PhD: Impact of climate change on marine plankton – lessons from a hot planet

Project Background

In 2014 the IPCC stated that “natural global climate change at rates slower than current anthropogenic climate
change caused significant ecosystem shifts and species extinctions during the past millions of years”. There is
growing concern what impact this rapid climate change has on marine ecosystems and the services these
provide. The geological record of climate change events of differing rates and amplitudes may allow us to
constrain tipping points within the Earth system.
Here we set out to assess whether the amplitude and rate of climate change scale linearly with ecosystem
response, or whether there is a tipping point beyond which marine plankton, specifically foraminifers, cannot
deal with the impact of warming by migration and changes in their abundance and size. Planktic foraminifera
have an amazing fossil record of more than 100 million years which allows us to quantify the impact of climate
change on this group through major perturbations in Earth History.

Project Aims and Methods

The aim of the project is to determine the biotic response to a number of environmental perturbations in the
geological record. This project will use the morphology of planktic foraminifers, with a focus on size, as a master
trait to assess the impact of climate change on the group. Size in planktic foraminifers indicates optimum
environmental conditions. The lab has two automated microscopes which can analyse 2000 specimens in 5
minutes, thereby allowing many events to be assessed.
The student will, jointly with the supervisors and case partner, identify the most promising events and generate
size records across for example the Cretaceous-Paleogene boundary, the Palaeocene Eocene boundary, the
Eocene hyperthermals. Changes in the ocean physical system will be analysed using trace elements in the
foraminiferal shells in Cardiff. Important species/lineages will be morphometrically analysed to address the
question at both the species level and the macroevolution/ecology of the group in discussion with the
supervisor and the case partner. For critical intervals and species, the underlying link between changes in size
and development of the species will be analysed using our in-house CT scanning facilities.

Candidate Requirements
The candidate will have a degree in Geology, Biology or a related subject. The candidate will be curious,
organised and self-motived to take charge of the sample ordering, preparation and analysis of morphological
and geochemical data. The candidate will be confident in handling large datasets which will be generated by
the automated microscope and the generation of age models.

CASE or Collaborative Partner
The student will get biostratigraphic training including the use of specialist industry standard software. They will
be taken through the various aspects of the business, as well as day to day running. This will give them an
appreciation of the industry and how it differs from academic work.

Training
The student will join the world leading Bristol Palaeobiology group and be a member of outstanding research
environments in all three host institutions. The student will get first-class in-house training in automated image
analysis, morphometrics, generation of age models, geochemistry, CT scanning, 3D reconstructions taxonomy
and stratigraphy of foraminifers. Additional courses in R, statistic etc are offered by the group and the university.
No previous knowledge in taxonomy or geochemistry is expected as all the training will be provided. The Cabot
Institute for the Environment provides training in Science communication and the applicant will be encouraged
to participate in outreach activities.

References / Background reading list
Jennions, S.M., Thomas, E., Schmidt, D.N., Lunt, D. and Ridgwell, A. (2015) Changes in benthic ecosystems and
ocean circulation in the Southeast Atlantic across Eocene Thermal Maximum 2. Paleoceanography 30, 1059-
1077.
Lear, C. H., E. M. Mawbey and Y. Rosenthal, 2010: Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records:
Toward unlocking temperatures and saturation states. Paleoceanography, 25 (4), PA4215,
doi:10.1029/2009pa001880.
Littler, K., U. Röhl, T. Westerhold and J. C. Zachos, 2014: A high-resolution benthic stable-isotope record for the
South Atlantic: Implications for orbital-scale changes in Late Paleocene–Early Eocene climate and carbon cycling.
Earth and Planetary Science Letters, 401 (0), 18-30, doi:http://dx.doi.org/10.1016/j.epsl.2014.05.054.
Schmidt, D.N., et al. 2003. Response of planktic foraminiferal size to late Quaternary climate change.
Paleoceanography 18, 10.1029/2002PA000831.
Schmidt, D.N., et al. 2004. Abiotic Forcing of Plankton Evolution in the Cenozoic. Science 303, 207-210.
Schmidt, D.N. (2018) Determining climate change impacts on ecosystems: the role of palaeontology.
Palaeontology 61, 1-12.
Schmidt, D.N., Thomas, E., Authier, E., Saunders, D. and Ridgwell, A. (2018) Strategies in times of crisis—insights
into the benthic foraminiferal record of the Palaeocene–Eocene Thermal Maximum. Phil. Trans. of the Royal
Society A 376.