A Compilation of Marine Photosynthesis–Irradiance Data from 14C Incubation Experiments

pi-14C-raw-data.csv

Contains the individual measurements of PI curves. Each row represents a photosynthetic-rate measurement at a specific experimental irradiance level.

Variables include:

• reportName: identifier linking the observation to its cruise report,
• photosynthesis_rate: measured ¹⁴C-based photosynthetic rate (mg C (mg chl a)^-1 h^-1).
• irradiance: experimental irradiance (W m^-2).
• dataType: classification of the observation labeled by piCurve library,
• depth: sampling depth (m).
• latitude: sampling latitude in decimal degrees.
• longitude: sampling longitude in decimal degrees.
• date: sampling date (YYYY-MM-DD).

pi-bio-variable-data.csv

Contains biological measurements associated with the PI experiments.

Variables include:

• reportName: identifier linking the observation to its cruise report,
• ice: sea-ice presence during sampling (0 = absent; 1 = present),
• PN: particulate nitrogen concentration (mg m^-3).
• PC: particulate carbon concentration (mg m^-3).
• Chla: chlorophyll-a concentration (mg m^-3).

pi-env-variables-data.csv

Contains environmental and physicochemical measurements associated with the PI experiments.

Variables include:

• reportName: identifier linking the observation to its cruise report,
• in_situ_temp: in situ water temperature (^oC).
• nitrate: nitrate concentration (mg m^-3).
• silicate: silicate concentration (mg m^-3).
• phosphate: phosphate concentration (mg m^-3).
• ammonia: ammonia/ammonium concentration (mg m^-3).
• PAR: photosynthetically active radiation (W m^-2).
• salinity: salinity (PSU).
• nitrite: nitrite concentration (mg m^-3).

pi-methodology-info-data.csv

Contains methodological information describing the sampling and experimental procedures associated with the PI experiments.

Variables include:

• reportName: identifier linking the observation to its cruise report,
• size_fraction: phytoplankton size fraction used in the experiment.
• light_bulb: light source inside the incubator.
• incub_duration: incubation duration (hour).
• incub_temp: incubation temperature (^o C).
• sampling_time: time of sample collection (HH:MM).

Linking the files

reportName provides a common identifier that can be used to associate observations and metadata among the four files. Missing measurements are represented by NA.

PI parameter estimates

Photosynthesis–irradiance fitted model parameters and associated statistical metrics are available from the corresponding published study [1] and are deposited on Zenodo (https://zenodo.org/records/16748102)

Citation

This database is described and analyzed in the publications below. The piCurve R package was used for the statistical analysis. If you use this database in your research, we kindly request that you cite the relevant publications.

1. Amirian, M. M., Devred, E., Clay, S., Finkel, Z. V., & Irwin, A. J. A Compilation of Marine Photosynthesis–Irradiance Data from ¹⁴C Incubation Experiments. Submitted to Earth System Science Data.
2. Amirian, M. M., Finkel, Z. V., Devred, E., & Irwin, A. J. (2025). Parameterization of photoinhibition for phytoplankton. Communications Earth & Environment, 6, 707. https://doi.org/10.1038/s43247-025-02686-3
   
   
3. Amirian, M. M., & Irwin, A. J. (2025). piCurve: An R package for modeling photosynthesis–irradiance curves. arXiv:2508.14321 [stat.AP]. https://doi.org/10.48550/arXiv.2508.14321