Predictive capacity of phytoplankton functional groups in a tropical wetland (Pantanal, Brazil)

Capacidade preditiva dos grupos funcionais fitoplanctônicos em uma área úmida tropical (Pantanal, Brasil)

Abstract:

Aim  Considering the prediction capacity of the phytoplankton community, this study analyzed the environmental factors that influenced the Reynolds Functional Groups (RFG) in hydrological period (dry, rising, flood and ebb) and the type of environment (river and lake), in the Pantanal wetland (Brazil). We expect environmental variability to reflect in the predictive ability of phytoplankton to describe habitat types and flood-pulse periods, where the seasonality (high and low water) are the main drivers of phytoplankton distribution, biomass and functional groups.

Methods  We collected environmental variables and phytoplankton quarterly in 2018 from 18 points in the flood, rising, dry and ebb.

Results  recorded 425 taxa distributed into 13 taxonomic groups and 20 RFGs, of which nine groups (D, F, J, G, K, MP, N, S1, and P), represented by green algae, cyanobacteria, and diatoms, had the highest predictive value, characterizing lentic environments as rich in nutrients and light, and the Paraguay River as having a lower availability of these resources for phytoplankton. The variation in biomass was related to the phases of the flood pulse, being higher in low waters in floodplain lakes and smaller in high waters in the river.

Conclusions  Thus, the predictability of the phytoplankton community structure was directly associated with the environment types in the Pantanal wetland and with the homogenization or isolation of the systems promoted by the flood pulse that acted as drivers of phytoplankton distribution, biomass and functional groups.

Keywords:
environmental variability; microalgae; wetlands; predictive ability