Universität zu Köln

Berg, Sonja ORCID: 0000-0002-9629-6007, Jivcov, Sandra, Kusch, Stephanie ORCID: 0000-0002-2708-4975, Kuhn, Gerhard, White, Duanne, Bohrmann, Gerhard, Melles, Martin ORCID: 0000-0003-0977-9463 and Rethemeyer, Janet ORCID: 0000-0001-6698-4186 (2021). Increased petrogenic and biospheric organic carbon burial in sub-Antarctic fjord sediments in response to recent glacier retreat. Limnol. Oceanogr., 66 (12). S. 4347 - 4363. HOBOKEN: WILEY. ISSN 1939-5590

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Abstract

Fjords are recognized as hotspots of organic carbon (OC) burial in the coastal ocean. In fjords with glaciated catchments, glacier discharge carries large amounts of suspended matter. This sedimentary load includes OC from bedrock and terrigenous sources (modern vegetation, peat, soil deposits), which is either buried in the fjord or remineralized during export, acting as a potential source of CO2 to the atmosphere. In sub-Antarctic South Georgia, fjord-terminating glaciers have been retreating during the past decades, likely as a response to changing climate conditions. We determine sources of OC in surface sediments of Cumberland Bay, South Georgia, using lipid biomarkers and the bulk C-14 isotopic composition, and quantify OC burial at present and for the time period of documented glacier retreat (between 1958 and 2017). Petrogenic OC is the dominant type of OC in proximity to the present-day calving fronts (60.4 +/- 1.4% to 73.8 +/- 2.6%) and decreases to 14.0 +/- 2.7% outside the fjord, indicating that petrogenic OC is effectively buried in the fjord. Beside of marine OC, terrigenous OC comprises 2.7 +/- 0.5% to 7.9 +/- 5.9% and is mostly derived from modern plants and Holocene peat and soil deposits that are eroded along the flanks of the fjord, rather than released by the retreating fjord glaciers. We estimate that the retreat of tidewater glaciers between 1958 and 2017 led to an increase in petrogenic carbon accumulation of 22% in Cumberland West Bay and 6.5% in Cumberland East Bay, suggesting that successive glacier retreat does not only release petrogenic OC into the fjord, but also increases the capacity of OC burial.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Berg, Sonja UNSPECIFIED orcid.org/0000-0002-9629-6007 UNSPECIFIED Jivcov, Sandra UNSPECIFIED UNSPECIFIED UNSPECIFIED Kusch, Stephanie UNSPECIFIED orcid.org/0000-0002-2708-4975 UNSPECIFIED Kuhn, Gerhard UNSPECIFIED UNSPECIFIED UNSPECIFIED White, Duanne UNSPECIFIED UNSPECIFIED UNSPECIFIED Bohrmann, Gerhard UNSPECIFIED UNSPECIFIED UNSPECIFIED Melles, Martin UNSPECIFIED orcid.org/0000-0003-0977-9463 UNSPECIFIED Rethemeyer, Janet UNSPECIFIED orcid.org/0000-0001-6698-4186 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-588492
DOI:	10.1002/lno.11965
Journal or Publication Title:	Limnol. Oceanogr.
Volume:	66
Number:	12
Page Range:	S. 4347 - 4363
Date:	2021
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1939-5590
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SOUTH GEORGIA; METHANE SEEPAGE; CUMBERLAND BAY; FATTY-ACIDS; TERRESTRIAL; MATTER; LIPIDS; GEOMORPHOLOGY; FLUCTUATIONS; DEGLACIATION Multiple languages Limnology; Oceanography Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/58849