Data for Plant community shapes ecosystem carbon sink strength and methane offset in subtropical coastal brackish marshes

Dataset overview This dataset accompanies a study of carbon dioxide (CO2) exchange andmethane (CH4) emissions in three monodominant brackish-marsh plantcommunities in the Shanyutan wetland of the Min River estuary,subtropical China. The study period is April 2023 to March 2025. Theplant communities are Phragmites australis, Fimbristylis dichotoma, andScirpus mariqueter. Dataset structure The dataset is organized into folders and numbered Excel files. Folderand file names below follow the structure shown in the prepared dataset.Before publishing, verify that every listed name exactly matches theuploaded item. Folders - Raw_instrument_data_CO2_CH4_2023-2025/ - Contains instrument-export data for CO2 and CH4 measurements. - Subfolders: F. dichotoma/, P. australis/, and S. mariqueter/. - These are the original instrument records. Preserve the original measured values and instrument-export structure.- Monthly_CO2_flux_model_calculations_2023-2025/ - Contains CO2 flux model calculations for ecosystem respiration (ER) and gross primary productivity (GPP). - Files are organized by plant community and study period: April 2023–March 2024 (23.4-24.3) and April 2024–March 2025 (24.4-25.3). - The folder contains files for F. dichotoma, P. australis, and S. mariqueter, with ER and GPP files for each community and period.- 08_model_parameters/ - Contains model parameter files: - ER_T_model_parameters.xlsx - GPP_PAR_model_parameters.xlsx - PAR_Fitting_Params.xlsx Numbered data files - 01_Environmental Conditions.xlsx — Environmental-condition data associated with the flux measurements. Refer to the worksheet headers for variables, temporal resolution, and units.- 02_instant_CO2_flux.xlsx — Instantaneous CO2 flux data or calculations.- 03_high_frequency_CO2_flux_data.xlsx — High-frequency CO2 flux data or estimates.- 04_daily_flux_CO2_flux_estimates.xlsx — Daily CO2 flux estimates.- 05_Instant_monthly_CH4_flux.xlsx — Instantaneous and/or monthly CH4 flux data. Consult the worksheet headers to distinguish observation-level records from monthly summaries.- 06_seasonal_CH4_offset.xlsx — Seasonal estimates of the fraction of net CO2 uptake offset by CH4 emissions.- 07_carbon_sink.xlsx — Carbon-sink and/or CO2-equivalent balance estimates used in the manuscript.- 09_CH4_plot_level_flux_calculations_2023-2025.xlsx — Plot-level CH4 flux calculation records, including concentration-change rates, fit statistics where available, chamber information, instantaneous flux, and daytime/nighttime emission calculations.- 10_Daily_flooding_characteristics_2023-2025.xlsx — Daily flooding or inundation characteristics used to describe tidal exposure.- 11_Sediment_properties.xlsx — Sediment property measurements associated with the study sites.- 12_Daily_NEE_tidal_correction_results_2023-2025.xlsx — Daily net ecosystem exchange (NEE) estimates after tidal correction. This is processed data, not raw instrument output.- 13_Instantaneous_CO2_flux_calculations_2023-2025.xlsx — Instantaneous CO2 flux calculations. Plant communities and terminology - F. dichotoma refers to Fimbristylis dichotoma.- P. australis refers to Phragmites australis.- S. mariqueter refers to Scirpus mariqueter.- GPP means gross primary productivity.- ER means ecosystem respiration.- NEE means net ecosystem exchange.- CH4 means methane; CO2 means carbon dioxide. Data interpretation and reuse - Variable names and units are provided in worksheet column headers or instrument-export headers.- Raw instrument exports are distinguished from calculated fluxes, model parameters, tidal-correction results, and other derived estimates.- Blank cells indicate values that were missing or unavailable in the supplied source files. They should not be interpreted as zero unless explicitly stated in the relevant worksheet or manuscript.- Consult the manuscript’s Methods section for details of chamber measurements, flux calculations, environmental-response models, tidal correction, temporal upscaling, and CO2-equivalent accounting.- The files are provided in Microsoft Excel (.xlsx) format. Repository information Repository: Zenodo Dataset DOI: To be added after the dataset ispublished and a DOI is registered. Permanent URL: To be added afterpublication. Final upload check Before publishing, confirm that the filenames in this README exactlymatch the uploaded files. Remove any entries for files not included inthe final dataset, and update the repository DOI and URL afterpublication.