Bianca Trevizan Segovia

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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(More)
We evaluated the relative importance of bottom-up and top-down mechanisms in controlling the density of a heterotrophic nanoflagellate (HNF) community in a shallow lake (Guaraná Lake) on the Paraná River floodplain (State of Mato Grosso do Sul, Brazil). Samples were taken monthly from March 2007 through February 2008, in three strata (surface, middle and(More)
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., microbial: bacteria, flagellate, and ciliate; and grazing: zooplankton and phytoplankton) were(More)
Recent studies reported comparatively lower heterotrophic bacteria (HB) abundances in tropical regions, indicating that factors involved in bacterial losses could be more relevant in the tropics. Heterotrophic nanoflagellates (HNF) are considered the main predators of HB in aquatic ecosystems, and one should expect higher abundances in the tropics because(More)
With its network of lotic and lentic habitats that shift during changes in seasonal connection, the tropical and subtropical large-river systems represent possibly the most dynamic of all aquatic environments. Pelagic water samples were collected from Brazilian floodplain lakes (total n = 58) in four flood-pulsed systems (Amazon [n = 21], Araguaia [n = 14],(More)
Dispersal potential of organisms is directly related to the hydrological connectivity among habitats. We investigated if the relative role of the environmental and spatial components in structuring the heterotrophic flagellates depends on the degree of hydrological connectivity. Samplings were performed in aquatic environments of the Paraná River(More)
Modern metagenomic environmental DNA studies are almost completely reliant on next-generation sequencing, making evaluations of these methods critical. We compare two next-generation sequencing techniques - amplicon and shotgun - on water samples across four of Brazil's major river floodplain systems (Amazon, Araguaia, Paraná, and Pantanal). Less than 50%(More)
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(More)
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