Research note: Preliminary report on the extreme endolithic microbial consortium of ‘Pailas Frías’, ‘Rincón de la Vieja’ Volcano, Costa Rica

Abstract

Flakes detached from rocks of a volcano rivulet at ‘National Park Rincón de la Vieja Volcano’, Guanacaste, Costa Rica, revealed a green layer 2–3 mm deep into the rock matrix. Analysis by scanning electron microscopy showed a complex assemblage of microorganisms, beginning with a thin layer of Cyanidium and followed by diatoms of the genus Pinnularia and curved and straight bacteria. To our knowledge, this is the first description of an endolithic microbial consortium dominated by diatoms, and also the first report of endolithobionts from volcanic rocks in a tropical area.