News

Life on the edge: active microbial communities in the Kryos MgCl2-brine basin at very low water activity

Abstract.

"The Kryos Basin is a deep-sea hypersaline anoxic basin (DHAB) located in the Eastern Mediterranean Sea (34.98°N 22.04°E). It is filled with brine of re-dissolved Messinian evaporites and is nearly saturated with MgCl2-equivalents, which makes this habitat extremely challenging for life. The strong density difference between the anoxic brine and the overlying oxic Mediterranean seawater impedes mixing, giving rise to a narrow chemocline. [...]"

Source: The ISME Journal
Authors: Lea Steinle et al.
DOI: 10.1038/s41396-018-0107-z

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The hunt for the most-wanted chemolithoautotrophic spookmicrobes

Abstract.

"Microorganisms are the drivers of biogeochemical methane and nitrogen cycles. Essential roles of chemolithoautotrophic microorganisms in these cycles were predicted long before their identification. Dedicated enrichment procedures, metagenomics surveys and single-cell technologies have enabled the identification of several new groups of most-wanted spookmicrobes, including novel methoxydotrophic methanogens that produce methane from methylated coal compounds and acetoclastic ‘Candidatus Methanothrix paradoxum’, which is active in oxic soils. [...]"

Source: FEMS Microbiology Ecology
Authors: Michiel H in ‘t Zandt et al.
DOI: 10.1093/femsec/fiy064


Coccolithovirus facilitation of carbon export in the North Atlantic

Abstract.

"Marine phytoplankton account for approximately half of global primary productivity, making their fate an important driver of the marine carbon cycle. Viruses are thought to recycle more than one-quarter of oceanic photosynthetically fixed organic carbon, which can stimulate nutrient regeneration, primary production and upper ocean respiration2 via lytic infection and the ‘virus shunt’. [...]"

Source: Nature Microbiology
Authors: Christien P. Laber
DOI: 10.1038/s41564-018-0128-4

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A missing link in the estuarine nitrogen cycle?: Coupled nitrification-denitrification mediated by suspended particulate matter

Abstract.

"In estuarine and coastal ecosystems, the majority of previous studies have considered coupled nitrification-denitrification (CND) processes to be exclusively sediment based, with little focus on suspended particulate matter (SPM) in the water column. Here, we present evidence of CND processes in the water column of Hangzhou Bay, one of the largest macrotidal embayments in the world. [...]"

Source: Scientific Reports
Authors: Weijing Zhu et al.
DOI: 10.1038/s41598-018-20688-4

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The microbial nitrogen-cycling network

Abstract.

"Nitrogen is an essential component of all living organisms and the main nutrient limiting life on our planet. By far, the largest inventory of freely accessible nitrogen is atmospheric dinitrogen, but most organisms rely on more bioavailable forms of nitrogen, such as ammonium and nitrate, for growth. [...]"

Source: Nature Reviews Microbiology
Authors: Marcel M. M. Kuypers, Hannah K. Marchant & Boran Kartal
DOI: 10.1038/nrmicro.2018.9

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Insights into the metabolic functioning of a multipartner ciliate symbiosis from oxygen-depleted sediments

Abstract.

"Symbioses between anaerobic or microaerophilic protists and prokaryotes are common in anoxic and oxygen-depleted habitats ranging from marine sediments to gastrointestinal tracts. Nevertheless, little is known about the mechanisms of metabolic interaction between partners. In these putatively syntrophic associations, consumption of fermentative end products (e.g., hydrogen) by the prokaryotic symbionts is thought to facilitate protistan anaerobic metabolism.  [...]"

Source: Molecular Ecology
Authors: R. A. Beinart et al.
DOI: 10.1111/mec.14465

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Diverse Marinimicrobia bacteria may mediate coupled biogeochemical cycles along eco-thermodynamic gradients

Abstract.

"Microbial communities drive biogeochemical cycles through networks of metabolite exchange that are structured along energetic gradients. As energy yields become limiting, these networks favor co-metabolic interactions to maximize energy disequilibria. Here we apply single-cell genomics, metagenomics, and metatranscriptomics to study bacterial populations of the abundant “microbial dark matter” phylum Marinimicrobia along defined energy gradients. [...]"

Source: Nature Communications
Authors: Alyse K. Hawley et al.
DOI: 10.1038/s41467-017-01376-9

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