Holocene range of Mytilus edulis in central East Greenland

Radiocarbon age determinations on shells of the common mussel (Mytilus edulis) show that this species was present in central East Greenland from approximately 9500 to 5400 cal. years BP. It probably arrived first at the outer coast, at a time when the inner parts of the fjords were still occupied by glaciers. After perhaps a millennium it spread to the central fjord region where it lived for at least three millennia. The former occurrence of Mytilus edulis indicates higher sea surface temperatures than at present and more extensive fjord water, which may have been a consequence of higher summer insolation, perhaps amplified by changes in atmospheric circulation, bringing more warm air masses to the north. The timing of the Holocene thermal maximum in the lowlands of East Greenland was later than recorded in the Renland ice core. This delay was probably related to the continuing recession of the margin of the Greenland ice sheet in the early Holocene. The lingering decaying ice meant that large lowland areas were still ice covered, and other areas were cooled by the ice.