Glacial secrets uncovered: Revealing the modes of survival of metabolically active microbial communities entrapped in polar glacial ice

• Main Authors: O'Connor, Brady, Whyte, Lyle
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Pensoft Publishers 2023
• Subjects: Cryobiology; Astrobiology; Microbial Ecology; Ice; Glaciers; Arctic; Titan; Global warming; Sea ice
• Online Access: https://doi.org/10.3897/aca.6.e108883

Glaciers, once dismissed as inhospitable environments, have been overlooked in scientific investigations. Previous studies have primarily focused on the supraglacial (cryoconite holes, snow, and meltwater) and subglacial (bedrock and soils, among others) environments, neglecting the englacial (inside ice) realm. Despite evidence demonstrating the survival of cells in glacial/sea ice (Christner 2000, Junge et al. 2002, Miteva et al. 2004, Miteva and Brenchley 2005) and theoretical predictions and indirect evidence hinting at active microbial communities within glacial ice (Krembs et al. 2002, Junge et al. 2004, Price and Sowers 2004, Tung et al. 2005, Tung et al. 2006, Rohde et al. 2008), the englacial environment has remained largely unexplored. Recognizing that englacial ice hosts potentially active microbial communities carries significant implications for the future of these habitats in the face of escalating global warming and glacial retreat. As glaciers rapidly melt due to the effects of global warming, the liberation of these microbial communities will undoubtedly exert profound effects on local ecosystems and biogeochemical cycles, presenting an array of unknown consequences. Furthermore, considering the ability of microbial communities to persist in such extreme conditions on Earth, they become intriguing subjects for the search for life on celestial bodies such as Mars, Europa, Enceladus, and Titan, all of which house vast ice deposits. However, several fundamental questions persist. The extent of metabolic activity in glacial ice remains uncertain, as does the identification of microorganisms capable of sustaining metabolic processes. Most importantly, understanding the survival strategies employed by these organisms in such an extreme environment remains unknown. To answer these questions, we present metagenomes and what we believe to be the first metatranscriptomes ever analyzed from glacial ice. We have developed a method which allows us to melt ice cores without altering the mRNA profile of the ...