Tidal variability of CO2 and CH4 emissions from the water column within a Rhizophora mangrove forest (New Caledonia)

CO₂ and CH₄ emissions from the water column within a Rhizophora mangrove forest in New Caledonia exhibit significant tidal variability, driven primarily by flow/ebb cycles, water column thickness, and neap/spring tides. Emissions were inversely proportional to water column depth, with higher rates observed during ebb tides due to increased residence time over the forest floor, leading to progressive enrichment of the water column. Spring tides further amplified emissions, suggesting enhanced soil-water exchange and electron acceptor renewal. δ¹³CO₂ values indicated mixing between CO₂-enriched pore waters and lagoon waters. This study highlights that such emissions cannot be overlooked in mangrove carbon budgets, emphasizing the need for tidal dynamics to be integrated into future assessments.

Jacotot, A., Marchand, C., & Allenbach, M. (2018). Tidal variability of CO2 and CH4 emissions from the water column within a Rhizophora mangrove forest (New Caledonia). Science of the Total Environment, 631-632, 334–340. https://doi.org/10.1016/j.scitotenv.2018.03.006