biostudies-literatureArce-Rodriguez AEuropean Research CouncilSwedish University of Agricultural SciencesEuropean Union’s Horizon 2020Universidad de Costa RicaEuropean Union's Horizon 20206https://www.ebi.ac.uk/biostudies/studies/S-EPMC9854191biostudies-literatureUnknown18(1)<h4>Background</h4>Río Celeste ("Sky-Blue River") is a river located in the Tenorio National Park (Costa Rica) that has become an important hotspot for eco-tourism due to its striking sky-blue color. A previous study indicated that this color is not caused by dissolved chemical species, but by formation of light-scattering aluminosilicate particles at the mixing point of two colorless streams, the acidic Quebrada Agria and the neutral Río Buenavista.<h4>Results</h4>We now present microbiological information on Río Celeste and its two tributaries, as well as a more detailed characterization of the particles that occur at the mixing point. Our results overturn the previous belief that the light scattering particles are formed by the aggregation of smaller particles coming from Río BuenavistaEnvironmental microbiomeOut of the blue: the independent activity of sulfur-oxidizers and diatoms mediate the sudden color shift of a tropical river.PMC9854191ERC250350Pry01-1747-2022VI 809-B6-524892961Castellon ECambronero JCArce-Rodriguez APieper DHPuente-Sanchez FLibby EAvendano RBertilsson SChavarria MVargas MfalseOut of the blue: the independent activity of sulfur-oxidizers and diatoms mediate the sudden color shift of a tropical river.<h4>Background</h4>Río Celeste ("Sky-Blue River") is a river located in the Tenorio National Park (Costa Rica) that has become an important hotspot for eco-tourism due to its striking sky-blue color. A previous study indicated that this color is not caused by dissolved chemical species, but by formation of light-scattering aluminosilicate particles at the mixing point of two colorless streams, the acidic Quebrada Agria and the neutral Río Buenavista.<h4>Results</h4>We now present microbiological information on Río Celeste and its two tributaries, as well as a more detailed characterization of the particles that occur at the mixing point. Our results overturn the previous belief that the light scattering particles are formed by the aggregation of smaller particles coming from Río Buenavista2023-01-01T00:00:00Z2023 Jan2026-05-28T16:27:33.438Z2024-11-19T16:25:09.719ZS-EPMC98541913665860410.1186/s40793-023-00464-2