Beggiatoa ssp. have similar relative abundances in
Camarma, and Las Matas-PenÄ ascales plants, and higher
than those observed in Boadilla plant. S. natans also presented signi®cant differences by the plant, but the Boadilla
plant values were higher than those observed in the others
plants, and all of them were lower than those observed for
Beggiatoa ssp.