WHITENING

(LAKE) A phenomenon which occurs in moderately productive lakes when photosynthetic uptake of carbon dioxide (CO2) causes the precipitation of small particles of calcite (mostly calcium carbonate, CaCO3). Since small particles have a greater effect on water transparency and typical calcite particles are only 1-2 micrometers (µm) in diameter, the lake's water takes on a milky appearance, hence lending to its name.