This year's green algae-like slime scum covered 1000 square miles of Lake Erie, according to the National Oceanic and Atmospheric Administration (NOAA). This is ten per cent of Lake Erie, twice the size of New York City and Chicago.

The NOAA uses satellites to monitor the nation's weather all day long. Their data is used in every weather report in the U.S. The above picture is taken from one of their satellites in September.

The poison bacteria blob was concentrated in western Lake Erie. It covered the fresh water lake from Toledo, Ohio to Ontario, Canada, to Detroit, Michigan. This above picture is from a weather satellite of western Lake Erie in September.

The toxic bacteria bloom was the third worst of the century for Lake Erie, according to the National Centers for Coastal Ocean Science (NCCOS). Only the blooms in 2015 and 2011 were worse. The 2015 blob was the size of New York City.

The scum, a bacteria rather than algae, is poison. If people drink it, they die. Its musty-smelling odor "stinks", and has been described as "green pea soup". Others describe the bloom as green paint, a skin-like substance so thick that people could write on it.

When the bacteria decays at the end of the year, it sinks to the lake's bottom and browns. The bacteria remains active there, removing oxygen from the water. This creates huge "dead zones" causing massive fish kills and destroys vegetation at the bottom of the lake. 

Without proof, farmers are blamed for the water pollution. It is assumed that phosphorus contained in fertilizers run off their farms into the water system, causing the problem.

Farmers claim their changes in farming techniques make it impossible for phosphorus to drain into the water system. They blame raw sewage runoffs from city and county water sewage systems for the problem. 

According to the U.S. Environmental Protection Agency (EPA), there are 28 public water treatment facilities in Ohio that discharge unsafe amounts of phosphorus into the state's water supply.

https://cfpub.epa.gov/dmr/data_explorer.cfm

https://coastalscience.noaa.gov/research/stressor-impacts-mitigation/hab-forecasts/

A satellite picture from the National Weather Service showing this year's Lake Erie bacteria blob bloom. The light green color in the lower left is where the poison bacteria blob slimed Lake Erie this year.