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.

KEYWORDS:

• Greenland
• Petermann ice tongue
• foraminifera
• arctic
• marine

Acknowledgments

We thank the captain and crew of icebreaker Oden and the scientific party of OD1507 and the BAS ice shelf drilling team and Lawrence Dyke for their help in obtaining the samples. We thank Professor Marit-Solveig Seidenkrantz and an anonymous reviewer for their helpful critique of the manuscript. We acknowledge the use of imagery from the NASA Worldview application (https://worldview.earthdata.nasa.gov/), part of the NASA Earth Observing System Data and Information System (EOSDIS).

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

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Additional information

Funding

This research was supported by NSF-PLR-ANS 1417784, “Collaborative Research: Petermann Gletscher, Greenland—Paleoceanography and Paleoclimatology.” Undergraduate student at CU, Ethan Bailey, did the faunal analyses of OD1507-39MC-04 and -06.