A combined lipidomic and 16S rRNA gene amplicon sequencing approach reveals archaeal sources of intact polar lipids in the stratified Black Sea water column

Abstract

Archaea are important players in marine biogeochemical cycles, and their membrane lipids are useful biomarkers in environmental and geobiological studies. However, many archaeal groups remain uncultured and their lipid composition unknown. Here, we aim to expand the knowledge on archaeal lipid biomarkers and determine the potential sources of those lipids in the water column of the euxinic Black Sea. The archaeal community was evaluated by 16S rRNA gene amplicon sequencing and by quantitative PCR . The archaeal intact polar lipids ( IPL s) were investigated by ultra‐high‐pressure liquid chromatography coupled to high‐resolution mass spectrometry. Our study revealed both a complex archaeal community and large changes with water depth in the IPL assemblages. In the oxic/upper suboxic waters (<105 m), the archaeal community was dominated by marine group ( MG ) I Thaumarchaeota, coinciding with a higher relative abundance of hexose phosphohexose crenarchaeol, a known marker for Thaumarchaeota. In the suboxic waters (80–110 m), MGI Nitrosopumilus sp. dominated and produced predominantly monohexose glycerol dibiphytanyl glycerol tetraethers ( GDGT s) and hydroxy‐ GDGT s. Two clades of MGII Euryarchaeota were present in the oxic and upper suboxic zones in much lower abundances, preventing the detection of their specific IPL s. In the deep sulfidic waters (>110 m), archaea belonging to the DPANN Woesearchaeota, Bathyarchaeota, and ANME ‐1b clades dominated. Correlation analyses suggest that the IPL s GDGT ‐0, GDGT ‐1, and GDGT ‐2 with two phosphatidylglycerol ( PG ) head groups and archaeol with a PG , phosphatidylethanolamine, and phosphatidylserine head groups were produced by ANME ‐1b archaea. Bathyarchaeota represented 55% of the archaea in the deeper part of the euxinic zone and likely produces archaeol with phospho‐dihexose and hexose‐glucuronic acid head groups.

Assessing the Effect of Humic Substances and Fe(III) as Potential Electron Acceptors for Anaerobic Methane Oxidation in a Marine Anoxic System

“…Another filter was directly stored at −80 °C for analysis of the in situ microbial community. Water column samples for nutrient and DNA analysis were collected as described in Sollai et al (2019) and Suominen et al (2020) [ 30 , 33 ].…”

“…10–15 µM [ 26 , 27 ]. ANME-1 have been detected in the Black Sea water column before [ 28 , 29 , 30 , 31 ]. The 13 C-depleted stable carbon isotopic composition of a- and monocyclic biphytanes derived from the characteristic membrane lipids of ANME-1 revealed that these archaea actively consume methane in the water column [ 29 ].…”

Particulate Organic Carbon Deconstructed: Molecular and Chemical Composition of Particulate Organic Carbon in the Ocean

“…studies of specific lipid biomarkers and untargeted surveys of the entire POC lipidome (Kharbush et al, 2016;Becker et al, 2018;Sollai et al, 2019).…”

Analytical and Computational Advances, Opportunities, and Challenges in Marine Organic Biogeochemistry in an Era of “Omics”

“…Adding compound-specific isotope analysis in the context of natural isotope abundances (e.g., Schubotz et al, 2009;Pearson et al, 2016) or tracer experiments (e.g., Kellermann et al, 2016) can give further insight into elemental flow within ancient or currently active communities. However, analytical refinements, along with extensive large-scale environmental and laboratory-based surveys, have highlighted the complexity in interpreting the biomarker record solely from a single influencing parameter point of view (Hurley et al, 2016;Sollai et al, 2019). Recent advances have focused on increasing the resolution and sensitivity of lipid analysis.…”