PhD: The role of marine plankton in the Earth’s chemistry

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”. There is growing concern what
impact this rapid climate change has on marine ecosystems and the services these provide to humans.
Marine calcifying plankton have an amazing fossil record of more than 100 million years. Interestingly, the
composition of marine carbonates evolved from a coccolithophore dominated ooze to a balance between
foraminiferal (marine protist) and coccolithophore. This project aims to assess 1) the link between
oceanography and evolution in changing this carbonate factory; 2) modern drivers of carbonate production
3) and vulnerability of carbonate production in response to changing climate. You will use the geological
record and an Earth system model to determine the environmental and ecological drivers behind this change
and whether there is a tipping point beyond which marine plankton cannot deal with the impact of climate
change.

Project Aims and Methods.
The aim of the project is to test the hypothesis that environmental change will reduce carbonate production
by marine plankton in the future. Laboratory experiments are impossible to conduct which would consider
timescales of adaptation and the complexity of plankton ecology and diversity. Therefore, this project will
use a combination of the geological record of biotic response to several environmental perturbations and its
impact on the carbon cycle with Earth System modelling. You will, jointly with the supervisors, identify the
most promising events and generate size records across events. You will (1) determine the impact of abiotic
versus biotic drivers on the long term composition of marine carbonates. You will (2) use a novel a size
structure trait-based plankton model within an Earth system model of these historical time intervals to
disentangle different drivers of change. You will (3) use the model to quantify how traits might change across
the transitions (4) compare modelled changes in traits to evidence from geological record. You will consider
environmental pressures under different futures and develop projections of how carbonate production
might change in response. The labs in Bristol and Exeter have automated microscopes, flow cytometers, and
SEMs for size analysis of coccoliths.

Candidate requirements
The candidate will have a degree in Geology, Environmental Sciences, Physics, or a related subject. The
candidate will be numerate, curious, organised and self-motived to take charge of model development and
laboratory work. The candidate will be confident in handling large datasets and ideally have some
background using a programming language, such as R, Python, etc. We welcome and encourage student
applications from under-represented groups. We value a diverse research environment.

Collaborative partner
The collaborative partner MBA hosts a wide range of academics interested in marine plankton. The Brownlee
lab cultures coccolithophores and investigates their physiology. The lab is leading in the UK in understanding
calcification processes in marine plankton. The student would be embedded in the lab activity, learn to
culture and perform experiments. The understand will be fed back into the models to test the set up.

Training
The student will join the world leading Bristol Palaeobiology group, the climate modelling group Bridge, and
be a member of outstanding research environments at the host institutions. The student will get first-class
in-house training in writing code, earth system modelling, automated image analysis, morphometrics and
analysis of large data sets. Additional courses in R, Python, statistics etc are offered by the group and the
university. 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.