The researchers studied carbon flux in Brazilian tropical savanna ecosystems using eddy covariance and inventory methods. Both methods gave similar estimates of carbon exchange, primary production, and total plant growth. Belowground plant growth was the biggest contributor to total growth, followed by aboveground litter and wood production. More water led to more carbon storage, but the effect varied between savanna types. The mixed grassland had lower productivity and carbon use efficiency compared to the Cerrado forest. The estimates from both methods matched well, increasing confidence in the productivity estimates for these ecosystems.