Lake Hydrography
Bottom water of lakes may feature lower level of oxygen, to the point of completely vanished dissolved oxygen (i.e., becoming anaerobic), and higher levels of chlorinity and organic-induced acidity. In many lakes, especially in the zones of continental climate, summer heating and winter cooling create strong vertical temperature gradients which oppose water intermixing, resulting in the periods of summer and winter thermal lake stratification. They are intervened by bottom water overturning, which happens in autumn (autumn overturn) and in spring (spring overturn) due to equalizing of temperature gradients and the resulting easier intermixing by wind and other sources of turbulence.
Read more about this topic: Bottom Water
Famous quotes containing the word lake:
“They who know of no purer sources of truth, who have traced up its stream no higher, stand, and wisely stand, by the Bible and the Constitution, and drink at it there with reverence and humility; but they who behold where it comes trickling into this lake or that pool, gird up their loins once more, and continue their pilgrimage toward its fountain-head.”
—Henry David Thoreau (1817–1862)