Microbial ecology of the cryosphere (glacial and permafrost habitats): current knowledge

Margesin, Rosa; Collins, Tony

doi:10.1007/s00253-019-09631-3

Cited by 123 publications

(76 citation statements)

References 116 publications

(119 reference statements)

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“…Study of microbial diversity in polar and high alpine regions has revealed a higher diversity of viruses, bacteria, and eukaryotic microbes than expected, and these extreme cold habitants are hot spots of microbial diversity and evolution ( Anesio and Bellas, 2011 ; Margesin and Collins, 2019 ). In the present study, we compared 21 genomes of psychrophilic Cryobacterium to their mesophilic counterparts from the same family Microbacteriaceae with the aim to identify unique genomic features of the psychrophilic Cryobacterium strains isolated from polar and alpine environments.…”

Section: Discussionmentioning

confidence: 99%

Genomic Insights of Cryobacterium Isolated From Ice Core Reveal Genome Dynamics for Adaptation in Glacier

et al. 2020

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Glacier is the dominant cold habitat in terrestrial environments, providing a model ecosystem to explore extremophilic strategies and study early lives on Earth. The dominant form of life in glaciers is bacteria. However, little is known about past evolutionary processes that bacteria underwent during adaptation to the cryosphere and the connection of their genomic traits to environmental stressors. Aiming to test the hypothesis that bacterial genomic content and dynamics are driven by glacial environmental stressors, we compared genomes of 21 psychrophilic Cryobacterium strains, including 14 that we isolated from three Tibetan ice cores, to their mesophilic counterparts from the same family Microbacteriaceae of Actinobacteria. The results show that psychrophilic Cryobacterium underwent more dynamic changes in genome content, and their genomes have a significantly higher number of genes involved in stress response, motility, and chemotaxis than their mesophilic counterparts ( P < 0.05). The phylogenetic birth-and-death model imposed on the phylogenomic tree indicates a vast surge in recent common ancestor of psychrophilic Cryobacterium (gained the greatest number of genes by 1,168) after the division of the mesophilic strain Cryobacterium mesophilum . The expansion in genome content brought in key genes primarily of the categories “cofactors, vitamins, prosthetic groups, pigments,” “monosaccharides metabolism,” and “membrane transport.” The amino acid substitution rates of psychrophilic Cryobacterium strains are two orders of magnitude lower than those in mesophilic strains. However, no significantly higher number of cold shock genes was found in psychrophilic Cryobacterium strains, indicating that multi-copy is not a key factor for cold adaptation in the family Microbacteriaceae, although cold shock genes are indispensable for psychrophiles. Extensive gene acquisition and low amino acid substitution rate might be the strategies of psychrophilic Cryobacterium to resist low temperature, oligotrophy, and high UV radiation on glaciers. The exploration of genome evolution and survival strategies of psychrophilic Cryobacterium deepens our understanding of bacterial cold adaptation.

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Section: Discussionmentioning

confidence: 99%

Genomic Insights of Cryobacterium Isolated From Ice Core Reveal Genome Dynamics for Adaptation in Glacier

et al. 2020

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“…Such cold-loving microorganisms are known to have several modifications at cellular and biochemical levels to alleviate the effect of low temperatures and other associated stress conditions. These extreme low temperatures are dependent on these environment-specific microorganisms for their several ecological processes [8]. In the socio-economic perspective, Himalayan ranges serve as home to the population living in it.…”

Section: Himalaya: Geographic Importance and Its Uniquenessmentioning

confidence: 99%

Microbial Ecology from the Himalayan Cryosphere Perspective

Dhakar

Pandey

2020

Microorganisms

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Cold-adapted microorganisms represent a large fraction of biomass on Earth because of the dominance of low-temperature environments. Extreme cold environments are mainly dependent on microbial activities because this climate restricts higher plants and animals. Himalaya is one of the most important cold environments on Earth as it shares climatic similarities with the polar regions. It includes a wide range of ecosystems, from temperate to extreme cold, distributed along the higher altitudes. These regions are characterized as stressful environments because of the heavy exposure to harmful rays, scarcity of nutrition, and freezing conditions. The microorganisms that colonize these regions are recognized as cold-tolerant (psychrotolerants) or/and cold-loving (psychrophiles) microorganisms. These microorganisms possess several structural and functional adaptations in order to perform normal life processes under the stressful low-temperature environments. Their biological activities maintain the nutrient flux in the environment and contribute to the global biogeochemical cycles. Limited culture-dependent and culture-independent studies have revealed their diversity in community structure and functional potential. Apart from the ecological importance, these microorganisms have been recognized as source of cold-active enzymes and novel bioactive compounds of industrial and biotechnological importance. Being an important part of the cryosphere, Himalaya needs to be explored at different dimensions related to the life of the inhabiting extremophiles. The present review discusses the distinct facts associated with microbial ecology from the Himalayan cryosphere perspective.

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“…These microhabitats exist in a wide variety of icy environments: snow, glacial ice, deep glacial ice, frozen ponds, sea ice, etc. (Margesin and Miteva, 2011 ; Margesin and Collins, 2019 ). For example, glacial ice cores collected from the West Antarctic Ice Sheet (WAIS) Divide borehole in Antarctica contained prokaryotic cell concentrations from 10 4 to 10 6 cells/cm 3 at a depth of 1.7–2.7 km below the surface (Santibáñez et al , 2018 ).…”

Section: Introductionmentioning

confidence: 99%

“…(Priscu et al , 1998 , 1999; Price, 2006 ; Priscu and Hand, 2012 ; Boetius et al , 2015 ; D'Andrilli et al , 2017 ; Garcia-Lopez and Cid, 2017 ). In particular, understanding how organic materials (nutrients, building blocks) and microbial cells in terrestrial ice sheets are distributed and interrelated in ice microenvironments (Priscu et al , 2007 ; Margesin and Collins, 2019 ) will aid in the exploration of these alien worlds.…”

Section: Introductionmentioning

confidence: 99%

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Subsurface In Situ Detection of Microbes and Diverse Organic Matter Hotspots in the Greenland Ice Sheet

et al. 2020

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We used a deep-ultraviolet fluorescence mapping spectrometer, coupled to a drill system, to scan from the surface to 105 m depth into the Greenland ice sheet. The scan included firn and glacial ice and demonstrated that the instrument is able to determine small (mm) and large (cm) scale regions of organic matter concentration and discriminate spectral types of organic matter at high resolution. Both a linear point cloud scanning mode and a raster mapping mode were used to detect and localize microbial and organic matter “hotspots” embedded in the ice. Our instrument revealed diverse spectral signatures. Most hotspots were <20 mm in diameter, clearly isolated from other hotspots, and distributed stochastically; there was no evidence of layering in the ice at the fine scales examined (100 μm per pixel). The spectral signatures were consistent with organic matter fluorescence from microbes, lignins, fused-ring aromatic molecules, including polycyclic aromatic hydrocarbons, and biologically derived materials such as fulvic acids. In situ detection of organic matter hotspots in ice prevents loss of spatial information and signal dilution when compared with traditional bulk analysis of ice core meltwaters. Our methodology could be useful for detecting microbial and organic hotspots in terrestrial icy environments and on future missions to the Ocean Worlds of our Solar System.

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Microbial ecology of the cryosphere (glacial and permafrost habitats): current knowledge

Cited by 123 publications

References 116 publications

Genomic Insights of Cryobacterium Isolated From Ice Core Reveal Genome Dynamics for Adaptation in Glacier

Genomic Insights of Cryobacterium Isolated From Ice Core Reveal Genome Dynamics for Adaptation in Glacier

Microbial Ecology from the Himalayan Cryosphere Perspective

Subsurface In Situ Detection of Microbes and Diverse Organic Matter Hotspots in the Greenland Ice Sheet

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