Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician

Nature Ecology & Evolution (2026)Cite this article

Subjects

Abstract

Initial land plant diversification occurred over the Ordovician, Silurian and Devonian periods (~460–360 Ma) and fundamentally transformed Earth’s biosphere and the composition of the oceans and atmosphere. Yet, the exact timing of the impact of land plants on the Earth system remains uncertain. Here we find evidence for a substantial shift in organic carbon to total phosphorus ratios (Corg/Ptotal) in marine siliciclastic strata beginning around 455 million years ago. Building from the prominent observed difference in C/P ratios of modern terrestrial and marine organic matter, we link this change to the initial spread of land plants. Given the common assumption that phosphorus limits global primary productivity and that organic carbon burial regulates atmospheric oxygen levels, this shift is likely to have driven Earth’s surface oxygenation. Palaeogeographic analyses suggest that land plants may have spread in Laurentia earlier than on other palaeocontinents.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to the full article PDF.

USD 39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Evolution of the Corg/Ptotal ratio of marine siliciclastic sediments during the Phanerozoic.
Fig. 2: Comparison of the Corg/Ptotal ratio of marine siliciclastic sediments before and after 455 Ma.
Fig. 3: Comparison of Corg/Ptotal records with (C/P)org values across different biota.
Fig. 4: Evolution of the Corg/Ptotal ratio of marine siliciclastic sediments from different palaeocontinents.

Data availability

All compiled and newly analysed data for this study are available in Supplementary Data 1–3, and the associated data files are available via figshare at https://doi.org/10.6084/m9.figshare.31080109 (ref. 78).

Code availability

All codes are available via Zenodo at https://doi.org/10.5281/zenodo.15878677 (ref. 79).

References

  1. Chapin, F. S., Matson, P. A. & Vitousek, P. M. Principles of Terrestrial Ecosystem Ecology (Springer, 2011); https://doi.org/10.1007/978-1-4419-9504-9

  2. Cai, J., Ju, P., Liu, M., Xue, J. & Zhao, M. Environmental effects of land plants evolution in the phanerozoic. Chin. Sci. Bull. https://doi.org/10.1360/TB-2025-0173 (2025).

  3. Beerling, D. J. & Butterfield, N. J. in Fundamentals of Geobiology (eds Knoll, A. H. et al.) Ch. 11 (Blackwell, 2012).

  4. Algeo, T. J., Berner, R. A., Maynard, J. B. & Scheckler, S. E. Late Devonian oceanic anoxic events and biotic crises: ‘rooted’ in the evolution of vascular land plants?. GSA Today 5, 64–66 (1995).

    Google Scholar 

  5. Algeo, T. J. & Scheckler, S. E. Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events. Philos. Trans. R. Soc. Lond. B 353, 113–130 (1998).

    Article  Google Scholar 

  6. Algeo, T. J., Scheckler, S. E. & Maynard, J. B. in Plants Invade the Land (eds Gensel, P. G. & Edwards, D.) 213–236 (Columbia Univ. Press, 2001); https://doi.org/10.7312/gens11160-013

  7. Retallack, G. J. in Treatise on Geochemistry Vol. 5 (eds Holland, H. D. & Turekian, K. K.) Ch. 5.18 (Elsevier, 2003); https://doi.org/10.1016/B0-08-043751-6/05087-8

  8. Gibling, M. R. & Davies, N. S. Palaeozoic landscapes shaped by plant evolution. Nat. Geosci. 5, 99–105 (2012).

    Article  CAS  Google Scholar 

  9. Lenton, T. M., Daines, S. J. & Mills, B. J. W. COPSE reloaded: an improved model of biogeochemical cycling over Phanerozoic time. Earth-Sci. Rev. 178, 1–28 (2018).

    Article  CAS  Google Scholar 

  10. Donoghue, P. C. J., Harrison, C. J., Paps, J. & Schneider, H. The evolutionary emergence of land plants. Curr. Biol. 31, R1281–R1298 (2021).

    Article  CAS  PubMed  Google Scholar 

  11. Wellman, C. H., Steemans, P. & Vecoli, M. Palaeophytogeography of Ordovician-Silurian land plants. Memoirs 38, 461–476 (2013).

    Article  Google Scholar 

  12. Cascales-Miñana, B. Apparent changes in the Ordovician–Mississippian plant diversity. Rev. Palaeobot. Palynol. 227, 19–27 (2016).

    Article  Google Scholar 

  13. Servais, T. et al. Revisiting the Great Ordovician diversification of land plants: recent data and perspectives. Palaeogeogr. Palaeoclimatol. Palaeoecol. 534, 109280 (2019).

    Article  Google Scholar 

  14. Liu, L. et al. Ordovician marine charophyceae and insights into land plant derivations. Nat. Plants 11, 1116–1126 (2025).

    Article  PubMed  Google Scholar 

  15. Rubinstein, C. V. & Vajda, V. Baltica cradle of early land plants? Oldest record of trilete spores and diverse cryptospore assemblages; evidence from Ordovician successions of Sweden. GFF 141, 181–190 (2019).

    Article  CAS  Google Scholar 

  16. Yuan, W. et al. Mercury isotopes show vascular plants had colonized land extensively by the early Silurian. Sci. Adv. 9, eade9510 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  17. Kump, L. R. Chemical stability of the atmosphere and ocean. Palaeogeogr. Palaeoclimatol. Palaeoecol. 75, 123–136 (1989).

    Article  Google Scholar 

  18. Lenton, T. M. in Fire Phenomena and the Earth System (ed. Belcher, C. M.) 289–308 (Wiley, 2013); https://doi.org/10.1002/9781118529539.ch15

  19. Redfield, A. C. in James Johnstone memorial volume (ed. Daniel, R. J.) 176–192 (University Press of Liverpool, 1934).

  20. McGroddy, M. E., Daufresne, T. & Hedin, L. O. Scaling of C:N:P stoichiometry in forests worldwide: implications of terrestrial redfield-type ratios. Ecology 85, 2390–2401 (2004).

    Article  Google Scholar 

  21. Tanioka, T. et al. Global patterns and predictors of C:N:P in marine ecosystems. Commun. Earth Environ. 3, 271 (2022).

    Article  PubMed  PubMed Central  Google Scholar 

  22. Liu, X., Wang, Z., Li, X., Bao, W. & Rousk, K. The C: N: P stoichiometry in bryophytes: relationships with habitat, climate and growth form. Natl Sci. Rev. 10, nwad060 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Regnier, P., Resplandy, L., Najjar, R. G. & Ciais, P. The land-to-ocean loops of the global carbon cycle. Nature 603, 401–410 (2022).

    Article  CAS  PubMed  Google Scholar 

  24. Blair, N. E. & Aller, R. C. The fate of terrestrial organic carbon in the marine environment. Annu. Rev. Mar. Sci. 4, 401–423 (2012).

    Article  Google Scholar 

  25. Lenton, T. M. et al. Earliest land plants created modern levels of atmospheric oxygen. Proc. Natl Acad. Sci. USA 113, 9704–9709 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Algeo, T. J. & Ingall, E. Sedimentary Corg:P ratios, paleocean ventilation, and Phanerozoic atmospheric pO2. Palaeogeograp. Palaeoclimatol. Palaeoecol. 256, 130–155 (2007).

    Article  Google Scholar 

  27. Sharoni, S. & Halevy, I. Geologic controls on phytoplankton elemental composition. Proc. Natl Acad. Sci. USA 119, e2113263118 (2022).

    Article  PubMed  Google Scholar 

  28. Velthuis, M. et al. Differential effects of elevated pCO2 and warming on marine phytoplankton stoichiometry. Limnol. Oceanogr. 67, 598–607 (2022).

    Article  CAS  Google Scholar 

  29. Schaum, E., Rost, B., Millar, A. J. & Collins, S. Variation in plastic responses of a globally distributed picoplankton species to ocean acidification. Nat. Clim. Change 3, 298–302 (2013).

    Article  CAS  Google Scholar 

  30. Planavsky, N. J. et al. The evolution of the marine phosphate reservoir. Nature 467, 1088–1090 (2010).

    Article  CAS  PubMed  Google Scholar 

  31. Rogger, J. et al. Biogeographic climate sensitivity controls Earth system response to large igneous province carbon degassing. Science 385, 661–666 (2024).

    Article  CAS  PubMed  Google Scholar 

  32. Reinhard, C. T. et al. Evolution of the global phosphorus cycle. Nature 541, 386–389 (2017).

    Article  CAS  PubMed  Google Scholar 

  33. Alcott, L. J., Mills, B. J. W., Bekker, A. & Poulton, S. W. Earth’s Great Oxidation Event facilitated by the rise of sedimentary phosphorus recycling. Nat. Geosci. 15, 210–215 (2022).

    Article  CAS  Google Scholar 

  34. Dahl, T. W. et al. Devonian rise in atmospheric oxygen correlated to the radiations of terrestrial plants and large predatory fish. Proc. Natl Acad. Sci. USA 107, 17911–17915 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. Stacey, J. et al. Ocean oxygenation and ecological restructuring caused by the late Paleozoic evolution of land plants. Geology 52, 948–952 (2024).

    Article  CAS  Google Scholar 

  36. Gill, B. C., Lyons, T. W. & Saltzman, M. R. Parallel, high-resolution carbon and sulfur isotope records of the evolving Paleozoic marine sulfur reservoir. Palaeogeograp. Palaeoclimatol. Palaeoecol. 256, 156–173 (2007).

    Article  Google Scholar 

  37. Bergmann, K. D., Macdonald, F. A. & Swanson-Hysell, N. L. The causes and consequences of ordovician cooling. Annu. Rev. Earth Planet. Sci. 53, 651–685 (2025).

    Article  CAS  Google Scholar 

  38. Scotese, C. R. An atlas of phanerozoic paleogeographic maps: the seas come in and the seas go out. Ann. Rev. Earth Planet. Sci. 49, 679–728 (2021).

    Article  CAS  Google Scholar 

  39. Torsvik, T. H. et al. Phanerozoic polar wander, palaeogeography and dynamics. Earth-Sci. Rev. 114, 325–368 (2012).

    Article  Google Scholar 

  40. Ruttenberg, K. C. & Berner, R. A. Authigenic apatite formation and burial in sediments from non-upwelling, continental margin environments. Geochim. Cosmochim. Acta 57, 991–1007 (1993).

    Article  CAS  Google Scholar 

  41. Quigg, A. et al. The evolutionary inheritance of elemental stoichiometry in marine phytoplankton. Nature 425, 291–294 (2003).

    Article  CAS  PubMed  Google Scholar 

  42. Falkowski, P. G. et al. The evolution of modern eukaryotic phytoplankton. Science 305, 354–360 (2004).

    Article  CAS  PubMed  Google Scholar 

  43. Zhao, M. et al. Drivers of the global phosphorus cycle over geological time. Nat. Rev. Earth Environ. 5, 873–889 (2024).

    Article  CAS  Google Scholar 

  44. Zhao, M., Zhang, S., Tarhan, L. G., Reinhard, C. T. & Planavsky, N. The role of calcium in regulating marine phosphorus burial and atmospheric oxygenation. Nat. Commun. 11, 2232 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. Kump, L. R. in Interactions of C, N, P and S Biogeochemical Cycles and Global Change (eds Wollast, R. et al.) 475–490 (Springer, 1993).

  46. Porada, P. et al. High potential for weathering and climate effects of non-vascular vegetation in the Late Ordovician. Nat. Commun. 7, 12113 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  47. Floudas, D. et al. The paleozoic origin of enzymatic lignin decomposition reconstructed from 31 fungal genomes. Science 336, 1715–1719 (2012).

    Article  CAS  PubMed  Google Scholar 

  48. Ben-Israel, M. et al. Late Paleozoic oxygenation of marine environments supported by dolomite U-Pb dating. Nat. Commun. 15, 2892 (2024).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Berbee, M. L., James, T. Y. & Strullu-Derrien, C. Early diverging fungi: diversity and impact at the dawn of terrestrial life. Annu. Rev. Microbiol. 71, 41–60 (2017).

    Article  CAS  PubMed  Google Scholar 

  50. Redecker, D., Kodner, R. & Graham, L. E. Glomalean fungi from the Ordovician. Science 289, 1920–1921 (2000).

    Article  CAS  PubMed  Google Scholar 

  51. Burdige, D. J. Burial of terrestrial organic matter in marine sediments: a re-assessment. Glob. Biogeochem. Cycles 19, 2004GB002368 (2005).

    Article  Google Scholar 

  52. Houghton, R. A. Balancing the global carbon budget. Annu. Rev. Earth Planet. Sci. 35, 313–347 (2007).

    Article  CAS  Google Scholar 

  53. Wei, G.-Y. et al. Lithium isotopic constraints on the evolution of continental clay mineral factory and marine oxygenation in the earliest Paleozoic Era. Sci. Adv. 10, eadk2152 (2024).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  54. Glasspool, I. J., Edwards, D., & Axe, L. Charcoal in the Silurian as evidence for the earliest wildfire. Geology 32, 381–383 (2004).

    Article  Google Scholar 

  55. Glasspool, I. J. & Scott, A. C. Phanerozoic concentrations of atmospheric oxygen reconstructed from sedimentary charcoal. Nat. Geosci. 3, 627–630 (2010).

    Article  CAS  Google Scholar 

  56. Longman, J., Mills, B. J. W., Manners, H. R., Gernon, T. M. & Palmer, M. R. Late Ordovician climate change and extinctions driven by elevated volcanic nutrient supply. Nat. Geosci. 14, 924–929 (2021).

    Article  CAS  Google Scholar 

  57. Kump, L. R. Terrestrial feedback in atmospheric oxygen regulation by fire and phosphorus. Nature 335, 152–154 (1988).

    Article  CAS  Google Scholar 

  58. Lenton, T. M., Crouch, M., Johnson, M., Pires, N. & Dolan, L. First plants cooled the Ordovician. Nat. Geosci. 5, 86–89 (2012).

  59. Goldberg, S. L., Present, T. M., Finnegan, S. & Bergmann, K. D. A high-resolution record of early Paleozoic climate. Proc. Natl Acad. Sci. USA 118, e2013083118 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  60. Wang, Y. et al. The influence of Late Ordovician volcanism on the marine environment based on high-resolution mercury data from South China. Geol. Soc. Am. Bull. 135, 787–798 (2023).

    Article  CAS  Google Scholar 

  61. Algeo, T. J. & Shen, J. Theory and classification of mass extinction causation. Natl Sci. Rev. 11, nwad237 (2024).

    Article  CAS  PubMed  Google Scholar 

  62. Zhang, Z. et al. Tempo of the Late Ordovician mass extinction controlled by the rate of climate change. Sci. Adv. 11, eadv6788 (2025).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  63. Cai, J. Environmental Constraints on the Evolution of Vertebrate Diversity during the Silurian to Early Devonian periods in Eastern Yunnan (Univ. Chinese Academy of Sciences, 2024).

  64. Cai, J., Sun, H., Zhao, W., Wang, J. & Zhu, M. The Early Devonian Xitun vertebrate fauna in South China inhabited a shallow marine environment with changing salinity. J. Geol. Soc. https://doi.org/10.1144/jgs2023-146 (2024).

  65. Farrell, Ú. C. et al. The Sedimentary Geochemistry and Paleoenvironments Project. Geobiology 19, 545–556 (2021).

    Article  PubMed  PubMed Central  Google Scholar 

  66. Planavsky, N. J. et al. A sedimentary record of the evolution of the global marine phosphorus cycle. Geobiology 21, 168–174 (2023).

    Article  CAS  PubMed  Google Scholar 

  67. Rudnick, R. L. & Gao, S. in Treatise on Geochemistry (eds Holland, H. D. & Turekian, K. K.) Vol. 3, 1–64 (Elsevier-Pergamon, 2003).

  68. Algeo, T. J. & Liu, J.-S. A re-assessment of elemental proxies for paleoredox analysis. Chem. Geol. 540, 119549 (2020).

    Article  CAS  Google Scholar 

  69. Algeo, T. J. & Li, C. Redox classification and calibration of redox thresholds in sedimentary systems. Geochim. Cosmochim. Acta 287, 8–26 (2020).

    Article  CAS  Google Scholar 

  70. Tribovillard, N., Algeo, T. J., Lyons, T. & Riboulleau, A. Trace metals as paleoredox and paleoproductivity proxies: an update. Chem. Geol. 232, 12–32 (2006).

    Article  CAS  Google Scholar 

  71. Algeo, T. J. & Tribovillard, N. Environmental analysis of paleoceanographic systems based on molybdenum–uranium covariation. Chem. Geol. 268, 211–225 (2009).

    Article  CAS  Google Scholar 

  72. Keller, C. B. & Schoene, B. Statistical geochemistry reveals disruption in secular lithospheric evolution about 2.5 Gyr ago. Nature 485, 490–493 (2012).

    Article  CAS  PubMed  Google Scholar 

  73. Keller, C. B. et al. Neoproterozoic glacial origin of the Great Unconformity. Proc. Natl Acad. Sci. USA 116, 1136–1145 (2019).

    Article  CAS  PubMed  Google Scholar 

  74. Efron, B. Bootstrap methods: another look at the jackknife. Ann. Stat. 7, 1–26 (1979).

    Article  Google Scholar 

  75. Anderson, L. D., Delaney, M. L. & Faul, K. L. Carbon to phosphorus ratios in sediments: implications for nutrient cycling. Glob. Biogeochem. Cycles 15, 65–79 (2001).

    Article  CAS  Google Scholar 

  76. Ielpi, A., Lapôtre, M. G. A., Gibling, M. R. & Boyce, C. K. The impact of vegetation on meandering rivers. Nat. Rev. Earth Environ. 3, 165–178 (2022).

    Article  Google Scholar 

  77. Zondervan, J. R. et al. Rock organic carbon oxidation CO2 release offsets silicate weathering sink. Nature 623, 329–333 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  78. Cai, J. et al. Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician. figshare https://doi.org/10.6084/m9.figshare.31080109 (2026).

  79. Cai, J. & Zhao, M. The updated COPSE model and the data processing and plotting codes accompany this paper: Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician. Zenodo https://doi.org/10.5281/zenodo.15878677 (2025).

  80. Gurung, K. et al. Climate windows of opportunity for plant expansion during the Phanerozoic. Nat. Commun. 13, 4530 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  81. Morris, J. L. et al. The timescale of early land plant evolution. Proc. Natl Acad. Sci. USA 115, E2274–E2283 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  82. Scotese, C. R. An atlas of phanerozoic paleogeographic maps: the seas come in and the seas go out. Annu. Rev. Earth Planet. Sci. 49, 679–728 (2021).

    Article  CAS  Google Scholar 

  83. Sharoni, S. & Halevy, I. Rates of seafloor and continental weathering govern Phanerozoic marine phosphate levels. Nat. Geosci. 16, 75–81 (2023).

    Article  CAS  Google Scholar 

  84. Saltzman, M. R. & Thomas, E. in The Geologic Time Scale 207–232 (Elsevier, 2012); https://doi.org/10.1016/B978-0-444-59425-9.00011-1

Download references

Acknowledgements

We thank X. W. Li, Z. J. Yang, Y. C. Wang and Z. L. Yi at the Institute of Geology and Geophysics for the assistance with TOC measurements. This work was supported by Progress of Strategy Priority Research Program (Category A) of Chinese Academy of Sciences (grant no. XDA0430202) and National Key Research and Development Program of China (grant no. 2023YFF0806200) to M.Z., National Key Research and Development Program of China (grant no. 2020YFA0607700) to Z.X. and National Natural Science Foundation of China (grant no. 92479106) to J.C.

Author information

Authors and Affiliations

  1. State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China

    Jiachen Cai, Ruoyuan Qiu, Zhifang Xu, Hui Zhang & Mingyu Zhao

  2. Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA

    Lidya G. Tarhan & Noah J. Planavsky

  3. Global Systems Institute, University of Exeter, Exeter, UK

    Timothy M. Lenton

  4. School of Earth and Environment, University of Leeds, Leeds, UK

    Caroline L. Peacock

  5. National Key Laboratory of Deep Space Exploration/School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China

    Pengcheng Ju

  6. Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Palaeontology and Palaeoanthropology, Chinese Academy of Sciences, Beijing, China

    Wenjin Zhao

  7. University of Chinese Academy of Sciences, Beijing, China

    Wenjin Zhao

Authors
  1. Jiachen Cai
    View author publications

    Search author on:PubMed Google Scholar

  2. Lidya G. Tarhan
    View author publications

    Search author on:PubMed Google Scholar

  3. Timothy M. Lenton
    View author publications

    Search author on:PubMed Google Scholar

  4. Ruoyuan Qiu
    View author publications

    Search author on:PubMed Google Scholar

  5. Caroline L. Peacock
    View author publications

    Search author on:PubMed Google Scholar

  6. Noah J. Planavsky
    View author publications

    Search author on:PubMed Google Scholar

  7. Pengcheng Ju
    View author publications

    Search author on:PubMed Google Scholar

  8. Wenjin Zhao
    View author publications

    Search author on:PubMed Google Scholar

  9. Zhifang Xu
    View author publications

    Search author on:PubMed Google Scholar

  10. Hui Zhang
    View author publications

    Search author on:PubMed Google Scholar

  11. Mingyu Zhao
    View author publications

    Search author on:PubMed Google Scholar

Contributions

M.Z. designed the study. J.C. analysed and complied the data. M.Z. ran the biogeochemical model. J.C., M.Z., L.G.T. and T.M.L. wrote the initial paper. C.L.P., J.C., M.Z. and T.M.L. discussed the model inputs and interpreted the results. All authors contributed to the discussion and the final version of the paper.

Corresponding author

Correspondence to Mingyu Zhao.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Ecology & Evolution thanks Lee Kump, Wenhui Wang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Evolution of Corg/Ptotal ratio of marine siliciclastic sediments from 500 to 400 Ma.

Corg/Ptotal ratio of siliciclastic sediments in oxic (a), ferruginous (b), and euxinic (c) marine environments. (d) Corg/Ptotal ratio of all siliciclastic sediments. (e) Mean Corg/Ptotal ratio of the same stratigraphic formation within the same region (from the same reference). The number in the top left corner of each figure panel represents the original sample count or formation count. Blue curves and shadings indicate the bin-averaged Corg/Ptotal ratios and their 2 weighted standard deviation (2σ), which are generated through Monte Carlo analysis with weighted bootstrap resampling. Light and dark gray dots represent data points and outliers. Purple dots show the data measured in this study. (f) Proportion of terrigenous organic carbon (OC) in oxic marine environments. A notably increase in the Corg/Ptotal ratio was observed between 455 and 445 Ma, as shown in panels a–e.

Extended Data Fig. 2 Trends in Corg/Ptotal and change-point analysis based on time-series.

(a) Bin average plot of Corg/Ptotal for siliciclastic sediments deposited under oxic conditions, with a bin duration of 0.5 Myr. Grey lines indicate ±1 SD. Blue and light gray dots represent data points and outliers. The sample sizes refer to the number of independent siliciclastic samples. (b) Change-point analysis was conducted with 1 change-point specified. Grey and red lines in b indicate the raw data line and the detected change-point, respectively. Yellow-shaded regions in a–b indicate the interval of 455–445 Ma. Results from the change-point analysis reveal a marked shift in Corg/Ptotal values at 458 Ma, aligning with the timing of increased Corg/Ptotal values observed in this study.

Extended Data Fig. 3 Comparison of multiple indexes of marine siliciclastic sediments before and after 455 Ma.

Comparison of maximum pyrolysis temperature (Tmax) (a) and hydrogen index (HI) (b) between 1000 and 445 Ma. (c) Comparison of Ptotal between 400 and 500 Ma. (d) Comparison of Porg/Ptotal over the interval 0–600 Ma.The figure shows the median, upper quartile, lower quartile, whiskers (1.5x IQR) and the outliers (grey circles). Dark grey circles represent outliers that exceed the y-axis range. Sample sizes for each panel used in both plots (≥455 vs <455 Ma): panel a, b = 67 vs 91; panel c = 1040 vs 1905; panel d = 44 vs 180. The sample sizes refer to the number of independent siliciclastic samples. See Supplementary Data 1, 3 for the compiled data.

Extended Data Fig. 4 Model estimates of variations in global mean temperature and surface-ocean phosphate concentrations through the Phanerozoic.

(a) global mean temperature27,83. (b) surface-ocean phosphate concentrations27,83. Curves and shadings indicate the mean and standard deviation of a discrete density distribution for each time bin. Detailed calculation methods and model parameter settings for these estimates are available in the references cited above.

Extended Data Fig. 5 The evolution of TOC during the Phanerozoic.

The TOC data is derived from the entire dataset and has undergone temporally weighted resampling, employing the same methodology as applied to Corg/Ptotal (Methods). Bars illustrate the number of data utilized in the bootstrap analyses for each bin. In each box, the lower and upper bounds represent the first and third quartiles, respectively, while red squares within the box mark the median. The sample value refers to the number of independent siliciclastic samples.

Extended Data Fig. 6 Evolution of the Corg/Ptotal ratio and the proportion of terrigenous organic carbon in oxic marine environments from 600 Ma to present.

(a) Corg/Ptotal ratio for all siliciclastic sediments. The number in the top left corner of the figure represents the original sample count. Blue curves and shadings indicate the bin-averaged Corg/Ptotal ratios and their 2 weighted standard deviation (2σ), which were generated through Monte Carlo analysis with weighted bootstrap resampling. Light and dark gray dots represent data points and outliers. Purple dots show the data measured in this study. (b) Proportion of terrigenous organic carbon (OC) in total marine sedimentary organic carbon. See Extended Data Fig. 1 for the proportion of terrigenous OC in oxic marine conditions. Yellow-shaded regions in a–b indicate the interval of 455–445 Ma.

Extended Data Fig. 7 Model estimates of the burial rates of marine and terrestrial organic carbon from 600 Ma to present45.

Grey- and green-shaded regions indicate the marine (grey) and terrestrial (green) components, shown as a stacked area chart. Detailed calculation methods and model parameter settings for these estimates are available in the reference cited above.

Extended Data Fig. 8 Assessment of Corg/Ptotal trends across palaeocontinents.

(a) Corg/Ptotal trends obtained through repeated subsampling (10,000 replicates) with a fixed sample size (n = 163). Bin-averaged values were calculated using a bin duration of 2 Myr. Curves and shadings indicate the bin-averaged Corg/Ptotal ratios and their associated uncertainties (2 SEM). Automated detection of geochemical response thresholds across Laurentia (b), South China (c), Gondwana (d), and Baltica (e). Pink and purple dashed lines in b–e are detection baseline and response time, respectively. Smoothed Corg/Ptotal trajectories used for threshold detection were calculated using a bin duration of 6 Myr with ~66.67% overlap. (f) Permutation test histogram comparing response times of Laurentia to other palaeogeographic regions. Δobs is the observed difference in response time between the focal group (Laurentia) and the average of the remaining groups (other palaeocontinents).

Extended Data Fig. 9 Trends of Corg/Ptotal for oxic marine siliciclastic sediments and model results from 470 to 430 Ma.

(a) Bin average plot of Corg/Ptotal for oxic marine siliciclastic sediments, with a bin duration of 0.5 Myr. Grey lines with caps indicate ±1 SD. Histograms illustrate the number of observations in each bin. The sample sizes refer to the number of independent siliciclastic samples. (b) Carbon isotopes of carbonates56,84. Evolution of land plant relative abundance calculated using the above bin average results of Corg/Ptotal (c) and estimated impact of the evolution of land plants on the strength of weathering (d), atmospheric pCO2 (e) and pO2 (f) levels, and carbon isotopes (g) calculated using the COPSE model9. See Methods for the detailed description of this simulation. Grey-shaded regions in c–g indicate the density plot derived from the Monte Carlo analysis with a bin duration of 1 Myr.

Supplementary information

Supplementary Information

Supplementary Text, Figs. 1–5, Table 1 and References.

Reporting Summary

Peer Review File

Supplementary Data 1

Dataset of Corg/Ptotal.

Supplementary Data 2

Dataset of biota (C/P)org.

Supplementary Data 3

Dataset of Corg/Ptotal and phosphorus speciation.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Cai, J., Tarhan, L.G., Lenton, T.M. et al. Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician. Nat Ecol Evol (2026). https://doi.org/10.1038/s41559-026-02995-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Version of record:

  • DOI: https://doi.org/10.1038/s41559-026-02995-6

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing