Astronaut snaps salty, pink Valentine’s Day ‘heart’ shining in Argentina — Earth from space
QUICK FACTS
Where is he? Salinas Las Barrancas, Argentina [-38.75293078, -62.95083234]
What’s in the photo? A heart-shaped pink salt lake
Who took the photo? An anonymous astronaut aboard the International Space Station (ISS)
When was it taken? January 16, 2024
This lovey-dovey astronaut photo, first released by NASA on Valentine’s Day 2025, highlights a heart-shaped pink salt lake in Argentina.
Salinas Las Barrancassometimes known as Laguna de Salinas Chicas, is a shallow salt lake located in the plains of the Argentine province of Buenos Aires, approximately 53 kilometers west of the port city of Bahía Blanca.
The lake bed is approximately 10 km in diameter at its widest point and regularly fills with water after heavy rains. However, this liquid quickly evaporates due to the region’s intense sun, exposing the crystal-rich salt pans that are exploited by the local population, according to NASA Earth Observatory.
In this photo, the lake appears almost empty due to its lighter pink hue, which is likely the result of an imbalance between Dunaliella saline — a species of dark red algae that thrives in most of Earth’s salt lakes — and other microorganisms in water, according to a 2022 study Smithsonian magazine article about similar colored salt lakes.
“We have rainy seasons, where salinity levels decrease [because there’s more water in the ponds]. When there is less salt, the Dunaliella survives and the ponds appear brownish red,” Lilliam Casillas Martinezmicrobiologist at the University of Puerto Rico in Humacao, told Smithsonian magazine when explaining the colors of similar salt ponds in Puerto Rico. “During the dry season it gets really salty. Dunaliella dies and archaea and bacteria take over. Then it turns pink, pink, pink.”
Locals extract up to 330,000 US tons (300,000 metric tons) of salt from the Salinas Las Barrancas plains twice a year, between the region’s rainy seasons, according to a 2019 study of the lake. by the Argentinian news site La Nación. Most of this salt is replenished during the next major rains, and experts predict that mining there will remain viable for 5,000 years.
Mining is largely carried out using traditional processes, including scraping salt from the surface of flats with hand-held tools. Workers should take precautions to protect their eyes and skin from the sun’s intense rays reflecting off the pure white crystals. “Salt is part of your life,” Chepo, a local worker, told La Nación (translated from Spanish). “For someone else, it’s a hellish place, but for me, the salt flats are my home, you get used to not being able to see.”
The high salinity of Salinas Las Barrancas means that few things can survive there. However, according to the Earth Observatory, salt-resistant vegetation grows around the edges of the lake.
It is also home to colorful birds, including bright yellow cardinals (Gubernatrix cristata) and Chilean flamingos (Phoenicopterus chilensis). These birds feed on tiny crustaceans rich in carotenoids, organic pigments synthesized by plants, algae and bacteria.
These specific carotenoids come from Dunaliella The algae that the tiny crustaceans feed on naturally produce red and yellow pigments. Without these pigments in their diet from birth, the two species of birds would have different colors; Yellow cardinals are naturally red, while flamingos are born grayish white.
A photo taken by a Bahamas astronaut in 2016 shows a series of bright, undulating sandbars partly carved out by a coral reef. The image also reveals subtle differences in the ocean surface caused by a steep, hidden ocean dropoff.
A 2021 astronaut photo shows a triple valley system in Argentina’s Los Glaciares National Park, where a huge climate-resistant glacier, a pristine turquoise lake and a murky green “river” come together at a single point.
A satellite image from 2025 shows a series of ghostly ice swirls carved into the surface of Lake Michigan by strong winds during an extreme cold snap that covered Chicago in a blanket of snow.
