Geochemical and micropaleontological character of Deep-Sea sediments from the Northwestern Pacific near the Kuril–Kamchatka Trench

Sediments from the abyssal plain adjacent to the Kuril–Kamchatka Trench were collected during the German–Russian cruise for the Kuril Kamchatka Biodiversity Study, and the chemical composition, quantitative content, and species composition of collected diatoms were studied. The collected sediments are silt and clayey silt, the SiO2 am and Corg contents range 7.58–19.38% and 0.44–1.55%, respectively. The enrichment of silts by amorphous silica indicates the presence of a significant number of organisms (predominantly diatoms) with an opal skeleton. High Corg content in sediments reflects biological productivity, which is controlled by factors such as water circulation and the distribution of nutrients. Interrelation trends among chemical constituents is investigated via multi-component statistics. Diatom assemblages reflect present-day water masses characterized by high nutrient content, surface water circulation, and sedimentation conditions for different parts of the study area. Analysis of this new data also highlights changes in the response of diatom flora due to abiotic factors.