The ARCUS Arctic Research Seminar Series invites leading Arctic researchers and community leaders to share the latest findings in Arctic research and what they mean for decision-making. These webinar events are free and open to the public, and will be of particular interest to the international Arctic research community, federal agency officials, non-governmental organizations, Arctic educators, and the public.
Registration is required for each event.
For those of you on Twitter, we also invite you to join our online discussion of each event using the hashtag #arcuswebinar.
The ARCUS Arctic Research Seminar Series is made possible with support by the National Science Foundation under Cooperative Agreement No. PLR-1928794.
Please contact Stacey Stoudt at stacey [at] arcus.org with any questions.
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Upcoming Webinars
- Wednesday, 5 October 2022: Charlie Paull (Monterey Bay Aquarium Research Institute [MBARI]) - Decomposing Submarine Permafrost in the Canadian Beaufort Sea
- Thursday, 10 November 2022: Sarah Laske (USGS Alaska Science Center) - Circumpolar Patterns of Arctic Freshwater Fish Diversity: A baseline for monitoring
Decomposing Submarine Permafrost in the Canadian Beaufort Sea
Abstract
Sediments beneath the Arctic continental shelf are undergoing substantial warming. This warming is associated with the sea level transgression at the end of the last ice age, when relatively warm ocean water flooded over a much colder terrestrial periglacial landscape. The warming is still propagating down into subsurface sediments causing the glacial-aged permafrost wedge to thin and retreat landwards. Models of the impact of transgression on subsea permafrost have recognized the potential existence of a slowly moving groundwater system that carries waters seaward under the extensive glacial-age relict permafrost bodies hosted within shelf sediments. Pore waters sampled in 50 sediment cores taken from 90 to 1000 m water depths along the shelf edge and upper slope of the Canadian Beaufort Sea freshen with sub-bottom depth, suggesting near-seafloor sediments are pervasively bathed in brackish water. Their isotopic composition suggests relict permafrost is the source for the freshening waters along the shelf edge. High-resolution bathymetric surveys of the shelf edge of the Canadian Beaufort Sea reveal a remarkable coalescence of seafloor morphologic features (e.g., slump-scars, submarine-pingos and steep-sided closed depressions) in the areas where these waters are emerging. Repeat mapping also shows multiple new steep-sided depressions that developed in the 9-year-long interval between surveys. The largest is 28 m in depth and 220 m across. These morphological changes occur near the maximum seaward limit of the submerged glacial-age permafrost and are attributed to groundwater flow, ascending along the relict permafrost boundaries and inducing segregated ice in relict permafrost to melt.
Speaker Details
Charlie Paull presently holds a position as a Senior Scientist at the Monterey Bay Aquarium Research Institute (MBARI). He is a marine geologist with ~45 years of experience studying seafloor morphology, sediment transport, and pore water geochemistry to understand the processes that shape continental margins. In recent years he has focused on the utilization of Autonomous Underwater Vehicles and Remotely Operated Vehicles to image, observe, and sample the seafloor. Through collaborations with colleagues at the Geological Survey of Canada, Fisheries and Oceans Canada, and the Korean Polar Research Institute, he as participated in seven expeditions to the Canadian Beaufort Sea. On all these expeditions MBARI’s robotic tools have been utilized to investigate seafloor geomorphic features that may have geohazard implications.