Elling Felix J.

No Thumbnail Available
Last Name
Elling
First Name
Felix J.
ORCID
0000-0003-0405-4033

Filters

2016 - 2019 1 2020 - 2021 1
1 1
2
Reset filters

Settings

Search Results

Now showing 1 - 2 of 2
  • Preprint
    Unusual butane- and pentanetriol-based tetraether lipids in Methanomassiliicoccus luminyensis, a representative of the seventh order of methanogens
    ( 2016-05) Becker, Kevin W. ; Elling, Felix J. ; Yoshinaga, Marcos Y. ; Sollinger, Andrea ; Urich, Tim ; Hinrichs, Kai-Uwe
    A new clade of archaea has recently been proposed to constitute the seventh methanogenic order, the Methanomassiliicoccales, which is related to the Thermoplasmatales and the uncultivated archaeal clades deep-sea hydrothermal vent Euryarchaeota group 2 and marine group II Euryarchaeota but only distantly related to other methanogens. In this study, we investigated the membrane lipid composition of Methanomassiliicoccus luminyensis, the sole cultured representative of this seventh order. The lipid inventory of M. luminyensis comprises a unique assemblage of novel lipids as well as lipids otherwise typical for thermophilic, methanogenic, or halophilic archaea. For instance, glycerol sesterpanyl-phytanyl diether core lipids found mainly in halophilic archaea were detected, and so were compounds bearing either heptose or methoxylated glycosidic head groups, neither of which have been reported so far for other archaea. The absence of quinones or methanophenazines is consistent with a biochemistry of methanogenesis different from that of the methanophenazine-containing methylotrophic methanogens. The most distinctive characteristic of the membrane lipid composition of M. luminyensis, however, is the presence of tetraether lipids in which one glycerol backbone is replaced by either butane- or pentanetriol, i.e., lipids recently discovered in marine sediments. Butanetriol dibiphytanyl glycerol tetraether (BDGT) constitutes the most abundant core lipid type (>50% relative abundance) in M. luminyensis. We have thus identified a source for these unusual orphan lipids. The complementary analysis of diverse marine sediment samples showed that BDGTs are widespread in anoxic layers, suggesting an environmental significance of Methanomassiliicoccales and/or related BDGT producers beyond gastrointestinal tracts.
  • Article
    Linking diatom-diazotroph symbioses to nitrogen cycle perturbations and deep-water anoxia: insights from Mediterranean sapropel events
    (Elsevier, 2021-07-30) Elling, Felix J. ; Hemingway, Jordon D. ; Kharbush, Jenan J. ; Becker, Kevin W. ; Polik, Catherine A. ; Pearson, Ann
    Elevated organic matter (OM) export flux promotes marine anoxia, thus increasing carbon sequestration efficiency and decreasing atmospheric carbon dioxide levels. However, the mechanisms that trigger and sustain anoxic events—particularly those associated with nutrient-poor, oligotrophic surface waters—remain poorly constrained. Mediterranean Sea sapropels are well-preserved sediments deposited during episodic anoxic events throughout the Plio-Pleistocene; as such, they may provide unique insight into the biogeochemical and ecological drivers of—and responses to—marine anoxia. Using biomarker distributions, we demonstrate that anaerobic ammonium oxidizing (anammox) bacteria and diazotrophic endosymbionts of mat- and/or raft-forming diatoms were both abundant during sapropel events, particularly in the Ionian and Libyan seas. In these sapropels, the carbon isotope compositions of anammox biomarkers directly capture progressive 13C-depletion in deep-water dissolved inorganic carbon, indicating sustained carbon sequestration. To explain these observations, we propose a reinforcing feedback whereby initial nutrient and/or circulation perturbations promote fixed nitrogen loss via intensified anammox and heterotrophic denitrification, which in turn favors proliferation of rapidly sinking diatom-diazotroph symbiotic consortia, increases OM burial flux, and sustains anoxia. This mechanism resolves the long-standing conundrum that small and buoyant diazotrophs are apparently associated with high OM export during periods of marine anoxia and oligotrophy.