.  The survival of shelled organisms depends largely on the integrity of their shells, and if environmental changes render them incapable of producing viable shells, their survival will be threatened.  The trace chemistry of shells is known to vary considerably with environmental changes, which suggests micro-structural variations are also likely.  I study the effects of environmental perturbations on biologically produced calcite and aragonite from a structural perspective.  This involves the adaptation of common mineralogical techniques (X-Ray Diffraction, Infrared Spectroscopy, Raman Spectroscopy) to investigate these fine-scale changes, as well as applying more specialised techniques at Synchrotron light sources (XANES/NEXAFS, STXM, Total-X-Ray Scattering).

My research can be summed up by several questions: 

  • Does biomineral microstructure vary with changes in the external environment, and if so how do these changes effect the physical characteristics of the biominerals?
  • How do the trace elements we use as palaeoenvironmental proxies get into biominerals - is it thermodynamically or biologically mediated?
  • What is the structure of the 'Amorphous Calcium Carbonate' precursor that many (most?) organisms employ in calcification, and what can this tell us about their calcification mechanisms?

 

 

Links: 

Ocean Acidification Research: 

EPOCA - The European Project on OCean Acidification

UKOA - The UK Ocean Acidification research program

BIOACID - The Biological Impacts of Ocean ACIDification (German program) 

Other: 

The Cost Of Knowledge - petition against the excessive cost of accessing publicly funded academic research


Publications: 2006-Present

Last updated on 10-Apr-12 12:39