ANTarctic Sea Ice Evolution from a novel biological archive

Project Information

ANTSIE

Grant agreement ID: 864637

DOI

10.3030/864637

Project closed

EC signature date 4 May 2020

Start date 1 June 2020

End date 30 November 2025

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 999 928,75

EU contribution

€ 1 999 928,75

Coordinated by

UNIVERSITY OF DURHAM
United Kingdom

Periodic Reporting for period 3 - ANTSIE (ANTarctic Sea Ice Evolution from a novel biological archive)

Reporting period: 2023-06-01 to 2024-11-30

Summary of the context and overall objectives of the project

Antarctic sea ice is globally important, because it influences how heat is stored and transferred through our climate system, and affects the transfer of gases including carbon dioxide (CO2) between the ocean and the atmosphere. Antarctic ecosystems are closely associated with the seasonal fluctuations in sea ice, and vulnerable to future climate change. The complexity of the sea-ice environment, and the relatively short duration of measurements by ships and satellites, means that there are both large uncertainties and model disagreements about future sea ice. The geological record shows there have been large changes to the extent and nature of Antarctic sea ice over thousands to millions of years, offering us opportunities to explore both the drivers and ecosystem impacts of changes to the sea-ice environment. In this project, we are developing and learning from a novel biological sampling approach: using the snow petrels (Pagodroma nivea) as recorders of Antarctic sea-ice conditions, now and in the past.

The aim of the ANTSIE project is to reconstruct and assess the evolution of the sea-ice environment in the eastern Weddell Sea over the last ~40,000 years. This covers the time window before, during and after the Last Glacial Maximum (when sea ice extended thousands of km to the north of its current limit). Our aim is being achieved by addressing the following objectives:
1. tracking the use of sea-ice habitats by snow petrels and measuring the biochemical signature of foraging behaviour in stomach oils and tissues;
2. reconstructing snow petrel diet over time using biochemical and geochemical analyses of a network of well-dated snow petrel stomach-oil deposits;
3. inferring changes to conditions within the sea ice through time by combining objectives 1 and 2
4. assessing climate model simulations for sea-ice conditions through comparison with the data from objectives 1-3, and exploring the climatic impact of changes to sea ice over time.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

ANTSIE has developed activities related to all four objectives during the first 30 months of the project, having now recruited all of the new staff. We have presented the plans for our project and initial results at four international conferences, ten national conferences, three public talks and an online blog.

Our main activities and results so far:
1. We successfully deployed GPS trackers on snow petrels during the 2021-2022 Antarctic field season, and collected stomach oil and feather samples for diet analysis. The fieldwork was based at the Princess Elisabeth Station, Antarctica, supported by the International Polar Foundation. We have been able to determine patterns of snow petrel foraging and links to sea ice distribution. Conference presentations include Honan, E.M. et al. (2022) World Seabird Conference, Cork, Ireland.
2. We retrieved 10 new snow petrel stomach-oil deposits from near Princess Elisabeth Station, Antarctica. The deposits have been radiocarbon dated, and chemical analyses have begun so that we can reconstruct diet through time. Conference presentations introducing the project include Cole, Y., Penny, C. et al. (2022) British Organic Geochemistry Society, Southampton, U.K.
3. We began chemical analyses on existing, radiocarbon-dated stomach-oil deposits from the Coats Land region, Antarctica. We have been able to detect changes in snow petrel diet occurring during the Holocene (the time since the Last Glacial Maximum). Conference presentations showing initial results include Stevenson, M.A. et al. (2022) British Organic Geochemistry Society, Southampton, U.K.
4. We published the results from a stomach-oil deposit in Dronning Maud Land. Here we combined bio- and geo-chemical analyses of the element content, fatty acid distributions, and stable isotope ratios to identify changes to snow petrel diet occurring over thousands of years during an interval of expanding sea ice before the Last Glacial Maximum (McClymont et al., 2022, Climate of the Past). We have presented this work at several conferences including the Geological Society of America (2021) and the Scientific Committee on Antarctic Research Open Science Meeting (2022).

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

We are generating novel assessments of Antarctic sea-ice ecosystems and environments, by reconstructing regional networks of changing snow petrel diet. This is being achieved by producing overlapping sequences of bio- and geo-chemical information from snow petrel stomach-oil deposits. This is the first time that we have been able to generate such long and multi-disciplinary time series of sea-ice environments from the perspective of a predator. We have been able to add a second suite of deposits to our original network, through the fieldwork in 2021-2022 based at Princess Elisabeth Station (Sor Rondane Mountains, Antarctica). The Sor Rondane deposits are providing diet information from a new area of Antarctica, which both complements and contrasts with the samples from Coats Land and Dronning Maud Land we are also analysing.

Our interpretations of the changes in snow petrel diet through time are being refined by our new results of the tracking analysis, where we have been able to assess the foraging behaviour of the snow petrels in relation to environmental variables including sea ice. Our next step is to combine the tracking data with analysis of snow petrel stomach oils, to link the biochemical signals in the deposits directly to conditions in the sea ice environment.

Our initial results from the stomach-oil deposits show that for the first time we will be able to reconstruct long time series of snow petrel diet, which will extend through the Holocene and Last Glacial Maximum. We also have samples spanning the time interval immediately preceding the Last Glacial Maximum when there is other geological evidence for expanding Antarctic sea ice. We will be able to compare and contrast the results we generate from our western (Coats Land) and eastern (Sor Rondane) sites, to consider local variability in snow petrel diet over time. We expect that we will be able to draw on our tracking and modern diet sampling analysis to consider what these results mean in terms of changes in the sea-ice environment over time.

We will draw together our analysis of snow petrel diet through time with state-of-the-art climate modelling evidence for changes to sea ice in the same region. We will explore whether our data align with climate model outputs for sea-ice extent and sea-ice properties, and investigate the climatic impact of different sea ice scenarios for the Last Glacial Maximum and Holocene.

ANTSIE researcher Ellie Honan sub-sampling snow petrel stomach-oil deposits. Credit: Steph Prince

Adult snow petrel (Pagodroma nivea) nesting beneath boulders in Antarctica. Credit: Ewan Wakefield

ANTSIE researcher Yas Cole sub-sampling snow petrel stomach-oil deposit. Credit: Erin McClymont