*2.4. Flux Partitioning*

Through CO2 flux (NEE) partitioning, we obtained: gross primary production (GPP) and ecosystem respiration (Reco). For the Cerrado and Pantanal sites, NEE is given as a proxy of the turbulent flow. At the other sites, NEE was composed of turbulent flow and storage. We used the flux partitioning method based on nighttime hours [46]. Since GPP = 0 at the nighttime period, NEE is given as:

$$NEE = \mathcal{R}\_{\text{eco}\prime} \text{ for nighttime hours} \tag{1}$$

$$NEE = R\_{\varepsilon\infty} - GPP,\text{ for daytime hours}\tag{2}$$

where *Reco* (μmol m<sup>−</sup>2s−2) is the sum of autotrophic and heterotrophic respiration. *Reco* and *GPP* were calculated using the online tool provided by the Max Planck Institute for Biogeochemistry (http://www.bgc-jena.mpg.de/~MDIwork/eddyproc/, accessed on 2 February 2022).

Diurnal corrections of missing NEE data were modeled based on daytime data using the common rectangular hyperbolic light-response curve model [47,48]:

$$NEE = \frac{\boldsymbol{\alpha} \cdot \boldsymbol{\beta} \cdot \boldsymbol{R}\_{\mathcal{S}}}{\boldsymbol{\alpha} \cdot \boldsymbol{R}\_{\mathcal{S}} + \boldsymbol{\beta}} + \gamma \tag{3}$$

where *α* (μmol C J−1) is light-use efficiency and represents the initial slope of the lightresponse curve; *β* (μmol C m<sup>−</sup>2s−1) is the maximum CO2 absorption rate of the canopy at light saturation; *γ* (μmol C m<sup>−</sup>2s−1) is ecosystem respiration and *Rg* (W m<sup>−</sup>2) is global radiation. GPP was calculated as:

$$\text{GPP} = \text{NEE} + \text{R}\_{\text{qCO}} \tag{4}$$

To provide a better comparison with literature data (more in situ studies), we calculated Ecosystem WUE, calculated as:

$$\text{WUE} = \text{GPP}/\text{ET} \tag{5}$$

where ET (mm) is evapotranspiration.
