15
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Low Energy Subsurface Environments as Extraterrestrial Analogs

      review-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Earth’s subsurface is often isolated from phototrophic energy sources and characterized by chemotrophic modes of life. These environments are often oligotrophic and limited in electron donors or electron acceptors, and include continental crust, subseafloor oceanic crust, and marine sediment as well as subglacial lakes and the subsurface of polar desert soils. These low energy subsurface environments are therefore uniquely positioned for examining minimum energetic requirements and adaptations for chemotrophic life. Current targets for astrobiology investigations of extant life are planetary bodies with largely inhospitable surfaces, such as Mars, Europa, and Enceladus. Subsurface environments on Earth thus serve as analogs to explore possibilities of subsurface life on extraterrestrial bodies. The purpose of this review is to provide an overview of subsurface environments as potential analogs, and the features of microbial communities existing in these low energy environments, with particular emphasis on how they inform the study of energetic limits required for life. The thermodynamic energetic calculations presented here suggest that free energy yields of reactions and energy density of some metabolic redox reactions on Mars, Europa, Enceladus, and Titan could be comparable to analog environments in Earth’s low energy subsurface habitats.

          Related collections

          Most cited references237

          • Record: found
          • Abstract: not found
          • Article: not found

          Early oxidation of organic matter in pelagic sediments of the eastern equatorial Atlantic: suboxic diagenesis

            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Nature and composition of the continental crust: A lower crustal perspective

              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Global distribution of microbial abundance and biomass in subseafloor sediment.

              The global geographic distribution of subseafloor sedimentary microbes and the cause(s) of that distribution are largely unexplored. Here, we show that total microbial cell abundance in subseafloor sediment varies between sites by ca. five orders of magnitude. This variation is strongly correlated with mean sedimentation rate and distance from land. Based on these correlations, we estimate global subseafloor sedimentary microbial abundance to be 2.9⋅10(29) cells [corresponding to 4.1 petagram (Pg) C and ∼0.6% of Earth's total living biomass]. This estimate of subseafloor sedimentary microbial abundance is roughly equal to previous estimates of total microbial abundance in seawater and total microbial abundance in soil. It is much lower than previous estimates of subseafloor sedimentary microbial abundance. In consequence, we estimate Earth's total number of microbes and total living biomass to be, respectively, 50-78% and 10-45% lower than previous estimates.
                Bookmark

                Author and article information

                Contributors
                Journal
                Front Microbiol
                Front Microbiol
                Front. Microbiol.
                Frontiers in Microbiology
                Frontiers Media S.A.
                1664-302X
                18 July 2018
                2018
                : 9
                : 1605
                Affiliations
                Bigelow Laboratory for Ocean Sciences , East Boothbay, ME, United States
                Author notes

                Edited by: Doug LaRowe, University of Southern California, United States

                Reviewed by: Doug Bartlett, University of California, San Diego, United States; Christopher Kenneth Algar, Marine Biological Laboratory, United States

                *Correspondence: Beth N. Orcutt, borcutt@ 123456bigelow.org

                This article was submitted to Extreme Microbiology, a section of the journal Frontiers in Microbiology

                Article
                10.3389/fmicb.2018.01605
                6058055
                30072971
                e14456ed-b5cb-445d-9992-fc51d0f52728
                Copyright © 2018 Jones, Goordial and Orcutt.

                This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

                History
                : 27 February 2018
                : 27 June 2018
                Page count
                Figures: 4, Tables: 2, Equations: 0, References: 256, Pages: 18, Words: 0
                Funding
                Funded by: National Science Foundation 10.13039/100000001
                Award ID: OCE-0939564
                Award ID: NNA13AA92A
                Funded by: National Aeronautics and Space Administration 10.13039/100000104
                Categories
                Microbiology
                Review

                Microbiology & Virology
                deep biosphere,subsurface,astrobiology,low energy,energy limitation
                Microbiology & Virology
                deep biosphere, subsurface, astrobiology, low energy, energy limitation

                Comments

                Comment on this article