Prokaryotic Diversity of Arctic Ice Shelf Microbial Mats

Department of Natural Resource Sciences, McGill University, Montreal, Canada.
Environmental Microbiology (Impact Factor: 6.2). 04/2008; 10(4):950-66. DOI: 10.1111/j.1462-2920.2007.01516.x
Source: PubMed


The prokaryotic diversity and respiratory activity of microbial mat communities on the Markham Ice Shelf and Ward Hunt Ice Shelf in the Canadian high Arctic were analysed. All heterotrophic isolates and > 95% of bacterial 16S rRNA gene clone library sequences from both ice shelves grouped within the phyla Bacteroidetes, Proteobacteria and Actinobacteria. Clone library analyses showed that the bacterial communities were diverse and varied significantly between the two ice shelves, with the Markham library having a higher estimated diversity (Chao1 = 243; 105 operational taxonomic units observed in 189 clones) than the Ward Hunt library (Chao1 = 106; 52 operational taxonomic units observed in 128 clones). Archaeal 16S rRNA gene clone libraries from both ice shelves were dominated by a single Euryarchaeota sequence, which appears to represent a novel phylotype. Analyses of community activity by radiorespiration assays detected metabolism in mat samples from both ice shelves at temperatures as low as -10 degrees C. These findings provide the first insight into the prokaryotic biodiversity of Arctic ice shelf communities and underscore the importance of these cryo-ecosystems as a rich source of microbiota that are adapted to extreme cold.

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    • "vel III ( Figure 6 , R 2 = 0 . 952 ) . Overall , polar mats ( e . g . , Markham , Ward Hunt , and McMurdo ) had strong correlation of pathways in SEED than other ecosystems ( Figure 6 , R 2 > 0 . 900 ) . Markham mats like Clinton Creek microbialites are dominated by Proteobacteria , and have Gemmatimonadetes present at 3% of the total 16S clones ( Bottos et al . , 2008 ) . Polar mats , whether on microbialites or on ice shelves , appear to have functional gene similarities ; this likely relates to handling shifts in temperature , including temperatures well below freezing ( −10 • C ; Varin et al . , 2012 ) . SEED based functional genes present in Clinton Creek microbialites were also analyzed across b"
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    Frontiers in Microbiology 09/2015; 6. DOI:10.3389/fmicb.2015.00966 · 3.99 Impact Factor
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    • "The seasonal changes in microbial productivity and biomass can be generally observed in modern settings (e.g. Sundback and McGlathery, 2005; Bottos et al., 2008) up to entire disassembling of the mat during autumn and winter seasons (Lindemann et al., 2013). Thus, the hypothesis that the Ediacaran mat was depressed in winter time and had a strong growth during the summer, can be suggested, but it will need further testing in the future. "
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    • "Martian ice wedges are high-priority targets in the search for life beyond Earth, and to expand our understanding of the habitability of such ice environments, we elected to study analog ice wedge environments from the Canadian high Arctic. The microbial communities of a variety of terrestrial cryoenvironments have been studied, such as those found in glacier ice (Skidmore et al., 2000; Miteva et al., 2004), subglacial environments (Yde et al., 2010), cryoconite holes (Sä wströ m et al., 2002), Arctic permafrost soil (Steven et al., 2009; Wilhelm et al., 2011), Antarctic Dry Valley soils and endoliths (Pointing et al., 2009), cryopegs (Gilichinsky, 2002), ice shelves (Bottos et al., 2008), high Arctic saline perennial spring environments (Perreault et al., 2007; Niederberger et al., 2009, 2010), and various other ice environments (Lacelle et al., 2011). These studies reveal complex cold-tolerant microbial communities, some of which exhibit active metabolism at in situ temperatures in ice and brine (-5°C) (Niederberger et al., 2010; Bakermans and Skidmore, 2011) and permafrost (-15°C) (Steven et al., 2008). "

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