TIDAL AND LUNAR VARIABILITY IN SOIL GREENHOUSE GAS FLUXES IN A BRAZILIAN MANGROVE FOREST

Mangroves are valuable coastal ecosystems known to sequester carbon at high rates compared to other tropical forests. Greenhouse gas (GHG) emissions affect the carbon balance in these forests, but there is limited information on the temporal variability in these fluxes along tidal and lunar cycles. We conducted high-frequency daily measurements in an urban mangrove forest in southeast Brazil for 14 days measuring soil GHG fluxes (CO2 and CH4) following a static closed opaque chamber technique using a LI-COR LI-7810 analyzer. Overall, we observed average flows of 65.15±30.49 mmol/m2/day for CO2 and 0.97±1.43 mmol/m2/day for CH4. Both gases showed daily variation in flux, with marginal influences of tidal regime for CO2 flux. During the ebb tide, the CO2 flux was slightly higher (69.56±26.15 mmol/m2/day) than during the flood tide (60.95±33.64 mmol/m2/day). The CH4 flux did not showed differences among ebb (1.16±1.87 mmol/m2/day) and flood tide (0.78±0.75 mmol/m2/day). Further, the CH4 flux was directly associated with the temperature inside the chamber. When extrapolating to the total radiative balance (GWP100), the CH4 fluxes potentially reduce in 43% the carbon burial in the mangrove forests. Total soil GHG emissions were equivalent to 14.70±8.62 Mg CO2e/ha/year, which represents an emission of 17645 Mg CO2e/year for the entire mangrove forest area in the study site.

Presentation Preference: Oral

Primary Presenter: Gabriel Coppo, Universidade Federal do Espirito Santo (coppogabriel@gmail.com)

Authors:

Gabriel Coppo, Universidade Federal do Espírito Santo  (coppogabriel@gmail.com)

André Vassoler, Universidade Federal do Espírito Santo  (andrevassoler2001@gmail.com)

Carla Pacheco, Universidade Federal do Espírito Santo  (carlafrechiani@yahoo.com.br)

Fernanda Maria Alves, Universidade Federal do Espírito Santo  (fernanda.m.alves@edu.ufes.br)

Priscila Demier, Universidade Federal do Espírito Santo  (priscila.demier@edu.ufes.br)

Maressa Costa, Universidade Federal do Espírito Santo  (maressacosta31@gmail.com)

Tiago Ferreira, Universidade de São Paulo  (toferreira@usp.br)

Angelo Bernardino, Universidade Federal do Espírito Santo  (angelo.bernardino@ufes.br)