Experimental evaluation of microplastic consumption by using a size-fractionation approach in the planktonic communities.

The increasing amount of plastic particles introduced into continental aquatic environments has drawn the attention of researchers around the globe. These particles can be assimilated by a wide range of aquatic organisms, from microorganisms to fish, causing detrimental effects on trophic webs. Using an experimental approach, we investigated the effect of microplastic particles of different sizes on the planktonic trophic chain by sampling natural plankton communities from a lake located in the Upper Paraná River floodplain, Brazil.

Microeukaryotic Communities Associated With the Seagrass Zostera marina Are Spatially Structured.

Epibiotic microorganisms link seagrass productivity to higher trophic levels, but little is known about the processes structuring these communities, and which taxa consistently associate with seagrass. We investigated epibiotic microeukaryotes on seagrass (Zostera marina) leaves, substrates, and planktonic microeukaryotes in ten meadows in the Northeast Pacific. Seagrass epibiotic communities are distinct from planktonic and substrate communities.

Protist Biodiversity and Biogeography in Lakes From Four Brazilian River-Floodplain Systems.

The biodiversity and biogeography of protists inhabiting many ecosystems have been intensely studied using different sequencing approaches, but tropical ecosystems are relatively under-studied. Here, we sampled planktonic waters from 32 lakes associated with four different river-floodplains systems in Brazil, and sequenced the DNA using a metabarcoding approach with general eukaryotic primers. The lakes were dominated by the largely free-living Discoba (mostly the Euglenida), Ciliophora, and Ochrophyta.

Common and Rare Taxa of Planktonic Ciliates: Influence of Flood Events and Biogeographic Patterns in Neotropical Floodplains.

After much discussion about the cosmopolitan nature of microbes, the great issue nowadays is to identify at which spatial extent microorganisms may display biogeographic patterns and if temporal variation is important in altering those patterns. Here, planktonic ciliates were sampled from shallow lakes of four Neotropical floodplains, distributed over a spatial extent of ca. 3000 km, during high and low water periods, along with several abiotic and biotic variables potentially affecting the ciliate community.

Anthropogenic disturbances influencing ciliate functional feeding groups in impacted tropical streams.

Anthropogenic disturbances change the trophic structure of streams, ultimately affecting ecosystem functioning. We investigated the effects of human disturbances, mainly organic pollution, on ciliate functional feeding groups (FFG) in 10 tropical streams near agricultural and urban habitats, in the dry and rainy seasons. We hypothesised that the organic pollution would affect the ciliate composition and that the richness and abundance of ciliate FFG would be associated with different disturbances, such that an increase in the load of organic matter would result in an increase in the percentage of bacterivores ciliates, while streams with low organic matter concentration and wide canopy openness will determine a higher contribution of algivorous ciliates.

The role of microorganisms in a planktonic food web of a floodplain lake.

Food webs include complex ecological interactions that define the flow of matter and energy, and are fundamental in understanding the functioning of an ecosystem. Temporal variations in the densities of communities belonging to the planktonic food web (i.e.