Arctic Ocean borealization during past warm climates

This project aims to investigate borealization of the Arctic Ocean during interglacial periods of the past one million years, as analogues for the future.

Borealization refers to the expansion of subpolar marine species into the Arctic basin, which threaten to disrupt endemic ice-adapted ecosystems.

The process is closely coupled to ‘Atlantification’ and ‘Pacification’, involving northward expansion of these water masses into the Arctic.

The project will focus on fossil planktonic foraminifera, microscopic shell-building members of the zooplankton that are sensitive indicators of ocean conditions.

Previous work by my group has shown at least 2 borealizationevents in the past 1 myrs, involving pan-Arctic invasions of subpolar foraminifera.

How this happened, if it involved Atlantic or Pacific water inflows, and what the impact was on existing ecosystems remains uncertain.

The project will recruit a PhD student to analyze marine sediment cores across the Arctic Ocean and subpolar seas, and generate new and synthesize existing data on past plankton communities and their ecology.

Geochemical signals, including oxygen and carbon stable isotopes, clumped isotopes and B/Ca will provide information on past ocean temperature, salinity, nutrients and pH, useful for identifying water mass source and environmental conditions.

New climate model simulations will be used to help understand if borealization events have common drivers and what humans can expect in coming decades.