What's the oldest lake on Earth?

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Just like the mountains , lakes on Earth can be ancient , or more than 1 million years quondam . There are only 20 ancient lakes on the planet , but which is the sure-enough ?

Earth ’s oldest lake has a clear winner : Lake Baikalin southeast Siberia . Scientists calculate that this enormous fresh water consistence is 25 million years previous , according toTed Ozersky , an associate professor of biologic limnology ( the study of inland bodies of water ) at the University of Minnesota . By contrast , the Great Lakes formedless than 20,000 years ago . The second oldest lake on Earth is Lake Issyk - Kul in Kyrgyzstan , which formed about20 million eld ago .

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Lake Baikal is 25 million years old, making it the oldest lake on Earth.

Lake Baikal measure 12,239 square Roman mile ( 31,700 hearty km ) , making it Earth’sseventh - largest lake . It is not only the humans ’s honest-to-god lake but also the deep one , at about 1 nautical mile ( 1.6 kilometers ) . But that ’s just the water depth . " The actual basin is much more than a mi mysterious , " Ozersky told Live Science , including between 3.1 and 4.3 miles ( 5 to 7 kilometer ) of deposit at the bottom . In the case of Lake Baikal , where there are miles of sediment , researchers practice seismal surveys to forecast the average rate of deposit formation , Ozersky say .

This sediment is primal to dating the lake . Researchers measure a lake ’s age through isotopic dating . This technique involves measuring the ratio of radioactive isotopes . In this vitrine , limnologist take apart lake sediments for radioactive versions of cesium , leading and carbon . This analysis tells them how old the dissimilar layer of sediment are and how tight that deposit accumulates , Ozersky explicate

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A picture of a large blue lake with a hilly, forested shoreline

Lake Baikal is 25 million years old, making it the oldest lake on Earth.

By understanding lake formation — and Lake Baikal ’s organisation , in finical — researchers can get a better musical theme of how it has persisted for millions of years . Many lakes form as glacial features , Mark Edlund , a elderly scientist and the director of aquatic research and collections at the Science Museum of Minnesota , order Live Science . glacier mark a pocket in the landscape painting and deposit chunks of chicken feed that finally melt and fill the depression . " But in the grand scheme , they ’re very curtly - lived systems , " Edlund said .

On the other manus , Lake Baikal is a rift lake . rupture lakes bod when two continental plates start moving away from each other , creating a chasm . This chasm is ring a graben . As these plates extend to drift apart , the graben continues to deepen . " As a outcome , that web site never fills in , " Edlund said , which is why rift lakes can last so long .

In fact , Ozersky said Lake Baikal catch an column inch ( 2.5 cm ) wider every year . Some of the earthly concern ’s other old lakes , like Lake Malawi ( up to 5 million geezerhood old ) and Lake Tanganyika ( up to 12 million years sure-enough ) — both in Southeast Africa — also come from rift .

a baikal seal on a frozen over lake

The Baikal seal (Pusa sibirica) is the only freshwater seal species on Earth.

Lake Baikal also take the title of Earth ’s most biologically diverse lake , according to Ozersky .

" Evolution has had so much meter to forge in that arrangement without being interrupt , " he said . It also has the highest charge per unit of flora and zoology autochthonal to its ecosystem , meaning those plants and beast are n’t see anywhere else on Earth . Perhaps the best and most darling example is theBaikal seal(Pusa sibirica ) , the only freshwater seal of approval species . ( Although other Navy SEAL metal money may inhabit lakes , those seals have " invaded " them through streams , Ozersky remark . )

This ancient lake also host hundreds of species of freshwater prawn , which gives researcher the chance to study speciation and diversification . " Trying to understand how evolution work out is one affair that is really interesting about Baikal , " Ozersky say .

Reconstruction of an early Cretaceous landscape in what is now southern Australia.

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a photo of an eye looking through a keyhole

Edlund also studies diatoms , which are a unicellular type of algae . These organisms rive fade out silicon oxide from the water and become it into biologically produce Methedrine , which encase them . Diatoms are typically between 10 and 50 microns ( about half the width of a human hair ) in diam , but Baikal ’s diatoms are remarkably large at about 50 to 150 micron . " When we look at the diatoms in Lake Baikal , they just blow your mind , " Edlund said .

The lake is also open to human visitors . But because it ’s covered with meth five month out of the yr , it ’s not a swell swimming destination . Itsaverage open temperatureis 39 degrees Fahrenheit ( 4 degrees Anders Celsius ) . " It ’s a bitterly cold lake , " Edlund said . " If you need to swim in it , you ’ve got to encircle your loins . "