Planktonic Microalgae in Recreational Fishponds of the Crato Municipality, Ceará State, Brazil

This study aimed to evaluate the occurring phytoplankton composition in the two recreational fishponds in Crato municipality, south of Ceará. Samples for the study were collected monthly, from June 2012 to March 2013, using plankton net and glass separator (20 μm), fixed with 4% formalin and deposited in the Botany Laboratory of the assets of Regional University of Cariri, where were made analysis and taxonomic identification. The phytoplankton community proved to be represented by 100 taxa belonging to five divisions: Chlorophyta which contributed 56% of total taxa, followed by Euglenophyta (18%), Cyanobacteria (16%), Bacillariophyta (7%) and Dinophyta (3% ). The Scenedesmaceae family presented the highest number of taxa (19) and Scenedesmus and Desmodesmus genres presented greater number of species. Desmodesmus comunis (Hegewald) Hegewald and Desmodesmus opoliensis (P. Hichter) Hegewald (Chlorophyta) and Aphanocapsa sp. (Cyanobacteria) were classified as dominant and other two named species of Chlorophyta abundant Desmodesmus armatus (R. Chodat) E. Hegewald and Scenedesmus producto-capitatus Schumula. As the frequency 10% were classified as very frequent, 14% frequent and the others too infrequent. 75% had average diversity and the community with equitable distribution of taxa. The set of information made in relation to the phytoplankton community characterized the ecosystems studied from meso to eutrophic.