scholarly journals Evolution of sea‐surface conditions on the northwestern Greenland margin during the Holocene

2019 ◽  
Vol 34 (7) ◽  
pp. 569-580 ◽  
Author(s):  
Myriam Caron ◽  
André Rochon ◽  
Jean‐Carlos Montero‐Serrano ◽  
Guillaume St‐Onge
2020 ◽  
Author(s):  
Estelle Allan ◽  
Anne de Vernal ◽  
Marit-Solveig Seidenkrantz ◽  
Claude Hillaire-Marcel ◽  
Christof Pearce ◽  
...  

<p>Palynomorph analysis of marine cores raised off Nuuk (southwestern Greenland) provided records of sea-surface conditions and climate-ocean-ice dynamics at centennial resolution over the last 12,000 years. Transfer functions using dinocyst assemblages provided information about the sea-ice cover, seasonal sea-surface temperature (SST) and salinity (SSS), as well as primary productivity. At about 10,000 cal. years ago, an increase in species diversity and the rapid increase of phototrophic taxa (light-dependent), marks the onset of interglacial conditions, with summer temperature increasing up to ~10°C during the Holocene Thermal Maximum (HTM). Low SSS and high productivity conditions are recorded during the interval, which we associate to increased meltwater and nutrient input from the Greenland Ice Sheet. After ~5000 cal. years BP, the decrease of phototrophic taxa marks a two-steps cooling associated with the Neoglacial trend. Since ~2000 cal. years BP, an increase in the high-frequency variability of sea surface conditions is noticeable. The second step change towards colder and more unstable conditions starting about 3000 cal. years BP coincides with the disappearance of the Saqqaq culture. The gap of human occupation in western Greenland, between the Dorset and the Norse settlements, i.e., from ca. 2000 to 1000 cal. years BP, may thus be linked to the highly unstable conditions in surface waters.</p>


The Holocene ◽  
2016 ◽  
Vol 26 (5) ◽  
pp. 722-735 ◽  
Author(s):  
Nicolas Van Nieuwenhove ◽  
Astrid Baumann ◽  
Jens Matthiessen ◽  
Sophie Bonnet ◽  
Anne de Vernal

2020 ◽  
Vol 16 (4) ◽  
pp. 1369-1386
Author(s):  
Abigail G. Hughes ◽  
Tyler R. Jones ◽  
Bo M. Vinther ◽  
Vasileios Gkinis ◽  
C. Max Stevens ◽  
...  

Abstract. An ice core drilled on the Renland ice cap in east-central Greenland contains a continuous climate record dating through the last glacial period. The Renland record is valuable because the coastal environment is more likely to reflect regional sea surface conditions compared to inland Greenland ice cores that capture synoptic variability. Here we present the δ18O water isotope record for the Holocene, in which decadal-scale climate information is retained for the last 8 kyr, while the annual water isotope signal is preserved throughout the last 2.6 kyr. To investigate regional climate information preserved in the water isotope record, we apply spectral analysis techniques to a 300-year moving window to determine the mean strength of varying frequency bands through time. We find that the strength of 15–20-year δ18O variability exhibits a millennial-scale signal in line with the well-known Bond events. Comparison to other North Atlantic proxy records suggests that the 15–20-year variability may reflect fluctuating sea surface conditions throughout the Holocene, driven by changes in the strength of the Atlantic Meridional Overturning Circulation. Additional analysis of the seasonal signal over the last 2.6 kyr reveals that the winter δ18O signal has experienced a decreasing trend, while the summer signal has predominantly remained stable. The winter trend may correspond to an increase in Arctic sea ice cover, which is driven by a decrease in total annual insolation, and is also likely influenced by regional climate variables such as atmospheric and oceanic circulation. In the context of anthropogenic climate change, the winter trend may have important implications for feedback processes as sea ice retreats in the Arctic.


2021 ◽  
Author(s):  
Harikrishnan Guruvayoorappan ◽  
Arto Miettinen ◽  
Dmitry Divine ◽  
Rahul Mohan

<p>Certain past climatic events act as an analogue for future climatic conditions. The Holocene epoch featured a number of climatic variations of which Holocene Thermal Maximum (HTM) stands out as a recognizable phenomenon, especially in the North Atlantic and the Arctic. Similar to modern warming, HTM in Svalbard recorded extreme warmth along with intense deglaciation and sea ice retreat. Therefore, predictions of future climate using HTM depends on understanding the changes in interactions between ocean, sea ice, and atmospheric conditions. While many studies exist on this period, only few have reconstructed ocean surface conditions in the Arctic at high resolution. Here we present the first diatom-based high-resolution quantitative reconstruction of sea surface conditions from Kongsfjorden, Svalbard covering the period of ca. 10.5 to 7.5 cal. kyr BP. Our reconstructions of sea surface temperature (SST) and sea ice conditions are based on diatom microfossil records from a 454 cm long marine sediment core from Kongsfjorden, Svalbard. The section from 454 to 300 cm was used for reconstructions owing to the lack of availability of diatom microfossils. Owing to their high sensitivity towards SST and sea ice, diatoms act as excellent proxies of these environmental conditions in the past. The SST record from Kongsfjorden reveals moderately warm open water conditions and highly variable sea ice conditions during the HTM. The SST achieves maximum values during the early Holocene insolation maxima ca. 10.5 to 7.5 cal. kyr BP, followed by a slow cooling trend simultaneously with the decreasing insolation intensity. Our results emphasize the regional heterogeneity observed in ocean surfaces during the HTM and how modern warming in the study area has already reached sea surface temperatures comparable to the HTM. </p>


Boreas ◽  
2021 ◽  
Author(s):  
Estelle Allan ◽  
Anne de Vernal ◽  
Marit‐Solveig Seidenkrantz ◽  
Jason P. Briner ◽  
Claude Hillaire‐Marcel ◽  
...  

2001 ◽  
Vol 16 (4) ◽  
pp. 353-363 ◽  
Author(s):  
Elisabeth Levac ◽  
Anne De Vernal ◽  
Weston Blake Jr

2016 ◽  
Vol 31 (3) ◽  
pp. 380-398 ◽  
Author(s):  
Nicolas Van Nieuwenhove ◽  
Claude Hillaire-Marcel ◽  
Henning A. Bauch ◽  
Anne de Vernal

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