How deep is deep?

In the article ``Saving Siberia's Unique Lake Baikal Region,'' Aug. 2, the author erroneously states that the lake holds a volume equal to one-fifth of all the fresh water on Earth.

What the author should have said was that it holds a volume of water equal to one-fifth of all of the fresh liquid surface water on Earth. Fresh water includes glaciers, icecaps, and fresh subsurface water.

In terms of all fresh water, the volume in Lake Baikal is less than 0.1 percent. Even if you consider just liquid fresh water, its volume is less than 1 percent of that. Michael Campana, Sandia Park, N.M.

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