Widespread energy limitation to life in global subseafloor sediments
Bradley, J.A.; Arndt, S.; Amend, P; Burwicz, E.; Dale, A. W.; Egger, M.; LaRowe, D. E. (2020). Widespread energy limitation to life in global subseafloor sediments. Science Advances 6(32): eaba0697. https://dx.doi.org/10.1126/sciadv.aba0697
In: Science Advances. AAAS: New York. e-ISSN 2375-2548, more
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| Authors | | Top |
- Bradley, J.A.
- Arndt, S., more
- Amend, P
- Burwicz, E.
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- Dale, A. W.
- Egger, M., more
- LaRowe, D. E.
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| Abstract |
Microbial cells buried in subseafloor sediments comprise a substantial portion of Earth’s biosphere and control global biogeochemical cycles; however, the rate at which they use energy (i.e., power) is virtually unknown. Here, we quantify organic matter degradation and calculate the power utilization of microbial cells throughout Earth’s Quaternary-age subseafloor sediments. Aerobic respiration, sulfate reduction, and methanogenesis mediate 6.9, 64.5, and 28.6% of global subseafloor organic matter degradation, respectively. The total power utilization of the subseafloor sediment biosphere is 37.3 gigawatts, less than 0.1% of the power produced in the marine photic zone. Aerobic heterotrophs use the largest share of global power (54.5%) with a median power utilization of 2.23 × 10−18 watts per cell, while sulfate reducers and methanogens use 1.08 × 10−19 and 1.50 × 10−20 watts per cell, respectively. Most subseafloor cells subsist at energy fluxes lower than have previously been shown to support life, calling into question the power limit to life. |
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