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Reconstructing interglacial marine environments helps us understand the climate change mechanisms of the past. To contribute to this body of knowledge, we studied a high-resolution 455 cm-thick sediment sequence of the Boreal (Eemian) marine beds directly overlying Moscovian (Saalian) moraine in the Bychye-2 section on the Pyoza River. We analyzed lithological and microfossil (foraminifers, ostracods, pollen, aquatic palynomorphs) variations at the studied site. Stratigraphical zonation is based on the local and well-established regional pollen zones, correlated with the western European pollen zones. The studied marine beds accumulated from the end of the Moscovian glacial (>131 ka) until ca. 119.5 ka. We distinguished three successive phases: a seasonally sea-ice-covered, relatively deep, freshened basin in the initial rapid flooding stage (>131–130.5 ka); a deep basin in the maximum flooding phase with less extensive sea ice cover (130.5–130.25 ka); and a shallow basin with reduced sea ice cover (130.25–119.5 ka). According to a pollen zone comparison with other sites, the regional glacioisostatic rebound started ca. 130 ka. The diverse warm-water assemblages of benthic foraminifers and ostracods containing typical Baltic Sea species occurred during the regression, mainly 128–124 ka, thus giving evidence for a relatively long-lasting connection between the White and Baltic Seas.

In order to reconstruct the late glacial to Holocene history of Atlantic-derived water (ADW) inflow into the Arctic Ocean along the northern Eurasian margin, past freshwater inputs and variability in sea-ice extent we carry out investigation of the distribution and abundance of benthic and planktic foraminifers in the AMS14C-dated sediment core PS2458-4 from the eastern Laptev Sea continental slope (78°10.0’N, 133°23.9’E) located at 983 m water depth in front of the position of the former Lena and Yana river mouths on the shelf break (Spielhagen et al., 2005). The 822 cm long sediment sequence was sampled continuously in 2 cm thick slices. The core is well-dated from 201 cm down to 625 cm, this sediment interval corresponds in time to 8.9-14.6 cal.ka (Spielhagen et al., 2005), whereas the basal and uppermost parts of the core lack sufficient amount of datable material. Based on preliminary data on taxonomic composition and abundance of benthic and planktic foraminifers several intervals were distinguished corresponding to certain changes in past environments. The oldest lateglacial period (822-660 cm) is characterized by very low abundance of microfossils suggesting harsh environmental conditions with heavy sea-ice cover. However, high percentages of ADW-indicative benthic foraminifer Cassidulina neoteretis and the presence of diverse planktic subpolar species give evidence for the strong subsurface inflow of ADW along the Laptev Sea continental slope. The increasing representation of Elphidium clavatum, higher foraminiferal abundance and species diversity imply growing fluvial influence during early deglaciation (660-600 cm, until 14.2 cal.ka). The abundance of subpolar planktic foraminifers is the highest although their diversity considerably decreases compared with the earlier lateglacial times. Enhanced ADW inflow to the core site is manifested by the sharp dominance of C. neoteretis in the record during the Bølling-Allerød period (600-520 cm, 14.2-12.9 cal.ka).

The eastward penetration of Atlantic-derived water (ADW) into the Eurasian Basin of the Arctic Ocean was investigated at the western Laptev Sea continental margin for the time since c. 17.6 ka. Using a high-resolution investigation of the lithology, geochemistry, planktic and benthic foraminifers, and ostracods on a sediment core from 270 m water depth major steps in the environmental evolution of the region are recognized. In general, ADW was continuously present in the study area. Between 17.6 and 15.4 ka ADW manifested itself through open-water polynyas and associated upwelling events. Comparison between the Laptev Sea and northern Svalbard shelf using Cassidulina neoteretis allows assuming an unmodified subsurface inflow of ADW within its northern branch between 15.4-13.2, which was strongest after 14.7 ka and in line with the overall climate amelioration. A local freshwater event at 13 ka followed by shelf flooding and the establishment of a freshened shelf water mass resulted in an off-shelf displacement of ADW from the studied site as suggested by the disappearance of C. neoteretis between 12 and 7 ka. As evidenced by an abundance peak in Nonion labradoricum, the sea-ice marginal zone was located at the site around 12-11 ka but then shifted northward during the early Holocene warming. Enhanced ADW inflow since 7 ka correlated with climate cooling and southward retreat of the seasonal drift-ice margin. The inflow of ADW during mid-late Holocene differed from deglacial times because of the combined influence of northern and eastern ADW branches.

On a global scale, the last interglacial period is generally regarded a time of extreme climate warmth, high sea-level and largely reduced ice sheet size, for instance, on Greenland. In order to properly interpret the climate of the last interglacial in this region, it is critical to understand its development from the Saalian glacial maximum through the ensuing deglaciation (Termination 2). For this purpose we have compared deep-sea marine records from the Nordic seas with a high-resolution sequence of Eemian marine beds directly overlying Saalian till in northern Russia. The latter record allows for a fresh, detailed evaluation of a sequence of events on the basis of changes in lithology, microfossils (foraminifers, ostracods, pollen, aquatic palynomorphs) and benthic foraminiferal stable isotope data. The record is marked by the collapse of the huge Saalian shelf-based ice sheet which left a glaciostatically overdeepened Barents-Kara Sea shelf region, giving way to a rapid marine inundation. Although the early accumulation of marine sediments features a period of harsh, fluvially-affected environmental conditions with cold turbid waters and heavy seasonal sea-ice cover, the later occurrence of a typical Arctic shelf and deep-sea microfossil assemblage together with broad-leaved species in pollen spectra is representative of a climatic amelioration that ocurred in various steps. The recognition of a stepwise nature of the environmental development in northern Russia is recorded also in the deep-sea. There we note already during early Termination II a clear signal for intrusions of Atlantic water masses on the one hand, and high discharge rates of icebergs on the other. If these icebergs derived from a rapid collapse of the Barents-Kara seas ice sheet – this was much thicker and larger than in the Weichselian – then it seems very probable that the Atlantic water masses were able to protrude far eastward along the northern Eurasian periphery as a direct consequence