Microbial ecology at the Rio celeste origin

Rio 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 colour. The river originates at the mixing point of two colourless streams, the acidic Quebrada Agria and the neutral Rio Buenavista. A previous work showed that the blue color is not caused by dissolved chemical species, but by the presence of suspended particles that originate when the colloidal silica present in Rio Buenavista aggregates due to the decrease in pH when the neutral river mixes with the acidic and aluminum-rich Quebrada Agria. We now present the microbiological characterization of Rio Celeste and its two tributaries.