Environmental ancient DNA as proxy for sea ice reconstructions

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2017

End date

12/31/2020

Budget

983,754 EUR

Fundings

Abstract

Arctic sea ice extent has been declining rapidly over the past decades. Projections indicate that the Arctic will be sea ice free during summer well before the end of the century. This will bring about a major change in the Arctic with consequences for local communities as well as global climate. To understand the implication of changes in Arctic sea ice cover, it is essential to document the variability and rates of such changes. Satellite and historical accounts fail to grasp these sufficiently, therefore we have to document sea ice extent on longer, geological timescales. To reconstruct past sea ice extent, we use signals of sea ice stored in ocean sediments (proxies). There are few proxies available, and each have strengths but also limitations. In aDNAPROX, a cross-disciplinary project that brings together paleoceanographers and molecular ecologists, we developed and assessed sedimentary ancient DNA as a novel proxy for reconstructing Arctic sea ice evolution. The project aimed to be the starting point for developing an innovative technique that will allow us to get better insight into the variability of sea ice extent in the past. Eventually, this will increase the knowledge about the changing Arctic cryosphere and its local and global impact. In this project, we have generated sea ice biomarker data, palynological records and molecular data from surface sediments and sediment cores in the Arctic Ocean, Greenland Sea and Labrador Sea. In a sediment core from the Greenland Sea dating back to almost 100,000 year ago, we recorded sedimentary ancient DNA which showed changes in the molecular assemblage related to changes in sea ice cover. We also successfully tracked the genetic sequence of a single, sea ice organism in this sediment core and in seafloor sediments from different locations in the Arctic. We analysed the sedimentary DNA in recent seafloor sediments from areas with different sea ice regimes, which reveal strong differences in biological diversity. Bringing all our new insights together, we demonstrated a strong potential of sedimentary ancient DNA as a sea ice proxy. This pioneering work will be continued in a new ERC funded research project (2019?2024), where the results from aDNAPROX will be integrated with new data to fully explore the value of using sedimentary ancient DNA for sea ice reconstructions and even broader, for paleoceanography.