Radiocarbon-dated Mytilus edulis and Modiolus modiolus from northern Svalbard: Climatic implications

Eighteen new age determinations on Mytilus edulis shells from northern Svalbard and two new age determinations on Modiolus modiolus shells are presented. Mytilus edulis appeared on the northern coast of Spitsbergen c . 9400 yr BP. Its maximum extension there seems to have been c . 7250 yr BP, which is also indicative of a climatic optimum. The first finding of Modiolus modiolus shells from northern Spitsbergen is reported, and revealed the age of c . 8300 yr BP, which is also indicative of marine climatic optimum conditions. Mytilus lived at the head of Woodfjorden until at least 5300 yr BP, but it is not possible to date its final disappearance from the northern coast. Mytilus has been absent from large parts of the coasts of Svalbard during the entire Holocene, indicating limited influence of warm Atlantic water there. Recent reports of living Mytilus edulis on Bjørnøya indicate a probable new occurrence there, and the question about a further immigration to Spitsbergen should be kept in mind. Such a faunistic change may provide data about a more general climatic warming in this part of the Arctic.