Paleoceanography of Arctic Sea Ice and Sediment Dynamics

Paleoceanography of the Arctic combines sedimentary archives with a suite of biological, geochemical and molecular proxies to reconstruct past variations in sea-ice cover, ocean circulation and sediment delivery. Marine sediments beneath the central basin and continental margins preserve evidence of changing ice shelves, sea-ice extent, meltwater pulses and current-strength shifts over timescales from millennia to millions of years. Microfossil assemblages, ice-rafted debris, biomarkers and ancient DNA each record the ebb and flow of sea ice and the influx of Atlantic or Pacific waters. These reconstructions illuminate how Arctic sea ice has responded to natural warming events such as the Last Interglacial and Holocene Thermal Maximum, and how feedbacks between ice cover, ocean stratification and sediment transport regulate regional and global climate. Understanding these dynamics is vital for anticipating future sea-ice trajectories and the impact on marine ecosystems, carbon cycling and sea-level rise.

Research from Nature Portfolio

Recent studies have shown that during the early Last Interglacial, southward export of Arctic freshwater suppressed deep-water formation in the Nordic Seas, altering ocean heat transport and regional climate stability. Sediment-based microfossil analyses from the central Arctic indicate that summers were largely ice free, as revealed by subpolar foraminifera penetrating into the basin, offering a prime analogue for future seasonal sea-ice loss. Advances in molecular palaeoceanography demonstrate that sedimentary ancient DNA from the sea-ice microalga Polarella glacialis can serve as a high-resolution proxy for past sea-ice conditions, surpassing traditional micropalaeontological methods and enabling circum-polar reconstructions over the last 12 000 years.

Paleoceanography of Arctic Sea Ice and Sediment Dynamics publication trend

The graph below shows the total number of articles in paleoceanography of arctic sea ice and sediment dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Paleoceanography: The study of past ocean conditions using geological and proxy data.

Proxy: A preserved physical or chemical indicator used to infer past environmental variables.

Biomarker: Organic molecules preserved in sediments that reflect the presence or activity of particular organisms.

Foraminifera: Single-celled marine protists whose shells (tests) record environmental parameters.

Sedimentary ancient DNA (sedaDNA): Genetic material preserved in sediments, used to trace past biological communities.

Ice shelf: A floating extension of a land-based glacier or ice sheet, often leaving distinct seafloor imprints when grounded.

References

1. Arctic freshwater outflow suppressed Nordic Seas overturning and oceanic heat transport during the Last Interglacial. Nature Communications (2024).
2. A seasonally ice-free Arctic Ocean during the Last Interglacial. Nature Geoscience (2023).
3. Millennial-scale variations in Arctic sea ice are recorded in sedimentary ancient DNA of the microalga Polarella glacialis. Communications Earth & Environment (2024).
4. Non-linear response of glacier melting to Holocene warming in Svalbard recorded by sedimentary iron (oxyhydr)oxides. Earth and Planetary Science Letters (2023).
5. Holocene history of the 79∘ N ice shelf reconstructed from epishelf lake and uplifted glaciomarine sediments. The Cryosphere (2023).