Rapid seafloor changes associated with the degradation of Arctic submarine permafrost

Repeated high-resolution bathymetric surveys of the shelf edge of the Canadian Beaufort Sea during 2- to 9-y-long survey intervals reveal rapid morphological changes. New steep-sided depressions up to 28 m in depth developed, and lateral retreat along scarp faces occurred at multiple sites. These mo...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences
Main Authors: Paull, Charles K., Dallimore, Scott R., Jin, Young Keun, Caress, David W., Lundsten, Eve, Gwiazda, Roberto, Anderson, Krystle, Hughes Clarke, John, Youngblut, Scott, Melling, Humfrey
Format: Text
Language:English
Published: National Academy of Sciences 2022
Subjects:
Physical Sciences
Arctic
Beaufort Sea
Ice
permafrost
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8944826/
http://www.ncbi.nlm.nih.gov/pubmed/35286188
https://doi.org/10.1073/pnas.2119105119
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Summary:Repeated high-resolution bathymetric surveys of the shelf edge of the Canadian Beaufort Sea during 2- to 9-y-long survey intervals reveal rapid morphological changes. New steep-sided depressions up to 28 m in depth developed, and lateral retreat along scarp faces occurred at multiple sites. These morphological changes appeared between 120-m and 150-m water depth, near the maximum limit of the submerged glacial-age permafrost, and are attributed to permafrost thawing where ascending groundwater is concentrated along the relict permafrost boundary. The groundwater is produced by the regional thawing of the permafrost base due to the shift in the geothermal gradient as a result of the interglacial transgression of the shelf. In contrast, where groundwater discharge is reduced, sediments freeze at the ambient sea bottom temperature of ∼−1.4 °C. The consequent expansion of freezing sediment creates ice-cored topographic highs or pingos, which are particularly abundant adjacent to the discharge area.

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