Fig. 3: Reconstructed DOC concentration and δ¹³C records.

a, Relevant Earth-system evolution and innovations, including predicted [O₂] in continental shelves relative to modern (\({[{{\rm{O}}}_{2}]}_{{\rm{shelf}}}^{* }\), fractional; grey-shaded region)⁹; range of body sizes for archaea, bacteria, algae and protozoa from the fossil record (biovolume, mm³; orange-shaded region)⁸; timing of Neoproterozoic snowball Earth events (vertical blue bars)¹⁷; proposed timing of algal carbon-concentrating mechanism (CCM) evolution (grey boxes with dashed line)⁵⁹; and timing of land-plant and tree evolution (horizontal green bars)⁵⁸. b,c, Predicted [DOC] relative to modern ([DOC]*; fractional) (b) and δ¹³C_DOC (% VPDB) (c) since the late Palaeoproterozoic. Results are separated by mineralogy and microorganism evolution scenario (rise of algae: green represents goethite and purple represents haematite; Proterozoic active eukaryotes: blue represents goethite and orange represents haematite) and staggered for visual clarity. Opaque markers and vertical black lines are 100 Ma time-binned averages and 95% confidence intervals as predicted by our Monte Carlo model. The grey-shaded regions and thick black lines in c are compiled δ¹³C ranges and 100 Ma running averages for carbonates⁵⁶, kerogen and crude oil (note broken y-axis). See Supplementary Discussion for model derivation, implementation and crude oil and kerogen compilation.