Phytoplankton functional groups in a subtropical Brazilian reservoir: responses to impoundment

Abstract

The discontinuity in rivers caused by the construction of reservoirs disrupts the longitudinal gradient and decreases the natural connectivity of lotic systems. We evaluated the dynamics of Reynolds functional groups (RFGs) in response to the formation of a subtropical reservoir, in relation to the environmental changes between the pre-and post-impoundment periods. We hypothesized that the disruption of longitudinal connectivity and the changes in the light and mixing regime after the impoundment would directly influence the phytoplankton functional structure. Significant changes in the light and mixing regimes were observed after the impoundment, with the formation of a lacustrine zone, influencing the dynamics of RFGs. Fourteen RFGs were recorded. RFG C (diatoms) dominated in the pre-impoundment period. In the post-impoundment period, RFGs C, P (diatoms), and J (chlorophyceans) codominated with the highest mean values of biovolume. RFGs MP, N, H1, W2, F, E, A, W1, B, X1, and S1 contributed relatively little to the biovolume, although with higher values in the post-impoundment period. RFGs F and S1 were recorded only after the impoundment. This study revealed the important roles of physical processes and nutrients in the spatial and seasonal gradient, and in the selection of phytoplankton functional groups in a subtropical reservoir.

Environmental and spatial processes influencing phytoplankton biomass along a reservoirs‐river‐floodplain lakes gradient: A metacommunity approach

“…Many of these factors vary spatially and temporally along the longitudinal axes of the river and are related to spatial patterns in hydrology, geomorphology, resource gradients, and river regulation (Vannote, Minshall, Cummins, Sedell, & Cushing, ; Ward & Stanford, ). In addition, negative influences of the reservoirs on the phytoplankton community in the downstream stretch decrease phytoplankton richness and biomass due to sedimentation processes (Bovo‐Scomparin, Train, & Rodrigues, ; de Souza et al., ; Soares, Huszar, & Roland, ), supporting species sorting as a mechanism structuring the phytoplankton community. Thus, it is important to recognise that regional and local factors can coexist and be reflected in the metacommunity structure (Driscoll & Lindenmayer, ; Spasojevic, Copeland, & Suding, ), as evidenced in our study.…”

Driving Factors and Dynamics of Phytoplankton Community and Functional Groups in an Estuary Reservoir in the Yangtze River, China

“…The functional groups theory can be highlighted with two ideas: (1) a species belonging to a functionally well-adapted group can tolerate the limiting environment of factor deficiency more successfully than a less adapted species; (2) a light, P, or C or N constrained habitat is more likely to be populated by species with the appropriate adaptation properties [20]. Although phytoplankton functional groups have been described for lakes, this approach has also been applied to certain types of reservoirs in various regions [12,16,[22][23][24]. This has proved to be a useful method of evaluating ecological status in reservoir ecosystems.…”

Morphology-based functional groups as the best tool to characterize shallow lake-dwelling phytoplankton on an Amazonian floodplain

“…Many studies have used phytoplankton functional groups in analyses of different systems around the world, such as reservoirs (e.g., Rangel et al, 2016;de Souza et al, 2016), rivers (e.g., Abonyi et al, 2012;Devercelli and O'Farrell, 2013), and floodplain lakes (e.g., Stanković et al, 2012a,b;Stević et al, 2013). Floodplain systems consist of flooded areas along the main river that periodically oscillate between the aquatic-terrestrial transition zone (ATTZ).…”