Dr T Ezard, Prof P Wilson
No more applications being accepted
Competition Funded PhD Project (European/UK Students Only)
About the Project
Project Rationale :
Ongoing declines in biodiversity call for accurate predictions of extinction risk arising from climate change. Long-term studies of evolutionary response to climate change require investigation of the fossil record, but very few fossil records allow us to make highly resolved reconstructions of evolution. The exceptionally well-preserved fossil record of planktonic foraminifera, an abundant and wide-spread group of marine zooplankton, allows for detailed analyses of evolutionary change across diverse environmental settings and climate states.
Planktonic foraminifera diversity has decreased steadily over the past 5 million years [1,2]. Over this interval Earth’s climate transitioned from a warm distinctly unipolar (Antarctic) glacial climate state to become cold enough to support large ice polar sheets in both hemispheres; initially during ~41 thousand year (kyr)-paced glacial cycles, eventually during the large ~100 kyr-paced Ice Age cycles [3]. It is widely suggested that climate played a role in this decline in diversity, but the causes of individual extinctions remain unknown.
This project will study all 46 extinctions of planktonic foraminifera species in the past 5 million years in order to investigate common driving mechanisms and early warning signals. Changes in shell size and shape of extinct-going and surviving species will be compared to local records of environmental change using multivariate statistical techniques [4] to test for threshold response behaviour to climate change-forcing.
Methodology:
To compare high-resolution morphological change to high-resolution local environmental change, this project will quantify multivariate morphological change preceding extinction, as well as measure the chemical composition of individual shells to study climatic conditions in the specimens’ direct environment. Well-preserved foraminifera will be picked, mounted, imaged and measured, after which they will be analyzed for Mg/Ca using LA-ICP-MS to study morphological response to temperature changes in its direct environment, and oxygen and carbon isotopes to study vertical habitat shifts. Foraminiferal assemblage studies will be carried out to compare the surviving species’ responses, including changes in morphology, relative abundance or depth habitat. Comparisons between morphology and environment will be made using multivariate regression techniques, including generalized linear models and linear mixed effect models.
Training:
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 at the University of Southampton. Specific training will
include:
• Multivariate morphometrics
• Neogene planktonic foraminifera taxonomy
• Stable oxygen and carbon isotope analysis
• Trace element analysis
• Multivariate regression techniques
Funding Notes
You can apply for fully-funded studentships (stipend and fees) from INSPIRE if you:
Are a UK or EU national.
Have no restrictions on how long you can stay in the UK.
Have been 'ordinarily resident' in the UK for 3 years prior to the start of the project.
Please click http://inspire-dtp.ac.uk/how-apply for more information on eligibilty and how to apply
References
[1] Aze, T. et al. A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological reviews of the Cambridge Philosophical Society 86, 900-927 (2011).
[2] Ezard, T.H.G., Aze, T., Pearson, P.N. & Purvis, A. Interplay Between Changing Climate and Species' Ecology Drives Macroevolutionary Dynamics. Science 332, 349-351 (2011)
[3] Lisiecki, L.E. & Raymo, M.E. A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records. Paleoceanography 20 (2005).
[4] Brombacher, A., Wilson, P.A., Bailey, I. & Ezard, T.H. Temperature is a poor proxy for synergistic climate forcing of plankton evolution. Proc. R. Soc. B 285, 20180665 (2018).
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