Benthic archaea as potential sources of tetraether membrane lipids in sediments across an oxygen minimum zone
Besseling, M.A.; Hopmans, E.C.; Boschman, R.C.; Sinninghe Damsté, J.S.; Villanueva, L. (2018). Benthic archaea as potential sources of tetraether membrane lipids in sediments across an oxygen minimum zone. Biogeosciences 15: 4047-4064. https://doi.org/10.5194/bg-15-4047-2018
In: Gattuso, J.P.; Kesselmeier, J. (Ed.) Biogeosciences. Copernicus Publications: Göttingen. ISSN 1726-4170; e-ISSN 1726-4189, more
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| Authors | | Top |
- Besseling, M.A., more
- Hopmans, E.C., more
- Boschman, R.C., more
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- Sinninghe Damsté, J.S., more
- Villanueva, L., more
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| Abstract |
Benthic archaea comprise a significant part of thetotal prokaryotic biomass in marine sediments. Recent genomicsurveys suggest they are largely involved in anaerobicprocessing of organic matter, but the distribution and abundanceof these archaeal groups are still largely unknown. Archaealmembrane lipids composed of isoprenoid diethers ortetraethers (glycerol dibiphytanyl glycerol tetraether, GDGT)are often used as archaeal biomarkers. Here, we compare thearchaeal diversity and intact polar lipid (IPL) compositionin both surface (0–0.5 cm) and subsurface (10–12 cm) sedimentsrecovered within, just below, and well below the oxygenminimum zone (OMZ) of the Arabian Sea. Archaeal 16SrRNA gene amplicon sequencing revealed a predominance ofThaumarchaeota (Marine Group I, MG-I) in oxygenated sediments.Quantification of archaeal 16S rRNA and ammoniamonoxygenase (amoA) of Thaumarchaeota genes and theirtranscripts indicated the presence of an active in situ benthicpopulation, which coincided with a high relative abundanceof hexose phosphohexose crenarchaeol, a specific biomarkerfor living Thaumarchaeota. On the other hand, anoxic surfacesediments within the OMZ and all subsurface sedimentswere dominated by archaea belonging to the MiscellaneousCrenarchaeota Group (MCG), the Thermoplasmatalesand archaea of the DPANN (superphylum grouping Micrarchaeota,Diapherotrites, Aenigmarchaeota, Nanohaloarchaeota,Parvarchaeota, Nanoarchaeota, Pacearchaeota andWoesearchaeota). Members of the MCG were diverse, witha dominance of subgroup MCG-12 in anoxic surface sediments.This coincided with a high relative abundance ofIPL GDGT-0 with an unknown polar head group. Subsurfaceanoxic sediments were characterized by higher relativeabundance of GDGT-0, -2 and -3 with dihexose IPL types,GDGT-0 with a cyclopentanetetraol molecule and hexose, aswell as the presence of specific MCG subgroups, suggestingthat these groups could be the biological sources of these archaeallipids. |
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