Who put red at the bottom of this Colombian river?

In some images of Caoo Cristales, red surfaces appear to have been painted underwater. The first explanation to look for is neither a touch-up nor a substance poured into the river. An aquatic plant, often called Macarenia clavigera, contributes to these striking colors.

The National Natural Parks of Colombia describe this spectacle in the La Macarena region, within the department of Meta. Light and aquatic vegetation contribute to the appearance of the landscape. The colors observed vary with the conditions; the stream does not offer an identical image at each visit.

The nickname Five Color River is an invitation to watch, not a guarantee of five regular stripes. Above all, it does not mean that all water suddenly changes its nature. The effect comes from a living environment visible through it. What one admires as a palette is also a fragile habitat.