Regional East Antarctic and its Provinces
The imprint of anthropogenic climate change on Antarctica and the Southern Ocean has so far revealed a pronounced asymmetry between West and East Antarctica, with distinct differences in air and sea-surface temperature as well as sea-ice changes, and ice shelf meltwater rates. P2 will focus on exploration of the causal linkages between atmosphere, ocean, cryosphere in both the present day and geological past to better inform future projections of how East Antarctica will be altered in the coming decades. This program will also investigate the consequent effects of a changing East Antarctica on open water and under ice biogeochemistry and ecology, using a combination of palaeo, contemporary and future model projections. Addressing these issues needs a multi-faceted archive derived from a combination of observations (regional remote-sensing, core records), improved mechanistic understanding from process studies (transdisciplinary voyages, links to P3) and advances in modelling (links with large scale climate/carbon cycle modelling in P1). P2 will forge linkages with allied activities (international (ACEAS PIs) and P1) taking place in West Antarctica to improve our understanding of the drivers of these conspicuous trends between the sub-continents.
What are the causal linkages between atmosphere, ocean, cryosphere, and their consequent effects on open water and under ice biogeochemistry and ecology in the East Antarctic under past, present and future conditions?
- Assess how Southern Ocean wind changes affect the regional oceanic circulation and sea ice (e.g. sea ice transport, creation of polynyas) on timescales ranging from decadal (e.g. over the last few centuries to millennia) to centennial (e.g. past abrupt climate change), to multi-millennial (e.g. glacial-interglacial timescales) using ocean/sea-ice models.
- Assess how the above regional changes in wind, oceanic circulation and sea-ice impact ocean temperature, salinity, biogeochemical properties (e.g. O2, DIC, PO4, chlorophyll), and atmospheric CO2 combining ocean/sea-ice/carbon cycle models and palaeo-proxy records.
- Use palaeo-proxy records to identify past Antarctic meltwater events in East Antarctica, and assess their influence on oceanic circulation and sea-ice using proxy records and coupled modelling.
- Evaluate the consequent effects on open water and under ice biogeochemistry and ecology for both contemporary and past climate.
- Use palaeo-proxy records to assess past changes in ecosystem structure and function and export production near the Marginal Ice Zone (MIZ), and their potential link to changes in iron supply from the cryosphere and atmosphere.
- Assess the impact of changes in oceanic circulation, sea-ice and iron inputs on ecosystems and the carbon cycle in the MIZ using Earth system models.
- Perform contemporary measurements in the MIZ on under ice and open water food webs, coupled biogeochemistry, downward carbon export, water column and sea ice chemistry, and isotopes of oxygen, carbon and neodymium to calibrate palaeo proxy records.