500 year old mollusc tells about past climate changes – University of Copenhagen

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14 June 2012

500 year old mollusc tells about past climate changes

This Arctica islandica mollusc (shell no. 061294, nicknamed 'Hafrún' in Icelandic) was caught alive north of Iceland in 2006, having lived there for 507 years (transition from larval stage in AD 1499).

The marine mollusc Arctica islandica ranks among the longest lived non-colonial animals known to science. The species has been called the tree of the sea, because each year, a growth band of carbonate is added to the shell, similar to the growth of trees.

Living and fossil shells of this species were collected from the sea-floor north of Iceland in order to study past climate changes and the links between oceanographic and atmospheric changes in the North Atlantic region.

The oldest individual animal (caught alive) turned out to be over 500 years old. Radiocarbon data from the mollusc shells give information on the history of the ocean circulation history of the North Atlantic, which is a major factor in the European climate system.

Guest researcher at GeoGenetics Jón Eiriksson contributed to the article 'Surface changes in the North Atlantic meridional overturning circulation during the last millennium' in Nature Communications (doi:10.1038/ncomms1901).

A shell dredge haul from the RV Bjarni Sæmundsson cruise in 2006, organised by the EU funded Millennium project. Jón Eiríksson (Cruise leader) and William E. Austin standing by.