Multi-scale observations of mangrove blue carbon ecosystem fluxes: The NASA Carbon Monitoring System BlueFlux field campaign

Abstract

The BlueFlux field campaign, supported by NASA’s Carbon Monitoring System, will develop prototype blue carbon products to inform coastal carbon management. While blue carbon has been suggested as a nature-based climate solution (NBS) to remove carbon dioxide (CO₂) from the atmosphere, these ecosystems also release additional greenhouse gases (GHGs) such as methane (CH₄) and are sensitive to disturbances including hurricanes and sea-level rise. To understand blue carbon as an NBS, BlueFlux is conducting multi-scale measurements of CO₂ and CH₄ fluxes across coastal landscapes, combined with long-term carbon burial, in Southern Florida using chambers, flux towers, and aircraft combined with remote-sensing observations for regional upscaling. During the first deployment in April 2022, CO₂ uptake and CH₄ emissions across the Everglades National Park averaged -4.9 ± 4.7 µmol CO₂ m⁻² s⁻¹ and 19.8 ± 41.1 nmol CH4 m⁻² s⁻¹, respectively. When scaled to the region, mangrove CH₄ emissions offset the mangrove CO₂ uptake by about 5% (assuming a 100 year CH₄ global warming potential of 28), leading to total net uptake of 31.8 Tg CO₂-eq y⁻¹. Subsequent field campaigns will measure diurnal and seasonal changes in emissions and integrate measurements of long-term carbon burial to develop comprehensive annual and long-term GHG budgets to inform blue carbon as a climate solution.