## 4 Discussion
In the Pampa, there were no differences in mean \(\mathrm{SIF_{d}}\) at the biome level with the Atlantic Forest, Cerrado, and Pantanal and analyses of mean differences in SIF among vegetation classes did not reveal any contrasts with the other biomes. However, the Pampa was unique having positive correlations with climate variables compared to other biomes, which likely result from the cooler and more temperate climate (i.e., lower values of \(\mathrm{T_{can}}\), \(\mathrm{T_{air}}\), and VPD; Figures S2-S4) in the Pampa compared to the other biomes [124]. The stark contrast of \(\mathrm{T_{can}}\) and \(\mathrm{T_{air}}\) ranges in the Pampa (from 286K to 311K) to the ranges in the Caatinga and Cerrado (from 297K to 319K) paired with lower VPD values in the Pampa then the Caatinga and Cerrado highlight the contrast in this Brazilian biome. The Pampa grassland dominate the vegetation and its' phytogeography in in contrast to the biomes to its North. It is for these reasons the Pampa was expected to display different behavior, which the satellite-based SIF from OCO-2 was able to capture. It was expected that the seasonality analysis may reveal a more distinct pattern in the Pampa, such as shorter length of seasons, yet, aside from the most uniform lengths of seasons among the vegetation classes (maximum difference in length of seasons = 30), this was not the case in this study. Also unique to the Pampa biome, we showed that \(\mathrm{T_{can}}\) in the Pampa is the most correlated with all vegetation classes' SIF, except DBF. The opposite is true for \(\mathrm{DBF\ SIF_{d}}\), where \(\mathrm{T_{can}}\) is the least correlated, however, the low number of samples of DBF in the Pampa and their lack of representation in the time series consistently make these results less reliable. Based on mean \(\mathrm{SIF_{d}}\) analysis, the Pantanal would not appear to have clear distinctions from the other biomes. No difference in biome level mean \(\mathrm{SIF_{d}}\) for the Pantanal was found with the Atlantic Forest, Cerrado, and Pampa and, like other biomes mean SIF for EBF in the Pantanal was significantly higher than all other classes in the Pantanal. Yet analyses of mean \(\mathrm{SIF_{d}}\) relationships to \(\mathrm{T_{can}}\), \(\mathrm{T_{air}}\)and VPD and seasonality analysis revealed important distinctions in the Pantanal. Unique to the Pantanal, we found no significant correlations with T\({}_{\text{can}}\), T\({}_{\text{air}}\), and VPD. This may be indicative of the unique patterns of evapotranspiration in this biome that is a seasonally flooded wetland, whose climate and phytogeographical distribution is unique to Brazil and the world, emphasized by its status as a UNESCO world heritage site [109; 124; 143]. Values of T\({}_{\text{can}}\), T\({}_{\text{air}}\) and VPD for the Pantanal reach the highest values of all the biomes in the study, the mean SIF\({}_{\text{d}}\) length of season is longer than other biomes, and vegetation class total integrated SIF\({}_{\text{d}}\) is higher for all classes except SAV in the Pantanal compare to other biomes. Furthermore, seasonality analysis shows that total integrated SIF\({}_{\text{d}}\) of EBF in the Pantanal exceeds total integrated SIF\({}_{\text{d}}\) of EBF in the Amazon due to a large seasonal pulse of EBF in the Pantanal. The degree to which the total integrated SIF\({}_{\text{d}}\) in the Pantanal exceeded the other biomes' total integrated EBF prompted us to investigate outliers and anomalies carefully, yet none were found with these methods. These results suggest that these unique conditions give rise to vegetation responses we do not yet understand due to a lack of research in this region. To better understand SIF\({}_{\text{d}}\), productivity, and the climate influences on SIF\({}_{\text{d}}\) in the Pantanal, more detailed climate and SIF\({}_{\text{d}}\) data are needed.