Microorganisms in the atmosphere over Antarctica

Abstract

Antarctic microbial biodiversity is the result of a balance between evolution, extinction and colonization, and so it is not possible to gain a full understanding of the microbial biodiversity of a location, its biogeography, stability or evolutionary relationships without some understanding of the input of new biodiversity from the aerial environment. In addition, it is important to know whether the microorganisms already present are transient or resident - this is particularly true for the Antarctic environment, as selective pressures for survival in the air are similar to those that make microorganisms suitable for Antarctic colonization. The source of potential airborne colonists is widespread, as they may originate from plant surfaces, animals, water surfaces or soils and even from bacteria replicating within the clouds. On a global scale, transport of air masses from the well-mixed boundary layer to high-altitude sites has frequently been observed, particularly in the warm season, and these air masses contain microorganisms. Indeed, it has become evident that much of the microbial life within remote environments is transported by air currents. In this review, we examine the behaviour of microorganisms in the Antarctic aerial environment and the extent to which these microorganisms might influence Antarctic microbial biodiversity.

Potential sources of microbial colonizers in an initial soil ecosystem after retreat of an alpine glacier

“…One aim of this study was to identify whether potential microbial colonizers of mineral debris were deposited from the atmosphere. Microorganisms travelling through the atmosphere represent perfect immigrant candidates (Pearce et al, 2009) to establish in nutrient-poor soils formed after glacier retreat because they can thrive and remain active under high UV exposure, osmotic stress and C depletion (Amato et al, 2007;Šantl-Temkiv et al, 2012;Šantl-Temkiv et al, 2013). We found, however, that atmospheric bacterial and fungal communities deposited in the Damma glacier catchment were different from those of soils.…”

Microbiology of Eutrophic (Ornithogenic and Hydrocarbon-Contaminated) Soil

“…The harshness of Antarctic soils make them inhospitable to many potential colonizing bacteria ; however, soils of lower diversity may be more susceptible to colonization by foreign organisms (Van Elsas et al 2012). While there is evidence of inputs of foreign organisms to Antarctic environments through natural atmospheric processes (Vincent 2000), these exchanges are thought to be restricted by the geographic isolation of the continent and barriers to foreign air masses produced by the Antarctic Circumpolar Current (Pearce et al 2009). Traces of the human enteric bacteria Escherichia coli have been detected in Dry Valley field camps (Sjoling and Cowan 2000) and the human skin commensal Staphylococcus epidermis has been detected through PCR amplification in soils at frequently visited sites (Ah Tow and Cowan 2005).…”

Microbial metabolism directly affects trace gases in (sub) polar snowpacks

“…Microbial presence is ubiquitous in the polar regions, and recent research into the polar aerobiome points towards a dynamic polar microbial community and the possibility of significant input of metabolically active bacteria onto the snowpack [23], even to remote locations [24,25]. To this end, research into the aerobiome and polar environments have demonstrated that microorganisms in aerial fallout remain viable, as cultures from aerobiological samples can grow under favourable conditions [26,27].…”