The dark color occurs when high concentrations of phytoplankton (microscopic algae) or colored dissolved organic matter in the water absorb the blue light.
On rare occasions, these fine organic and iron sediments can get stirred up and cause discolored water. When this happens, customers commonly describe their water as “dirty” or rusty in color. Sediment can be stirred up when the direction or flow of water changes in the water mains.
Typically, brown lakes are surrounded by forests or wetlands. Dense forests provide dark organic material that dissolves in lake water like a teabag. This dissolved organic material stains the water brown and shades the underwater world. Overall, brown water lakes tend to be light-limited.
Florida has more naturally formed lakes than other southeastern States, where many lakes are created by building dams across streams. The abundance of lakes on the Florida peninsula is a result of the geology and geologic history of the State. An estimated 7,800 lakes in Florida are greater than 1 acre in surface area.
Marine and freshwater beaches, lakes, rivers, and ponds can be contaminated with a number of things. Bacteria, chemicals, and other pollutants from sewage bypasses, combined sewer overflows, human and animal feces, urban runoff – can all pollute and contaminate waterways.
Sargassum is a type of brown seaweed that is washing up on beaches in Florida. As it rots, it gives off a substance called hydrogen sulfide. Hydrogen sulfide has a very unpleasant odor, like rotten eggs.