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

Abstract

Concentrations of trace gases trapped in ice are considered to develop uniquely from direct snow/atmosphere interactions at the time of contact. This assumption relies upon limited or no biological, chemical or physical transformations occurring during transition from snow to firn to ice; a process that can take decades to complete. Here, we present the first evidence of environmental alteration due to in situ microbial metabolism of trace gases (methyl halides and dimethyl sulfide) in polar snow. We collected evidence for ongoing microbial metabolism from an Arctic and an Antarctic location during different years. Methyl iodide production in the snowpack decreased significantly after exposure to enhanced UV radiation. Our results also show large variations in the production and consumption of other methyl halides, including methyl bromide and methyl chloride, used in climate interpretations. These results suggest that this long-neglected microbial activity could constitute a potential source of error in climate history interpretations, by introducing a so far unappreciated source of bias in the quantification of atmospheric-derived trace gases trapped within the polar ice caps.

Microbial genomics amidst the Arctic crisis

“…Snowpacks on Arctic glacial surfaces are vast environments that both support distinctive microbial consortia and are highly sensitive to warming [ 95–97 ]. The potential for snowpack bacteria to cycle climate-relevant trace gases has recently been highlighted as an emerging area [ 98, 99 ]. However, the growth and pigmentation of green algae in the family Chlamydomonadaceae in discrete patches on snow is particularly apparent.…”

Should We Not Further Study the Impact of Microbial Activity on Snow and Polar Atmospheric Chemistry?

“…Redeker et al [39] investigated the exchanges of methyl iodide between snow and atmosphere in Svalbard and at Signy Island, Antarctica. To determine the possible role of microbes, they worked on snow irradiated with UV-C (for sterilization) and on untreated snow.…”

“…It is not certain, however, that the snow studied was not melting, since the air temperature was close to 0 °C, and accurately measuring surface snow temperature in the presence of solar radiation is a delicate process. Incidentally, Redeker et al [39] ignored the previous work of Amoroso et al [6] and of Antony et al [38], and they wrongfully claimed that they “present the first evidence of environmental alteration due to in situ microbial metabolism of trace gases … in polar snow.” I report this omission here to illustrate how many snow chemists are little aware of microbial activity in snowpacks.…”

“…Since the ground was frozen, it was implicitly understood that there was no significant local source of NO x to the polar troposphere. Likewise, the possibility exists that microbes in snow could release hydrocarbons [9], halocarbons [39], aldehydes, mercury [16], etc., thus modifying both snow and atmospheric composition (Figure 1). Campaigns to study snow and atmospheric chemistry in polar regions usually take place in spring or summer and their focus is on photochemistry.…”

Brief survey on organometalated antibacterial drugs and metal-based materials with antibacterial activity

“…High-resolution microscopy and isotopic analyses of some Archaean (4-2.5 Ga) rocks show that ancestors of modern bacteria existed on earth between 3.47 and 2.7 Ga, [1][2][3] whereas studies on 1.88 Ga old stromatolites showed Fe 2 O 3 -mineralized microfossils of bacterial cells. 4 Bacteria inhabit all ecological niches including extreme environments like hydrothermal vents, 5 hot springs, 6 the deep sub-seafloor, 7 sub-polar snowpacks, 8 the Antarctic desert 9 and even nuclear waste. 10 The human body also represents an ecological niche which harbors more than 100 trillion bacteria and other microorganisms of microbiota.…”