This study evaluated CO2 flux from soils and pneumatophores of Avicennia germinans mangrove trees subjected to nitrogen and phosphorus fertilization versus an unfertilized control with a basin mangrove ecosystem. Data were collected twice, once in the summer (June 2020) and once in the winter (November 2020) and will be used to help develop a carbon budget for basin mangroves on Sanibel Island, Florida. These data were presented as part of an M.S. Thesis (Florida Atlantic University, Natalie T. Faron, 2021), entitled “The impact of nutrient loading on the soil and root respiration rates of Florida mangroves”.