Wuchter Cornelia

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Wuchter
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Cornelia
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  • Article
    Microbial diversity and methanogenic activity of Antrim Shale formation waters from recently fractured wells
    (Frontiers Media, 2013-12-06) Wuchter, Cornelia ; Banning, Erin C. ; Mincer, Tracy J. ; Drenzek, Nicholas J. ; Coolen, Marco J. L.
    The Antrim Shale in the Michigan Basin is one of the most productive shale gas formations in the U.S., but optimal resource recovery strategies must rely on a thorough understanding of the complex biogeochemical, microbial, and physical interdependencies in this and similar systems. We used Illumina MiSeq 16S rDNA sequencing to analyze the diversity and relative abundance of prokaryotic communities present in Antrim shale formation water of three closely spaced recently fractured gas-producing wells. In addition, the well waters were incubated with a suite of fermentative and methanogenic substrates in an effort to stimulate microbial methane generation. The three wells exhibited substantial differences in their community structure that may arise from their different drilling and fracturing histories. Bacterial sequences greatly outnumbered those of archaea and shared highest similarity to previously described cultures of mesophiles and moderate halophiles within the Firmicutes, Bacteroidetes, and δ- and ε-Proteobacteria. The majority of archaeal sequences shared highest sequence similarity to uncultured euryarchaeotal environmental clones. Some sequences closely related to cultured methylotrophic and hydrogenotrophic methanogens were also present in the initial well water. Incubation with methanol and trimethylamine stimulated methylotrophic methanogens and resulted in the largest increase in methane production in the formation waters, while fermentation triggered by the addition of yeast extract and formate indirectly stimulated hydrogenotrophic methanogens. The addition of sterile powdered shale as a complex natural substrate stimulated the rate of methane production without affecting total methane yields. Depletion of methane indicative of anaerobic methane oxidation (AMO) was observed over the course of incubation with some substrates. This process could constitute a substantial loss of methane in the shale formation.
  • Preprint
    Archaeal nitrification in the ocean
    ( 2006-01-30) Wuchter, Cornelia ; Abbas, Ben ; Coolen, Marco J. L. ; Herfort, Lydie ; van Bleijswijk, Judith ; Timmers, Peer ; Strous, Marc ; Teira, Eva ; Herndl, Gerhard J. ; Middelburg, Jack J. ; Schouten, Stefan ; Sinninghe Damste, Jaap S.
    Marine Crenarchaeota are the most abundant single group of prokaryotes in the ocean but their physiology and role in marine biogeochemical cycles are unknown. Recently, a member of this clade was isolated from a sea aquarium and shown to be capable of nitrification, tentatively suggesting that they may play a role in the oceanic nitrogen cycle. We enriched a crenarchaeote from North Sea water and show that it oxidizes ammonium to nitrite. A time series study in the North Sea revealed that the abundance of the gene encoding for the archaeal ammonia monooxygenase alfa subunit (amoA) is correlated with the decline in ammonium concentrations and with the abundance of Crenarcheota. Remarkably, the archaeal amoA abundance was 1-2 orders of magnitude higher than those of bacterial nitrifiers which are commonly thought to mediate the oxidation of ammonium to nitrite in marine environments. Analysis of Atlantic waters of the upper 1000 m, where most of the ammonium regeneration and oxidation takes place, showed that crenarchaeotal amoA copy numbers are also one to three orders of magnitude higher than those of bacterial amoA. Our data thus suggest a major role for Archaea in oceanic nitrification.
  • Article
    Neoglacial climate anomalies and the Harappan metamorphosis
    (Copernicus Publications on behalf of the European Geosciences Union, 2018-11-13) Giosan, Liviu ; Orsi, William D. ; Coolen, Marco J. L. ; Wuchter, Cornelia ; Dunlea, Ann G. ; Thirumalai, Kaustubh ; Munoz, Samuel E. ; Clift, Peter D. ; Donnelly, Jeffrey P. ; Galy, Valier ; Fuller, Dorian Q.
    Climate exerted constraints on the growth and decline of past human societies but our knowledge of temporal and spatial climatic patterns is often too restricted to address causal connections. At a global scale, the inter-hemispheric thermal balance provides an emergent framework for understanding regional Holocene climate variability. As the thermal balance adjusted to gradual changes in the seasonality of insolation, the Intertropical Convergence Zone migrated southward accompanied by a weakening of the Indian summer monsoon. Superimposed on this trend, anomalies such as the Little Ice Age point to asymmetric changes in the extratropics of either hemisphere. Here we present a reconstruction of the Indian winter monsoon in the Arabian Sea for the last 6000 years based on paleobiological records in sediments from the continental margin of Pakistan at two levels of ecological complexity: sedimentary ancient DNA reflecting water column environmental states and planktonic foraminifers sensitive to winter conditions. We show that strong winter monsoons between ca. 4500 and 3000 years ago occurred during a period characterized by a series of weak interhemispheric temperature contrast intervals, which we identify as the early neoglacial anomalies (ENA). The strong winter monsoons during ENA were accompanied by changes in wind and precipitation patterns that are particularly evident across the eastern Northern Hemisphere and tropics. This coordinated climate reorganization may have helped trigger the metamorphosis of the urban Harappan civilization into a rural society through a push–pull migration from summer flood-deficient river valleys to the Himalayan piedmont plains with augmented winter rains. The decline in the winter monsoon between 3300 and 3000 years ago at the end of ENA could have played a role in the demise of the rural late Harappans during that time as the first Iron Age culture established itself on the Ghaggar-Hakra interfluve. Finally, we speculate that time-transgressive land cover changes due to aridification of the tropics may have led to a generalized instability of the global climate during ENA at the transition from the warmer Holocene thermal maximum to the cooler Neoglacial.
  • Article
    Climate oscillations reflected within the microbiome of Arabian Sea sediments
    (Nature Publishing Group, 2017-07-20) Orsi, William D. ; Coolen, Marco J. L. ; Wuchter, Cornelia ; He, Lijun ; More, Kuldeep D. ; Irigoien, Xabier ; Chust, Guillem ; Johnson, Carl G. ; Hemingway, Jordon D. ; Lee, Mitchell ; Galy, Valier ; Giosan, Liviu
    Selection of microorganisms in marine sediment is shaped by energy-yielding electron acceptors for respiration that are depleted in vertical succession. However, some taxa have been reported to reflect past depositional conditions suggesting they have experienced weak selection after burial. In sediments underlying the Arabian Sea oxygen minimum zone (OMZ), we performed the first metagenomic profiling of sedimentary DNA at centennial-scale resolution in the context of a multi-proxy paleoclimate reconstruction. While vertical distributions of sulfate reducing bacteria and methanogens indicate energy-based selection typical of anoxic marine sediments, 5–15% of taxa per sample exhibit depth-independent stratigraphies indicative of paleoenvironmental selection over relatively short geological timescales. Despite being vertically separated, indicator taxa deposited under OMZ conditions were more similar to one another than those deposited in bioturbated intervals under intervening higher oxygen. The genomic potential for denitrification also correlated with palaeo-OMZ proxies, independent of sediment depth and available nitrate and nitrite. However, metagenomes revealed mixed acid and Entner-Dourdoroff fermentation pathways encoded by many of the same denitrifier groups. Fermentation thus may explain the subsistence of these facultatively anaerobic microbes whose stratigraphy follows changing paleoceanographic conditions. At least for certain taxa, our analysis provides evidence of their paleoenvironmental selection over the last glacial-interglacial cycle.