2024-B13 Identifying critical temperature thresholds in marine ecosystems

Project highlights

Join a world-class team of scientists working to understand the links between extreme climate events and ecosystem dynamics
Constrain the dominant patterns, responses, and driver(s) of marine ecosystem change
Learn a diverse range of key statistical, palaeobiological and geochemical techniques to investigate past life and climates

Overview

Anthropogenic climate change is impacting biodiversity with direct consequences for ecosystem functioning and Earth system dynamics. However, our ability to predict changes is largely limited by the lack of clarity in the complex relationship between environmental and community change. This is particularly true of planktic foraminifera, a major group of calcifying marine plankton and key players in global carbon cycling. Fortunately, planktic foraminifera have an exceptional fossil record that spans multiple short-lived (~100-170 kyrs) global warming events or ‘hyperthermals’ that occurred between ~57-48 Myrs ago, our best geological analogues for the ongoing anthropogenic change. The fossil record across these events provide a unique and direct window into how foraminifera responded to multiple synergistic drivers, accounting for species/trophic level interactions and adaptation, difficult or impossible to observe in laboratory cultures or ecological models. However, how planktic foraminiferal ecosystems change and scale with key environmental parameters such as temperature across hyperthermal events is not well known. Here, we will generate high-resolution records of planktic foraminiferal community and temperature (a “master” climate variable and important driver of planktic foraminiferal diversity) from the same samples across the early Paleogene, an interval characterized by different rates and magnitudes of temperature and associated environmental change. This will allow identification for the first time of critical temperature thresholds for planktic foraminiferal community changes, as well as any characteristic (and therefore) predictable biotic responses, filling key gaps in our understanding of both past and modern ecosystem evolution.

Project research objectives are:

[1] What is the timing and amplitude of sea surface temperatures (SST) change across early Paleogene background (i.e., between events) and “hyperthermal” events?

[2] How do planktic foraminiferal communities change across the early Paleogene background and “hyperthermal” events?

[3]: What are the SST thresholds for inducing different types (e.g., richness, origination, extinction, ecology) of planktic foraminiferal community change and are they the same everywhere in the ocean?

[4] How do SST thresholds compare between different time intervals and thus, what can they tell us about modern and future communities.

Figure 1: The IODP ship Joides Resolution leaving Hawaii (William Crawford IODP/TAMU) and below fossil planktic foraminiferal tests.

Host

University of Birmingham

Theme

Climate and Environmental Sustainability
Organisms and Ecosystems

Supervisors

Project investigator

Dr Kirsty Edgar, University of Birmingham, [email protected]

Co-investigators

Dr Shan Huang (University of Birmingham; [email protected])

Prof. Carrie Lear (Cardiff University; [email protected])

Dr Sonal Khanolkar (GEOMAR, Germany; [email protected])

How to apply

Each host has a slightly different application process.
Find out how to apply for this studentship.
All applications must include the CENTA application form.
Choose your application route

Methodology

The student will disaggregate deep–sea sediments, pick and identify planktic foraminifera shells from sites with good age models and carbonate preservation across key global warming events. Provisionally, the PETM, ETM2 and ETM3 from IODP sites U1514 and 1209 to test for similarities and differences in high versus low latitude responses. New foraminiferal-based stable isotope (𝛿13C and 𝛿 18O) and trace element (Mg/Ca) sea surface temperature records will be generated where not already available. Planktic foraminiferal assemblages will be assessed using a range of community and ecological measures to quantify the type and amount of change. Subsequently, the amount, type and rate of biological change versus temperature change at each site will be determined. New data will be compared with published assemblage and SST data from other sites, and time intervals to contextualise these data and finally, temperature thresholds will be considered in the context of different IPCC Shared Socioeconomic Pathways.

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

The student will gain a broad range of micropaleontological and palaeoclimatic skills. Lab-work will develop specific skills in sedimentology and sediment-based proxies, palaeoclimatology, foraminiferal taxonomy, taphonomy, palaeobiological and geochemical analyses. The student will learn how to use the free R environment to conduct diversity and uncertainty analyses, multivariate statistical modelling, graphing and mapping. Opportunities for travel to visit core repositories and attend relevant international summer schools are possible. Acquired skills are highly transferable within academia and industry, and will enable the student to specialise as a palaeontologist or palaeoclimatologist.

Partners and collaboration

Prof. Caroline Lear is a palaeoclimatologist based at Cardiff University with >25 years’ experience developing and applying geochemical proxies for past climate and oceanographic change. In particular, she pioneered the development and application of the Mg/Ca paleothermometer to reconstruct ocean temperature and salinity in the Cenozoic. She has also developed and applied proxies for seawater carbonate chemistry and redox conditions. Prof. Lear will host the PhD researcher for 1-3 months in Cardiff within Years 1-2 of the PhD to conduct trace element analyses (depending on sample numbers).

Dr Sonal Khanolkar is currently based at GEOMAR, Helmholtz Centre for Ocean Research, Germany. She is a foraminiferal geochemist and taxonomist specialising in novel trace element techniques, and Paleogene shallow water communities and stratigraphies. She will be involved with supporting the student throughout the project particularly with regards to compilation of data from shallow water envrionments.

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here:

For any enquiries related to this project please contact Dr Kirsty Edgar ([email protected]).

To apply to this project:

You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024.
You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.
Please submit your application and complete the host institution application process via: https://sits.bham.ac.uk/lpages/LES068.htm. Please select the PhD Geography and Environmental Science (CENTA) 2024/25 Apply Now button. The CENTA application form 2024 and CV can be uploaded to the Application Information section of the online form. Please quote CENTA 2024-B13  when completing the application form.

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024.

Check out the Palaeobiology and Palaeoclimate group webpages for more information on the group that you would be joining: https://www.birmingham.ac.uk/research/activity/earth-sciences/index.aspx or follow us on twitter @Palaeo_bham.

Possible timeline

Year 1

Processing and picking of deep-sea sediments, generation of stable isotope and trace element records. Attendance at palaeoclimate summer school and short research visit to Cardiff University to conduct trace element analyses.

Year 2

Planktic foraminiferal assemblage analysis across hyperthermal events. Imaging of specimens. Preparation of first paper(s) on temperature change across Paleogene hyperthermal events.

Year 3

Continued planktic foraminiferal community analysis. Determination of biotic sensitivity. Comparisons to other events and sites. Preparation of paper(s) on biotic sensitivity (and possibly planktic foraminiferal assemblages). Write-up of thesis.