Dataset Information

Archaeal lipid biomarker constraints on the Paleocene-Eocene carbon isotope excursion.

ABSTRACT: A negative carbon isotope excursion recorded in terrestrial and marine archives reflects massive carbon emissions into the exogenic carbon reservoir during the Paleocene-Eocene Thermal Maximum. Yet, discrepancies in carbon isotope excursion estimates from different sample types lead to substantial uncertainties in the source, scale, and timing of carbon emissions. Here we show that membrane lipids of marine planktonic archaea reliably record both the carbon isotope excursion and surface ocean warming during the Paleocene-Eocene Thermal Maximum. Novel records of the isotopic composition of crenarchaeol constrain the global carbon isotope excursion magnitude to -4.0?±?0.4‰, consistent with emission of >3000?Pg C from methane hydrate dissociation or >4400?Pg C for scenarios involving emissions from geothermal heating or oxidation of sedimentary organic matter. A pre-onset excursion in the isotopic composition of crenarchaeol and ocean temperature highlights the susceptibility of the late Paleocene carbon cycle to perturbations and suggests that climate instability preceded the Paleocene-Eocene Thermal Maximum.

SUBMITTER: Elling FJ

PROVIDER: S-EPMC6778145 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Archaeal lipid biomarker constraints on the Paleocene-Eocene carbon isotope excursion.

Elling Felix J FJ Gottschalk Julia J Doeana Katiana D KD Kusch Stephanie S Hurley Sarah J SJ Pearson Ann A

Nature communications 20191004 1

A negative carbon isotope excursion recorded in terrestrial and marine archives reflects massive carbon emissions into the exogenic carbon reservoir during the Paleocene-Eocene Thermal Maximum. Yet, discrepancies in carbon isotope excursion estimates from different sample types lead to substantial uncertainties in the source, scale, and timing of carbon emissions. Here we show that membrane lipids of marine planktonic archaea reliably record both the carbon isotope excursion and surface ocean wa ...[more]

PMID: 31586063

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Project description:The remote Dallol Hot Springs, an active hydrothermal system in the volcanic region of Danakil (Ethiopia), is an interesting yet poorly studied polyextreme environment for investigating the limits of life. Here, we explored the presence of signs of life in five samples of sinter deposits at Dallol, by means of lipid biomarkers and stable isotope composition. The results reveal the existence of biological material with predominance of (presently or recently active) microbial sources, according to the relative abundance of low-over-high molecular weight moieties (n-alkanes, n-carboxylic acids, or n-alkanols), and the detection of diverse microbial-diagnostic compounds (i.e., monomethyl alkanes; C16:1 ?7, C18:1 ?9, C18:1 ?10, C18:2 ?6,9 and iso/anteiso C15 and C17 carboxylic acids; or short-chained dicarboxylic acids). The molecular lipid patterns at Dallol suggest a microbial community largely composed of thermophilic members of the Aquificae, Thermotogae, Chroroflexi, or Proteobacteria phyla, as well as microbial consortia of phototrophs (e.g., Cyanobacteria-Chloroflexi) in lower-temperature and higher-pH niches. Autotrophic sources most likely using the Calvin cycle, together with the acetyl coenzyme A (CoA) pathway, were inferred from the depleted bulk ?13C ratios (-25.9/-22.6‰), while sulfate-reducing bacteria were considered according to enriched sulfate (7.3/11.7‰) and total sulfur (20.5/8.2‰) ?34S ratios. The abundance of functionalized hydrocarbons (i.e., n-carboxylic acids and n-alkanols) and the distinct even-over-odd predominance/preference on the typically odd n-alkanes (CPIalkanes ? 1) pointed to active or recent microbial metabolisms. This study documents the detection of biosignatures in the polyextreme environment of Dallol and raises the possibility of finding life or its remnants in other remote locations on Earth, where the harsh environmental conditions would lead to expect otherwise. These findings are relevant for understanding the limits of life and have implications for searching for hypothetical life vestiges in extreme environments beyond Earth.

Dataset Information

Archaeal lipid biomarker constraints on the Paleocene-Eocene carbon isotope excursion.

Publications

Archaeal lipid biomarker constraints on the Paleocene-Eocene carbon isotope excursion.

Similar Datasets

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