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Dr Joseph Stewart

Boron isotopes in deep sea corals

I am an isotope geochemist studying the chemistry of marine biogenic carbonates to better understand the chemistry of the seawater in which these organisms lived.

My previous research has involved the taxonomic classification and geochemical measurement of ancient calcified plankton (foraminifera) recovered from deep ocean sediment cores to reconstruct ancient seawater temperatures (e.g. Mg/Ca) and changing patterns of continental weathering (e.g. Nd isotopes)

More recently research efforts have been focused on the refinement and application of boron isotope proxy for seawater pH measured in corals and calcified algae. The aims of this research are (i) to identify suitable coral substrates for use as pH biosensors, (ii) document changes in past ocean pH and (iii) to further our understanding of coral bio-mineralization and the impact of ocean acidification on marine califiers. 

Research keywords

  • Coral
  • Foraminifera
  • Coralline Algae
  • Isotope geochemistry
  • Trace metals in carbonates