Black water, a dark discoloration of sea water off the 
Florida coast, was discovered in 2002. Although fisherman haved complained and asked the government to "do something" about it, scientists say that black water was a non-toxic bloom, similar to 
red tide and probably caused by 
diatoms.
Black water is also a type of sewage water.
 
All Wikipedia text 
is available under the 
terms of the GNU Free Documentation License