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Abstract. Biogeochemical cycling in the semi-enclosed Arctic Ocean is stronglyinfluenced by land–ocean transport of carbon and other elements and isvulnerable to environmental and climate changes. Sediments of the ArcticOcean are an important part of biogeochemical cycling in the Arctic andprovide the opportunity to study present and historical input and the fate oforganic matter (e.g., through permafrost thawing). Comprehensive sedimentary records are required to compare differencesbetween the Arctic regions and to study Arctic biogeochemical budgets. Tothis end, the Circum-Arctic Sediment CArbon DatabasE (CASCADE) wasestablished to curate data primarily on concentrations of organic carbon(OC) and OC isotopes (δ13C, Δ14C) yet also ontotal N (TN) as well as terrigenous biomarkers and other sedimentgeochemical and physical properties. This new database builds on thepublished literature and earlier unpublished records through an extensiveinternational community collaboration. This paper describes the establishment, structure and current status ofCASCADE. The first public version includes OC concentrations in surfacesediments at 4244 oceanographic stations including 2317 with TNconcentrations, 1555 with δ13C-OC values and 268 with Δ14C-OC values and 653 records with quantified terrigenous biomarkers(high-molecular-weight n-alkanes, n-alkanoic acids and lignin phenols).CASCADE also includes data from 326 sediment cores, retrieved by shallowbox or multi-coring, deep gravity/piston coring, or sea-bottom drilling.The comprehensive dataset reveals large-scale features of both OC contentand OC sources between the shelf sea recipients. This offers insight intorelease of pre-aged terrigenous OC to the East Siberian Arctic shelf andyounger terrigenous OC to the Kara Sea. Circum-Arctic sediments therebyreveal patterns of terrestrial OC remobilization and provide clues about thawing of permafrost. CASCADE enables synoptic analysis of OC in Arctic Ocean sediments andfacilitates a wide array of future empirical and modeling studies of theArctic carbon cycle. The database is openly and freely available online(https://doi.org/10.17043/cascade; Martens et al., 2021), is provided in variousmachine-readable data formats (data tables, GIS shapefile, GIS raster), andalso provides ways for contributing data for future CASCADE versions. Wewill continuously update CASCADE with newly published and contributed dataover the foreseeable future as part of the database management of the BolinCentre for Climate Research at Stockholm University.
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This content will become publicly available on April 1, 2027
Radiocarbon constraints on the sources and fluxes of sinking particulate organic carbon to the deep Sargasso Sea
Not AvailThe oceanic biological carbon pump (BCP) is thought to be driven by the vertical export of particulate organic carbon (POC) derived from fresh photosynthetically-fixed carbon in the surface waters to depth. Yet the chemical and isotopic composition of deep ocean POC is often inconsistent with this one-dimensional perspective of the BCP. Here, we investigate the sources and temporal dynamics of POC in the deep-sea using the concentration and carbon isotopic composition (Δ14C and δ13C) of POC intercepted by time-series sediment traps deployed in the Sargasso Sea near Bermuda over a 43-month time period. Seasonal variability in POC collected at 3200 m between 2012 and 2015 reveals a recurring springtime increase in Δ14C and δ13C, indicating rapid transfer of POC produced in the surface ocean to depth. In contrast, summer and autumn periods are characterized by lower Δ14C and δ13C values, reflecting higher contributions of millennial to centennial aged carbon sources. Isotopic mass balance calculations indicate that, on average, 63 ± 14 % of sinking POC originates from freshly produced surface-derived OC and 24 ± 15 % derives from mineral-free suspended pre-aged POC (partly surface-derived), while mineral-associated OC (8 ± 6 %), and DOC (5 ± 4 %) further contribute to the aged carbon signature. The contribution of surface-derived OC is highest during spring, while the fraction of aged mineral-bound OC, likely linked to Gulf Stream-driven lateral sediment transport from the Northwest Atlantic continental margin, is highest in autumn. Our findings highlight the complexity of the BCP in the open ocean, where pre-aged OC contributes significantly to deep-sea carbon sequestration, challenging traditional one-dimensional vertical perspectives of carbon export.able
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- PAR ID:
- 10704612
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Deep Sea Research Part I: Oceanographic Research Papers
- Volume:
- 228
- Issue:
- C
- ISSN:
- 0967-0637
- Page Range / eLocation ID:
- 104663
- Subject(s) / Keyword(s):
- sinking particles particulate organic carbon 14C radiocarbon Sargasso Sea Oceanic Flux Program
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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