00:57 Toxic Algae Bloom Can Be Seen From Space A toxic algae bloom in Lake Erie has grown so large it can be seen from space.

At a Glance An outbreak of microcystis cyanobacteria, the organism responsible for harmful algae blooms, has become a yearly occurrence on Lake Erie.

NASA captured an image the massive bloom on July 30, when it covered 300 square miles, roughly the size of New York City.

By Aug. 13, the bloom had doubled to more than 620 square miles, eight times the size of Cleveland.

A harmful algae bloom that began growing in western Lake Erie in July has more than doubled in size in a few weeks.

On July 30, NASA captured an image of the bloom from space. At the time, the bloom covered 300 square miles, roughly the size of New York City. By Aug. 13, the bloom had doubled to more than 620 square miles, according to NASA. That's eight times the size of Cleveland, which sits on the shore of Lake Erie.

Outbreaks of microcystis cyanobacteria, the organism responsible for harmful algae blooms, has become a yearly occurrence on Lake Erie. Earlier this year, the National Oceanic and Atmospheric Administration predicted a severe bloom this summer, which became a reality in July primarily as a result of calm winds and abundant rainfall.

"Calm winds in July allowed algal toxins to accumulate at the surface (instead of being dispersed). Strong winds in August have since mixed some surface algae to deeper depths. Heavy rains carry excess nutrients (often fertilizer) from farms into the lake," NASA said in a statement.

NOAA noted in its prediction that this summer's bloom was expected to be larger than the mild bloom in 2018 and would measure greater than a 7 on the severity index, which is based on a bloom’s biomass, or the amount of its harmful algae, over a sustained period.

The largest blooms, 2011 and 2015, were 10 and 10.5, respectively, according to NOAA.

<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/2019projectionfinal.png?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/2019projectionfinal.png?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/2019projectionfinal.png?v=ap&w=980&h=551 800w" > NOAA's 2019 harmful algae bloom outlook on Lake Erie, compared to previous years. (NOAA)

On July 29, NOAA reported unsafe toxin concentrations in Lake Erie and have since advised people and their pets to stay away from areas where "scum is forming on the water surface."

"Green patches show where the bloom was most dense and where toxicity levels were unsafe for recreational activities," NASA said in its statement.

On Thursday, NOAA said in a weekly Lake Erie bulletin that measured toxin concentrations had decreased since the previous week but "may continue to exceed the recreational threshold where the bloom is most dense (appearing green from a boat)." The agency continued to warn people to keep themselves and their pets out of water where scum had formed.

Harmful algal blooms come from the runoff from nearby farms and ordinary neighborhoods that contain human waste and fertilizers. Nitrogen and phosphorus, as well as other nutrients in the polluted runoff, can act like fertilizer for the algae, creating large and extensive blooms.

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NASA noted that this spring's heavy rainfall was a mixed blessing: It helped create the bloom in the first place but also prevented the situation from becoming worse.

"Nutrient runoff may have been less than anticipated this year because heavy spring rains and flooding prevented many farmers from planting crops," NASA said.

NOAA said the bloom is expected to continue into early fall.

If ingested, water contaminated with toxic cyanobacteria can cause nausea, vomiting and, in severe cases, acute liver failure, according to Florida's FWCC. While there have been no documented cases of anyone becoming ill from drinking water containing these toxins, it remains a concern.

The Centers for Disease Control says coming in direct contact with the algae can cause a rash and some research indicates a link between long-term inhalation of toxic algae fumes and neurological disorders like Parkinson’s and Lou Gehrig’s diseases.