About the project
Almost all marine life depends (either directly or indirectly) on the rate of phytoplankton growth using sunlight, nutrients and carbon (i.e. the rate of primary production). It also impacts atmospheric oxygen and carbon dioxide. This project will produce new, improved estimates of oceanic primary production through time.
Two previous studies suggesting control by phosphorus (ref. 1) and nitrogen (ref. 2) have each been cited more than 1500 times. The role of iron was not addressed directly in either study, however, but a new biogeochemical model (ref. 3), just developed, includes all three nutrients, and gives a new and improved understanding of how oceanic primary production responds to changes in their input rates.
In this PhD project, you will estimate how nutrient inputs (P, N & Fe) have changed over the Phanerozoic, using plate tectonic reconstruction software (e.g. GPlates) and simulations based on geological data spanning the last 550 million years – a time in which animal and plant life has proliferated and diversified in the oceans and on land. This will include developing estimates of Fe and P release scenarios associated with rock uplift using spatially explicit models of plate tectonics and global lithologies. You will then apply your nutrient input rates to the new biogeochemical model (an extension of the cGENIE Earth system model of intermediate complexity) to calculate how oceanic primary production has feasibly changed. Finally, you will look to understand how variable rates of oceanic primary production can help us understand changes in marine life, including evolution of new forms, and changes in Earth’s environment including its climate.
If time permits, the understanding developed will also be used to reconstruct the ocean’s role during times of large changes to Earth, such as at the Paleocene-Eocene Thermal Maximum (PETM) or through the last glacial maximum (LGM).
Supervision
As well as the University of Southampton team, you will also receive supervision from Dr Jamie Wilson (University of Liverpool).
