Elisha Hayward

Generating high-resolution foraminiferal records to explore the response of oceans and marine ecosystems across a major climate transition

PhD project title:

Investigating Climate, Ocean Circulation and Marine Ecosystem Changes Across the Late Eocene to Early Oligocene

Project description:

Elisha Hayward

The Eocene-Oligocene transition (~34 million years ago) represents one of the most prominent climate transitions of the Cenozoic. Thought to signify Earth’s shift from ‘greenhouse’ to ‘icehouse’ climate, dramatic cooling resulted in the first continental-scale glaciation of Antarctica. Declining atmospheric carbon dioxide (CO2) has been suggested as the principal cause, however, systematic changes in ocean circulation have been implicated as additional drivers. Including an initiation or strengthening of the Atlantic Meridional Overturning Circulation and opening of Southern Ocean gateways. Nevertheless, a paucity of high-resolution records prevents the timing, magnitude and mechanism(s) of the climate transition from being fully resolved.
My research seeks to generate new, high-resolution foraminiferal assemblage and geochemical (stable isotopes and trace metals) data from a selection of Atlantic Ocean sediment cores. Allowing derivation of new temperature and CO2 records, and investigation into the role/response of Atlantic water masses/circulation changes across the climate transition. Additionally, the response of marine ecosystems will be explored through morphological analysis of micro- and macrofossil museum specimens alongside foraminiferal assemblage changes.
Reconstruction of late Eocene to early Oligocene climate allows the interplay of climate forcings, feedback mechanisms and key thresholds to be investigated in a time of CO2 concentrations approximately double present-day levels. Whilst also providing insight into the physical response of marine organisms through a major climate transition.

Resources: