Exploring Microbial Diversity and Heavy Metals Resistance in an Active Volcanic Geothermal System

URBIETA M.S.; LIMA A.; MASSELLO F.; LOPEZ BEDOGNI G.; GIAVENO A.; DONATI E.R.

Extreme Environments: Unique Ecosystems ? Amazing Microbes

CRC PRESS

Año: 2021; p. 49 - 61

The Copahue geothermal system is an extreme environment with unique characteristics associated with two main factors: the still-active Copahue volcano and the geochemical composition, rich in sulfur and iron compounds. It presents two distinctive parts: the ponds and the acidic river Río Agrio. Natural acidic rivers are uncommon environments and particularly Río Agrio has been scarcely explored. The origin of the river is associated to two geothermal sources close to the crater of Copahue volcano at almost 3,000 m a.s.l.; consequently, its physicochemical conditions are markedly extreme with temperatures of 70-30°C and pH from 0.5-2, depending on the volcanic activity and the input of the snowmelt. After emerging from the rock, the river runs down the volcano hill receiving tributary courses of snowmelt; however, its acidity does not change throughout its course. The microbial biodiversity of Río Agrio is quite rich, dominated by acidic-iron, and sulfur-oxidizing bacteria and archaea. Besides, the microorganisms that inhabit it have an outstandingly high tolerance to heavy metals and metalloids. In this chapter, we summarize our work in the assessment and characterization of the extreme microbial biodiversity of Río Agrio, its relationship with the biogeochemistry of the environment, and its tolerance to toxic elements.