Heart-Shaped Pink Lake in Argentina Captured by Astronauts from Space

A striking image captured by an astronaut aboard the International Space Station (ISS) and released by NASA on Valentine’s Day 2025 reveals a heart-shaped salt lake in Argentina. The unusual formation, known as Salinas Las Barrancas, or Laguna de Salinas Chicas, presents a captivating visual phenomenon and offers insight into the dynamic interplay of climate, geology, and biology.

A Heart-Shaped Wonder in Argentina

Salinas Las Barrancas is located in the Buenos Aires province of Argentina, approximately 33 miles (53 kilometers) west of Bahía Blanca. The lakebed spans roughly 6 miles (10 km) at its widest point. It’s a shallow body of water that regularly fills with rainfall, but the intense regional sunlight quickly causes evaporation, leaving behind expansive salt flats.

Did You Know? Locals mine up to 330,000 U.S. Tons (300,000 metric tons) of salt from the flats of Salinas Las Barrancas twice a year, between rainy seasons.

The Science Behind the Pink Hue

The photograph, taken on January 16, 2024, shows the lake with a lighter-pink hue, suggesting a lower water level. This color variation is likely due to a shift in the balance between Dunaliella salina, a species of dark-red algae, and other microorganisms within the water. According to a 2022 Smithsonian magazine article, when salinity decreases with increased water, Dunaliella salina thrives, resulting in a brownish-red color. Conversely, during drier periods and higher salinity, the algae dies off, allowing archaea and bacteria to proliferate and turn the water pink.

Expert Insight:

Expert Insight: The color changes in salt lakes like Salinas Las Barrancas demonstrate the sensitivity of these ecosystems to environmental factors. Fluctuations in water levels and salinity directly impact the microbial communities that inhabit them, highlighting the interconnectedness of biological and geological processes.

The lake’s salt is actively mined by local workers, who traditionally scrape the crystals from the surface using hand tools. This labour requires precautions to protect skin and eyes from the intense sunlight reflecting off the salt. As one local worker, Chepo, told Argentine news site La Nación, “The salt becomes part of your life.”

A Sustainable Resource

Despite ongoing extraction, experts predict that salt mining at Salinas Las Barrancas will remain viable for another 5,000 years, as the salt is replenished with each rainfall. The lake also supports some salt-resistant vegetation around its edges and provides a habitat for wildlife, including vibrant yellow cardinals and bright-pink Chilean flamingos. These birds obtain their distinctive colors from carotenoids found in the algae and crustaceans they consume.

Frequently Asked Questions

Where is Salinas Las Barrancas located?

Salinas Las Barrancas is located in the Buenos Aires province of Argentina, roughly 33 miles (53 kilometers) west of the port city of Bahía Blanca.

Who captured the image of the heart-shaped lake?

The image was taken by an unnamed astronaut on board the International Space Station (ISS).

What causes the pink color of the lake?

The pink color is influenced by the presence and activity of Dunaliella salina algae and other microorganisms, with the shade varying based on salinity levels and water depth.

What role does the lake play in the local community, and how might changing environmental conditions impact its future?