Some of the most common and abundant diatoms in Deserta Grande Island: 1- Nitzschia inconspicua; 2- Nitzschia valdestriata; 3- Nitzschia microcephala; 4- Aulacoseira cf. perglabra 5- Epithemia sorex; 6- Epithemia operculata; 7- Achnanthes brevipes var. intermedia; 8- Achnanthes coarctata; 9- Navicula vilaplanii; 10- Navicula cari; 11- Navicula sp.1; 12- Humidophila contenta; 13- Pseudostaurosira sp.1; 14- Planothidium frequentissimum; 15- Sellaphora nigri; 16- Navicula radiosafallax; 17- Caloneis molaris; 18- Pleurosira laevis; 19- Surirella ovalis; 20- Tryblionella apiculata 21- Navicula veneta; 22- Halamphora veneta; 23- Planothidium delicatulum; 24- Luticola mutica; 25- Halamphora paraveneta; 26- Fallacia pygmaea; 27- Denticula subtilis; 28- Pseudofallacia monoculata. Scale bar on picture 6 applies for all images, except picture 18.