Planktic foraminifera and structure of surface water masses at the SW Svalbard margin in relation to climate changes during the last 2000 years

Abstract. We present a high-resolution record of properties in the subsurface (250–100 m), near surface (100–30 m) and surface (30–0 m) water masses at the SW Svalbard margin in relation to climate changes during the last 2000 years. The study is based on planktic foraminiferal proxies including the distribution patterns of planktic foraminiferal faunas, δ¹⁸O and δ¹³C values measured on Neogloboquadrina pachyderma, Turborotalita quinqueloba, and Globigerinita uvula, Mg / Ca-, δ¹⁸O- and transfer function-based sea surface temperatures, mean shell weights and other geochemical and sedimentological data. We compared paleo-data with modern planktic foraminiferal fauna distributions and the carbonate chemistry of the surface ocean. The results showed that cold sea surface conditions prevailed at ~ 400–800 AD and ~ 1400–1950 AD are associated with the local expression of the Dark Ages Cold Period and Little Ice Age, respectively. Warm sea surface conditions occurred at ~ 21–400 AD, ~ 800–1400 AD and from ~ 1950 AD until present and are linked to the second half of the Roman Warm Period, Medieval Warm Period and recent warming, respectively. On the centennial to multi-centennial time scale, sea surface conditions seem to be governed by the inflow of Atlantic water masses (subsurface and surface) and the presence of sea-ice and the variability of sea-ice margin (near surface water masses). However, the close correlation of sea surface temperature recorded by planktic foraminifera with total solar irradiance implies that solar activity could have exerted a dominant influence on the sea surface conditions on the decadal to multidecadal time scale.