Some lakes are "naturally acidic." How can that be possible?

Question

What will be an ideal response?

Answer 1

If the lake is formed from water gathered in a hollow with the inflow source
mostly rain and groundwater seepage and the outflow solely evaporation, the chemistry of
the underlying soil and rocks can strongly affect the water and can cause acidity of the water
held there. Lack or presence of local limestone, which acts to neutralize acid, is an example
of such a condition.
Lakes such as this are classified as "seepage lakes." These lakes tend to form more in
northern climes. Sweden, for example, has many granitic rocks and has poor soils, has
many naturally acid lakes. This is characteristic of many other parts of northern Eurasia
stretching into Siberia. The same is true in the Adirondack region in upstate New York, the
northern New England states, northern Wisconsin, northern Minnesota, and much of
Canada. Lakes in these regions can be very much affected by acid rain.