Controls on mangrove forest‐atmosphere carbon dioxide exchanges in western Everglades National Park

We report on net ecosystem production (NEP) and key environmental controls on net ecosystem exchange (NEE) of carbon dioxide (CO₂) between a mangrove forest and the atmosphere in the coastal Florida Everglades. An eddy covariance system deployed above the canopy was used to determine NEE during January 2004 through August 2005. Maximum daytime NEE ranged from −20 to −25 μmol (CO₂) m⁻² s⁻¹ between March and May. Respiration (R_d) was highly variable (2.81 ± 2.41 μmol (CO₂) m⁻² s⁻¹), reaching peak values during the summer wet season. During the winter dry season, forest CO₂ assimilation increased with the proportion of diffuse solar irradiance in response to greater radiative transfer in the forest canopy. Surface water salinity and tidal activity were also important controls on NEE. Daily light use efficiency was reduced at high (>34 parts per thousand (ppt)) compared to low (