Tropical cyclones cumulatively control regional carbon fluxes in Everglades mangrove wetlands (Florida, USA)

Abstract

Mangroves are the most blue-carbon rich coastal wetlands contributing to the reduction of atmospheric CO₂ through photosynthesis (sequestration) and high soil organic carbon (C) storage. Globally, mangroves are increasingly impacted by human and natural disturbances under climate warming, including pervasive pulsing tropical cyclones. However, there is limited information assessing cyclone’s functional role in regulating wetlands carbon cycling from annual to decadal scales. Here we show how cyclones with a wide range of integrated kinetic energy (IKE) impact C fluxes in the Everglades, a neotropical region with high cyclone landing frequency. Using long-term mangrove Net Primary Productivity (Litterfall, NPP_L) data (2001–2018), we estimated cyclone-induced litterfall particulate organic C (litter-POC) export from mangroves to estuarine waters. Our analysis revealed that this lateral litter-POC flux (71–205 g C m⁻² year⁻¹)—currently unaccounted in global C budgets—is similar to C burial rates (69–157 g C m⁻² year⁻¹) and dissolved inorganic carbon (DIC, 61–229 g C m⁻² year⁻¹) export. We proposed a statistical model (PULITER) between IKE-based pulse index and NPP_L to determine cyclone’s impact on mangrove role as C sink or source. Including the cyclone’s functional role in regulating mangrove C fluxes is critical to developing local and regional climate change mitigation plans.