# WUE and CO2 Estimations by Eddy Covariance and Remote Sensing in Different Tropical Biomes
## 5 Conclusions  
In this study, we presented data on the seasonal variations of energy fluxes, climatic variables, GPP, ET and WUE for different tropical biomes in Brazil. Furthermore, correlations between observed carbon exchange data and remotely sensed data were also assessed. Results showed that GPP and ET responses to meteorological variables (solar radiation, air temperature, precipitation and VPD) are in phase, suggesting that this meteorological variability controls photosynthesis and ET in a similar fashion on a monthly scale, despite both direct and inverse relationships having been found depending on the type of environment. Based on our results, our study concludes that inconsistent MODIS GPP estimates for some months and sites indicate that the parametrizations used in the MOD17A2H GPP algorithm (such as FPAR) may need to be enhanced over certain land covers in order to improve estimates. WUE in the studied sites varied annually from 0.95 to 5.79 gC kg\({}^{-1}\) H\({}_{2}\)O, with minimum and maximum values differing from usually found values for other environments worldwide. This study will aid future studies regarding the influence of global warming and water stress on carbon and water fluxes in similar tropical forests.  
**Author Contributions:** In the present research article the individual contributions was followed by: Conceptualization, G.B.C., K.R.M., C.M.S.e.S. and B.G.B.; methodology, G.B.C., K.R.M., L.B.V., G.V.A., P.R.M., T.V.M. and R.R.F.; software, G.B.C., K.R.M., L.B.V., G.V.A., T.V.M. and R.R.F.; validation, J.G.M.d.S., T.T.A.T.N., P.R.M., H.G.G.C.N., L.V.P. and R.A.S.S.; formal analysis, G.B.C., K.R.M., C.M.S.e.S., J.G.M.d.S., B.G.B., A.S.S., C.P.O., T.R.R., J.B.S., W.A.G., and S.C.; investigation, G.B.C., K.R.M., T.R.R., H.J.D., C.M.S.e.S. and B.G.B.; resources, G.B.C., B.G.B. and H.J.D.; data curation, G.B.C., K.R.M., T.R.R., J.B.S., L.B.V. and G.V.A.; writing--original draft preparation, G.B.C., K.R.M., J.G.M.d.S., C.M.S.e.S. and B.G.B.; writing--review and editing, T.V.M., T.T.A.T.N., P.R.M., C.P.O., A.S.S., T.R.R., J.B.S., C.P.O., W.A.G., S.C. and M.U.G.A.; visualization, G.B.C., K.R.M. and C.M.S.e.S.; supervision, G.B.C., K.R.M., C.M.S.e.S. and T.R.R.; project administration, H.J.D., C.M.S.e.S. and B.G.B.; funding acquisition, G.B.C., H.J.D., C.M.S.e.S. and B.G.B. All authors have read and agreed to the published version of the manuscript.  
**Funding:** The authors are also thankful to the Coordination for the Improvement of Higher Education Personnel (CAPES) for the postdoctoral funding granted to KRM and to the National Council for Scientific and Technological Development (CNPq) for the research productivity grant of C.M.S.e.S. (Process n\({}^{\circ}\) 303802/2017-0), the financial support of CNPq, through undergraduate research project (PIBIC-UFQPA for L.B.V. and G.V.A.) and the project NOWDCCB: National Observatory of Water and Carbon Dynamics in the Caating Biome (INCT-MCTI/CNPq/CAPES/FAPs 16/2014, grant: 465764/2014-2) and (MCTI/CNPq N\({}^{\circ}\) 28/2018, grant 420854/2018-5). The APC was funded by PAPCIQ-UFQPA.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors are thankful to AMERIFLUX and LBA project for provide free access to the EC data used in this study.  
**Conflicts of Interest:** The authors declare no conflict of interest and the funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.