Mangroves as a Source of Greenhouse Gases to the Atmosphere and Alkalinity and Dissolved Carbon to the Coastal Ocean: A Case Study From the Everglades National Park, Florida

Mangroves in the Everglades National Park release significantly more greenhouse gases and dissolved carbon to the atmosphere and coastal ocean than previously estimated. A study found that the Shark River estuary emits substantial amounts of CO2, methane (CH4), and nitrous oxide (N2O) while exporting dissolved inorganic carbon (DIC) and organic carbon (DOC) at rates several times higher than sediment burial. Notably, most DIC is exported as total alkalinity (TAlk), which persists in the ocean for millennia, acting as a long-term carbon sink. The research used spatial surveys and time-series measurements to quantify these fluxes, linking them to porewater inputs via radon-222 tracking. These findings suggest that future blue carbon budgets must account for both greenhouse gas emissions and alkalinity/dissolved carbon export from mangroves.

Reithmaier, G. M. S., Ho, D. T., Johnston, S. G., & Maher, D. T. (2020). Mangroves as a Source of Greenhouse Gases to the Atmosphere and Alkalinity and Dissolved Carbon to the Coastal Ocean: A Case Study From the Everglades National Park, Florida. Journal of Geophysical Research: Biogeosciences, 125(12). Portico. https://doi.org/10.1029/2020jg005812