Distribution of diatoms in seafloor surface sediments of the Laptev, East Siberian, and Chukchi seas: implication for environmental reconstructions

Our research was motivated by significant warming in the Arctic in recent decades and the influence of this warming on diatoms, which are the main producers in the seas of the Eastern Arctic. For this purpose, we studied the qualitative concentrations and quantitative ratio of diatoms from the surface sediments of the Laptev Sea (LS), the East Siberian (ESS) and Chukchi seas (ChS), and the Arctic Ocean (AO), obtained by box corers in 2016 and 2018. The ecological structure of the diatom assemblages of these sediments, reflecting the current environmental conditions, was also analyzed. Compared with the end of the last century, there were significant changes in species composition and quantitative ratio of the diatom assemblages in the sediments from the AO and the LS and ESS. In contrast, the diatom assemblages in the sediments from the ChS had not significantly changed in terms of species composition or quantitative ratio over the same three decades. The observed transformations in the diatom assemblages of the surface sediments were associated with substantial changes in water temperature, current flow, salinity, ice melting, and prolonged ice-free periods associated with global warming in the Northern Hemisphere in recent decades. The foregoing processes have clearly had strong impacts on the environment and the biota of the Arctic region.