Resolving Antarctic meltwater events in marine sediments and exploring their significance using climate models

Dr Alessandro Silvano, Dr Claire Allen, Main Supervisor, British Antarctic Survey (BAS),; Dr Louise C Sime, BAS,; Dr George Swann, Nottingham University,; Prof Melanie Leng, BGS, Nottingham University,,

Project Overview

The principal aim is to understand how enhanced melting of the Antarctic ice sheet affects global ocean circulation, sea level and climate. Proxy records of glacial discharge for past high sea-levels will be used with model simulations to resolve the processes and impacts of greater freshwater-flux to the Southern Ocean.

Project Description

Ice that has built up in Antarctica and Greenland over thousands of years is discharging into the ocean at an accelerating rate. Injecting fresh, cold water into the ocean can slow circulation and reduce the transfer of heat, carbon, oxygen and nutrients throughout the global ocean.

This project combines proxy and modelling components to impart a truly multi-disciplinary approach to understand the global impacts of Antarctica’s meltwater inputs.

Last Interglacial (LIG; 130-120 ka): A lasting enigma in climate research is to establish the source and forcing at the peak of the LIG (~127ka) when global mean sea level (GMSL) was 6-9 m higher than present. Ice loss from Greenland alone cannot account for this, so sights have turned to Antarctica to account for the bulk of the LIG sea level rise (Fig.2).

Historical (~1 ka to present): Existing records of Antarctic glacial discharge either do not include the Anthropocene (Fig.3-green), are at very low resolution (Fig.3-orange) or are from sites on the inner continental shelf where glacial discharge is likely dominated by local glacier conditions (Fig.3-blue & pink). As such, historical records of continental-scale ice discharge are urgently needed.

The results of this project will deliver timely evidence of Antarctica’s role in ocean circulation, GMSL rise and climate change to a broad range of research themes such as SCAR’s (Scientific Committee on Antarctic Research) INSTANT Scientific Research Programme, WCRP’s (World Climate Research Programme) CliC Project and the PAGES (Past Global Changes) CLIVASH2k, QUIGS and PALSEA working groups.




University of Southampton/National Oceanography Centre

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the British Antarctic Survey. Specific training will include:

Proxy component: The diatom-based oxygen isotope (δ18O(diatom)) proxy for Antarctic glacial discharge will be anlysed on LIG and recent sediments from the iceberg alley in the deep Southern Ocean. δ18O(diatom) and other proxies (eg. ice-rafted debris, diatom assemblages) will be employed to resolve Antarctic ice sheet discharge events. Modelling component: There are multiple benefits that arise from including water tracers in climate models, including (1) the ability to assess relationships between isotopic concentrations and ocean-climate variables, ensuing the most accurate interpretation of stable water isotopic measurement from sediment cores to provide important long-term records of past changes, and (2) representation of water tracers and isotopes within UKESM2 (UK Earth System Model) allows us to gain a better understanding of crucial hydrological processes within the model and better predict how the earth system will respond to Antarctic meltwater events under future climate change.


Eligibility & Funding Details: 
Background Reading: 

> Silvano, A., Rintoul, S.R., Peña-Molina, B. et al. (2018) Freshening by glacial meltwater enhances melting of ice shelves and reduces formation of Antarctic Bottom Water. Science Advances 4, eaap9467. doi:10.1126/sciadv.aap9467

> Pike, J., Swann, G., Leng, M. et al. (2013) Glacial discharge along the west Antarctic Peninsula during the Holocene. Nature Geoscience 6, 199–202.