Benthic cyanoprocaryota and microalgae (Chlorophyceae and Bacillariophyceae) dominant in rivers of Costa Rica. Samples taken from 17 Costa Rican rivers were analyzed for benthonic Cyanoprocaryota and microalgae (Chlorophyceae and Bacillariophyceae). The samples were observed under the light microscope for species identification, and then cultured with three artificial media: Z8, BG11 and BG110. In the field samples, four genera of Cyanoprocaryota were found; the most common were Phormidium sp. and Scenedesmus dimorphus (Chlorophyceae), there were also five genera and 52 species of Bacillariophyceae. In the isolates, the dominant species were Cyanoprocaryota (Aphanocapsa hyalina, Cyanobium diatomicola, Hapalosiphon fontinalis, Leptolyngbya boryana, Leptolyngbya, Pseudophormidium tenue and Xenococcus sp.), and Clorophyceae (Chlorella vulgaris, Chlorococcum infusionum, Dilabiphilum printzii, Scenedesmus dimporphus), while Bacillariophyceae (Navicula minima, N. seminulum and Aulacoseira) were less frequent. Rev. Biol. Trop. 56 (Suppl. 4): 221-235. Epub 2009 June 30.
Keywords: microalgae, tropical rivers, culture, diatoms, Cyanoprocaryota, Chlorophyceae, Bacillariophyceae, limnology, Costa Rica