Ancient DNA may rewrite the story of Iceland's earliest settlers

Biochemical evidence suggests Norse people settled in Iceland almost 70 years before the accepted arrival date of the 870s, and didn't chop down the island's forests. Researchers (Eske Willerslev and colleagues) examined environmental DNA (eDNA) from sediment cores at Lake Tjörnin in central Reykjavík and, using tephra layers, radiocarbon dating and plutonium isotope analysis, reconstructed a timeline from about AD 200 to the modern day. They report increases in levoglucosan (a biomass-burning marker) and sewage-associated viruses around ~AD 810, and later evidence of livestock, hay meadows and small-scale barley cultivation. Pollen eDNA indicates birch and willow expansion during settlement, and pronounced loss of biodiversity (including birch and willow) not until after 1200, likely linked to climatic cooling (Little Ice Age), volcanic activity and storm surges. The news article summarises the preprint posted to bioRxiv (DOI: 10.1101/2025.10.08.681091).