Late inception of a resiliently oxygenated upper ocean

Lu, Wanyi; Ridgwell, Andy; Thomas, Ellen; Hardisty, Dalton S.; Luo, Genming; Algeo, Thomas J.; Saltzman, Matthew R.; Gill, Benjamin C.; Shen, Yanan; Ling, Hong; Edwards, Cole T.; Whalen, Michael T.; Zhou, Xiaoli; Gutchess, Kristina M.; Jin, Li; Rickaby, Rosalind E. M.; Jenkyns, Hugh C.; Lyons, Timothy W.; Lenton, Timothy M.; Kump, Lee R.; Lu, Zunli

doi:10.1126/science.aar5372

Cited by 179 publications

(169 citation statements)

References 53 publications

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“…Any data falling outside those ranges are considered outliers and plotted as points. Residual errors (re) are from the change‐point analyses (data compiled from the following: Canfield et al, ; Hardisty et al, and references therein; Isson et al, ; Liu et al, ; Lu et al, ; Partin et al, ; Planavsky, Cole, et al, and references therein; Reinhard et al, , ; Scott et al, ; Wallace et al, and references therein)…”

Section: Point–counterpoint Argumentsmentioning

confidence: 99%

On the co‐evolution of surface oxygen levels and animals

et al. 2020

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Few topics in geobiology have been as extensively debated as the role of Earth's oxygenation in controlling when and why animals emerged and diversified. All currently described animals require oxygen for at least a portion of their life cycle. Therefore, the transition to an oxygenated planet was a prerequisite for the emergence of animals. Yet, our understanding of Earth's oxygenation and the environmental requirements of animal habitability and ecological success is currently limited; estimates for the timing of the appearance of environments sufficiently oxygenated to support ecologically stable populations of animals span a wide range, from billions of years to only a few million years before animals appear in the fossil record. In this light, the extent to which oxygen played an important role in controlling when animals appeared remains a topic of debate. When animals originated and when they diversified are separate questions, meaning either one or both of these phenomena could have been decoupled from oxygenation. Here, we present views from across this interpretive spectrum—in a point–counterpoint format—regarding crucial aspects of the potential links between animals and surface oxygen levels. We highlight areas where the standard discourse on this topic requires a change of course and note that several traditional arguments in this “life versus environment” debate are poorly founded. We also identify a clear need for basic research across a range of fields to disentangle the relationships between oxygen availability and emergence and diversification of animal life.

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Section: Point–counterpoint Argumentsmentioning

confidence: 99%

On the co‐evolution of surface oxygen levels and animals

et al. 2020

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“…In particular, it remains ambiguous as to whether the NOE served as a cause or a consequence of the origin of animals (Och and Shields-Zhou, 2012;Lyons et al, 2014). The timing is also very variable, with evidence from selenium isotopes apparently not ruling out the onset of the NOE as early as 0.75 Ga (Pogge von Strandmann et al, 2015) while iron-and iodine-based proxies seem to demonstrate significant oxygenation only as recently as ∼ 0.4 Ga (Sperling et al, 2015;Lu et al, 2018). If we take the mean of these two quantities, the NOE would have taken place 0.55 Ga and this estimate is roughly consistent with recent analyses that have yielded values of ∼ 0.5-0.6 Ga (Chen et al, 2015;Knoll and Nowak, 2017).…”

Section: What Were the Five Critical Steps?mentioning

confidence: 99%

Role of stellar physics in regulating the critical steps for life

Lingam

Loeb

2019

International Journal of Astrobiology

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We use the critical step model to study the major transitions in evolution on Earth. We find that a total of five steps represents the most plausible estimate, in agreement with previous studies, and use the fossil record to identify the potential candidates. We apply the model to Earth-analogs around stars of different masses by incorporating the constraints on habitability set by stellar physics including the habitable zone lifetime, availability of ultraviolet radiation for prebiotic chemistry, and atmospheric escape. The critical step model suggests that the habitability of Earth-analogs around M-dwarfs is significantly suppressed. The total number of stars with planets containing detectable biosignatures of microbial life is expected to be highest for Kdwarfs. In contrast, we find that the corresponding value for intelligent life (technosignatures) should be highest for solar-mass stars. Thus, our work may assist in the identification of suitable targets in the search for biosignatures and technosignatures.

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“…The evolutionary process that produced such innovations in marine picocyanobacteria (Fig. 4) stretches out across the Neoproterozoic and Phanerozoic [63,64], which is relevant to discussion that ocean oxygenation played out over hundreds of millions of years [38,[93][94][95][96]. Further, the innovations seen in marine picocyanobacteria (Fig.…”

mentioning

confidence: 93%

“…400 Mya) [92] or even the Triassic (ca. 200 Mya) [93] -but evidence for the initiation of this process reaches back to the Neoproterozoic [38,[92][93][94][95][96]. Several biogeochemical feedbacks have been proposed to explain why the deep open ocean remained anoxic during the Proterozoic.…”

mentioning

confidence: 99%

Evolution of cellular metabolism and the rise of a globally productive biosphere

Braakman

2019

Preprint

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The metabolic processes of cells and chemical processes in the environment are fundamentally intertwined and have evolved in concert over billions of years. Here I argue that intrinsic properties of cellular metabolism imposed central constraints on the historical trajectories of biopsheric productivity and atmospheric oxygenation. Photosynthesis depends on iron, but iron is highly insoluble under the aerobic conditions produced by oxygenic photosynthesis. These counteracting constraints led to two major stages of Earth oxygenation. Cyanobacterial photosynthesis drove a major biospheric expansion near the Archean-Proterozoic boundary but subsequently remained largely restricted to continental boundaries and shallow aquatic environments, where weathering inputs made iron more accessible. The anoxic deep open ocean was rich in free iron during the Proterozoic, but this iron remained effectively inaccessible since a photosynthetic expansion would have quenched its own supply. Near the Proterozoic-Phanerozoic boundary, bioenergetic innovations allowed eukaryotic photosynthesis to expand into the deep open oceans and onto the continents, where nutrients are inherently harder to come by. Key insights into the ecological rise of eukaryotic photosynthesis emerge from analyses of marine Synechococcus and Prochlorococcus, abundant marine picocyanobacteria whose ancestors colonized the oceans in the Neoproterozoic. The reconstructed evolution of Prochlorococcus reveals a sequence of innovations that ultimately produced a form of photosynthesis more like that of green plant cells than other cyanobacteria. Innovations increased the energy flux of cells, thereby enhancing their ability to acquire sparse nutrients, and as by-product also increased the production of organic carbon waste. Some of these organic waste products in turn had the ability to chelate iron and make it bioavailable, thereby indirectly pushing the oceans through a transition from an anoxic state rich in free iron to an oxygenated state with organic carbon-bound iron. The periods of Earth history around cyanobacteria- and eukaryote-driven biospheric expansions share several other parallels. Both epochs have also been linked to major carbon cycle perturbations and global glaciations, as well as changes in the nature of mantle convection and plate tectonics. This suggests the dynamics of life and Earth are intimately intertwined across many levels and that general principles governed Neoarchean and Neoproterozoic transitions in these coupled dynamics.

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Late inception of a resiliently oxygenated upper ocean

Cited by 179 publications

References 53 publications

On the co‐evolution of surface oxygen levels and animals

On the co‐evolution of surface oxygen levels and animals

Role of stellar physics in regulating the critical steps for life

Evolution of cellular metabolism and the rise of a globally productive biosphere

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