A PRONOUNCED 11-YEAR OSCILLATION IN HIGH ARCTIC MARINE BIVALVE SHELLS DURING THE EARLY HOLOCENE CLIMATE OPTIMUM
![](/images/orcid_16x16.png)
Bivalve shells are reliable bio-archives for sub-annual to multi-decadal climate reconstructions. The well-established and calibrated bivalve species <em>Arctica islandica</em> is long-lived (400 yrs), abundant in the fossil record and widely distributed in the North Atlantic. The reconstruction of atmosphere-ocean phenomena, such as NAO, has been demonstrated successfully in this species. Here we present data from early Holocene (9800 cal yrs BP) <em>A. islandica</em> specimens from Svalbard (78°N). All analysed specimens exhibit a dominant 11-year periodicity in their annual shell growth banding pattern. We hypothesise that this cycle is associated with insolation changes driven by the solar sunspot cycle. So far we can only hypothesize about the mechanistic link between the solar cycle and bivalve shell growth. In the high Arctic, where the summer bivalve growing season is characterised by 24 hour daylight, solar energy is the key limiting factor of plankton growth, the main food source for this species. Changes in plankton availability, as a direct result of varying solar insolation, are likely to be reflected in annual shell growth increments.
![](/images/orcid_16x16.png)
AWI Organizations > Graduate Research Schools > ESSReS