Research ArticleGEOLOGY

Molecular fossils from phytoplankton reveal secular Pco2 trend over the Phanerozoic

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Science Advances  28 Nov 2018:
Vol. 4, no. 11, eaat4556
DOI: 10.1126/sciadv.aat4556
  • Fig. 1 δ13Cphytane.

    Phanerozoic compilation of the δ13Cphytane from literature (pink) and data from this study (blue), and from sediment (square) and oil (circle). Age uncertainties are shown in the horizontal error bars.

  • Fig. 2 Ɛp calculated from phytane.

    Phanerozoic Ɛp calculated from the δ13Cphytane and δ13C of dissolved CO2 estimated from δ13C of foraminifera from literature (pink) and data from this study (blue), and from sediment (square) and oil (circle). Horizontal error bars indicate dating uncertainty in sample age. Vertical error bars indicate 1 SD (68%) uncertainty in Ɛp estimation based on Monte Carlo simulations, culminating the uncertainty in δ13C of the photosynthetic biomass (based on uncertainty in δ13C of phytane ± 0.5‰ uniform distribution and the uncertainty in offset between biomass and phytane of 1.3‰ SD) and the δ13C of dissolved CO2 (based on uncertainty in δ13C of planktonic foraminifera ± 0.4‰ uniform distribution and uncertainty in SST ± 4°C SD).

  • Fig. 3 Phanerozoic Pco2 from phytane.

    Estimated Phanerozoic Pco2 (on a log scale) from literature (pink) and data from this study (blue), and from sediment (square) and oil (circle). Horizontal error bars indicate uncertainty in age. Vertical error bars indicate 1 SD (68%) uncertainty in Pco2 estimation based on Monte Carlo simulations, culminating the uncertainty in b (±60‰ kg μM−1 SD), Ɛf (±1.5‰ uniform distribution), and Ɛp (combined uncertainty in δ13C of phytane ± 0.5‰ uniform distribution, the offset between biomass and phytane ± 1.3‰ SD, δ13C of planktonic foraminifera ± 0.4‰ uniform distribution, and SST ± 4°C SD). Plotted for comparison, the Foster et al. compilation shows the Monte Carlo resampling and LOESS fit of ca. 1500 data points from the five most robust Pco2 proxies: δ13C of long-chain alkenones, δ11B of marine carbonate, δ13C of paleosols, stomatal densities and indices in plants, and δ13C of liverworts. Sixty-eight percent and 95% confidence intervals are shown in gray and light gray, respectively. The light blue bars represent glacial paleolatitude, as determined by the literature compilation of glaciogenic detritus (46).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/11/eaat4556/DC1

    Supplementary Materials and Methods

    Supplementary Text

    Fig. S1. Isotopic offset between biomass and phytol.

    Fig. S2. Trends from reported δ13Cphytane data to Pco2.

    Fig. S3. Uncertainties associated with equation parameters.

    Fig. S4. Pco2 from phytane over the Phanerozoic in time slices.

    Table S1. Isotopic offset between biomass and phytol.

    Table S2. Estimating b from marine OM in modern-day oceans.

    Table S3. Estimating b from phytol across an equatorial Pacific Ocean transect.

    Code S1. Python code used for Monte Carlo simulations to calculate uncertainty for Pco2 estimations by considering every parameter involved in the equations.

    Data S1. All data used to reconstruct Pco2 from the δ13Cphytane.

    References (5296)

  • Supplementary Materials

    The PDF file includes:

    • Supplementary Materials and Methods
    • Supplementary Text
    • Fig. S1. Isotopic offset between biomass and phytol.
    • Fig. S2. Trends from reported δ13Cphytane data to PCO2.
    • Fig. S3. Uncertainties associated with equation parameters.
    • Fig. S4. PCO2 from phytane over the Phanerozoic in time slices.
    • Table S1. Isotopic offset between biomass and phytol.
    • Table S2. Estimating b from marine OM in modern-day oceans.
    • Table S3. Estimating b from phytol across an equatorial Pacific Ocean transect.
    • Legend for code S1
    • Legend for data S1
    • References (5296)

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • Code S1 (.pdf format). Python code used for Monte Carlo simulations to calculate uncertainty for PCO2 estimations by considering every parameter involved in the equations.
    • Data S1 (Microsoft Excel format). All data used to reconstruct PCO2 from the δ13Cphytane.

    Files in this Data Supplement:

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