Just like the mountains, the lakes on earth can be old, or more than a million years. There are only 20 ancient lakes on the planet, but what is the oldest?
The oldest lake in the earth has a clear winner: Baikal Lake In south-eastern Siberia. Scientists estimate that this huge freshwater body is 25 million years old, according to Ted OzerskyAssociate professor of biological limnology (the study of interior water bodies) at the University of Minnesota. On the other hand, the great lakes have formed Less than 20,000 years ago. The second oldest lake on Earth is Lake Issyk-Kul in Kyrgyzstan, which formed on 20 million years ago.
Lake Baikal measures 12,239 square miles (31,700 square kilometers), making it seventh lake. It is not only the oldest lake in the world but also the deepest, about 1 mile (1.6 kilometers). But it’s just the depth of the water. “The real basin is much more than a depth mile,” said Ozersky to Live Science, including between 3.1 and 4.3 miles (5 to 7 km) of sediments below. In the case of Lake Baikal, where there are miles of sediment, researchers use seismic surveys to estimate the average sediment rate, said Ozersky.
This sediment is the key to going out with the lake. Researchers measure the age of a lake by isotopic meetings. This technique consists in measuring radioactive isotopic reports. In this case, limnologists analyze the sediments of the lake for the radioactive versions of cesium, lead and carbon. This analysis tells them how old the different sediment layers are and how quickly these sediments accumulate, explained Ozersky
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By understanding the formation of lake – and the formation of Lake Baikal, in particular – the researchers can have a better idea of the way it has persisted for millions of years. Many lakes are formed as glacial characteristics, Mark EdlundA main scientist and director of aquatic research and collections at the Science Museum of Minnesota, told Live Science. The glaciers mark a pocket in the landscape and place pieces of ice that end up melting and filling depression. “But in the large scheme, these are short -term systems,” said Edlund.
On the other hand, Lake Baikal is a lake Rift. The Rift lakes are formed when two continental plates begin to move away from each other, creating a abyss. This chasm is called a Graben. While these plates continue to depart, the Graben continues to deepen. “Consequently, this site never fills up,” said Edlund, which is why Rift Lakes can last so long.
In fact, Ozersky said that Lake Baikal has an inch (2.5 centimeters) wider each year. Some of the other oldest lakes in the world, such as Lake Malawi (up to 5 million years) and Lake Tanganyika (up to 12 million years) – both in South -East Africa – also come from rifts.
Lake Baikal also claims the title of the most diverse lake of the earth, according to Ozersky.
“The evolution had so much time to work in this system without being interrupted,” he said. It also has the highest rate of flora and fauna endemic to its ecosystem, which means that these plants and animals are nowhere else on earth. Perhaps the best and most loved example is the Baikal seal (Pusa Sibirica), the only species of fresh water seal. (Although other seals species can live in lakes, these seals have “invaded” them through rivers, noted Ozersky.))
This old lake also welcomes hundreds of species of freshwater shrimp, which gives researchers the possibility of studying speciation and diversification. “Trying to understand how evolution works is something that is really interesting about Baikal,” said Ozersky.
Edlund also studies diatoms, which are a unicellular type of algae. These organisms draw the dissolved silica from water and transform it into biologically produced glass, which frames them. The diatoms are generally between 10 and 50 microns (about half of the width of a human hair) of diameter, but the baikal diatoms are unusually large at around 50 to 150 microns. “When we look at the diatoms of Lake Baikal, they breathe you,” said Edlund.
The lake is also open to human visitors. But because it is covered in ice at five months of the year, it is not an excellent swimming destination. It is Average surface temperature is 39 degrees Fahrenheit (4 degrees Celsius). “It’s a very cold lake,” said Edlund. “If you want to swim there, you need to stop your kidneys.”
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