A 100-year long record of alkenone-derived SST changes by Southeast Greenland

International audience; Sediment core ER07 from Sermilik Fjord by Helheim Glacier in Southeast Greenland was analysedfor alkenones to document sea surface temperature (SST) changes over the past 100 years. Thealkenone SST values, ranging from 8 to 12°C, contrasts with colder values (0-4°C) obtained fromrecent hydrographic surveys inside the fjord. We suggest that advection of allochtonous alkenonesproduced in the warm Irminger Current waters circulating on the shelf likely accounts for thisdifference. The temperature range of the alkenone-derived record is similar to in situ observationsof 8-11°C on the shelf just outside Sermilik Fjord, and its variability over the past 100 yearsresembles the constructed variability over the shelf using remote instrumental data. This suggeststhat oceanographic changes on the adjacent shelf are linked to regional changes of the IrmingerCurrent and the East Greenland Current. The subsurface water heat content has previously beensuggested as an important control on Greenland outlet glacier stability and underlined by an episodeof warm subsurface waters ~ 1940 concurrent with markedly increased calving and retreat ofHelheim Glacier. Our results therefore suggest that alkenone-derived SST time series from highsedimentation rate glacial fjords may provide a new approach for reconstruction of past changes ofshelf water properties and variability around Greenland.