Article Analysis
The article reviewed in the scope of this paper was written by Mirko Bassen and Volker Muller and published in Extremophiles journal in 2016. The article reviews a particular type of extremophiles, namely Thermoanaerobacteraceae. The mechanisms described in this paper, however, can easily be applied to astronomy research.
The article states that thermophilic life is ancient, dating back as far as the appearance of water on the surface of Earth. Back then, water temperature varied between 55 Co (131 F) on the poles, to 95 C o (203 F) around active underwater volcanoes (Bassen and Muller 15). Thermophilic bacteria had to survive in these extreme conditions, and do so even up to this day.
One of the most interesting features of thermophilic bacteria is their ability to survive in the conditions of extreme heat. There is a potential of finding similar organisms (or signs of their existence) on planets with extreme temperatures (such as Venus or Mars). Both planets feature signs of water existing on their surfaces, meaning that thermophilic acetogenic organisms could have once inhabited them.
Thermophilic acetogenic organisms conserve energy through a process of acetate formations with hydrogen and carbon dioxide acting as donors and acceptors of electrodes. The earliest examples of bacteria formed their biomass from CO2 or CO and exploited various existing chemical ingredients to conserve energy (Bassen and Muller 16). Based on this article, some of the universal properties of life must include mechanisms of surviving extreme temperatures, the ability to extract energy, and the capability of utilizing elements present in the atmosphere for gaining biomass and energy.
Article Summaries
The first article, written by Christopher Brooks, analyzes some of the organisms on Earth that can survive in extreme conditions. Such creatures include red flat bark beetle, desert ants, Himalayan jumping spiders, and tardigrades, all of which survive exposure to extreme heat or cold (Brooks). I think it is amazing how complex organisms managed to adapt to these environments. Question: What microorganisms did these extremophiles evolve from?
The second article, written by Carl Zimmer, examines the possibilities of life below freezing temperature in an Antarctic lake. Examination of samples of an organic lake shows the existence of numerous microorganisms that have adapted to life below zero (Zimmer). The article suggests that the presence of warm temperatures is not a requirement for life. Question: What is the lower temperature threshold for Earth microorganisms?
The third article, written by Laura Starr, tells the readers about unique bacteria named Candidatus Desulforudis audaxviator, which lives in a hot underground sulfur lake in Africa. It is a highly-resistant bacteria, able to survive at the temperature of 60 Co (140 F) at 9.7 pHs (Starr). What I found fascinating about it is that the bacteria continue a solitary existence. Question: What other bacteria would be able to survive under these conditions?
The fourth article presented in the form of a picture slide and assembled by Clara Moskowitz tells us about amazing creatures of Earth which can survive in extreme conditions, be those high temperatures, little to no water, extreme salt saturation, sulfuric conditions, and others (Moskowitz). This assembly of creatures expands the number of potential candidates to survive on other planets. Question: Did any of these microorganisms originate from outside of Earth?
The fifth article, written by Rothschild and Mancinelli, examines the possibility of life on other planets, even in extreme conditions. The researchers suggest that, as long as there is water on or under the surface of the planet, life can exist in it (Rothschild and Mancinelli 1092). As an example, they use extremophile organisms on Earth, which can survive in virtually any environment. Question: Can microorganisms exist in vapor or ice?
The last article, written by Seth Shostak, talks about halophile organisms on Earth and in space. He explains the mechanisms of their survival, stating that they survive extremely saline environments by increasing the salinity within their bodies (Shostak). I think it is an interesting way of surviving in saline environments. Question: How did mechanisms of adaptation to extreme environments develop?
Works Cited
Bassen, Mirko, and Volker Muller. “Hot” Acetogenesis.” Extremophiles, vol. 21, no. 1, 2017, pp. 15-26.
Brooks, Cristopher. “The Life of Extremophiles: Surviving in Hostile Habitats.” BBC. 2013, Web.
Moskowitz, Clara. “Extreme Life on Earth: 8 Bizarre Creatures.”LiveScience. 2011, Web.
Rothschild, Lynn J., and Rocco L. Mancinelli. “Life in Extreme Environments.” Nature, vol. 409, 2001, pp. 1092-1101.
Shostak, Seth. “Extremophiles: Not So Extreme?”Space.com. 2005, Web.
Starr, Laura. “One Is the Loneliest Number for Mine-Dwelling Bacterium.”Nature. 2009, Web.
Zimmer, Carl. “Comfortable in the Cold: Life Below Freezing in an Antarctic Lake.”PBS. 2013, Web.