7.3 Summary
To wrap up, while microbes are important everywhere and not just to microbiologists, they’re everything in the subsurface. They make up nearly 100% of life
underground. They’re self-sufficient, needing no help from plants or other photosynthetic organisms for their organic carbon or for oxygen, since they rely on
alternative electron acceptors. Life may have even started underground and only
later emerged into the light. They form an enormous and varied component of the
Earth’s biosphere, and yet they haven’t received scientific attention commensurate
with their biomass and diversity. My hope in writing this little review is that one or
two early career scientists looking for their niches will take up the mantle of
subsurface geomicrobiology and dive (well drill, actually) deep into the Earth’s
crust to find new treasure.
Thomas L. Kieft
References
Bar-On YM, Phillips R, Milo R (2018) The biomass distribution on earth. Proc Natl Acad Sci U S A
115(25):6506–6511. https://doi.org/10.1073/pnas.1711842115
Chivian D, Alm E, Brodie E, Culley D, Dehal P, DeSantis T, Gihring T, Lapidus A, Lin L-H,
Lowry S, Moser D, Richardson P, Southam G, Wanger G, Pratt L, Andersen G, Hazen T,
Brockman F, Arkin A, Onstott T (2008) Environmental genomics reveals a single species
ecosystem deep within the earth. Science 322:275–278. https://doi.org/10.1126/science.
1155495
Colman DR, Poudel S, Stamps BW, Boyd ES, Spear JR (2017) The deep hot biosphere: twenty-five
years of retrospection. Proc Natl Acad Sci U S A 114(27):6895–6903. https://doi.org/10.1073/
pnas.1701266114
Cotton CA, Edlich-Muth C, Bar-Even A (2018) Reinforcing carbon fixation: CO 2 reduction
replacing and supporting carboxylation. Curr Opin Biotechnol 49:49–56
Fuchs G (2011) Alternative pathways of carbon dioxide fixation: insights into the early evolution of
life? Ann Rev Microbiol 65:631–658
Gold T (1992) The deep, hot biosphere. Proc Nat Acad Sci 89:6045–6049
7 Lithotrophic (“Stone-Eating”) Microbes Provide the Foundation for Deep. . .
137
To wrap up, while microbes are important everywhere and not just to microbiologists, they’re everything in the subsurface. They make up nearly 100% of life
underground. They’re self-sufficient, needing no help from plants or other photosynthetic organisms for their organic carbon or for oxygen, since they rely on
alternative electron acceptors. Life may have even started underground and only
later emerged into the light. They form an enormous and varied component of the
Earth’s biosphere, and yet they haven’t received scientific attention commensurate
with their biomass and diversity. My hope in writing this little review is that one or
two early career scientists looking for their niches will take up the mantle of
subsurface geomicrobiology and dive (well drill, actually) deep into the Earth’s
crust to find new treasure.
Thomas L. Kieft
References
Bar-On YM, Phillips R, Milo R (2018) The biomass distribution on earth. Proc Natl Acad Sci U S A
115(25):6506–6511. https://doi.org/10.1073/pnas.1711842115
Chivian D, Alm E, Brodie E, Culley D, Dehal P, DeSantis T, Gihring T, Lapidus A, Lin L-H,
Lowry S, Moser D, Richardson P, Southam G, Wanger G, Pratt L, Andersen G, Hazen T,
Brockman F, Arkin A, Onstott T (2008) Environmental genomics reveals a single species
ecosystem deep within the earth. Science 322:275–278. https://doi.org/10.1126/science.
1155495
Colman DR, Poudel S, Stamps BW, Boyd ES, Spear JR (2017) The deep hot biosphere: twenty-five
years of retrospection. Proc Natl Acad Sci U S A 114(27):6895–6903. https://doi.org/10.1073/
pnas.1701266114
Cotton CA, Edlich-Muth C, Bar-Even A (2018) Reinforcing carbon fixation: CO 2 reduction
replacing and supporting carboxylation. Curr Opin Biotechnol 49:49–56
Fuchs G (2011) Alternative pathways of carbon dioxide fixation: insights into the early evolution of
life? Ann Rev Microbiol 65:631–658
Gold T (1992) The deep, hot biosphere. Proc Nat Acad Sci 89:6045–6049
7 Lithotrophic (“Stone-Eating”) Microbes Provide the Foundation for Deep. . .
137