Are thermophilic microorganisms active in cold environments?

Abstract

The mean air temperature of the Icelandic interior is below 10 °C. However, we have previously observed 16S rDNA sequences associated with thermophilic lineages in Icelandic basalts. Measurements of the temperatures of igneous rocks in Iceland showed that solar insolation of these low albedo substrates achieved a peak surface temperature of 44.5 °C. We isolated seven thermophilic Geobacillus species from basalt with optimal growth temperatures of ~65 °C. The minimum growth temperature of these organisms was ~36 °C, suggesting that they could be active in the rock environment. Basalt dissolution rates at 40 °C were increased in the presence of one of the isolates compared to abiotic controls, showing its potential to be involved in active biogeochemistry at environmental temperatures. These data raise the possibility of transient active thermophilic growth in macroclimatically cold rocky environments, implying that the biogeographical distribution of active thermophiles might be greater than previously understood. These data show that temperatures measured or predicted over large scales on a planet are not in themselves adequate to assess niches available to extremophiles at micron scales.

Prokaryotic Diversity and Metabolically Active Communities in Brines from Two Perennially Ice-Covered Antarctic Lakes

“…Now, the question is how such cold environment (temperature never raises over 0°C) into which these thermophilic organisms are delivered could sustain their growth. Cockell et al (2015) suggested that, for an Icelandic rocky environment, temperature-induced niche differentiation may permit the presence of thermophilic organisms in a cold environment as well. In our case, these types of temperature differentiations are hardly expected, and no evidence of geothermal activity is known in the BC area.…”

The UK Centre for Astrobiology: A Virtual Astrobiology Centre. Accomplishments and Lessons Learned, 2011–2016

“…A logical development of the first question is What adaptations have allowed microbes to persist in the planetary crust for over 3.5 billion years? Work we have undertaken that falls within this purview has included: (i) studies on the molecular (proteomic) responses of microbes to extreme conditions living within the planetary crust (Bryce et al, 2016 ); (ii) studies on the colonization of extreme volcanic environments (Kelly et al, 2014 ; Cockell et al, 2015b ); (iii) studies on habitats in impact craters (Pontefract et al, 2014 , 2016 ); and (iv) UKCA involvement, through science party membership, in the IODP (International Ocean Discovery Program) Expedition 364 to drill the peak ring of the Chicxulub impact crater (Morgan et al, 2016 ), linked to the end-Cretaceous mass extinction (Schulte et al, 2010 ). UKCA work in this project has been focused on understanding how impact craters produce habitats for deep subsurface life.…”

“…(ii) studies on the colonization of extreme volcanic environments (Kelly et al, 2014 ; Cockell et al, 2015b );…”

Cultivation With Powdered Meteorite (NWA 1172) as the Substrate Enhances Low-Temperature Preservation of the Extreme Thermoacidophile Metallosphaera sedula

“…Such temporary nanoniches provide short-termed limited conditions for alkaliphilic thermophilic bacteria and therefore dictate fastened growth rate in order to cope with this limitation (Wiegel, 2002). Icelandic basaltic and rhyolitic glass and minerals in a sub-Arctic environment with the temperature range below required for thermophile activity were proposed to support transient growth of thermophiles in summer months (Cockell et al, 2015). The low albedo of these rocks has been suggested to facilitate their thermal conductivity and support the function of these igneous materials as microclimatic environments to harbor thermophilic microbial communities (Kelly et al, 2010(Kelly et al, , 2011Cockell et al, 2015).…”

“…Icelandic basaltic and rhyolitic glass and minerals in a sub-Arctic environment with the temperature range below required for thermophile activity were proposed to support transient growth of thermophiles in summer months (Cockell et al, 2015). The low albedo of these rocks has been suggested to facilitate their thermal conductivity and support the function of these igneous materials as microclimatic environments to harbor thermophilic microbial communities (Kelly et al, 2010(Kelly et al, , 2011Cockell et al, 2015). Apparently, these nanoniches inside the rock pores provide a certain potential for their temporary "re-awakening" of such communities during the warm periods.…”