Yuncheng Salt Lake: A colorful "palette" that never fades for billions of years

This issue of the "Popular Science Talks about a Strong Country" column takes readers to the Yuncheng Salt Lake in Shanxi to explore the mystery of the formation of the colorful salt lake.

It is not uncommon for lake water to change color. For example, the "Dead Sea" in the Middle East, the "Rose Lake" in Senegal, Africa, and the "Pink Lake" in Hillier, Australia have all experienced this phenomenon. However, this magical lake is like a pot of "old soup". After hundreds of millions of years, it has not only not faded, but also has the same taste as before.

It is the largest lake in Shanxi Province - Yuncheng Salt Lake. Different from other salt lakes in the world, Yuncheng Salt Lake is colorful.

The Yuncheng Salt Lake in early winter is colorful and beautiful. Looking down from the sky, the salt fields in the lake are crisscrossed and dotted like a colorful "palette".

What secrets are hidden in the ancient Yuncheng Salt Lake? Why is it so colorful and ever-changing?

"Eternal Youth" is Mainly Caused by Two Types of Halophilic Organisms

Generally speaking, a salt lake refers to a lake with a salt content greater than 3.5% (35 g/L). Yuncheng Salt Lake is famous for its brilliant colors and its ever-changing appearance.

In fact, humans have already encountered Yuncheng Salt Lake more than 4,000 years ago. Salt crystallized under the sun, and people on the earth continued to collect it. Coupled with time and temperature, it quietly changed.

The colors of Yuncheng Salt Lake mainly include red, green, yellow, blue, etc. Its manifestation is the result of the interaction of multiple factors, mainly including biological factors, physical factors and chemical factors. Among them, biological factors are the main reason for the color change of salt lake.

Halophilic archaea and Dunaliella salina are two organisms that live in extreme saline environments, and each plays an important role. Halophilic archaea are mainly red in color, which is attributed to the red pigment they produce, bacterioerythrin. In the high-salt environment of Yuncheng Salt Lake, the massive reproduction of halophilic archaea combined with changes in light intensity and irradiation angle make the lake water appear in a variety of colors, including red, pink, and dark red.

Dunaliella salina grows in evaporation ponds of salt lakes and salt fields, and its optimal salt concentration is 20%. Under different growth conditions, Dunaliella salina has different colors: green when there are sufficient nutrients; orange-yellow under nitrogen deficiency; and yellow-green when there is a lack of phosphorus.

Not only that, when halophilic archaea and Dunaliella salt algae coexist, "red plus green" will form yellow. Different ratios of red to green will produce different colors.

Chemical factors play an important role in the formation of Yuncheng Salt Lake. The combination of different salinities and inorganic salt components is an important chemical basis for the colorful lake water.

A treasure trove of resources, both for sightseeing and practical use

As a gift from nature to mankind, Yuncheng Salt Lake is a treasure trove of resources. The extreme microorganisms it contains are not only a "scenery", but also a "practical product" that can be used in our daily lives.

In the treatment of food waste, various salt lake microbial strains with different enzyme activities can be compounded to make a composite bacterial agent for treating food waste. Due to the characteristics of salt lake microorganisms, this type of bacterial agent can effectively degrade high-salt food waste, providing a new method for the treatment of food waste in high-salt dietary areas in my country. Yuncheng Salt Lake microorganisms also play a big role in the degradation of organic pollutants.

In terms of scientific research, the research on microbial diversity of Yuncheng Salt Lake has made a breakthrough recently, and the first new genus-level species of Yuncheng Salt Lake, Yuncheng Salt Lake Bacillus, has been successfully isolated. This species not only represents the emergence of a new group of extreme microorganisms, but also has important academic value in microbial taxonomy. The relevant research results have been published in the latest issue of the international academic journal "Leewenhoek: International General Molecular Microbiology".

In terms of economic benefits, due to the special natural conditions, the microorganisms in Yuncheng Salt Lake have formed unique gene types, physiological structures and metabolic mechanisms, and are important materials for studying biological evolution, the origin of life and biodiversity.

In addition, as a type of microbial resource with great application prospects, salt lake microorganisms can produce many metabolites with special functions, which have important development and utilization value in the fields of food, medicine, papermaking and environmental protection, which is incomparable to ordinary microorganisms.

(The author Li Xin is the vice president of Yuncheng College, and Wang Chuanxu is the deputy director of the Shanxi Provincial Key Laboratory jointly built by the Yuncheng Salt Lake Ecological Protection and Resource Utilization Department and the city)

Further reading

When lake water meets black mud

Yuncheng Salt Lake, formerly known as Hedong Salt Lake, is located at the junction of Shanxi, Shaanxi and Henan provinces. It is the earliest salt lake developed and utilized in the world.

Black mud is a unique resource of Yuncheng Salt Lake. It is rich in minerals and trace elements and has the effects of sterilization, anti-inflammation, whitening and skin care. When lake water is mixed with black mud, the lake water will appear gray or black. When sunlight shines on the lake surface, the lake water will reflect a blue luster.

Check in at the Salt Lake

Qinghai Chaka Salt Lake: "Mirror of the Sky"

Chaka Salt Lake, known as the "Mirror of the Sky", is located in Chaka Town, Ulan County, Haixi Prefecture, Qinghai Province. It is a brine lake where both solid and liquid coexist. The lake covers an area of ​​105 square kilometers and is rich in "green salt".

The beauty of Chaka Salt Lake lies in its profound history and splendid culture. Here, you can experience the wonder of walking on the lake, watch the salt flowers through the clear lake water, and go to the Salt Culture Museum to "collect" green salt across thousands of years.

Barkol Lake in Xinjiang: Half salty and half fresh

Barkol Lake is a plateau saltwater lake, formerly known as Pulehai. It is located in Barkol Kazakh Autonomous County, Hami City, Xinjiang Uygur Autonomous Region, with an area of ​​about 113 square kilometers.

There is a north-south sand bank in Barkol Lake, which divides the lake into two parts, east and west. The East Lake is rippling with blue waves, while the West Lake is silvery white. The reason is that Barkol Lake is mainly replenished by the surrounding ice and snow meltwater and surface runoff, and most rivers flow into the East Lake, so the salinity is relatively low, belonging to a slightly salty lake. The West Lake is a famous salt lake because the sand bank blocks the water exchange, and the lake water has a higher salinity.

Qinghai Chaerhan Salt Lake: the world's second largest salt lake

The Qaidam Basin in Qinghai Province is home to my country's largest "plateau emerald", the Qarhan Salt Lake, which is also the place with the highest "salt content" in my country.

Compared with the exquisite Chaka Salt Lake, the Qarhan Salt Lake, as the world's second largest salt lake and Asia's largest salt lake, is vast and majestic, with a total area of ​​more than 5,800 square kilometers. Its real heritage lies in the various salt mine resources hidden under this blue wave, with a total reserve of up to 60 billion tons, mainly including potassium salt, magnesium, sodium, lithium, boron, iodine, chlorine and other minerals.