Modern distribution of dinocysts from the North Pacific Ocean (37-64°N, 144°E-148°W) in relation to hydrographic conditions, sea-ice and productivity

摘要: Abstract Palynological analyses were performed on 53 surface sediment samples from the North Pacific Ocean, including Bering and Okhotsk Seas (37–64°N, 144°E–148°W), in order to document relationships between dinocyst distribution sea-surface conditions (temperatures, salinities, primary productivity sea-ice cover). Samples are characterized by concentrations ranging 18 143 816 cysts/cm3 occurrence of 32 species. A canonical correspondence analysis (CCA) was carried out determine relationship environmental variables taxa. The first second axes represent, respectively, 47% 17.8% variance. Axis 1 is positively correlated with all parameters except August, which negative side. Results indicate that composition assemblages mostly controlled temperature together. CCA distinguishes 3 groups dinocysts: heterotrophic taxa, genera Impagidinium Spiniferites as well cyst Pentapharsodinium dalei Operculodinium centrocarpum. Five assemblage zones can be distinguished: 1) Sea zone, associated temperate eutrophic conditions, seasonal upwellings Amur River discharges. It dominance O. centrocarpum, Brigantedinium spp. Islandinium minutum; 2) Western Subarctic Gyre zone subpolar mesotrophic due Kamchatka Current Alaska Stream inflows. Assemblages dominated Nematosphaeropsis labyrinthus, Pyxidinopsis reticulata spp.; 3) depicting a environment, influenced inputs Anadyr Yukon Rivers. I. minutum 4) nutrient-enriched waters, N. labyrinthus 5) Kuroshio Extension-North Pacific-Subarctic subtropical oligotrophic warm taxa genus Impagidinium. Transfer functions tested using modern analog technique (MAT) Ocean (= 359 sites) entire Northern Hemisphere databases (= 1419 sites). confirm updated database suitable for further paleoenvironmental reconstructions, best results obtained temperatures an accuracy ± 1.7 °C.