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. 2019 Jun 11;142(1):105–125. doi: 10.1007/s11120-019-00648-3

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© The Author(s) 2019

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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Fig. 1 — Oxygen build-up in the Earth’s atmosphere on a time scale of billions of years (Ga) and some major events in the development of our planet. The red and green curves denote an upper and lower estimate of the oxygen in the atmosphere. Oxygenic photosynthesis started about ≈ 3.5 Ga ago (Planavsky et al. 2014), the release of O₂ in the atmosphere ≈ 2.4 Ga ago (Bekker et al. 2004). The present level of O₂ is ≈ 21% (Holland 2006)