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  Dr B Hoogakker  No more applications being accepted  Competition Funded PhD Project (Students Worldwide)

About the Project

Fully funded PhD position available to UK and international students! Apply by 12 noon, 5 January 2024 (international applicants must have contacted supervisor by 11 December 2023).

The oceans are expected to become less oxygenated and more acidic in relation to future warming and anthropogenic greenhouse gas emissions. These changes in seawater chemistry will negatively impact marine ecosystem and global biogeochemical cycles.

To understand the natural, longer-term cycling of seawater oxygen concentrations and pH across the geological record of environmental change, several novel proxy methods were recently developed. Until now individual projects have focused on reconstructing either oxygenation or pH, even though deoxygenation and ocean acidification seldom occur in isolation.

This project will consolidate recent progress made in such methodologies, using novel trace element ratios to concomitantly reconstruct seawater oxygen and pH during key warm intervals of the last ca. 3.6 million years, allowing to assess environmental conditions during intervals that were warmer, similar to, and colder than today. This may include the Piancenzian (2.6 to 3.6 Ma), and more recent interglacials of the Pleistocene.

The project will utilise geochemical information contained in the calcite shells of microscopic fossil foraminifera (Fig. 1). Examples of proxy methods that may be used to reconstruct seawater oxygen levels include bottom water and surface water oxygen reconstructions will be based on of carbon isotope gradients between different species of benthic foraminifera, complemented by morphology and trace element measurements, and planktonic foraminifera trace metal/calcium ratios (Lu et al., 2016). Bottom and surface water pH will be reconstructed using the boron isotope composition (11B) of benthic planktonic foraminifera (Foster & Rae 2016). These methods have provided several high profile reconstructions (e.g. de la Vega et al., 2020, Hoogakker 2018).

The tropical Pacific holds the worlds’ largest oxygen minimum zone (Fig. 2), which are of low pH. Reconstructions will focus on this area, utilizing sample material from the International Ocean Discovery Program (

The student will be trained in combining oxygen and pH reconstructions from critical periods with Earth System Model (cGENIE) simulations to identify and assess links between climate variability and ocean chemistry changes.


Marine carbonate samples are available from the IODP. Sample processing, and foraminifera identification, picking and cleaning will be carried out at Heriot-Watt’s Lyell Centre, while benthic foraminifera stable isotopes (for bottom water oxygen and age model reconstructions) will be measured at BGS Keyworth using IRMS. Benthic foraminifera B/Ca (for bottom water pH) will be analyzed at the Australian National University in collaboration with advisor Dr Jimin Yu, while planktonic foraminifera will be analysed for boron isotopes and trace elements (for surface water pH) in the St Andrews Isotope Geochemistry (STAiG) lab. Planktonic foraminifera trace metal/Ca ratios (for surface water oxygenation) will be measured at BGS Keyworth.

The project allows flexibility, with the opportunity to focus on approaches, time intervals, and techniques of particular interest to the student.

Project Timeline

Year 1

Inductions with the past climate change team.

Take part in Heriot-Watts’ postgraduate researcher development programme:

Training in foraminifera identification & cleaning, clean laboratory methods and mass spectrometry, initial measurements and training, literature review.

Year 2

Generate records across key warm intervals. cGENIE modelling. First manuscript.

Opportunity to take part in an IAPETUS placement scheme

Year 3

Finalize data sets including higher resolution intervals, prepare written manuscripts and write thesis.

Opportunity to take part in an IAPETUS placement scheme

Year 3.5

Focus on preparation of written manuscripts and thesis.

Training & Skills

The student will gain specific training in foraminifera identification, mass spectrometry, clean lab chemistry, and geochemical modelling, as well as broader education in geochemistry, oceanography, and climate science. To expand their network and skills, the student will participate in the Urbino Summerschool in Paleoclimatology in their first year, and spend two months at partner Dr Yu’s laboratory at the Australian National University in their second year.

Over the course of the PhD the student will gain transferable skills such as scientific writing, statistics and data analysis, and problem-solving, as well as time management and working towards a long-term goal.

The student will furthermore benefit from partnerships with Prof Leng (BGS), Prof Ridgwell (University of California Riverside), and Dr Pichevin (University of Edinburgh).


Eligibility is under UKRI Terms and Conditions, which means that UK and International candidates may apply. For International Students, UKRI only pay the equivalent of home fees. The differential between home and international fees will likely need to be self-funded. International applicants need to contact the primary supervisor (Prof Babette Hoogakker , [Email Address Removed]) of the project by no later than Monday 11th December 2023 in order to be considered for shortlisting.

How to Apply

All prospective students need to complete the online IAPETUS2 form (link here). Before completing this form, please read the DTP privacy policy as you will need to tick that you have read and understood this.

Both parts of the application must be made by Friday 5th January 2023 at 12pm (GMT), which is the public deadline for applications that will apply across all of the Partnership. 

If you are shortlisted you will be contacted by IAPETUS2 by 19th January 2024 and invited to submit a full application to Heriot Watt University by 9th February 2024.

Equality, Diversity and Inclusion

In order to address historical imbalances in the higher education sector, IAPETUS2 is committed to recruiting a diverse, representative community of researchers in Environmental Science. The DTP has developed an Equality, Diversity and Inclusion policy to further this. This includes the Widening Participation Scheme, which identifies Home applicants from underrepresented groups. The DTP aims to give up to 30% of interview places to those eligible for this scheme. Also we are pleased to introduce the IAPETUS2 Diversifying Talent Scholarship Scheme, a separate competition designed for those from underrepresented groups. For more, please see the IAPETUS2 website.

Further information

Please contact Prof Babette Hoogakker ([Email Address Removed]) if you require further information about the project.

Environmental Sciences (13)

Funding Notes

IAPETUS2’s postgraduate scholarships are tenable for up to 3.5 years and provide the following package of financial support:
A tax-free maintenance grant set at the UK Research Council’s national rate, which in 2023/24 is £18,622;
Payment of tuition fees at the Home rate*;
Access to extensive research support funding; &
Support for an external placement of up to six months.
Part-time award-holders are funded for seven years and receive a maintenance grant at 50% of the full-time rate.
*Eligibility is under UKRI terms and conditions. International Students can apply but it is expected that the differential between home and international fees will likely be self-funded.


De la Vega et al. (2020), Sci. Rep., 10:11002.
Foster & Rae (2016), AnnRev, 44, (207-237).
Hoogakker et al. (2015), Nat. Geosci., 15, 40-44.
Hoogakker et al. (2018), Nature, 562, 410-414.
Raven et al. (2005) Royal Society Policy document 12/05.