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TitleEroding permafrost coasts release low amounts of dissolved organic carbon (DOC) from ground ice into the nearshore zone of the Arctic Ocean
AuthorTanski, G; Couture, N; Lantuit, H; Eulenburg, A; Fritz, M
SourceGlobal Biogeochemical Cycles vol. 30, issue 7, 2016 p. 1054-1068, https://doi.org/10.1002/2015GB005337
Year2016
Alt SeriesEarth Sciences Sector, Contribution Series 20160006
PublisherWiley
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf; html; xls
ProvinceYukon
NTS117D/03; 117D/04; 117D/05; 117D/06; 117D/11; 117D/12
AreaArctoc Ocean; Beaufort Sea; Herschel Island; Roland Bay; Kay Point; King Point
Lat/Long WENS-139.5000 -138.0000 69.0000 9.0667
Subjectsenvironmental geology; marine geology; surficial geology/geomorphology; coastal studies; coastal erosion; permafrost; ground ice; organic carbon analyses; marine environments; nearshore environment; climate effects; sediments; soils; erosion rates; ecosystems; slumps; cores; core samples; glacial features; moraines; lacustrine deposits; biogeochemistry; climate change; volumetric ice content; bioavailability; ground thaw; Arctic carbon budget; Phanerozoic; Cenozoic; Quaternary
Illustrationslocation maps; photographs; tables; plots; sketch maps
ProgramCoastal Infrastructure, Climate Change Geoscience
LinksSupplementary Data - Données supplémentaires
AbstractIce-rich permafrost coasts in the Arctic are highly sensitive to climate warming and erode at a pace that exceeds the global average. Permafrost coasts deliver vast amounts of organic carbon into the nearshore zone of the Arctic Ocean. Numbers on flux exist for particulate organic carbon (POC) and total or soil organic carbon (TOC, SOC). However, they do not exist for dissolved organic carbon (DOC), which is known to be highly bioavailable. This study aims to estimate DOC stocks in coastal permafrost as well as the annual flux into the ocean. DOC concentrations in ground ice were analyzed along the ice-rich Yukon coast (YC) in the western Canadian Arctic. The annual DOC flux was estimated using available numbers for coast length, cliff height, annual erosion rate, and volumetric ice content in different stratigraphic horizons. Our results showed that DOC concentrations in ground ice range between 0.3 and 347.0 mgL-1 with an estimated stock of 13.6 ± 3.0 gm-3 along the YC. An annual DOC flux of 54.9 ± 0.9 Mgyr-1 was computed. These DOC fluxes are low compared to POC and SOC fluxes from coastal erosion or POC and DOC fluxes from Arctic rivers. We conclude that DOC fluxes from permafrost coasts play a secondary role in the Arctic carbon budget. However, this DOC is assumed to be highly bioavailable. We hypothesize that DOC from coastal erosion is important for ecosystems in the Arctic nearshore zones, particularly in summer when river discharge is low, and in areas where rivers are absent.
Summary(Plain Language Summary, not published)
Ice-rich permafrost coasts in the Arctic erode more quickly than the global average, thereby delivering vast amounts of organic carbon to the Arctic Ocean. Although we know how much particulate organic carbon (POC) is delivered to the ocean, there are no estimates for the flux of dissolved organic carbon (DOC), a type of carbon easily broken down by microbes. Our goal was to estimate how much DOC is found in ground ice along the Yukon coast and how quickly it is transferred into the ocean. Our results showed that DOC concentrations in ground ice range between 0.3 and 347.0 mg L-1, resulting in an annual flux of 54.4 Mg yr-1. This DOC flux is low compared to POC fluxes from coastal erosion or POC and DOC fluxes from Arctic rivers and plays a minor role in the Arctic carbon budget. However, this DOC is likely highly decomposable and therefore important for ecosystems in the Arctic nearshore zones.
GEOSCAN ID297862