DOI: 10.1016/j.epsl.2018.09.001
Scopus记录号: 2-s2.0-85053189063
论文题名: Radiolytic H2 production on Noachian Mars: Implications for habitability and atmospheric warming
作者: Tarnas J.D. ; Mustard J.F. ; Sherwood Lollar B. ; Bramble M.S. ; Cannon K.M. ; Palumbo A.M. ; Plesa A.-C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 502 起始页码: 133
结束页码: 145
语种: 英语
英文关键词: biosphere
; habitability
; hydrogen
; Mars
; radiolysis
; subsurface
Scopus关键词: Biospherics
; Eutectics
; Groundwater
; Hydrates
; Hydrogen
; Hydrogen production
; Martian surface analysis
; Petroleum tar
; Radiation chemistry
; Radiolysis
; Sodium chloride
; biosphere
; Freezing temperatures
; Groundwater composition
; habitability
; Mars
; Microbial communities
; Sub-freezing temperatures
; subsurface
; Dissolution
; biosphere
; concentration (composition)
; groundwater
; hydrogen
; Mars
; planetary atmosphere
; warming
; water-rock interaction
; Hesperia
英文摘要: Protected from harmful radiation, subfreezing temperatures, and low pressures, subsurface rock-hosted habitats provide potentially sustainable refugia for microbial ecosystems inside small rocky planets, such as Mars. For many chemolithotrophic communities on Earth, water–rock alteration reactions have been shown to produce the key electron donors and acceptors necessary to sustain microbial life on geologic timescales. Here we quantitatively demonstrate that radiolysis likely generated concentrations of dissolved H2 capable of sustaining microbial communities in the subsurface of Noachian Mars (3.7–4.1 Gyr ago). When considering an environment with H2O groundwater, dissolved H2 concentrations reach up to ∼55 mM in a cold early Mars climate scenario and ∼35 mM in a warm early Mars climate scenario; whereas when considering an environment with eutectic NaCl brine groundwater, dissolved H2 concentrations reach up to ∼85 mM in a cold early Mars climate scenario and ∼45 mM in a warm early Mars climate scenario. Specifically within the subsurface habitable zone, dissolved H2 concentrations range from ∼50–55 mM for a cold climate scenario with H2O groundwater. For a warm climate scenario with H2O groundwater, dissolved H2 concentrations within the subsurface habitable zone range from ∼1–30 mM. For a cold climate scenario with eutectic NaCl brine groundwater, dissolved H2 concentrations within the subsurface habitable zone range from ∼65–85 mM. For a warm climate scenario with eutectic NaCl brine groundwater, dissolved H2 concentrations within the subsurface habitable zone range from ∼1-40 mM. Radiolysis likely produced [1.3–4.8] × 1010 moles H2 per year globally during the Noachian depending on the assumed porosity and groundwater composition. Radiolytic H2, and CH4 derived from radiolytic H2, can be locked in hybrid clathrate hydrates within the cryosphere and released by large impacts, volcanism, or obliquity variations. This process could warm the Noachian climate to above-freezing temperatures, and we predict that ∼1–8 warming events would be possible during the Noachian and Hesperian solely from radiolytically produced H2. We demonstrate that the region immediately beneath the cryosphere, termed the subcryospheric highly-fractured zone (SHZ), likely contained dissolved H2 concentrations and temperatures suitable for life regardless of the background climate scenario, making it the most consistently habitable environment on ancient Mars in terms of reductant availability. Material from this zone can be exposed by faulting and in the ejecta and uplifts of impacts, making the SHZ a crucial astrobiological target for testing the subsurface biosphere hypothesis. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109642
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Brown University, Department of Earth, Environmental and Planetary Sciences, 324 Brook St., Box 1846, Providence, RI 02912, United States; University of Toronto Department of Earth Sciences, 22 Russell St., Ontario M5S 3B1, Toronto, Canada; University of Central Florida Department of Physics, Physical Sciences Building 430, 4111 Libra Drive, Orlando, FL 32816, United States; German Aerospace Center Institute of Planetary Research, Planetary Physics, Rutherfordstraße 2, Berlin, 12489, Germany
Recommended Citation:
Tarnas J.D.,Mustard J.F.,Sherwood Lollar B.,et al. Radiolytic H2 production on Noachian Mars: Implications for habitability and atmospheric warming[J]. Earth and Planetary Science Letters,2018-01-01,502