Rapid microbial response to the presence of an ancient relic in the Antarctic Dry Valleys

Soil Microbial Responses to Increased Moisture and Organic Resources along a Salinity Gradient in a Polar Desert

“…The dominance of Firmicutes observed here may in part be due to their Gram-positive cell walls and spore-forming ability, which make them resistant to desiccation stress and harsh environmental conditions (73,74). In recent studies in the MDV, Firmicutes were found to be abundant at high-elevation, low-SOM, and low-soil-moisture sites (17) and increased in response to resource additions (25).…”

“…Three studies have reported that altered soil conditions influence microbial communities, concluding that water additions had little discernible impact on soil respiration (23) but that nutritional resource addition in various forms increased soil respiration (24,25) and altered community composition (25). While these studies suggest that soil microbial communities in the MDV are responsive to change, a multisite study that simultaneously investigates the structural and functional responses of bacterial communities to disturbance is necessary to understand how both ecosystem functioning and community composition may respond to the environmental changes occurring and predicted to occur in the near future.…”

Microbiology of Eutrophic (Ornithogenic and Hydrocarbon-Contaminated) Soil

“…An experiment in Miers Valley, in which a mummified seal was transplanted to a previously pristine site, showed that bacterial community structure was also altered considerably in just 3 years (Tiao et al 2012). The augmentation resulted in a significant decrease in bacterial diversity and shifted the community structure from Actinobacteria dominated, to Proteobacteria and Firmicutes dominated.…”

“…Lithic communities in McKelvey Valley (Pointing et al 2009) and the Miers, Marshall, and Garwood Valleys (Khan et al 2011) were found to be distinct from surrounding soil communities, suggesting substantial dissemination of biomass to the local environment is restricted. Similarly, while the presence of an animal carcass at a site may drastically alter the physicochemical parameters and bacterial community composition of the soil, the effects have been found to be restricted to the immediate vicinity of the augmentation (Tiao et al 2012).…”

“…Bacteroidetes, Firmicutes, Cyanobacteria, and Alphaproteobacteria were found to be more abundant relative to other taxa in soils of Fossil Bluff (71°19 0 S) and Coal Nunatak (72°03 0 ) on Alexander Island than at sites on the Falkland Islands, Signy Island, and Anchorage Island (51°76 0 S-67°34 0 S) (Yergeau et al 2009). Several phyla were significantly influenced by soil physicochemical factors, as the proportion of Chloroflexi and Betaproteobacteria were negatively (Yergeau et al 2007b); West Antarctic soil sequences (180) are from a study in the Ellsworth Mountains (Yergeau et al 2007b); Victoria Land soil sequences, a total of 426 clone sequences and 25976 pyrosequencing reads, were included from the McMurdo Dry Valleys, from studies in the Miers Valley Tiao et al 2012), Beacon Valley, Wright Valley, Battleship Promontory , Luther Vale (Niederberger et al 2008), and Bull Pass and Vanda in the Wright Valley ); ornithogenic soil sequences (514) are from Cape Hallett and Cape Bird in the Ross Sea region (Aislabie et al 2009); East Antarctic soil sequences (1396) were included from the Larsmann Hills (Bajerski and Wagner 2013) and Schirmacher Oasis (Shivaji et al 2004); and the Transantarctic Mountain soil sequences (361) were from the Darwin Mountains (Aislabie et al 2013). The trees were constructed using ARB (Ludwig et al 2004), with DNADIST and Neighbor joining analysis, and the percentage of sequences in each phyla is shown (in brackets).…”