Dormant phytoplankton in shallow lake sediments: cyanobacteria, green algae, diatoms and phytoflagellates are recruited Patrícia Iatskiu, Felipe Morais Zanon, Márcio José Silveira, Luciane Maria Nogueira, Susicley Jati, et al. Hydrobiologia, 2026 Dormant phases, also known as resting stages, are a life-history trait observed in several groups of microalgae. These stages are formed in response to adverse environmental conditions and can remain viable in the sediment for extended periods, germinating and rejoining the photosynthetic community once conditions become favorable. This experimental study investigated how environmental factors (light, temperature and desiccation) influence the recruitment (germination) of microalgal resting stages. The experiment was conducted in two phases. In the first, sediment from a natural shallow lake was subjected to extreme desiccation under three temperature regimes (17, 25 and 34°C). In the second, water was added to the sediment and recruitment was monitored under different light intensities. A total of 35 phytoplankton taxa, including cyanobacteria, diatoms, green algae and phytoflagellates with distinct ecological traits, germinated during the experiment. Analysis of variance (ANOVA) indicated that 34°C reduced the recruitment, while community composition remained stable across treatments. These findings highlight the taxonomic and functional diversity of the recruited microalgae and underscore the ecological importance of resting stages in linking the benthic and planktonic phases of phytoplankton communities.
Phytoplankton functional groups evidence environmental differences in a temperate floodplain. Felipe Morais Zanon, Patrícia Iatskiu, Michael Joseph Lemke, Luiz Felipe Machado Velho, Luzia Cleide Rodrigues, et al. Oecologia Australis, 2021 Floodplain environments have high biodiversity and provide many ecosystem services maintained by the flood pulses. The phytoplankton is essential to the functioning of these ecosystems, acting upon primary productivity and biogeochemical cycles. We evaluated phytoplankton in a river-lake flood system (Illinois River floodplain-USA) during a hydrological cycle and compared the taxonomic (species) and functional (morphologic-based functional groups – MBFG) approaches. As expected, greater species richness was registered in the river and higher biovolume in the lake, as well as the predominance of different MBFGs in each environment. Furthermore, seasonality drove richness and biovolume temporal variation due to the higher water levels during spring. The MBFG IV (i. e. without specialized traits), V (phytoflagellates) and VI (diatoms) were more important for richness and biovolume in both environments. We reinforce the fundamental role of the hydrodynamics characteristics, with higher phytoplankton biovolume values in the lake. Using MBFG resulted in a better explanation to the phytoplankton-environment relationship. Constant water column mixture and high turbidity selected species with traits (e.g. small size, presence of silica) specifically adapted to these conditions.
A protection area in a subtropical floodplain influenced the phytoplankton taxonomic and functional diversity Alfonso Pineda, Aline Caroline Magro de Paula, Patrícia Iatskiu, Geovani Arnhold Moresco, Yasmin Rodrigues Souza, et al. Oecologia Australis, 2020 Protection areas favor diversity as they decrease the impact of anthropic disturbance on biological communities. Testing its effects on diverse biological communities is a pivotal step to understand how different trophic levels react to such management and conservation strategies. Here, we used data collected from 1993 to 2018 from a subtropical floodplain to evaluate the effect of the installation of a protection zone on the taxonomic and functional diversity of the phytoplankton community. We showed that the installation of the park had a positive effect on the aquatic community, mainly related to the decrease of cyanobacteria dominance and to the increase of phytoplankton functional groups. However, our results also suggested that dynamics occurring in a scale beyond the park seemed to influence key factors for the phytoplankton community, such as transparency and nutrient concentrations. Thus, although we showed that a compensatory measure had a positive effect on biodiversity, we believe that the establishment of protection zones must also consider and integrate the management of the river basin where the areas to be protected are located.
