2.2.3. Pantanal Site

The study was conducted at the Brazilian Northern Pantanal Wetland (BR-Npw) flux tower (Figure 1) located approximately 35 km SE of Pocone, Mato Grosso, Brazil (16◦2953.71"S: 56◦2445.91"W; 120 m altitude). The site is part of a research station managed by the Federal University of Mato Grosso (UFMT) within a national reserve managed by the Brazilian Social Service of Commerce (SESC Pantanal) [28,29]. According to Köppen classification, the regional climate is Aw, which is defined as a hot and wet climate with rainfall in the summer and dry in the winter [30]. The accumulated precipitation varies from 800 to 1500 mm/year [31,32]. The air temperature ranges between 29 and 32 ◦C (maximum) and between 17 and 20 ◦C (minimum) [33,34]. The soil type in the region is classified as Dystric Gleysol [35] with an average concentration of 429 g/kg of sand, 254 g/kg of silt, and 317 g/kg of clay, mean soil organic matter (SOM) (0–0.10 m depth) of 17 g/kg and a soil pH of 4.7 [36]. The vegetation of the site is typical of "scrub" forests in

the region, with a mean leaf area of 7.4 m<sup>2</sup> m<sup>−</sup><sup>2</sup> and a mean height of 6 m [37], dominated by *Combretum lanceolatum*, Phol (Combretaceae), a common species found on the riverbanks of the Pantanal region [38]. Vascular or semi-aquatic plants such as *Thalia geniculata* and *Nymphaea* sp. occur in more open areas [39]. These are dense forests that are referred to as "hyperseasonal" because they are subjected to both seasonal flooding and drought [40].

Our data were collected from 1 January 2015 to 31 December 2016. Micrometeorological variables were measured 20 m aboveground, close to the eddy covariance sensors. Air temperature (*Ta*, ◦C) and relative humidity (*RH*, %) were measured using a thermohygrometer (HMP45AC, Vaisala Inc., Woburn, MA, USA). Precipitation (*Ppt*, mm) was measured 2 m above the ground using a micrometeorological station (WXT520, Vaisala Inc., Helsinki, Finland) installed in an open area to avoid interception by the tower or tree canopy. The flood stage was determined by measuring water levels (*WL*) above the ground at the study site. These inundation levels (±1%) were measured along with water temperature (±0.3 ◦C) using a CTD-10 (Decagon Devices Inc., Pullman, WA, USA, ± 0.05% full scale at 20 ◦C) in 2015 and 2016. Due to instrument malfunction in 2014, the data for this year are not available. The start of each flood cycle began with the first reading of standing water at the site and ended when sensors indicated the absence of standing water. These flood cycles were then compared to the stage of the Cuiaba River collected by the RPPN-SESC Pantanal park rangers (pers. comm.) approximately 1 km away.
