The images above show Lake Urmia on April 23, left, and July 18, right. Seasonal precipitation and climate patterns change the lake from a green hue in the spring to a shade of red in the summer months.

(NASA Earth Observatory )

Over the past few decades, Iran’s salty Lake Urmia has shrunk rapidly and become even saltier. In addition to its disappearing act, the lake has also been undergoing spectacular color changes in the warmer seasons.

According to NASA, as Lake Urmia grows saltier, . Images captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured a transition in the lake’s color between April and July.

On April 23, the water was green, but by July 18, it looked more like a like a lake full of red wine. Encrusted with salt deposits, the shoreline appears white.

These color changes are common in the spring and early summer thanks to seasonal precipitation and climate patterns, NASA reports.

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Spring, northwestern Iran’s wettest season, usually brings peak rainfall in April. Snow on nearby mountains in the watershed also melts in the springtime. The combination of the two sends a surge of fresh water into Lake Urmia in April and May. By July, that influx of water has tapered off and levels begin to drop.

While the fresh water in the spring lowers salinity levels, the lake typically becomes saltier as summer heat and dryness come into play. This is also when the microorganisms show their colors.

According to NASA, scientists believe these organisms are likely two main groups: a family of algae called Dunaliella and a family of bacteria known as Halobacteriaceae.

(NASA Earth Observatory )

“Previous research suggests that Dunaliella salina is responsible for reddening of Lake Urmia,” University of Stuttgart scientist Mohammad Tourian told NASA. “In the marine environment, Dunaliella salina appears green; however, in conditions of high salinity and light intensity, the microalgae turns red due to the production of protective carotenoids in the cells.”

Other scientists believe Halobacteriaceae is the main driving force behind the lake’s reddening. These bacteria release bacteriorhodopsin, a red pigment that absorbs light and turns it into energy for the bacteria. When populations are large enough, the bacteria can stain bodies of water.

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Lake Urmia has shifted between green and red several times in recent years –a trend that suggests a red lake could become even more common. However, drought and intensive water diversion for farming have limited the amount of fresh water making it to the lake.

“The lake volume has been decreasing at an alarming rate of 1.03 cubic kilometers [0.25 cubic miles] per year,” said Tourian. “The results from satellite imagery revealed a loss of water extent at an average rate of 220 square kilometers [85 square miles] per year, which indicates that the lake has lost about 70 percent of its surface area over the last 14 years.”

Covering an area that varies from 2,000 to 2,300 square miles, .

However, combined with the shrinking, built to shorten travel time between Urmia and Tabriz, according to the Guardian.