North Atlantic and Arctic

Abstract

Preservation of diatoms in sediments of the North Atlantic and Arctic Ocean through geological time has been highly variable. The North Atlantic Ocean and the Nordic Seas were a region of high productivity of biogenic silica until the onset of Northern Hemisphere glaciations during the late Miocene. Later, fluctuating Pleistocene climatic conditions had a major impact on diatom productivity in the high-latitude North Atlantic. During interglacials, high diatom productivity took place in the North Atlantic, whereas glacial stages are often barren of diatoms due to the expansion of sea-ice cover. Diatom species show rapid evolution through time and therefore are an excellent biostratigraphic tool in this area. The high diversity of diatoms in polar and Arctic environments also makes them one of the foremost tools available for paleoclimatic reconstructions. They have been used for inferences of the former positions of the sea-ice margin and oceanic fronts, as well as for inferring the distribution of water masses and to provide quantitative estimates of past sea-surface temperatures (SSTs). These SST estimates are particularly being exploited for reconstructing the regional surface ocean conditions during the Holocene.