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| Earth on Oct 24, 2012

What is the world’s deepest lake?

The world’s deepest lake is also the world’s oldest lake.

The world’s deepest lake is Russia’s Lake Baikal. The water’s average depth is more than 700 meters – almost half a mile. In some places, Lake Baikal is more than twice as deep as that.

Lake Baikal is also the oldest lake in world. It began forming when a fissure in the Eurasian continent opened, more than 25 million years ago.

If you exclude polar ice caps and glaciers, Lake Baikal holds over one-fifth of all surface fresh water on Earth. Unlike other deep lakes, it contains dissolved oxygen right down to the lake floor. That means creatures thrive at all depths in the lake.

Photo credit: Kyle Taylor

Most of Lake Baikal’s 2,000-plus species of plants and animals are found nowhere else in the world. Scientists believe up to 40 per cent of the lake’s species haven’t been described yet. Species endemic to Lake Baikal have evolved over tens of thousands, perhaps millions, of years. They occupy ecological niches that were undisturbed – until the last few decades.

Now, industrial development, paper mills, mining, agriculture, and general population growth on the lake’s shores are putting toxic compounds, fertilizers and other pollutants into Lake Baikal.

Find out more about Lake Baikal and how scientists are studying how the lake is changing: How is pollution changing Lake Baikal?

Photo credit: Kyle Taylor