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Cited by 599Paleontology and Stratigraphy of FossilsEarth Systems and Cosmic EvolutionGeology and Paleoclimatology Research

COPSE: A new model of biogeochemical cycling over Phanerozoic time

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Bergman, N. M.·2004·American Journal of Science
DOI 10.2475/ajs.304.5.397
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Abstract

We present a new model of biogeochemical cycling over Phanerozoic time. This work couples a feedback-based model of atmospheric O~2~ and ocean nutrients (Lenton and Watson, 2000a, 2000b) with a geochemical carbon cycle model (Berner, 1991, 1994), a simple sulfur cycle, and additional components. The resulting COPSE model (Carbon-Oxygen-Phosphorus-Sulfur-Evolution) represents the co-evolution of biotic and abiotic components of the Earth system, in that it couples interactive and evolving terrestrial and marine biota to geochemical and tectonic processes. The model is forced with geological and evolutionary forcings and time-dependent solar insolation. The baseline model succeeds in giving simultaneous predictions of atmospheric O~2~, CO~2~, global temperature, ocean composition, δ^13^C and δ^34^S that are in reasonable agreement with available data and suggested constraints. The behavior of the coupled model is qualitatively different to single cycle models. While atmospheric *p*CO~2~ (CO~2~ partial pressure) predictions are mostly determined by the model forcings and the response of silicate weathering rate to *p*CO~2~ and temperature, multiple negative feedback processes and coupling of the C, O, P and S cycles are necessary for regulating *p*O~2~ while allowing δ^13^C changes of sufficient amplitude to match the record. The results support a *p*O~2~ dependency of oxidative weathering of reduced carbon and sulfur, which raises early Paleozoic *p*O~2~ above the estimated requirement of Cambrian fauna and prevents unrealistically large δ^34^S variation. They do not support a strong anoxia dependency of the C:P burial ratio of marine organic matter (Van Cappellen and Ingall, 1994, 1996) because this dependency raises early Paleozoic δ^13^C and organic carbon burial rates too high. The dependency of terrestrial primary productivity on *p*O~2~ also contributes to oxygen regulation. An intermediate strength oxygen fire feedback on terrestrial biomass, which gives a *p*O~2~ upper limit of ∼1.6PAL (present atmospheric level) or 30 volume percent, provides the best combined *p*O~2~ and δ^13^C predictions. Sulfur cycle coupling contributes critically to lowering the Permo-Carboniferous *p*CO~2~ and temperature minimum. The results support an inverse dependency of pyrite sulfur burial on *p*O~2~ (for example, Berner and Canfield, 1989), which contributes to the shuttling of oxygen back and forth between carbonate carbon and gypsum sulfur. A *p*O~2~ dependency of photosynthetic carbon isotope fractionation (Berner and others, 2000; Beerling and others, 2002) is important for producing sufficient magnitude of δ^13^C variation. However, our results do not support an oxygen dependency of sulfur isotope fractionation in pyrite formation (Berner and others, 2000) because it generates unrealistically small variations in δ^34^S. In the Early Paleozoic, COPSE predicts *p*O~2~=0.2--0.6PAL and *p*CO~2~\>10PAL, with high oceanic \[PO~4~^3-^\] and low \[SO~4~^=^\]. Land plant evolution caused a 'phase change' in the Earth system by increasing weathering rates and shifting some organic burial to land. This change resulted in a major drop in *p*CO~2~ to 3 to 4PAL and a rise in *p*O~2~ to ∼1.5PAL in the Permo-Carboniferous, with temperatures below present, ocean variables nearer present concentrations, and PO~4~:NO~3~ regulated closer to Redfield ratio. A second O~2~ peak of similar or slightly greater magnitude appears in the mid-Cretaceous, before a descent towards PAL. Mesozoic CO~2~ is in the range 3 to 7PAL, descending toward PAL in the Cretaceous and Cenozoic.

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  • The coupled carbon and sulphur cycle model follows the work of Garrels and Lerman, Berner, and Bergman et al.

    “This follows the work of Garrels and Lerman 30 , Berner 12 and Bergman et al . 31 .”

    From Possible links between extreme oxygen perturbations and the Cambrian radiation of animals (2019) · cites this paper as [31]

  • The initial O2 level may have been lower, approximately 5% in the Bergman et al. COPSE model.

    “although the initial O 2 level may have been lower (approximately 5% in Bergman et al. COPSE model) (23, 24).”

    From Pulse of atmospheric oxygen during the late Cambrian (2011) · cites this paper as [23]

  • The return to lower Δ13C likely indicates the role that fluctuations in atmospheric pCO2 may also play in photosynthetic carbon isotope fractionation.

    “This return to lower Δ 13 C likely indicates the role that fluctuations in atmospheric p CO 2 may also play in photosynthetic carbon isotope fractionation (20, 21, 23, 26 -29).”

    From Pulse of atmospheric oxygen during the late Cambrian (2011) · cites this paper as [23]

  • The rise of oxygen to present levels required an increase in organic carbon burial rate, which may have begun in the Neoproterozoic Era but in this model was not completed until the mid-Palaeozoic Era with the colonization of the land by plants and fungi.

    “The rise of oxygen to present levels simply required an increase in organic carbon burial rate, which may have begun in the Neoproterozoic Era10, but in our model was not completed until the mid-Palaeozoic Era with the colonization of the land by plants and fungi, liberating nutrient phosphorus from rocks and producing high C/P material for burial1113.”

    From Atmospheric oxygen regulation at low Proterozoic levels by incomplete oxidative weathering of sedimentary organic carbon (2017) · cites this paper as [11]

  • The P weathering flux is partly tied to bulk silicate weathering, and the silicate weathering flux of alkalinity is ultimately controlled by the degassing input of CO2 on timescales ≥1 My.

    “The P weathering flux is partly tied to bulk silicate weathering, for example, due to the dissolution of apatite inclusions in silicate rocks, and the silicate weathering flux of alkalinity is in turn set by negative feedback in the longterm carbon cycle, so is ultimately controlled by the degassing input of CO2 on timescales ≥ 1 My (7, 10).”

    From Earliest land plants created modern levels of atmospheric oxygen (2016) · cites this paper as [10]

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8 of the 81 references couldn’t be matched to a known paper.

Research works printed but not linked: 7

  1. [7]7. ------1998, The carbon cycle and CO 2 over Phanerozoic time: the role of land plants: Philosophical Transactions of the Royal Society of London: Biological Sciences, v. 353, p. 75-82.
  2. [30]30. Friend, A. D., 1998, Appendix: Biochemical modelling of leaf photosynthesis, in Jarvis, P. G., editor, European forests and global change: Cambridge, Cambridge University Press, p. 335-346.
  3. [31]31. Friend, A. D., Kelloma ¨ki, S., and Kruijt, B., 1998, Modelling leaf, tree and forest responses to increasing atmospheric CO 2 and temperature, in Jarvis, P. G., editor, European forests and global change: Cambridge, Cambridge University Press, p. 293-334.
  4. [35]35. Garrels, R. M., and Perry, E. A., Jr., 1974, Cycling of carbon, sulfur, and oxygen through geologic time, The Sea: New York, Wiley, p. 303-336.
  5. [44]44. Holser, W. T., Schidlowski, M., Mackenzie, F. T., and Maynard, J. B., 1988, Geochemical cycles of carbon and sulfur, in Gregor, C. B., Garrels, R. M., Mackenzie, F. T., and Maynard, J. B., editors, Chemical cycles in the Evolution of the Earth: New York, Wiley-Interscience, p. 105-173.
  6. [56]56. Mook, W. G., 1986, 13 C in atmospheric CO 2 : Netherlands Journal of Sea Research, v. 20, p. 211-223.
  7. [79]79. Watson, A. J., ms, 1978, Consequences for the Biosphere of Forest and Grassland Fires, Department of Cybernetics: Ph.D. thesis, Reading, United Kingdom, University of Reading, p. 276.

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Authors
Bergman, N. M.
Affiliations
University of East Anglia (GB)
Corresponding author
Bergman, N. M.
Venue
American Journal of Science
Publisher
American Journal of Science (AJS)
Published
2004-05-01
Volume
304
Issue
5
Pages
397-437
ISSN
0002-9599 (ISSN-L)
DOI
10.2475/ajs.304.5.397
OpenAlex
W2140479142
Cited by
599
References
81
Citations by year
2026: 19 · 2025: 32 · 2024: 24 · 2023: 53 · 2022: 29 · 2021: 47 · 2020: 25 · 2019: 38 · 2018: 46 · 2017: 31 · 2016: 39 · 2015: 31 · 2014: 17 · 2013: 31 · 2012: 30
FWCI
11.51
Type
journal article
Language
en
Open access
Locations
  • American Journal of Science (publishedVersion)
  • Figshare (submittedVersion, cc-by)
  • UEA Digital Repository (University of East Anglia) (submittedVersion)
Topics
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Stratigraphy of Fossils
  • Physical Sciences › Earth and Planetary Sciences › Atmospheric Science › Earth Systems and Cosmic Evolution
  • Physical Sciences › Earth and Planetary Sciences › Atmospheric Science › Geology and Paleoclimatology Research
Keywords
atmospheric oxygen evolution, carbon cycle, sulfur cycling, phosphorus cycling, silicate weathering, organic carbon burial, carbon isotope stratigraphy, global temperature, paleoceanography, anoxia, Cambrian fauna, Permo-Carboniferous

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