Modern foraminiferal assemblages in northern Nares Strait, Petermann Fjord, and beneath Petermann ice tongue, NW Greenland

Abstract

Calving events of Petermann Glacier, northwest Greenland, in 2010 and 2012 reduced the length of its ice tongue by c. 25 km, allowing exploration of newly uncovered seafloor during the Petermann 2015 Expedition. This article presents the results of foraminiferal analysis and environmental data from thirteen surface sediment samples in northern Nares Strait and Petermann Fjord, including beneath the modern ice tongue. This is the first study of living foraminifera beneath an arctic ice tongue and the first modern foraminiferal data from this area. Modern assemblages were studied to constrain species environmental preferences and to improve paleoenvironmental interpretations of foraminiferal assemblages. Sub-ice tongue assemblages differed greatly from those at all other sites, with very low faunal abundances and being dominated by agglutinated fauna, likely reflecting low food supply under the ice tongue. Fjord fauna were comprised of 80 percent or more calcareous species. Notably, Elphidium clavatum is absent beneath the ice tongue although it is dominant in the fjord. Increasing primary productivity associated with the transition to mobile sea ice, diminishing influence of the Petermann Glacier meltwater with distance from the grounding line, and increased influence of south-flowing currents in Nares Strait are the important controls on the faunal assemblages.

Holocene Interactions Between Glacier Retreat, Sea Ice Formation, and Atlantic Water Advection at the Inner Northeast Greenland Continental Shelf

“…This is supported by the dominance of C. neoteretis (60%), with low relative abundance of C. reniforme through the record and also other relatively warm water indicators also increasing (e.g., Nonionella iridea and Melonis barleeanum ) (Figure 8). However, the presence of Stetsonia horvathi and Glomulina oculus through this interval also supports the interpretation of more extensive sea ice during this interval (both species commonly found in regions influenced by a high concentration of sea ice, for example, Jennings et al, 2020; Wollenburg & Mackensen, 1998). Continuing high but variable AW advection toward the NEG continental shelf until about 8 ka is also recorded in the assemblages and isotope data of foraminifers at Core PS93/25 (Zehnich et al, 2020) as well as Core PS1230 (Bauch et al, 2001).…”

“…Paleoceanography and Paleoclimatology species commonly found in regions influenced by a high concentration of sea ice, for example, Jennings et al, 2020;Wollenburg & Mackensen, 1998). Continuing high but variable AW advection toward the NEG continental shelf until about 8 ka is also recorded in the assemblages and isotope data of foraminifers at Core PS93/25 (Zehnich et al, 2020) as well as Core PS1230 (Bauch et al, 2001).…”

Evidence for influx of Atlantic water masses to the Labrador Sea during the Last Glacial Maximum

“…As Arctic benthic foraminifera may grow primarily during the spring-summer-fall season 86 , our benthic foraminiferal records likely represents a "warm"-season environment. The ecological preferences of the species encountered in this study is relatively well known and our ecological interpretations are based on the modern habitat requirements of the species (e.g., 38,42,44 ). Although any given species is rarely dependent on only one parameter, they most commonly have a primary ecological requirement; here we have grouped the benthic foraminiferal species according to their primary habitat.…”

“…The strong Atlantic-sourced signal could in part be explained by a weaker Polar water flow from the East Greenland Current, but the Atlantic water signal appears so prominent that this cannot be the only explanation. Presently, Atlantic water can be found at subsurface depths below ice tongues and sea ice in northern Greenland 43,44 . A thick sea ice cover, reducing the melting from the Greenland ice sheet and thus the mixing of Atlantic Water with cold Polar Water during glacial conditions, could potentially cause the subsurface Atlantic Water to retain a higher temperature and salinity.…”

Comparative analysis of six common foraminiferal species of the genera <i>Cassidulina</i>, <i>Paracassidulina</i>, and <i>Islandiella</i> from the Arctic–North Atlantic domain

“…This shallow infaunal species typically dwells in fine-grained sediments in regions influenced by cool, modified Atlantic Water (with relatively stable salinities and temperatures) across the Nordic Seas (e.g. Mackensen and Hald, 1988;Gooday and Lambshead, 1989;Jennings and Helgadóttir, 1994;Rytter et al, 2002;Jennings et al, 2004;Knudsen et al, 2012), the Labrador Sea and Baffin Bay (Holocene records: Seidenkrantz et al, 2013;Hansen et al, 2020), and into the Arctic Ocean and its marginal seas (Wollenburg and Mackensen, 1998;Husum et al, 2015;Jennings et al, 2020). It is noteworthy that in the eastern Nordic Seas it is also found in Atlantic-sourced water at deeper sites with cooler and more stable conditions than usual for C. laevigata (cf.…”