title: The effect of seasonality on the structure of rotifers in a black-water shallow lake in Central Amazonia.
abstract: Rotifers have often been used as indicators of sudden changes in physical and chemical features of the aquatic environment. Such features vary greatly during flood pulse events in small lakes connected to major floodplains. However, few are the studies that investigate the consequences of the flood pulse in rotifer species composition, abundance, richness and diversity, especially in Amazonian lakes. We analyzed samples from a small blackwater lake of an "igarapé" connected permanently to the Negro river, in Central Amazonia. Samples were taken twice a year for two years, comprising flooding and receding periods of the flood pulse. Rotifer abundance increased significantly after draught events, and electrical conductivity and turbidity were intrinsically related to such variation. Species composition also changed from flooding to receding periods. Some taxa, such as Brachionus zahniseri reductus and Lecane remanei were restricted to receding periods, while Brachionus zahniseri, Brachionus gillardi and Lecane proiecta were only present during flooding. A shift in the composition of rotifer families was observed from one period to another, showing the effect of renewing waters of the flood pulse. These results suggest that the flood pulse acts as a driving force and stressing condition, considerably altering rotifer community dynamics, either changing species composition or decreasing abundance.
authors.affiliation: Departamento de Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro/ UFRJ, Rio de Janeiro, RJ, Brasil.
authors.forename: Clarice C
authors.initials: CC
authors.lastname: Nova
authors.affiliation: Departamento de Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Goiás /UFG, Goiânia, GO, Brasil.
authors.forename: Vanessa G
authors.initials: VG
authors.lastname: Lopes
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro/ UNIRIO, Rio de Janeiro, RJ, Brasil.
authors.forename: Leonardo Coimbra E
authors.initials: LC
authors.lastname: Souza
authors.affiliation: Departamento de Ecologia e Recursos Marinhos, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro/ UNIRIO, Rio de Janeiro, RJ, Brasil.
authors.forename: Betina
authors.initials: B
authors.lastname: Kozlowsky-Suzuki
authors.affiliation: Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello, Rio de Janeiro, RJ, Brasil.
authors.forename: Talita A A
authors.initials: TA
authors.lastname: Pereira
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro/ UNIRIO, Rio de Janeiro, RJ, Brasil.
authors.forename: Christina W C
authors.initials: CW
authors.lastname: Branco
mesh_terms: D000818:Animals; D001938:Brazil; D005618:Fresh Water; D060106:Lakes; D011156:Population Density; D011157:Population Dynamics; D012403:Rotifera / Q000145:classification*; D012621:Seasons