Interannual hydrological variations and ecological phytoplankton patterns in Amazonian floodplain lakes

Abstract

Amazonian aquatic environments are complex, and their interaction promotes heterogeneous environments that turn difficult the development of patterns to describe them. We evaluated if interannual variation in the physical-chemical structure and the phytoplankton community promote environmental and biological contrasted conditions between similar hydrological periods. Amazonian floodplain lakes have different environmental and biological responses in similar water periods due to the interannual variation. Phytoplankton community structure has differences between periods, but these differences do not necessary promote dissimilarities. Most of the phytoplankton species belong to the same functional groups. The composition of species and functional groups between sample units inside lakes is variable and may have or not significant differences in dissimilarity, but both periods are equally heterogeneous. Beta diversity has shown that the replacement of species and functional groups causes a great level of variation between sites, which maintain a high heterogeneity between periods. These variations have different responses for different scales turning a difficult task the interpretation of patterns for these environments. Hence, scale and interannual variability are factors that need to be carefully considered when setting standards to describe the ecological dynamics of floodplain lakes in the Amazonian system.

Phytoplankton Genera Structure Revealed from the Multispectral Vertical Diffuse Attenuation Coefficient

“…After the taxonomy analysis for both RW and FW was carried out, the results indicate that the phytoplankton community in the Curuai lake was composed of 97 genera (Supplementary Material Table S1), corroborating the high biodiversity reported for Amazon floodplain lakes [74,75]. Cyanophyceae was the class with the highest biovolume, followed by Bacillariophyceae, Cryptophyceae, and Chlorophyceae.…”

“…In this study, we explored the relationship between the underwater light field and phytoplankton taxonomy. As is well-known, the Amazon lakes present a pattern of cyanobacterial dominance in the phytoplankton community [74,75], and also it is not uncommon for lakes on the Amazon floodplain to have high turbidity [76], and a high eutrophic (nutrient-rich) state [77], especially during the rising and flushing periods.…”

Ecological Connectivity in Two Ancient Lakes: Impact Upon Planktonic Cyanobacteria and Water Quality

“…Furthermore, the higher cyanobacteria nestedness in relation to other phytoplankton taxa found in our study might also show the cyanobacteria's ability to adapt to unfavourable conditions. Kraus et al [49] studying hydrological variations and ecological phytoplankton patterns in Amazonian floodplain lakes, explained the absence of phytoplankton dissimilarities to the ability of cyanobacteria to adapt to contrasted ecological conditions. No dispersal limitation and high levels of stochastic cyanobacterial establishment with a weak influence of phosphorus has been found in peri-Alpine lakes [3].…”

Unraveling Flooding Dynamics and Nutrients’ Controls upon Phytoplankton Functional Dynamics in Amazonian Floodplain Lakes

“…During this period also, POC was very low and TOC was almost entirely in DOC form. As mentioned in Moreira-Turc et al [42], contrasting with the rising period when DOC is mainly imported from the Amazon River, high DOC lability is expected during the flushing period because it is mainly originating from phytoplankton production. Higher labile DOC concentration also helps to provide nutrients for the development and establishment of the cyanobacteria community [16][17][18].…”