Secrets of saltwater lakes around the world

Whether formed naturally or from a part of the ocean, saline lakes in the world are always the target of research by scientists and are a great attraction for tourists and explorers. .

A lake is considered saline when the salt concentration in the water is from 25gr / liter, while the average salt concentration in the sea water is from 35-42gr / liter. A lake is said to be too salty when there is salt concentration above 50gr / liter. However, the salinity concentration of the lakes is not fixed but varies according to geography and weather.

So far on the earth has formed two groups of saltwater lakes.The first type is formed from the ancient ocean plates divided by changing the structure of Earth's tectonic plates. Typical of this form is the Caspienne Sea and the Aral Sea (both of the former Soviet Union), the Dead Sea (between Israel and Jordanie) and the sea of ​​Tibériade (Somali). But those are only very rare cases. In fact, the above seas are saltwater lakes because there are no commercial roads with other seas or oceans.

While the Caspienne Sea and the Aral Sea are large saltwater lakes formed from the remains of an ancient sea divided by the ocean 5 million years ago, the Dead Sea has a salinity level 10 times higher than the average. usually due to the formation of a layer of salt at the thickness of 7 km. Meanwhile the waters of the sea of ​​Tibériade, formed from a split with the Indian Ocean, are becoming less salty as the salt does not settle at the bottom.

Caspienne Sea (former Soviet Union) covers an area of ​​374,000 km ² (Photo: Free.fr)

The second group of saltwater lakes includes closed lakes without commercial roads. Most of these lakes are formed in basins such as Australia's Eyre Lake or from cracks in strata such as Lake Issyk-Koul in Kirghizistan at 702m above sea level. In the lake, there are only deep pits with salt water, the rest are covered by a layer of salt up to 4m thick. Since the beginning of the twentieth century until now, Lake Eyre has only been submerged four times but the first time was in 1991.

In this group of closed saltwater lakes, they formed two small groups. In the first small group, salt formed from the geological structure of the lake bed, like saltwater swamps called sebkhas in Morocco, Mali and Niger (all in Africa). In this small group, there are also lakes that are saline by infiltrating water from the sea through layers of strata. Typically Assal saltwater lake in Djibouti. Formed 4 million years ago, Lake Assal is salty because seawater penetrates through layers of rock located at a depth of 165m at the bottom of the lake. Over time, a 25m thick salt layer formed over Lake Assal's heart and became a huge open-cast salt mine.

In the second small group, salt is flooded by rivers or flooded into the lake. Since there is no commercial branch with the sea or the ocean, the water of these lakes once evaporates, forming salt reservoirs clinging to the cliffs or mixing in the sand at the bottom of the lake. This type of saltwater lake appears in Canada's Saskatchewan and Manitoba states.

Lake Eyre (Australia) has an area of ​​7,700km ² (Photo: NASA)

However, whether salt is self-formed at the bottom of the lake or brought about by other factors, most lakes only become salty gradually over time, mainly through the form of evaporation of water. Containing large salinity, Walker Lake in Nevada, USA, Lake Magadi in Kenya, Lake Issyk-Koul in Kirghi Zistan are typical examples. Due to the absence of a branch, saline water in the lake evaporates and salinity increases. The more salty Lake is, like the Great Salt Lake, Aral Sea or Bolivia's Poopo Lake, the higher the salinity level.

In such a situation of saline intrusion, how does the living environment in the saline lakes grow? It is indeed a very difficult living condition because salt crystals are released from saline water, negatively impacting the cells of living organisms, causing rapid dehydration. In lakes with normal saline water (from 25-50gr salt / liter), life still forms normally like in the seas or oceans.

In contrast, in lakes with excessive salinity, vertebrates and invertebrates are less likely to exist. Very few types of fish, crustaceans and algae can survive. And to survive in an overly saline environment, some crustaceans have formed a special mechanism of self-protection. For example, shrimp called epinoche, when the concentration of salt in the water increases, the epinoche shrimp encapsulates all their parts with a thick layer of scales. But it is the excessive salinity of the Mono lake in California, USA, which is a condition for developing a crustacean with reserves of up to 4,000 billion children as food for artemia algae.

Aral Sea (former Soviet Union) 68,000 km ² and currently only 42,000 km ² (Photo: NASA)

Salt lakes are also the habitat of single-celled organisms such as green algae Fabrea salina. A special feature of this algae is that they can change color from green to orange depending on the salinity increase of the lake water. In addition, the water color of saltwater lakes always changes from green to pink and orange as a way to help the creatures absorb energy from the sun.

What future for saltwater lakes in the world? The warming of the earth accelerates the evaporation of water, which will make these lakes more saline and cause organisms to live in lakes to become extinct gradually. It is the people who make the saltwater lakes, which are wonders given to the earth by nature, will disappear in the future.

The four largest saltwater lakes in the world are: Caspienne Sea (former Soviet Union) covering an area of ​​374,000 km ² , Aral Sea (former Soviet Union) 68,000 km ² and now only 42,000 km ² , Lake Balkhash (Russia) 18,200 km ² , Lake Eyre (Australia) has an area of ​​7,700km ² .

Four lakes with excessive salinity are: Lake Patience (Canada) with salinity of 443gr / liter, Lake Assal (Djibouti) with salinity of 350gr salt / liter, Nhêm Mầu Big (USA) with 285 gr saline / liter salinity , Dead Sea (Middle East) 280gr salt / liter.

Lake Balkhash (Russia) 18,200 km ² (Photo: cache.eb.com)

Hoang Phu