Pristine but metal-rich Río Sucio (Dirty River) is dominated by Gallionella and other iron-sulfur oxidizing microbes

• Published in: Extremophiles : life under extreme conditions Vol. 21; no. 2; pp. 235 - 243
• Main Authors: Arce-Rodríguez, Alejandro, Puente-Sánchez, Fernando, Avendaño, Roberto, Libby, Eduardo, Rojas, Leonardo, Cambronero, Juan Carlos, Pieper, Dietmar H., Timmis, Kenneth N., Chavarría, Max
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.03.2017; Springer Nature B.V
• Subjects: Acid mine drainage; Acidity; Bacteria; Biochemistry; Biomedical and Life Sciences; Biotechnology; Chemoautotrophic Growth - physiology; Costa Rica; Drainage systems; Gallionellaceae - physiology; Heavy metals; Human factors; Humans; Iron; Life Sciences; Microbial Ecology; Microbiological studies; Microbiology; National parks; Original Paper; Oxidation; Physicochemical properties; Rivers; Rivers - microbiology; Space life sciences; Stream pollution; Streams; Sulfur; Volcanic rocks; Water Microbiology; Water pollution; Costa Rica; Río Sucio; Braulio Carrillo National Park; spp; Acid-rock drainage; Costa Rica; “Ferrovum” spp; Gallionella spp
• ISSN: 1431-0651; 1433-4909
• DOI: 10.1007/s00792-016-0898-7

Whether the extreme conditions of acidity and heavy metal pollution of streams and rivers originating in pyritic formations are caused primarily by mining activities or by natural activities of metal-oxidizing microbes living within the geological formations is a subject of considerable controversy. Most microbiological studies of such waters have so far focused on acid mine drainage sites, which are heavily human-impacted environments, so it has been problematic to eliminate the human factor in the question of the origin of the key metal compounds. We have studied the physico-chemistry and microbiology of the Río Sucio in the Braulio Carrillo National Park of Costa Rica, 22 km from its volcanic rock origin. Neither the remote origin, nor the length of the river to the sampling site, have experienced human activity and are thus pristine. The river water had a characteristic brownish-yellow color due to high iron-dominated minerals, was slightly acidic, and rich in chemolithoautotrophic iron- and sulfur-oxidizing bacteria, dominated by Gallionella spp. Río Sucio is thus a natural acid-rock drainage system whose metal-containing components are derived primarily from microbial activities.