PhD: Rate and amplitudes of climate change – are there tipping points in pelagic ecosystems

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 obvious concern over the impact the current unprecedented rate of change will have on marine ecosystems and the services these provide.

Marine zooplankton play a fundamental role in the marine ecosystem. They contribute to the export of carbon to the deep ocean thereby impacting the climate system via the carbon cycle. Here we set out to assess if the amplitude of climate change and the rate at which this change occurred scale linearly or if there is a tipping point when the ecosystem 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 quantifying the impact of climate change on the group through major perturbations in Earth History. Their abundance, distribution and geochemical composition of their shell are established ways of reconstructing past climates.
This project will use the size of planktic foraminifers as a master trait to assess the impact of climate change on the group. Size in planktic foraminifers indicates optimum environmental conditions and is readily preserved in marine records.

The student will generate size records across major events in Earth history such as the Cretaceous-Paleogene boundary, the Palaeocene Eocene boundary to name but a few. The student will use an automated microscope to generate size data of foraminifera as a group. Changes in the ocean physical system will be analysed using trace elements in the foraminiferal shell. Important species/lineages will be morphometrically analysed to address the question at both the species level and the macroevolution/ecology of the group. 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.

The student will get first class training in image analysis, morphometrics, geochemistry, CT scanning, taxonomy and stratigraphy of foraminifers. The student will join the world leading Bristol Palaeobiology group, be linked closely to the modelling group in Bridge.