Screening of thermophilic microalgae and cyanobacteria from Tunisian geothermal sources

Six geothermal sources distributed in the north and south of Tunisia were examined monthly during the period from August 2009 to April 2010, in order to determine mats communities' abundance and biodiversity. Twenty-seven taxa, belonging to three taxonomic groups: Cyanobacteria, Bacillariophyta and Chlorophyta were identified. The Cyanobacteria group was more prominent with a particular dominance of two genera Phormidium and Spirulina. Their maximum abundance was respectively 919.2 +/- 44.2 10(3) cells ml(-1) and 652.8 +/- 92.6 10(3) cells ml(-1). The dominant mats morphologies in prospected sites were filaments. Results demonstrate that biodiversity values ranged between 0.16 and 1.15 bits. cell(-1). The spatial variations showed that the regional specificity in mats species biodiversity and abundance between north and south were not signified, whereas, each site had specific species. Temporal variations showed an increase of microalgae and prokaryotes abundance in the dry season. (C) 2013 Elsevier Ltd. All rights reserved.