Universität zu Köln

Kusch, Stephanie ORCID: 0000-0002-2708-4975, Wakeham, Stuart G. and Sepulveda, Julio (2022). Bacteriohopanepolyols across the Black Sea redoxcline trace diverse bacterial metabolisms. Org. Geochem., 172. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 1873-5290

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Abstract

Redox gradients in oceanic oxygen minimum zones are hotspots of diverse bacterial populations and metabo-lisms. Here, we test whether bacteriohopanepolyols (BHPs), a suite of membrane-regulating pentacyclic tri-terpenoid lipids, are suitable tracers of major bacterial metabolisms and whether their structural diversity (BHP lipidomics) allows tracing the bacterial ecology across the Black Sea chemocline. We analyzed suspended par-ticulate matter (SPM) sampled along depth-profiles across the redox/chemocline at two sites in the eastern and western gyres and underlying core-top sediments at the western gyre site. Our results show that BHPs abun-dances reflect the stratification of the Black Sea and capture ecological niches across the chemocline, being highest in the lower suboxic zone and in upper to deep sulfidic waters. BHP-inferred bacterial metabolisms in the lower suboxic zone are dominated by anammox and aerobic methane oxidizers (primarily by Type I/gammap-roteobacteria). Bacterial biomass production in the upper to deep sulfidic zone is mirrored by a range of BHPs that are normally associated with aerobic metabolisms, most likely explained by either survival in oxygenated micro-niches or production by anaerobic bacteria (which could possibly include sulfate reducers and nitrite -dependent methane oxidizers). Most surprisingly, this ecological niche harbors seemingly unknown anaerobic bacteria which produce abundant C-2 and C-3 methylated BHPs. Core-top sediments reflect the BHP structural diversity found in SPM, but with notable compositional differences. Most strikingly, the export dynamics seem to result in near-absence of C-2 methylated BHPs in surface sediments. Sedimentary BHP distributions therefore underestimate the importance of C-2 methylated BHPs in the water column, which has implications for the geological record.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kusch, Stephanie UNSPECIFIED orcid.org/0000-0002-2708-4975 UNSPECIFIED Wakeham, Stuart G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Sepulveda, Julio UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-679976
DOI:	10.1016/j.orggeochem.2022.104462
Journal or Publication Title:	Org. Geochem.
Volume:	172
Date:	2022
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	1873-5290
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language PARTICULATE ORGANIC-MATTER; ANAEROBIC AMMONIUM OXIDATION; SULFATE-REDUCING BACTERIA; PROKARYOTIC TRITERPENOIDS; WATER COLUMN; 2-METHYLHOPANOID PRODUCTION; MICROBIAL ECOLOGY; AEROBIC METHANOTROPHY; OXIDIZING BACTERIA; METHANE OXIDATION Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/67997