About the project
The ocean is losing its breath. Persistent ocean deoxygenation causes disruptions in the nutrient cycle with devastating consequences for ecosystems, but its future remains unclear. This project will use cutting-edge geochemical proxies and climate simulations to better understand the response of oxygen minimum zones and the knock-on effects on marine biodiversity to climate change.
Ocean deoxygenation is a worrying consequence of anthropogenic climate change. As the world warms, oceanic low-oxygen zones are expanding. Deoxygenation is predicted to disrupt nutrient cycling, alter ecosystems and increase extinction risks. Yet these predictions come with big uncertainties. To address this problem, you will turn to Earth's geological past, which holds a wealth of well-documented global warming and cooling events that have not yet been fully explored for their paleo-oxygenation responses.
Focusing on the Cenozoic era (the last 66 million years), a period of substantial climatic transitions, you will investigate the variability of oxygen minimum zones during key events such as the Miocene Climatic Optimum (MCO), and Early Eocene Climatic Optimum (EECO). Recent studies suggest that during these warm periods, ODZs may have contracted, contrary to current trends of expansion.
You will work on sediment and fossil foraminiferal material from the International Ocean Discovery Program (IODP) and use advanced geochemical proxies, including foraminifera-bound nitrogen isotopes, foraminiferal I/Ca ratios, and lipid biomarkers, to reconstruct past marine oxygenation and explore the drivers behind these changes. You will then compare your generated paleo-oxygenation data with cutting-edge paleoclimate simulations to analyse the connections between ocean circulation, nutrient cycling, and oxygenation, shedding light on how these factors impacted carbon sequestration and marine ecosystems.
Using the intermediate complexity Earth system model cGENIE, you will have the opportunity to investigate climatic and tectonic drivers of oceanographic and ecological change, with specific modelling questions depending on your evolving personal research interests.
