What causes that milk-like substance to appear near the shore on my lake?
The white, milky-looking substance is most likely a “whiting” or sudden appearance of calcium monocarbonate (CaCO3) or calcite due to increased photosynthesis from algae or aquatic plants. This is a naturally occurring phenomenon associated with dissolved inorganic carbon concentrations in lake water. In high concentrations, calcite (also called marl) can accumulate on beaches and lake beds in some lakes. This can be associated with an algae bloom in backwater or protected inlets of lakes.