Establishing Long-term High-Resolution Coralline Algae Records of Arctic-Atlantic Ocean-Sea Ice Variability

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2019

End date

12/31/2023

Budget

1,224,342 EUR

Fundings

Abstract

The loss of Arctic sea ice in recent decades is well documented and is one of the most visible manifestations of ongoing climate change. The decline has been most significant during summer, and if current trends persist, prognoses suggest that Arctic summer sea ice may disappear within the next decades. Associated with the decline in sea ice cover is an increase in primary productivity, which partly can be attributable to reduced summer ice areal extent and a longer phytoplankton growing season, which have implications for the ecosystem. These marked changes have generated research interest in the seasonal prediction and predictability of the Arctic climate- and ecosystems. However, sea ice modeling uncertainties are large as long-term, multidecadal, sea ice variability is poorly understood due to short instrumental and satellite records. In the CARA-ICE-project, we will investigate how the poleward propagation of anomalous heat from the subpolar North Atlantic towards the Arctic Ocean affects the sea ice cover in the Arctic-Atlantic on multi-century timescales. We will use crustose coralline algae, a novel marine proxy for sea ice-covered regions that is the only archive known from the Subarctic and Arctic that can achieve this. Long-lived coralline algal buildups on the shallow Svalbard shelf will be used to reconstruct climate and ice variability for several centuries in the past. In CARA-ICE, we will test and quantitatively constrain the degree to which the annual growth and trace elemental ratios of crustose coralline algae living on the Svalbard shelf generally represent the ocean and sea ice in the exceptionally varying site characterized by a confluence of temperate and polar currents and Arctic sea ice. Further, CARA-ICE aims at providing ground-breaking data that will increase the potential for skillful climate prediction in the Arctic-Atlantic. The coralline algae Clathromorphum compactum is a crust-forming algae that lives on rocky shores around the Arctic. Divers collected specimens of C. compactum from areas north of Spitsbergen and along the coast of Nordaustlandet up to Nordkapp during a cruise during the summer of 2020. Every sample collected during the cruise (>100) has been checked to assess longevity and quality. In total 125 samples have been pre-selected and processed further. The samples of the highest quality have been chosen for LA-ICP-MS analysis. Preliminary data comprise a multi-specimen record of algae growth and sea ice going back 140 years, as well as a single-specimen record going back 280 years (AD 1740-2020).