Tengiz

Tengiz means "sea" or "big lake" in the Turkic languages. And the reservoir of the same name, located in the Akmola region in northern Kazakhstan, justifies its name at first glance.:

The area is about 1,590 km2 (may vary depending on the water level, which varies greatly).
The length is about 75 km.
The width is up to 40 km.
The maximum depth is small, about 7.75 m.
The average depth is 2.5 m.
The coastline is 470 km long.
The height above sea level is 304 m.

For the steppe regions of Kazakhstan, such vast water areas are a real treasure, but the water from the lake is unsuitable for irrigation or drinking. It is bitterly salty. This property of Lake Tengiz is due to the fact that its waters have no outflow — they have been in the basin for years, or rather, for centuries, pulling easily soluble compounds from the steppe salt marsh. The salinity of the reservoir is unstable, it varies from 50 to 200 grams of salt per liter of water. The most common mineral found in the waters of the lake is mirabilite, or Glauber's salt. Its content makes the waters of Tengiz twinned with the spa mineral springs in Karlovy Vary and Marienbad. The scientific name of Glauber's salt is ten—anhydrous sodium sulfate crystallohydrate. White crystals of this substance are used in medicine.

In the absence of fresh water, humans could hardly survive on the shores of Tengiz, and no fish species are found here either (rare carcasses washed up on land come here from the Nura and Kulanotpes rivers that feed the lake). But this does not mean that life has stopped around the bitter-salty reservoir.

The value of the reservoir lies in the fact that it is a habitat for a large number of waterfowl and aquatic birds. Some species nest here, some stop for fattening and short-term rest on the way from Western Siberia to India or Africa. In total, there are about 300 species of winged inhabitants on the lake, with 22 species listed in the Red Book. For example, a curly-haired pelican and a black stork, a beautiful crane and a steppe eagle are side by side here. There is enough food for everyone: the shallow water is richly strewn with larvae and puparia of shoreflies, mollusks, and gill-legged crustaceans.

Ornithologists all over the world know Lake Tengiz as the northernmost habitat of the pink flamingo. This beautiful and cautious bird never settles where it is in danger, but here it feels great, because the lake is part of the Ramsar wetland of international importance and part of the Korgalzhynsky Nature Reserve. In addition, flamingos live mainly on isolated islands located in the southeastern part of the reservoir.

The main attraction of the lake — birds — is also the most vulnerable part of the ecosystem. And it's not just the hunters who are to blame.

Different water levels are recorded in Tengiz from year to year. Many centuries ago, the bitter-salty lake formed in a drainless depression on the elevated Tengiz plain. Every spring, water from several rivers arrives in Tengiz — this is the time of the highest rise in the mirror level. During the spring and summer season, some of the water evaporates and by autumn the depth of the reservoir becomes much smaller, and the coastline expands. In winter, the lake freezes, which was experienced by the members of the Soyuz-23 space expedition in 1976. The lander, having landed, was trapped in ice.

In addition, the water level depends on the year. At one time, the lake is full of water, but in years with low water levels, its size decreases by 70%, and the maximum depth does not exceed 2.5 meters. This significantly worsens the living conditions of the local fauna. Scientists have determined that all changes in the water level in the lake occur with a multi-year cycle. However, due to the active agricultural activity in the Nura River basin, there is a very real threat of irreversible shallowing of Tengiz.

To prevent the destruction of the reservoir, haymaking and grazing have been prohibited in the Korgalzhynsky Reserve for half a century, villages and livestock wintering camps have been eliminated, and ways to water the lake are being sought.

Another anthropogenic problem is also being solved. Twenty years ago, birds died en masse from power lines located near the lake. It is a well-known fact that in 2000, in just a few days, about 800 individuals, including rare species, died on an 11-kilometer section of the lines. Now, thanks to the efforts of the Global Nature Fund (GNF), a solar energy processing power plant has been built in Tengiz with the participation of Living Lakes NABU (the German branch of Birdlife International) and the administration of the Korgalzhyn Nature Reserve. This forced measure made it possible to dismantle uninsulated power lines and prevent further deaths of rare birds.