Brazil's Lençóis Maranhenses National Park forms seasonal freshwater lagoons

A vast stretch of sand along Brazil’s northeastern coast, often mistaken for a barren desert, transforms each year into a network of freshwater lagoons. The dune field, part of the state of Rio Grande do Norte, receives a seasonal influx of rainwater that pools in depressions created by shifting sands, forming temporary lakes that support a range of aquatic life. Scientists note that the phenomenon is driven by a combination of the region’s unique topography and the seasonal rainfall pattern that peaks during the austral summer.

Ecologists are studying the lagoons’ role in sustaining local biodiversity, as they provide breeding grounds for fish, amphibians, and migratory birds that rely on the brief but productive wet season. The area also attracts ecotourists and researchers interested in the delicate balance between arid and aquatic ecosystems. While the dunes appear inhospitable, the annual freshwater influx underscores the dynamic nature of coastal landscapes and highlights the importance of preserving these fragile habitats.