The water of the Bacalar Lagoon, on the east coast of Mexico’s Yucatán Peninsula, is as pure as glacial ice. It contains scant organic material: some of its oldest inhabitants are oligotrophic microorganisms, so called for their minimal diet. As a result, the lagoon puts on a spectacular display in the sunlight. It’s said that there are seven distinct shades of blue in the water, from deep-sea indigo to sunset violet. In English, Bacalar is sometimes called the Lagoon of Seven Colors; its original name in Mayan, Siyan Ka’an Bakjalal, translates roughly to “place surrounded by reeds where the sky is born.”
