Late-Holocene diatom-inferred reconstruction of temperature variations of the West Greenland Current from Disko Bugt, central West Greenland

Abstract

The diatom flora from a high-resolution core collected from Disko Bugt, central West Greenland, records variations in surface water temperature for the late Holocene (1600—300 cal. BP). Our data support the existence of a previously identified anti-phase relationship between the surface water temperature from West Greenland and climate events recorded in the NE Atlantic and between surface and subsurface waters (identified from benthic foraminifera) of the West Greenland Current (WGC). The diatom flora record relatively cool surface water conditions during the end of the ‘Roman Warm Period’ and ‘Medieval Warm Period’ (MWP), and relatively warmer surface water conditions during the ‘Dark Ages Cold Period’ and ‘Little Ice Age’ (LIA). This is particularly pronounced during the MWP, experiencing the coldest conditions, and the LIA experiencing the warmest conditions through the whole sequence studied. The most likely explanation for this anti-phase relationship is linked to the flux of meltwater delivered to the WGC from sea ice and the Greenland ice sheet off the West Greenland margin. The generally warmer conditions of the MWP resulted in increased melting of sea ice and the Greenland ice sheet producing an increased meltwater flux and cooling of the surface waters of the WGC. In contrast, reduced meltwater flux during the relatively cold LIA resulted in reduced meltwater flux to the WGC, producing a relative warming of the surface waters recorded by the diatom flora.