We present 2500 years of reconstructed bottom-water temperatures (BWT) in annual to subdecadal resolution by using a fjord sediment archive from the NE Atlantic region. The BWT represent winter conditions due to the fjord hydrography and associated timing and frequency of bottom-water renewals. The study is based on a ca. 8-m long sediment core from Gullmar Fjord (Sweden), dated by 210Pb and AMS 14C and analysed for stable oxygen isotopes (δ18O) measured on shallow infaunal benthic foraminiferal species Cassidulina laevigata. The BWT, calculated by using the palaeotemperature equation of McCorkle et al (1997), range between 2.7 - 7.8°C and are within the annual temperature variability, instrumentally recorded in the deep fjord basin since the 1890s. The record demonstrates a warming during the Roman Warm Period (~350 BCE - 450 CE), variable BWT during the Dark Ages (~450 - 850 CE), positive BWT anomalies during the Viking Age/Medieval Climate Anomaly (~850 - 1350 CE) and a long-term cooling with distinct multidecadal variability during the Little Ice Age (~1350 - 1850 CE). The fjord BWT record also picks up the contemporary warming of the 20th century (presented here until 1996), which does not stand out in the 2500-year perspective and is of the same magnitude as the Roman Warm Period and the Medieval Climate Anomaly.

Supplement to: Polovodova Asteman, Irina; Filipsson, Helena L; Nordberg, Kjell (2018): Tracing winter temperatures over the last two millennia using a north-east Atlantic coastal record. Climate of the Past, 14(7), 1097-1118