After graduating from high school (Gymnasium) in Bammental, Germany, I completed my undergraduate degree in Geoecology at the University of Tuebingen. I then moved to Tempe, Arizona, for my Ph.D. in Environmental Life Sciences at Arizona State University before joining Stanford as a postdoc.
Honors & Awards
NASA Postdoctoral Program (NPP) Fellowship, NASA (2021-2024)
USAID Global Development Research scholarship, USAID (2017-2018)
APS/NAI Lewis & Clark Fund for Exploration and Field Research in Astrobiology, American Philosophical Society (2017)
ASU’s Graduate and Professional Association Outstanding Mentor Award, Arizona State University (2016)
NASA (NAI) Astrobiology Early Career Collaboration Award, NASA (2016)
DAAD (German Research Exchange Service) Doctoral fellowship, German Research Exchange Service (2014-2015)
Anne Dekas, Postdoctoral Faculty Sponsor
Current Research and Scholarly Interests
Earth has transitioned from an abiotic planet to a vibrant biosphere over billions of years. During the first half of this transition, all living entities were prokaryotic microorganisms centralized in marine ecosystems. The interplay of non-living matter and microorganisms played a key role in metabolic evolution. I envision the major biogeochemical cycles (C, N, S) as “mosaics” of enzymatic and non-enzymatic reactions that co-evolved on a transitioning planet. To understand the modern biosphere, we must learn more about its origin and how it came to be.
My research interests revolve around the co-evolution of microbial life and Earth processes, the relation of these to the planetary climate, as well as astrobiology. I combine fieldwork and in-situ experiments with laboratory analyses and apply cutting-edge geochemical and molecular biological techniques, including isotopic tracers, DNA and RNA analysis, gene tree/species tree reconciliation and ancestral character state reconstruction, fluorescence in-situ hybridization (FISH), and microbiological culturing. I am also familiar with lipid analysis and nanoscale secondary ion mass spectrometry (nanoSIMS).
In the spirit of the Stanford Doerr School of Sustainability, I am also passionate about seeking solutions for global climate change by focusing on greenhouse gas removal from the atmosphere. I see high potential in the carbon dioxide, methane, and nitrous oxide consumption by enhanced mineral-microbial catalysis – processes that have been controlling gas fluxes since billions of years.
Mcr-dependent methanogenesis in Archaeoglobaceae enriched from a terrestrial hot spring.
The ISME journal
The preeminent source of biological methane on Earth is methyl coenzyme M reductase (Mcr)-dependent archaeal methanogenesis. A growing body of evidence suggests a diversity of archaea possess Mcr, although experimental validation of hypothesized methane metabolisms has been missing. Here, we provide evidence of a functional Mcr-based methanogenesis pathway in a novel member of the family Archaeoglobaceae, designated Methanoglobus nevadensis, which we enriched from a terrestrial hot spring on the polysaccharide xyloglucan. Our incubation assays demonstrate methane production that is highly sensitive to the Mcr inhibitor bromoethanesulfonate, stimulated by xyloglucan and xyloglucan-derived sugars, concomitant with the consumption of molecular hydrogen, and causing a deuterium fractionation in methane characteristic of hydrogenotrophic and methylotrophic methanogens. Combined with the recovery and analysis of a high-quality M. nevadensis metagenome-assembled genome encoding a divergent Mcr and diverse potential electron and carbon transfer pathways, our observations suggest methanogenesis in M. nevadensis occurs via Mcr and is fueled by the consumption of cross-fed byproducts of xyloglucan fermentation mediated by other community members. Phylogenetic analysis shows close affiliation of the M. nevadensis Mcr with those from Korarchaeota, Nezhaarchaeota, Verstraetearchaeota, and other Archaeoglobales that are divergent from well-characterized Mcr. We propose these archaea likely also use functional Mcr complexes to generate methane on the basis of our experimental validation in M. nevadensis. Thus, divergent Mcr-encoding archaea may be underestimated sources of biological methane in terrestrial and marine hydrothermal environments.
View details for DOI 10.1038/s41396-023-01472-3
View details for PubMedID 37452096
View details for PubMedCentralID 5543129
- Mineral-catalysed formation of marine NO and N2O on the anoxic early Earth NATURE GEOSCIENCE 2022; 15 (12): 1056-+
Coupled abiotic-biotic cycling of nitrous oxide in tropical peatlands.
Nature ecology & evolution
Atmospheric nitrous oxide (N2O) is a potent greenhouse gas thought to be mainly derived from microbial metabolism as part of the denitrification pathway. Here we report that in unexplored peat soils of Central and South America, N2O production can be driven by abiotic reactions (≤98%) highly competitive to their enzymatic counterparts. Extracted soil iron positively correlated with in situ abiotic N2O production determined by isotopic tracers. Moreover, we found that microbial N2O reduction accompanied abiotic production, essentially closing a coupled abiotic-biotic N2O cycle. Anaerobic N2O consumption occurred ubiquitously (pH 6.4-3.7), with proportions of diverse clade II N2O reducers increasing with consumption rates. Our findings show that denitrification in tropical peat soils is not a purely biological process but rather a 'mosaic' of abiotic and biotic reduction reactions. We predict that hydrological and temperature fluctuations differentially affect abiotic and biotic drivers and further contribute to the high N2O flux variation in the region.
View details for DOI 10.1038/s41559-022-01892-y
View details for PubMedID 36202923
An essential role for tungsten in the ecology and evolution of a previously uncultivated lineage of anaerobic, thermophilic Archaea.
2022; 13 (1): 3773
Trace metals have been an important ingredient for life throughout Earth's history. Here, we describe the genome-guided cultivation of a member of the elusive archaeal lineage Caldarchaeales (syn. Aigarchaeota), Wolframiiraptor gerlachensis, and its growth dependence on tungsten. A metagenome-assembled genome (MAG) of W. gerlachensis encodes putative tungsten membrane transport systems, as well as pathways for anaerobic oxidation of sugars probably mediated by tungsten-dependent ferredoxin oxidoreductases that are expressed during growth. Catalyzed reporter deposition-fluorescence in-situ hybridization (CARD-FISH) and nanoscale secondary ion mass spectrometry (nanoSIMS) show that W. gerlachensis preferentially assimilates xylose. Phylogenetic analyses of 78 high-quality Wolframiiraptoraceae MAGs from terrestrial and marine hydrothermal systems suggest that tungsten-associated enzymes were present in the last common ancestor of extant Wolframiiraptoraceae. Our observations imply a crucial role for tungsten-dependent metabolism in the origin and evolution of this lineage, and hint at a relic metabolic dependence on this trace metal in early anaerobic thermophiles.
View details for DOI 10.1038/s41467-022-31452-8
View details for PubMedID 35773279