There Is a Lake That Changes Color

High atop the Kelimutu volcano on the Indonesian island of Flores, a truly unique geological spectacle awaits. Three separate crater lakes lie side-by-side, yet each possesses its own distinct and shifting personality. Local folklore gives these lakes evocative names tied to the afterlife: Tiwu Ata Bupu (Lake of Old People), Tiwu Nuwa Muri Koo Fai (Lake of Young Men and Maidens), and Tiwu Ata Polo (Enchanted or Bewitched Lake). For generations, these waters were believed to be the final resting place for souls, with their colors reflecting the mood of the departed spirits.

The dramatic color shifts are not supernatural (Review) but the result of complex and dynamic geochemistry. The volcano remains active, and gases like sulfur dioxide and hydrogen sulfide continuously seep up from fumaroles beneath the lakes. These gases react with the water and its rich concentrations of dissolved minerals, such as iron and manganese. This chemical process, known as oxidation-reduction, alters the state of the minerals, changing how they absorb and reflect sunlight. Because each lake has its own unique connection to the volcano's plumbing and its own mineral balance, they change color independently and on their own unpredictable timetable.