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The Great Oxygenation Event as a consequence of ecological dynamics modulated by planetary change - PubMed

  • ️Fri Jan 01 2021

The Great Oxygenation Event as a consequence of ecological dynamics modulated by planetary change

Jason Olejarz et al. Nat Commun. 2021.

Abstract

The Great Oxygenation Event (GOE), ca. 2.4 billion years ago, transformed life and environments on Earth. Its causes, however, are debated. We mathematically analyze the GOE in terms of ecological dynamics coupled with a changing Earth. Anoxygenic photosynthetic bacteria initially dominate over cyanobacteria, but their success depends on the availability of suitable electron donors that are vulnerable to oxidation. The GOE is triggered when the difference between the influxes of relevant reductants and phosphate falls below a critical value that is an increasing function of the reproductive rate of cyanobacteria. The transition can be either gradual and reversible or sudden and irreversible, depending on sources and sinks of oxygen. Increasing sources and decreasing sinks of oxygen can also trigger the GOE, but this possibility depends strongly on migration of cyanobacteria from privileged sites. Our model links ecological dynamics to planetary change, with geophysical evolution determining the relevant time scales.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Evidence for the GOE.

Multiple lines of geologic and geochemical evidence support the view that oxygen gas first became a permanent component of Earth’s atmosphere and surface ocean ca. 2.4 billion years ago. Sedimentary iron formation (a), which requires transport of ferrous iron through the ocean, is abundant in successions that predate the GOE but uncommon afterward (c, with resurgences around 1900–1850 and 715–660 Ma). Similarly, redox-sensitive minerals such as pyrite (FeS2) occur in detrital facies before the GOE (b) but not afterward. In contrast, red beds (d) and sulfate salts (e), which bespeak O2 in surface environments, have the opposite time distribution, gaining prominence only after the GOE. It is estimated that atmospheric pO2 increased from <10−5 to 1–10% of PAL at this time (c). (Data on iron formations in (c) are taken from Bekker et al.. The blue shaded region denoting atmospheric O2 levels is only notional, as it is possible that atmospheric pO2 dropped below 1% of PAL during the Proterozoic,.).

Fig. 2
Fig. 2. The stability properties of Equilibrium E1 (APB dominate) and Equilibrium E2 (cyanobacteria dominate) depend on the input rate of iron(II), f1, and the input rate of phosphate, f2.

High values of f1 and low values of f2 promote stability of E1 and instability of E2. Low values of f1 and high values of f2 promote instability of E1 and stability of E2. a If the proportional consumption rate of oxygen, b, is large, then intermediate values of f1 and f2 lead to both E1 and E2 being unstable, with Equilibrium E^ corresponding to stable coexistence. b For an intermediate value of b, either E1 is stable with E2 unstable, or E1 is unstable with E2 stable. c If b is small, then intermediate values of f1 and f2 lead to both E1 and E2 being stable.

Fig. 3
Fig. 3. The GOE can be triggered by a decline in the influx of iron(II) and is gradual if b > c(a − 1).

Equilibrium E1 (APB dominate) loses stability and Equilibrium E2 (cyanobacteria dominate) gains stability when f1 drops below f1* and f1′, respectively. We set f2 = 80, c = 10, a = 10, b = 100, and u1 = u2 = 10−3. a We simulate Eqs. (8) from Supplementary Note 1 with α1 = α2 = β1 = β2 = 1, and we set f1 = 100 − 40(t/105). t* denotes the time at which Equilibrium E1 loses stability. b There is stable coexistence of both types of bacteria for f1′<f1<f1*.

Fig. 4
Fig. 4. Phase portraits of Eqs. (14) from Supplementary Note 1 illustrating a gradual transition are shown for six distinct values of f1, the influx rate of iron(II).

For values of f1 = 17 (a), 12 (b), 11 (c), 10 (d), 9 (e), and 4 (f), the stable equilibrium (green dot) moves continuously from a world that is dominated by APB to one that is dominated by cyanobacteria. Parameter values are f2 = 10, c = 1, a = 10, b = 12, u1 = u2 = 1, and α1 = α2 = 1. The GOE is gradual.

Fig. 5
Fig. 5. The GOE can be triggered by a decline in the influx of iron(II) and is sudden if b < c(a − 1).

Equilibrium E2 (cyanobacteria dominate) gains stability and Equilibrium E1 (APB dominate) loses stability when f1 drops below f1′ and f1*, respectively. We set f2 = 80, c = 10, a = 10, b = 80, and u1 = u2 = 10−3. a We simulate Eqs. (8) from Supplementary Note 1 with α1 = α2 = β1 = β2 = 1, and we set f1 = 100 − 40(t/105). t* denotes the time at which Equilibrium E1 loses stability. b Bifurcation plots reveal bistability for f1*<f1<f1′.

Fig. 6
Fig. 6. Phase portraits of Eqs. (14) from Supplementary Note 1 illustrating a sudden transition are shown for six distinct values of f1, the influx rate of iron(II).

For f1 = 73 (a), there is a single stable equilibrium (green dot) describing a world dominated by APB. For values of f1 = 65 (b), 62 (c), 51 (d), and 47 (e), there is a second stable equilibrium (green dot) describing the dominance of cyanobacteria, and in addition, there is an unstable equilibrium (red dot). The unstable equilibrium moves as the value of f1 changes. For f1 = 40 (f), the only stable equilibrium is the one where cyanobacteria dominate. Parameter values are f2 = 10, c = 1, a = 10, b = 1, u1 = u2 = 1, and α1 = α2 = 1. The GOE is triggered by a saddle-node bifurcation and is sudden.

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References

    1. Planavsky NJ, Bekker A, Hofmann A, Owens JD, Lyons TW. Sulfur record of rising and falling marine oxygen and sulfate levels during the Lomagundi event. Proc. Natl Acad. Sci. USA. 2012;109:18300–18305. doi: 10.1073/pnas.1120387109. - DOI - PMC - PubMed
    1. Canfield DE, et al. Oxygen dynamics in the aftermath of the Great Oxidation of Earth’s atmosphere. Proc. Natl Acad. Sci. USA. 2013;110:16736–16741. doi: 10.1073/pnas.1315570110. - DOI - PMC - PubMed
    1. Lyons TW, Reinhard CT, Planavsky NJ. The rise of oxygen in Earth’s early ocean and atmosphere. Nature. 2014;506:307–315. doi: 10.1038/nature13068. - DOI - PubMed
    1. Bekker A, et al. Iron formation: the sedimentary product of a complex interplay among mantle, tectonic, oceanic, and biospheric processes. Econ. Geol. 2010;105:467–508. doi: 10.2113/gsecongeo.105.3.467. - DOI
    1. Roscoe, S. M. The Huronian Supergroup, a Paleoaphebian succession showing evidence of atmospheric evolution. In Huronian Stratigraphy and Sedimentation (ed. Young, G. M.) Geological Association of Canada special paper no. 12, 31–48 (Pierre Des Marais, 1973).

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