Heterotrophic bacterial diversity in aquatic microbial mat communities from Antarctica

Abstract

25Heterotrophic bacteria isolated from five aquatic microbial mat samples from different locations in 26 continental Antarctica and the Antarctic Peninsula were compared to assess their biodiversity. A total of 27 2225 isolates obtained on different media and at different temperatures were included. After an initial 28 grouping by whole-genome fingerprinting, partial 16S rRNA gene sequence analysis was used for further 29 identification. These results were compared with previously published data obtained with the same 30 methodology from terrestrial and aquatic microbial mat samples from two additional Antarctic regions. 31The phylotypes recovered in all these samples belonged to five major phyla, Actinobacteria, 32Bacteroidetes, Proteobacteria, Firmicutes and Deinococcus-Thermus, and included several potentially 33 new taxa. Ordination analyses were performed in order to explore the variance in the diversity of the 34 samples at genus level. Habitat type (terrestrial versus aquatic) and specific conductivity in the lacustrine 35 systems significantly explained the variation in bacterial community structure. Comparison of the 36 phylotypes with sequences from public databases showed that a considerable proportion (36.9%) is 37 currently known only from Antarctica. This suggests that in Antarctica both cosmopolitan taxa as well as 38 taxa with limited dispersal and a history of long-term isolated evolution occur.

Multiple-antibiotic-resistant bacteria from the maritime Antarctic

“…The common Antarctic bacterial phyla such as Actinobacteria, Bacteroidetes, and Proteobacteria, and genera such as Arthrobacter, Flavobacterium, Rhodococcus, Cryobacterium, and Pseudomonas reported by Foong et al (2010), Peeters et al (2012), and Teo and Wong (2014) were also found in Estrellas and CLs. Actinobacteria and Bacteroidetes were the most abundant bacterial families in CL, while Actinobacteria dominates the bacterial community in EL.…”

The spatial structure of Antarctic biodiversity

“…There is increasing molecular and classical biogeographic evidence for ancient radiations and vicariance (e.g., Allegrucci et al 2006, Maslen and Convey 2006, Chown and Convey 2007, and/or expansion from refugial centers within the region itself, and survival through (at least) multiple Pleistocene glacial cycles , McGaughran et al 2010, Mortimer et al 2011a). Even apparently highly dispersible groups such as some Antarctic soil microbiota carry a strong signal of long-term geographical isolation, suggesting that local radiation on evolutionary timescales has outweighed the influence of incoming dispersers (De Wever et al 2009, Chong et al 2012, Peeters et al 2012). …”

Bacterial Diversity Assessment in Antarctic Terrestrial and Aquatic Microbial Mats: A Comparison between Bidirectional Pyrosequencing and Cultivation

“…The cultured heterotrophic bacterial diversity of these samples was reported earlier [4], [33], [34], [35]. From these, we selected 1,666 high quality sequences for comparison with pyrosequencing.…”