Lake Baikal is located in southern Siberia on the Eurasian continent, with an overall length of about 636 km, a width of 48 km, and an area of approximately 31,500 km2, making it nearly equivalent to an entire “country within a country.”
Geologically, Lake Baikal sits at the intersection of tectonic plates. Approximately 25 million years ago, the Indian plate collided with the Eurasian plate, causing a powerful earthquake that led to the collapse of the tectonic structure where Lake Baikal is located, forming a depression into which several rivers flowed, eventually creating the lake.
Lake Baikal is located at the intersection of tectonic plates.
Lake Baikal has 336 rivers flowing into it, with a drainage area of 560,000 km2, of which the Selenga River provides more than half of the lake’s water. Lake Baikal has a water capacity of 23.6 trillion cubic meters (2015 data), which is nearly equivalent to the total water volume of the five Great Lakes in North America and exceeds the water volume of the entire Baltic Sea. Its absolute clean water reserves account for one-fifth of the world’s freshwater supply and are eight times greater than the freshwater reserves of China.
In general, the depth of lakes on land usually does not exceed 1,000 meters, because besides the inflowing rivers, lakes typically also have outflowing rivers. Overflow can cause flood disasters, and outflowing rivers usually form after flooding.
Additionally, the rivers flowing into the lake carry a certain amount of sediment, which settles to the lakebed. Over time, the lakebed gradually rises, and originally deep lakes can become very shallow and even fill up.
Lake Baikal has 336 rivers flowing into it.
However, Lake Baikal is an exception, with a depth of up to 1,637 meters. How is this possible?
It turns out that the 336 rivers flowing into Lake Baikal are relatively clear, especially the largest river, the Selenga River, which carries very little sediment. Furthermore, the stable topography and abundant aquatic vegetation can filter out sediments to a great extent, so despite over 20 million years, the deepest part of Lake Baikal remains above 1,600 m.
According to geological analyses, the depth and width of Lake Baikal could increase, potentially even becoming an ocean. This is because, like the East African Rift Valley, the Baikal Rift Valley is one of the most famous areas of tectonic stress in the world and is the largest active continental rift valley in Eurasia. Due to plate separation and frequent earthquakes, Lake Baikal is indeed expanding and deepening each year.
The biodiversity of the Lake Baikal region is rich, with approximately 1,080 species of plants and 2,565 species of animals in the lake area. Not only that, but there is also a large number of marine species such as sponges, seals, and even sharks residing in Lake Baikal.
There are about 1,080 species of plants and 2,565 species of animals in the lake area.
However, Lake Baikal is a freshwater lake located over 2,000 km from the ocean. How can there be so many marine organisms in it?
Before the 1990s, scientists explained this phenomenon. Just like the Himalayas were once a vast ocean, the reason there are marine organisms in Lake Baikal is that it was once a sea. During the Jurassic period of the Mesozoic era, there was indeed a vast sea stretching across eastern Baikal. But over the years, the movement of the Earth’s crust caused the Baikal Sea to “transform from a sea into a lake.” At the same time, Lake Baikal is gradually becoming a freshwater lake due to continuous erosion and dilution from the inflowing rivers and natural rainfall.
However, in the early 1990s, scientists found no materials related to the Mesozoic era in core samples taken from drilling in Lake Baikal. This means that previous explanations by scientists were incorrect, Lake Baikal has never experienced a marine phase and has always been a freshwater lake.
Regarding the many marine organisms in Lake Baikal, biologists explain this: the sponges in Lake Baikal are actually not marine organisms, as there are many types of sponges in the world, and some sponge species do not live in the ocean but thrive in freshwater.
Baikal Seal.
The “sharks” that people see in Lake Baikal are merely fish that resemble sharks.
As for the seals in Lake Baikal, they are indeed marine animals. Long ago, a group of seals swam into the Yenisei River from the Arctic Ocean, then traveled south along the Angara River, a tributary, and aggressively entered Lake Baikal.
Later, as the Ice Age came to an end, the Yenisei River became narrower and shallower, preventing the seals from returning to the ocean. They had to gradually adapt to the freshwater environment of Lake Baikal and thrive there.
