Earth Without Life: A Systems Model of a Global Abiotic Nitrogen Cycle

Laneuville, M.; Kameya, Masafumi; Cleaves, Henderson James

doi:10.1089/ast.2017.1700

Cited by 43 publications

(59 citation statements)

References 87 publications

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“…Comet delivery and impact fixation should also have supplied fixed nitrogen on prebiotic Earth; however, these mechanisms are thought to have supplied

ϕ_{{NO}_{X}^{-}} < 2 \times 1 0^{9} {cm}^{- 2} s^{- 1}

and typically less, well within the range bracketed by lightning production (Laneuville et al, ). Airapetian et al () suggest that energetic protons from flares on the young Sun might also have powered nitrogen fixation and the supply of

{NO}_{X}^{-}

to the surface; however, they do not quantify the magnitude of this supply.…”

Section: Kinetic Steady Statementioning

confidence: 99%

“…Under the assumption that the sole sink on

{NO}_{X}^{-}

was destruction at high‐temperature hydrothermal vents, Wong et al () computed [

{NO}_{X}^{-}

] in the bulk ocean to be ≥10μM, and [

{NO}_{X}^{-}

] =20 mM for pCO 2 = 1 bar. Laneuville et al () conducted a systems model of the prebiotic nitrogen cycle, including cometary delivery, impact synthesis, and lightning as sources of fixed nitrogen and destruction at hydrothermal vents as the sole sink of oceanic

{NO}_{X}^{-}

. They calculated [

{NO}_{X}^{-}

] ≈1μM to 10 mM in the bulk prebiotic oceans, depending on a number of variables including atmospheric nitrogen fixation rate.…”

Section: Introductionmentioning

confidence: 99%

“…These large ranges are due to the wide range of possible

{NO}_{X}^{-}

supply. Both Wong et al () and Laneuville et al () suggest that the prebiotic oceans should have had ≥1 μM [

{NO}_{X}^{-}

], thought to be adequate for prebiotic chemistry. For comparison, on modern Earth, bioavailable fixed

{NO}_{X}^{-}

achieves maximum concentrations of ∼40 μM in the deep Pacific (Olsen et al, ; Zehr & Ward, ).…”

Section: Introductionmentioning

confidence: 99%

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Nitrogen Oxide Concentrations in Natural Waters on Early Earth

Ranjan

Todd

Rimmer

et al. 2019

Geochem Geophys Geosyst

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A key challenge in origins‐of‐life studies is estimating the abundances of species relevant to the chemical pathways proposed to have contributed to the emergence of life on early Earth. Dissolved nitrogen oxide anions ( NOX−), in particular nitrate ( NO3−) and nitrite ( NO2−), have been invoked in diverse origins‐of‐life chemistry, from the oligomerization of RNA to the emergence of protometabolism. Recent work has calculated the supply of NOX− from the prebiotic atmosphere to the ocean and reported steady state [ NOX−] to be high across all plausible parameter space. These findings rest on the assumption that NOX− is stable in natural waters unless processed at a hydrothermal vent. Here, we show that NOX− is unstable in the reducing environment of early Earth. Sinks due to ultraviolet photolysis and reactions with reduced iron (Fe2+) suppress [ NOX−] by several orders of magnitude relative to past predictions. For pH = 6.5–8 and T = 0–50 °C, we find that it is most probable that [ NOX−] <1μM in the prebiotic ocean. On the other hand, prebiotic ponds with favorable drainage characteristics may have sustained [ NOX−] ≥1μM. As on modern Earth, most NOX− on prebiotic Earth should have been present as NO3−, due to its much greater stability. These findings inform the kind of prebiotic chemistries that would have been possible on early Earth. We discuss the implications for proposed prebiotic chemistries and highlight the need for further studies of NOX− kinetics to reduce the considerable uncertainties in predicting [ NOX−] on early Earth.

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“…Comet delivery and impact fixation should also have supplied fixed nitrogen on prebiotic Earth; however, these mechanisms are thought to have supplied

ϕ_{{NO}_{X}^{-}} < 2 \times 1 0^{9} {cm}^{- 2} s^{- 1}

{NO}_{X}^{-}

to the surface; however, they do not quantify the magnitude of this supply.…”

Section: Kinetic Steady Statementioning

confidence: 99%

“…Under the assumption that the sole sink on

{NO}_{X}^{-}

was destruction at high‐temperature hydrothermal vents, Wong et al () computed [

{NO}_{X}^{-}

] in the bulk ocean to be ≥10μM, and [

{NO}_{X}^{-}

{NO}_{X}^{-}

. They calculated [

{NO}_{X}^{-}

] ≈1μM to 10 mM in the bulk prebiotic oceans, depending on a number of variables including atmospheric nitrogen fixation rate.…”

Section: Introductionmentioning

confidence: 99%

“…These large ranges are due to the wide range of possible

{NO}_{X}^{-}

supply. Both Wong et al () and Laneuville et al () suggest that the prebiotic oceans should have had ≥1 μM [

{NO}_{X}^{-}

], thought to be adequate for prebiotic chemistry. For comparison, on modern Earth, bioavailable fixed

{NO}_{X}^{-}

achieves maximum concentrations of ∼40 μM in the deep Pacific (Olsen et al, ; Zehr & Ward, ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nitrogen Oxide Concentrations in Natural Waters on Early Earth

Ranjan

Todd

Rimmer

et al. 2019

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…A depiction of the Mesoproterozoic nitrogen cycle is shown in Figure . It is possible that abiotic processes generated additional marine

{NO}_{x}^{-}

(Laneuville, Kameya, & Cleaves, ).…”

Section: Introductionmentioning

confidence: 99%

Nitrous oxide from chemodenitrification: A possible missing link in the Proterozoic greenhouse and the evolution of aerobic respiration

et al. 2018

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The potent greenhouse gas nitrous oxide (N O) may have been an important constituent of Earth's atmosphere during Proterozoic (~2.5-0.5 Ga). Here, we tested the hypothesis that chemodenitrification, the rapid reduction of nitric oxide by ferrous iron, would have enhanced the flux of N O from ferruginous Proterozoic seas. We empirically derived a rate law, d N 2 O d t = 7.2 × 10 - 5 [ Fe 2 + ] 0.3 [ NO ] 1 , and measured an isotopic site preference of +16‰ for the reaction. Using this empirical rate law, and integrating across an oceanwide oxycline, we found that low nM NO and μM-low mM Fe concentrations could have sustained a sea-air flux of 100-200 Tg N O-N year , if N fixation rates were near-modern and all fixed N was emitted as N O. A 1D photochemical model was used to obtain steady-state atmospheric N O concentrations as a function of sea-air N O flux across the wide range of possible pO values (0.001-1 PAL). At 100-200 Tg N O-N year and >0.1 PAL O , this model yielded low-ppmv N O, which would produce several degrees of greenhouse warming at 1.6 ppmv CH and 320 ppmv CO . These results suggest that enhanced N O production in ferruginous seawater via a previously unconsidered chemodenitrification pathway may have helped to fill a Proterozoic "greenhouse gap," reconciling an ice-free Mesoproterozoic Earth with a less luminous early Sun. A particularly notable result was that high N O fluxes at intermediate O concentrations (0.01-0.1 PAL) would have enhanced ozone screening of solar UV radiation. Due to rapid photolysis in the absence of an ozone shield, N O is unlikely to have been an important greenhouse gas if Mesoproterozoic O was 0.001 PAL. At low O , N O might have played a more important role as life's primary terminal electron acceptor during the transition from an anoxic to oxic surface Earth, and correspondingly, from anaerobic to aerobic metabolisms.

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“…Studies have found a mantle nitrogen abundance of 7 ± 4 times the present atmospheric level (Johnson & Goldblatt, ) and coupled with modern subduction recycling rates (Mallik et al, ), these imply that the mantle is a long‐term sink of atmospheric nitrogen that has been monotonically sequestered over time. However, modern fluxes only apply if redox conditions were constant through time, yet models including nitrogen speciation change indicate that redox has a substantial effect on the atmospheric reservoir (Laneuville et al, ; Stüeken et al, ). The stable form of deep sea nitrogen for the Archean would have been NH 4 + (Holland, ), not oxidized species like NO 3 − as in modern oceans.…”

Section: Atmospheric Density In the Archeanmentioning

confidence: 99%

Eolianite Grain Size Distributions as a Proxy for Large Changes in Planetary Atmospheric Density

et al. 2018

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Atmospheres are dynamic over geologic timescales, making large changes in planetary air density possible. For the Earth, geological proxies suggest that air density in the Neoarchean was similar to or lower than today. This air density variation possibly affected eolian dune grain sizes by controlling the trajectories of grains though the air. Balancing the fall velocity and threshold friction velocity, a metric separating saltation and suspension transport, suggests that a lower air density could increase the mean grain size of dunes because decreased air drag extends the size range of grains in modified saltation and incipient suspension regimes. Consequently, the dune‐forming sand left behind in pure saltation, the dominant dune‐forming transport mode, could have coarser grains. We analyzed size distributions of two eolianites from 2.64 and 1.5 Ga (billion years ago) for deviations from modern sand dunes emplaced at sea level, which globally exhibit similar mean grain sizes. Both aeolianites have mean grain sizes within one standard deviation of the modern mean and are not statistically separable at 95% confidence. Overall, this suggests that while air density is important in eolian physics, a factor of 2 to 4 change in density is insufficient to produce an unambiguous grain size signal. This suggests that while eolian dune grain sizes have not significantly changed over the range of Earth's atmospheric conditions, they could be useful when investigating the order of magnitude changes thought to have occurred on Mars.

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Earth Without Life: A Systems Model of a Global Abiotic Nitrogen Cycle

Cited by 43 publications

References 87 publications

Nitrogen Oxide Concentrations in Natural Waters on Early Earth

Nitrogen Oxide Concentrations in Natural Waters on Early Earth

Nitrous oxide from chemodenitrification: A possible missing link in the Proterozoic greenhouse and the evolution of aerobic respiration

Eolianite Grain Size Distributions as a Proxy for Large Changes in Planetary Atmospheric Density

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