Dr Sarah Alvarez (née O’Dea) Image

Dr Sarah Alvarez (née O’Dea)

Research Associate and Lecturer

Lecturers & Tutors|Academic Researcher


Dr. Sarah Alvarez (née O’Dea) was awarded a PhD by the University of Southampton after successfully completing her studies at the School of Ocean and Earth Science. Her post-doctoral research was first based at the National Oceanography Centre, Southampton, and then at the University of Bristol, where she was part of a team of scientists funded by the European Research Council to investigate past links in the ocean’s environment and ecology (PALEOGENIE,


Sarah specialises in using the fossil remains of calcifying marine plankton (coccolithophores and calcareous nannoplankton) to explore ecosystem and evolutionary response to past environmental perturbation and ocean acidification. Her approach integrates geological evidence with insights of the modern ocean to better understand the implications of ongoing environmental change. Her most recent research has focussed on the early Paleogene, and in particular the recovery of the ocean ecosystem following the end-Cretaceous mass extinction (~66 million years ago).


  • Part-time lecturer for MSc in Marine Science and Climate Change

Other professional responsibilities:

  • Honorary Research Fellow, University College London
  • The Micropalaeontological Society Nannofossil Group Chair


  • Alvarez, S.A., Gibbs, S.J., Bown, P.R., Kim, H., Sheward, R.M., Ridgwell, A. Diversity decoupled from ecosystem function and resilience during mass extinction recovery. Nature doi: 10.1038/s41586-019-1590-8 (2019).
  • Gibbs, S.J., Sheward, R.M., Bown, P.R., Poulton, A.J., Alvarez, S.A. Warm plankton soup and red herrings: calcareous nannoplankton cellular communities and the Palaeocene-Eocene Thermal Maximum. Philosophical Transactions Royal Society A 376: 20170075 doi: 10.1098/rsta.2017.0075 (2018).
  • Gibbs, S.J., Bown, P.R., Young, J.R., Ridgwell, A., Poulton, A.J., O’Dea, S.A. Ocean warming, not acidification, controlled coccolithophore response during past greenhouse climate change. Geology doi: 10.1130/G37273.1 (2015).
  • Bown, P.R., Gibbs S.J., Sheward, R., O’Dea, S.A., Higgins, D. Searching for cells: the potential of fossil coccospheres in coccolithophore research. Journal of Nannoplankton Research Special Issue 34, 5-21 (2014)
  • O’Dea, S.A., Gibbs, S.J., Bown, P.R., Young, J.R., Poulton, A.J., Newsam, C., Wilson, P.A. Coccolithophore calcification response to past ocean acidification and climate change. Nature Communications 5, (2014).
  • Gibbs, S.J., Poulton, A.J., Bown, P.R., Daniels, C.J., Hopkins, J., Young, J.R., Jones, H.L., Thiemann, G.J., O’Dea, S.A., Newsam, C. Species-specific growth response of coccolithophores to Palaeocene-Eocene environmental change. Nature Geoscience 6, 218-222 (2013).

Invited presentations:

  • ‘Expanding the nannofossil toolkit to explore the Paleogene greenhouse’. The Micropaleontological Society Annual Conference, University of Leeds, U.K. (2018).

Conference abstracts – oral presentations:

  • Alvarez, S.A., Gibbs, S.J., Bown, P.R., Wilson, J.D., Ridgwell, A. Following the phytoplankton: Tracking ocean ecosystem recovery from the K/Pg mass extinction. American Geophysical Union Fall Meeting, Washington D.C., USA (2018).
  • Alvarez, S.A., Bown, P.R., Gibbs, S.J., Kim, H., Ridgwell, A. Re-building the ocean ecosystem after the K/Pg mass extinction event. Lyell Meeting 2018, Mass Extinctions: Understanding the World’s worst crises, The Geological Society, London (2018).
  • Alvarez, S.A., Bown, P.R., Gibbs, S.J., Ridgwell, A. The post-mass-extinction recovery of calcareous nannoplankton and the Paleogene emergence of new diversity, disparity and ecological strategies. Climatic and Biotic Events of the Paleogene, Snowbird Resort, Utah, U.S.A. (2017).
  • O’Dea, S.A., Gibbs, S.J., Bown, P.R., Sheward, R.S. Using coccolithophore geometry in the fossil record. The Micropaleontological Society Foraminifera and Nannofossil Groups Meeting, Angers, France (2016).
  • O’Dea, S.A., Gibbs, S.J., Bown, P.R. Exquisitely preserved fossil coccolithophores: a day in the life of ancient plankton. 10th North American Paleontological Convention, Florida, U.S.A. (2014).
  • O’Dea, S.A., Gibbs, S.J., Bown, P.R., Young, J.R., Poulton, A.J., Newsam, C., Wilson, P.A. A cellular perspective on coccolithophore growth and biomineralisation at the Paleocene Eocene Thermal Maximum. 14th International Nannoplankton Association Conference, Reston, U.S.A. (2013).
  • O’Dea, S.A., Gibbs, S.J., Bown, P.R., Young, J.R., Newsam, C., Poulton, A.J., Wilson, P.A.  Coccolithophore skeletal sensitivity to ocean acidification at the Paleocene Eocene Thermal Maximum. American Geophysical Union Fall Meeting, San Francisco, U.S.A. (2012).