Origin of driftwood in north Norway and its relevance for transport routes of drift ice and pollution to the Barents Sea

Abstract

Dendrochronological analysis of 481 driftwood specimens yielded five chronologies based on driftwood from Pinus (three), Picea (one) and Larix (one). Two main source areas, the Yenisey–Angara river basin and north-west Russia, dominated in north Norway, as former investigations have shown they do on Svalbard, Iceland, Jan Mayen and Bear Island. The influx of Pinus driftwood logs from the lower Angara region to north Norway amounts to approximately 50% of the pine logs examined. The ages of the end-years of Pinus driftwood are concentrated in the period 1940–1970, coinciding with an increase in logging in the two main source areas identified. The majority of logs have dated end-years 6–7 years or more prior to the sampling year and one log shows a transit time of ≤4 years from the Angara region to north Norway. Pinus and Picea driftwood from areas draining to the White Sea and Pinus driftwood from the Pechora basin account for a small percentage of the driftwood influx to north Norway. Increased driftwood influx to western parts of northern Norway most likely occur in spring time during recurrent episodes of persistent, strong, wind drift from melting drift ice in the Barents Sea. The results demonstrate a considerable influx to north Norway and the Barents Sea of driftwood originating in rivers draining to the Kara Sea. Dendrochronological dated driftwood can reveal the most likely origin and transport routes of drift ice and ice-rafted contaminants entering the melting zones in the Barents Sea.