Quantification of aquatic greenhouse gas emissions from the Biebrza River channel and floodplain

The data base show three sheets. 1. Montlhy Emission factor: Refers to the average of the CO2 and CH4 of the fluxes measurements with the chamber durign 2024-2025. 2. Daily average (2024-2025):FluxCal (Zhao, 2019) was used to estimate GHG fluxes from concentration measurements in the field during considering atmospheric pressure and temperature within the chamber. Then the arithmetic mean was calculated for CO2 daily emissions and the geometric mean for CH4. 3. Estimations (2015-2025): In order to calculate the estimated emissions of CH4 and CO2 from the floodplain area, the daily flooded area was calculated. The area was determined by incorporating water level data and the empirical equation developed by Grygoruk et al. (Grygoruk et al., 2013), which relates the water level in the Burzyn gauge to the total area of the floodplain. The following formula was applied to calculate the estimated daily GHG emissions over the study period (2015–2025):ECO2,CH4=A·EF where ECO2 and CH4 (Tg·year-1) are the estimated emissions of CO2 or CH4, A is the floodplain area (ha), and EF (t·ha-1·day-1) is the emission factor of CO2 and CH4