The Acid Test – high-resolution records of climate change across the PETM and other hyperthermals

Gavin Foster, Dr Andy Milton, Dr David Evans, Tali Babila, Case Western Ohio, US; James Zachos, UCSC, California, US

PLEASE NOTE:  Application deadline date 08 Jan 2024.  Applications are no longer being accepted for this project

Project Overview 

Anthropogenic climate change has no analogue but, in the last 60 million years, the hyperthermals of the early Cenozoic come the closest.  Here you will develop a new analytical tool for the boron isotope analysis of single planktic foraminifera to revolutionise our understanding of the Palaeocene-Eocene Thermal Maximum (PETM) and other hyperthermals.

Project Description 

Ocean pH is intimately related to the amount of carbon in the atmosphere-ocean system. Records of past surface ocean pH derived from the boron isotopic composition of planktic foraminifera therefore allow us to reconstruct both the amount of CO2 in the atmosphere in the past and determine why it changed (e.g., Gutjahr et al., 2017). Our current records of the early Cenozoic hyperthermals are however incomplete because these events are so rapid they are poorly captured by the sediment record. In this project, you will apply novel coupled laser ablation-MS methods (Babila et al. 2022) to single planktic foraminifera from newly drilled well-preserved material from the Mid-Atlantic Coastal Plain of the US.  When coupled with a sediment mixing model (e.g. Dolma and Laepple, 2018), this will let you to constrain C-emission scenarios from more complex biogeochemical models to “see-through” the inadequacies of the sediment record revealing the full magnitude and nature of ocean acidification and climate change that occurred during these rapid events for the first time.  Building on our recent work (Babila et al. 2022) we hypothesize that: i.)  the PETM, and potentially other hyperthermals, were comprised of multiple pulses of carbon addition and ii.) ocean acidification was more than the current bulk records imply (i.e. 0.3 pH units; Gutjahr et al. 2017). You will use archived and new samples that will be collected by you as part of ongoing onshore drilling activity in the Mid-Atlantic Coastal Plain by the USGS and via the International Continental Scientific Drilling Program to test these hypotheses.  

University of Southampton/National Oceanography Centre

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted in the School of Ocean and Earth Science, which cohabits the National Oceanography Centre Southampton. Specific training will


  • Boron isotopic analysis of foraminifera by laser ablation MC-ICPMS.
  • Elemental analysis of foraminifera shells using time-of-flight ICPMS and traditional ICP-MS.
  • Analytical methods of sediment sample preparation, foraminiferal cleaning and general isotope geochemistry wet chemistry.
  • Oxygen and carbon stable isotope analysis of foraminifera.
  • Correlation, integration, and interpretation of multi-proxy palaeoclimate datasets from marine drill cores to test forward models of the PETM. 
  • Foraminiferal taxonomy and physiology
  • Field experience in continental drilling, core logging, sedimentology description and stratigraphic correlation.
  • Oral communication of scientific findings at meetings, national and international conferences, workshops and outreach events.
  • Written communication of scientific findings in drilling reports and scientific journals.
  • Collaboration with international network of Geoscientists.

The student will spend at least 3 months at the University of California, Santa Cruz, with Zachos and Case Western University Ohio, with Babila. In addition, there will be an opportunity to take part in ICDP drilling of the Mid-Atlantic Coastal Plain and travel to relevant core repositories. The student will also participate in IODP/ICDP-related workshops and summer schools and will attend international scientific meetings to present project results. This project is part of a wider NERC-NSFGEO grant (C-FORCE) involving >15 researchers from UK and US institutions that the student will collaborate with. 



Eligibility & Funding Details: 
Background Reading: 

Babila, T.L., Penman, D.E., Standish, C.D., Doubrawa, M., Bralower, T.J., Robinson, M.M., Self-Trail, J.M., Speijer, R.P., Stassen, P., Foster, G.L., Zachos, J.C. (2022) Surface ocean warming and acidification driven by rapid carbon release precedes Paleocene-Eocene Thermal Maximum, Science Advances, 8, 11, eabg1025, doi: 10.1126/sciadv.abg1025.


Dolman, A.M., Laepple, T. (2018) Sedproxy: a forward model for sediment-archived climate proxies, Climate of the Past, 14, 1851-1868,


Gutjahr, M., Ridgwell, A., Sexton, P. F., Anagnostou, E., Pearson, P. N., Pälike, H., ... Foster, G. L. (2017). Very large release of mostly volcanic carbon during the Paleocene-Eocene Thermal Maximum. Nature, 548, 573-577. DOI: 10.1038/nature23646.