Publication
Title
Bacterial chemoautotrophic reoxidation in sub-Arctic sediments : a seasonal study in Kobbefjord, Greenland
Author
Abstract
Anoxic mineralization of organic matter releases dissolved inorganic carbon and produces reduced mineralization products. The reoxidation of these reduced compounds is essential for biogeochemical cycling in sediments and is mainly performed by chemoautotrophic microbes, which synthesize new organic carbon by dark CO2 fixation. At present however, the biogeochemical importance of chemoautotrophy in high-latitude sediments is largely unknown. Here, we determine the seasonal variation in sedimentary chemoautotrophic production in Kobbefjord (SW Greenland). Intact sediment cores from the fjord were incubated, and dark CO2 fixation was quantified by combining bacterial phospholipid-derived fatty acid analysis with C-13 stable isotope probing (PLFA-SIP). Our results reveal a distinct seasonal cycle in chemoautotrophic activity, which increases after the spring bloom and shows lowest activity in the late winter when the fjord is covered by sea ice. The depth distribution of chemoautotrophic activity also varied seasonally, likely due to seasonal variation in the bioturbation activity of sediment infauna. Although chemoautotrophy rates (0.4 +/- 0.2 mmol C m(-2) d(-1)) were in the low range for coastal sediments, they are comparable to those from intertidal sandflats and brackish tropical lagoons, and scale with the sulfide production through sulfate reduction in the fjord. Chemoautotrophic production in these fjord sediments thus appears to be mainly driven by sulfide oxidation and can re-fix 4% of the CO2 produced by mineralization.
Language
English
Source (journal)
Marine ecology progress series. - Halstenbek
Publication
Halstenbek : Inter-research , 2018
ISSN
0171-8630
Volume/pages
601 (2018) , p. 33-39
ISI
000441331000003
Full text (Publisher's DOI)
UAntwerpen
Faculty/Department
Research group
Project info
SEDBIOGEOCHEM 2.0: Hardwiring the ocean floor: the impact of microbial electrical circuitry on biogeochemical cycling in marine sediments
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 07.09.2018
Last edited 04.09.2021
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