Daghetu Lake, located in the Baideng Qaran Desert in Alsha League of Inner Mongolia, China, has water that constantly changes its appearance. This lake is one of five unique natural attractions in the region. Depending on the changing seasons, its water can look either pale pink or dark red.
The main reason for this color variation lies in the high content of salt, minerals, and specific microorganisms in the lake's water. The water of Daghetu differs significantly from ordinary fresh water due to its increased salinity and different chemical structure. It is in such conditions that specific microorganisms can inhabit. When their population increases, the pigments they produce give the water a pink or red hue.
Scientific research conducted at the lake has allowed for the study of changes in the water and its composition related to the weather. According to these studies, during the summer period when temperatures rise, certain microorganisms begin to multiply actively. Among these organisms are species that synthesize red or pink pigments, which explains the lake's redder or pinker hue in summer.
During the summer, the water in the lake heats up. At the same time, the conditions become suitable for the growth of some microorganisms along with salt and other minerals, leading to a change in water color. It is important to note that this does not mean that artificial red dye is added to the lake; the change occurs due to the interaction of small living organisms and chemical substances present in the water, allowing the color to change with the seasons.
Changes in weather conditions lead to a decrease in the volume of water in the lake. As the amount of water decreases, the concentration of salt and other minerals increases. Scientific investigations have identified the presence of sodium chloride crystals (common salt) and a mineral called hematite. Hematite has a reddish or reddish-brown color, and this sediment accumulated at the bottom of the lake can affect the color of the water and surface. Furthermore, fluctuations in water conditions and microorganism populations also contribute to the color change.
The Baideng Qaran Desert, where Daghetu Lake is located, is not only vast sand dunes. There are many other lakes between these dunes. According to UNESCO, there are about 144 interdune lakes in this area, meaning lakes formed between sand dunes. Most of these bodies of water have saline water. The Baideng Qaran Desert is located on the Alashan Plateau in northwestern China. UNESCO classifies it as the third largest desert massif in China. The height of some large sand dunes here reaches approximately 460 meters.
In 2024, the Baideng Qaran region—Sand Towers and Lakes—was included in the UNESCO World Heritage List. A characteristic feature of this area is the high sand dunes and the lakes situated among them. Daghetu Lake is part of this natural system. The color change of this lake is not the result of any mysterious anomaly. The color of the lake is determined by the combined effect of the salt level in the water, minerals, temperature, microorganisms, and seasonal changes.