Palynological evidence of sea-surface conditions in the Barents Sea off northeast Svalbard during the postglacial period

2020 ◽  
pp. 1-15
Author(s):  
Camille Brice ◽  
Anne de Vernal ◽  
Elena Ivanova ◽  
Simon van Bellen ◽  
Nicolas Van Nieuwenhove

Abstract Postglacial changes in sea-surface conditions, including sea-ice cover, summer temperature, salinity, and productivity were reconstructed from the analyses of dinocyst assemblages in core S2528 collected in the northwestern Barents Sea. The results show glaciomarine-type conditions until about 11,300 ± 300 cal yr BP and limited influence of Atlantic water at the surface into the Barents Sea possibly due to the proximity of the Svalbard-Barents Sea ice sheet. This was followed by a transitional period generally characterized by cold conditions with dense sea-ice cover and low-salinity pulses likely related to episodic freshwater or meltwater discharge, which lasted until 8700 ± 700 cal yr BP. The onset of “interglacial” conditions in surface waters was marked by a major change in dinocyst assemblages, from dominant heterotrophic to dominant phototrophic taxa. Until 4100 ± 150 cal yr BP, however, sea-surface conditions remained cold, while sea-surface salinity and sea-ice cover recorded large amplitude variations. By ~4000 cal yr BP optimum sea-surface temperature of up to 4°C in summer and maximum salinity of ~34 psu suggest enhanced influence of Atlantic water, and productivity reached up to 150 gC/m2/yr. After 2200 ± 1300 cal yr BP, a distinct cooling trend accompanied by sea-ice spreading characterized surface waters. Hence, during the Holocene, with exception of an interval spanning about 4000 to 2000 cal yr BP, the northern Barents Sea experienced harsh environments, relatively low productivity, and unstable conditions probably unsuitable for human settlements.

Author(s):  
Johan C. Faust ◽  
Mark A. Stevenson ◽  
Geoffrey D. Abbott ◽  
Jochen Knies ◽  
Allyson Tessin ◽  
...  

Over the last few decades, the Barents Sea experienced substantial warming, an expansion of relatively warm Atlantic water and a reduction in sea ice cover. This environmental change forces the entire Barents Sea ecosystem to adapt and restructure and therefore changes in pelagic–benthic coupling, organic matter sedimentation and long-term carbon sequestration are expected. Here we combine new and existing organic and inorganic geochemical surface sediment data from the western Barents Sea and show a clear link between the modern ecosystem structure, sea ice cover and the organic carbon and CaCO 3 contents in Barents Sea surface sediments. Furthermore, we discuss the sources of total and reactive iron phases and evaluate the spatial distribution of organic carbon bound to reactive iron. Consistent with a recent global estimate we find that on average 21.0 ± 8.3 per cent of the total organic carbon is associated to reactive iron (fOC-Fe R ) in Barents Sea surface sediments. The spatial distribution of fOC-Fe R , however, seems to be unrelated to sea ice cover, Atlantic water inflow or proximity to land. Future Arctic warming might, therefore, neither increase nor decrease the burial rates of iron-associated organic carbon. However, our results also imply that ongoing sea ice reduction and the associated alteration of vertical carbon fluxes might cause accompanied shifts in the Barents Sea surface sedimentary organic carbon content, which might result in overall reduced carbon sequestration in the future. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning’.


1998 ◽  
Vol 49 (2) ◽  
pp. 197-207 ◽  
Author(s):  
André Rochon ◽  
Anne de Vernal ◽  
Hans-Petter Sejrup ◽  
Haflidi Haflidason

Palynological analyses performed on cores from the Norwegian Channel (Troll 8903) led to reconstruction of the late-glacial variations in sea-surface conditions using dinoflagellate cyst data and permitted direct correlation with the vegetation history of northwestern Europe derived from pollen assemblages. By ∼15,000 yr B.P., ice rapidly receded from the Norwegian shelf and relatively warm summer conditions prevailed in surface waters. A first late-glacial cooling marked by extensive seasonal sea–ice cover is dated at ca. 13,600–13,000 14C yr B.P., which coincides with the Oldest Dryas interval. During the Bølling–Allerød interval, a rise in sea-surface temperature both in February (up to 3°C) and August (up to 15°C) led to the establishment of ice-free conditions in the northern North Sea, while pollen data reveal a densification of the vegetation cover. The beginning of the Younger Dryas interval is marked by an increase in nonarboreal pollen input indicative of the opening of the forest vegetation cover, concomitant with a cooling of surface waters during winter and development of sea–ice cover. However, sea-surface conditions remained relatively warm in summer until about 10,300 yr B.P., when extremely cold conditions and extensive sea–ice cover developed (up to 7 months/yr). Improving conditions are recorded in surface waters by ∼10,100 yr B.P., a few hundred years before the development of forest cover onshore, as shown by the pollen record. Such a discrepancy between marine and terrestrial indicators at the end of Younger Dryas time suggests a delayed response of the vegetation to regional climate warming.


2020 ◽  
pp. 1-65
Author(s):  
Pawel Schlichtholz

AbstractInvestigation of the predictability of sea ice cover in the Barents Sea is of paramount importance since sea ice changes in this part of the Arctic not only affect local marine ecosystems and human activities but may also influence weather and climate in northern mid-latitudes. Here, observational data from the period 1981-2018 are used to identify statistical linkages of wintertime sea ice cover in the Barents Sea region to preceding sea surface temperature (SST) and Atlantic water temperature anomalies in that region. We find that the ocean temperature anomalies formed by local air-sea interactions during the winter-to-spring season are a significant source of predictability for sea ice area (SIA) in the Barents Sea region the following winter. Optimal areas for constructing SST predictors of Barents Sea SIA and skill scores from retrospective statistical forecasts are shown to differ between the periods to and since the onset of rapid sea ice decline in the region. In the EARLY period (1982-2003), springtime SSTs in the western Barents Sea predicted 44% of the variance of the following winter Barents Sea SIA. In the LATE period (2003-2017), springtime SSTs in the southern Barents Sea predicted 70% of the variance of the following winter Barents Sea SIA. Regression analysis suggests that feedbacks from anomalous winds may be important for the predictability of wintertime sea ice cover in the Barents Sea region.


2019 ◽  
Vol 92 (2) ◽  
pp. 430-449 ◽  
Author(s):  
Elena Ivanova ◽  
Ivar Murdmaa ◽  
Anne de Vernal ◽  
Bjørg Risebrobakken ◽  
Alexander Peyve ◽  
...  

AbstractThe Barents Sea offers a suitable location for documenting advection of warm and saline Atlantic Water (AW) into the Arctic and its impact on deglaciation and postglacial conditions. We investigate the timing, succession, and mechanisms of the transition from proximal glaciomarine to marine environment in the northwestern Barents Sea. Two studied sediment cores demonstrate diachronous retreat of the grounded ice sheet from the Kvitøya Trough (core S2528) to Erik Eriksen Trough (core S2519). Oxygen isotope records from core S2528 depict a two-step pattern, with lower δ18O values prior to the Younger Dryas (YD), and higher values afterward because of advection of the more saline, 18O-enriched AW. At this location, subsurface AW penetration increased during the Allerød and YD/Preboreal transition. In the study area, foraminiferal and dinocyst data from the YD interval suggest cold conditions, extensive sea-ice cover, and brine formation, along with the flow of chilled AW at subsurface and the development of a high-productivity polynya in the Erik Eriksen Trough. Dense winter sea-ice cover with seasonal productivity persisted in the Kvitøya Trough area during the early Holocene, whereas surface warming seems to have occurred during the middle Holocene interval.


2017 ◽  
Vol 30 (2) ◽  
pp. 803-812 ◽  
Author(s):  
Vidar S. Lien ◽  
Pawel Schlichtholz ◽  
Øystein Skagseth ◽  
Frode B. Vikebø

Variability in the Barents Sea ice cover on interannual and longer time scales has previously been shown to be governed by oceanic heat transport. Based on analysis of observations and results from an ocean circulation model during an event of reduced sea ice cover in the northeastern Barents Sea in winter 1993, it is shown that the ocean also plays a direct role within seasons. Positive wind stress curl and associated Ekman divergence causes a coherent increase in the Atlantic water transport along the negative thermal gradient through the Barents Sea. The immediate response connected to the associated local winds in the northeastern Barents Sea is a decrease in the sea ice cover due to advection. Despite a subsequent anomalous ocean-to-air heat loss on the order of 100 W m−2 due to the open water, the increase in the ocean heat content caused by the circulation anomaly reduced refreezing on a time scale of order one month. Furthermore, it is found that coherent ocean heat transport anomalies occurred more frequently in the latter part of the last five decades during periods of positive North Atlantic Oscillation index, coinciding with the Barents Sea winter sea ice cover decline from the 1990s and onward.


Author(s):  
Katrine Husum ◽  
Ulysses Ninnemann ◽  
Tom Arne Rydningen ◽  
Elisabeth Alve ◽  
Naima E B Altuna ◽  
...  

The Nansen Legacy paleo cruise was carried out from September 26 to October 20, 2018 with RV “Kronprins Haakon”. The cruise took place in the northern Barents Sea and the Nansen Basin, and it went through the sea ice to 83.3 N. The overriding objective of the cruise was to reconstruct the natural variability and range of sea ice cover and Atlantic Water through flow in the Barents Sea on longer time scales. During the cruise four ocean moorings were deployed in northwest Barents Sea, where one ARGO float was also deployed. Twelve “paleo stations” were identified using multibeam and sub bottom profilers. At these stations, short and long sediment cores were obtained. This cruise report gives an overview of methods used and samples taken. 


2016 ◽  
Vol 52 (9) ◽  
pp. 1041-1050 ◽  
Author(s):  
L. M. Mitnik ◽  
M. L. Mitnik ◽  
G. M. Chernyavsky ◽  
I. V. Cherny ◽  
A. V. Vykochko ◽  
...  

2012 ◽  
Vol 69 (5) ◽  
pp. 833-840 ◽  
Author(s):  
Vladimir D. Boitsov ◽  
Alexey L. Karsakov ◽  
Alexander G. Trofimov

Abstract Boitsov, V. D., Karsakov, A. L., and Trofimov, A. G. 2012. Atlantic water temperature and climate in the Barents Sea, 2000–2009. – ICES Journal of Marine Science, 69: 833–840. Year-to-year variability in the temperature of Atlantic water (AW), which has a strong influence on the marine climate and ecosystem of the Barents Sea, was analysed using data from the Kola Section. With a positive trend in mean annual temperature during the late 20th century, only positive anomalies were registered during the past decade. In nine of those years, the temperature was warmer than the 1951–2000 long-term mean by 0.5–1.2°C, and in 2006, the historical maximum for the 110-year period of observations along the section was recorded. High air and water temperature coincided with reduced sea-ice cover, especially between October and April, when there is seasonal enlargement of the ice-covered area. An integral climate index (CI) of the Barents Sea based on the variability in temperature of AW, air temperature, and ice cover is presented. A prediction of future Barents Sea climate to 2020 is given by extrapolating the sixth degree polynomial approximating the CI.


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