title: Pristine but metal-rich Río Sucio (Dirty River) is dominated by Gallionella and other iron-sulfur oxidizing microbes.
abstract: 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.
authors.affiliation: Institute of Microbiology, Technical University of Braunschweig, 38106, Brunswick, Germany.|Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124, Brunswick, Germany.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Arce-Rodríguez
authors.affiliation: Department of Molecular Evolution, Centro de Astrobiología (INTA-CSIC), Carretera de Ajalvir Km 4, Torrejón de Ardoz, 28850, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Puente-Sánchez
authors.affiliation: Centro Nacional de Innovaciones Biotecnológicas (CENIBiot), CeNAT-CONARE, San José, 1174-1200, Costa Rica.
authors.forename: Roberto
authors.initials: R
authors.lastname: Avendaño
authors.affiliation: Escuela de Química & Centro de Investigaciones en Productos Naturales (CIPRONA), Universidad de Costa Rica, Sede Central, San Pedro de Montes de Oca, San José, 11501-2060, Costa Rica.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Libby
authors.affiliation: Escuela de Química & Centro de Investigaciones en Productos Naturales (CIPRONA), Universidad de Costa Rica, Sede Central, San Pedro de Montes de Oca, San José, 11501-2060, Costa Rica.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Rojas
authors.affiliation: Centro de Investigaciones en Productos Naturales (CIPRONA), Universidad de Costa Rica, San José, 11501-2060, Costa Rica.|Centro de Investigación en Biología Celular y Molecular (CIBCM), Universidad de Costa Rica, San José, 11501-2060, Costa Rica.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Cambronero
authors.affiliation: Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124, Brunswick, Germany.
authors.forename: Dietmar H
authors.initials: DH
authors.lastname: Pieper
authors.affiliation: Institute of Microbiology, Technical University of Braunschweig, 38106, Brunswick, Germany.
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Timmis
authors.affiliation: Centro Nacional de Innovaciones Biotecnológicas (CENIBiot), CeNAT-CONARE, San José, 1174-1200, Costa Rica. max.chavarria@ucr.ac.cr.|Escuela de Química & Centro de Investigaciones en Productos Naturales (CIPRONA), Universidad de Costa Rica, Sede Central, San Pedro de Montes de Oca, San José, 11501-2060, Costa Rica. max.chavarria@ucr.ac.cr.|Centro de Investigaciones en Productos Naturales (CIPRONA), Universidad de Costa Rica, San José, 11501-2060, Costa Rica. max.chavarria@ucr.ac.cr.
authors.forename: Max
authors.initials: M
authors.lastname: Chavarría
mesh_terms: D052837:Chemoautotrophic Growth / Q000502:physiology*; D003364:Costa Rica; D043372:Gallionellaceae / Q000502:physiology*; D006801:Humans; D045483:Rivers / Q000382:microbiology*; D014871:Water Microbiology
keywords: Acid-rock drainage; Braulio Carrillo National Park; Costa Rica; Gallionella spp.; Río Sucio; “Ferrovum” spp.