Estructura y composición de la comunidad de cianobacterias bentónicas de un arroyo de montaña mediterráneo, el arroyo Mediano (Madrid)

Abstract

Sixteen benthic cyanobacterial species were identified in the Mediano stream (Comunidad de Madrid), among them, 4 species are Chroococcales, 9 Oscillatoriales and 3 Nostocales. Seven "common species" were defined as important members of this benthic community, since they were observed in more than 25 % of all examined samples, the other 9 species showed a sporadic distribution, thus, they have been described as "rare species". Identified "common species" were Chamaesiphon minutus, Chroococcus minor, Chroococcus minutus, Synechococcus elongatus, Leptolyngbya nostocorum, Phormidium aerugineo-caeruleum and Nostoc carneum. There are some variations in community structure: while Chroococales keep constant in all defined stretches, Oscillatoriales increase their presence and Nostocales decrease in medium and low stretches. Taxonomical studies have been carried out using two different methodologies: observation of fixed and cultured samples. From the total cyanobacterial community, 37 % (all belonging to "rare species"), were only seen in cultured samples. Therefore, we propose that, the combined use of both methodologies is highly useful to achieve a cyanobacterial community analysis. Additionally, it also allows an help in taxonomic identification for some species. © Asociación Española de Limnología, Madrid.