Taxonomy and ecology of order Surirellales (Bacillariophyceae) in tropical reservoirs

Krysna Stephanny Morais, Elaine Rodrigues Bartozek, Stéfano Zorzal-Almeida, Denise Campos Bicudo, Carlos Eduardo de Mattos Bicudo

Resumo


Abstract: Aim: Aim of this study was to record the diatom species of order Surirellales present in the surface sediments of tropical reservoirs with environmental (pH, total phosphorus, and total nitrogen) and spatial predictors. Methods: Samplings were carried out in 31 reservoirs between 2009 and 2014. Water samples were collected in the summer and winter along the reservoir vertical profile, and their water column mean results were used to characterize each sampling site. We measured water transparency, euphotic zone, depth, pH, dissolved oxygen, total nitrogen, and total phosphorus. Surface sediments samples were collected only during the winter saving the top 2 cm sections for diatom analyses. A partial RDA was preformed between species abundance (response matrix) and environmental and spatial variables (predictor matrices). Results: 14 species of Surirellales were identified from the surface sediment samples, five of them being identified only at the genus level. Overall, partial RDA showed that the species distribution is constrained by both environmental and spatial predictors. Species were mainly ordinated in relation to pH and light availability. Conclusion: Our results demonstrated that the Surirellales species revealed preferences to low nutrient concentrations, neutral to slightly acidic waters, and higher light availability values. Moreover, Surirellales showed some degree of geographical distribution, suggesting that both environmental and spatial factors are important for their species distribution.


Palavras-chave


surface sediment; Stenopterobia; Surirella; Brazil.

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