A lot of tourists head to Florida's sparkling, blue beaches for vacation. In fact, Florida is the top travel destination in the world with a record 116.5 million tourists visiting the state in 2017, according to Visit Florida, the official Florida tourism industry marketing corporation.

But this summer, many tourists are being greeted by thick layers of green rancid sludge on the water. These are blooms of blue-green algae, technically cyanobacteria, that have affected the water for miles along the Atlantic Coast near Palm Beach and parts of the Gulf Coast near Fort Myers Beach and Sanibel Island. The infestation is so bad that Gov. Rick Scott declared a state of emergency for Palm Beach, Martin, St. Lucie, Glades, Hendry, Lee and Okeechobee counties.

The governor asked the Department of Environmental Protection, Army Corps of Engineers and South Florida Water Management District "to take emergency action to help redirect the flow of water and curb the potential for algae blooms, including deploying additional water monitoring stations."

Why this is an ongoing problem

algae bloom Awful smelling algae is seen along the St. Lucie River on July 11, 2016 in Stuart, Florida. (Photo: Joe Raedle/Getty Images)

This isn't the first time Gov. Scott has declared a state of emergency for algae bloom. In 2016, he took similar measures after the algae reached both coasts in the state.

Lake Okeechobee, it seems, is the problem. The nation's second largest freshwater lake and the largest lake in Florida, Lake Okeechobee is a repository for nutrient-rich runoff from surrounding farms and suburbs, reports the Tampa Bay Times. Those nutrients come from septic waste, fertilizer and manure.

Because the dike built around the rim of the lake is aging and at risk of collapsing, the Army Corps of Engineers releases controlled discharges from the lake to protect nearby towns from flooding, according to the New York Times. When the polluted water hits areas downstream, the blend of fresh and saltwater, along with environmental factors such as warm weather, create ideal conditions for the blue-green algae to grow.

Florida algae bloom Green algae blooms are seen at the Port Mayaca Lock and Dam on Lake Okeechobee on July 10. (Photo: Joe Raedle/Getty Images)

But the algal bloom isn't just an annoyance. It can also cause health problems for people and animals, according to the Florida Fish and Wildlife Conservation Commission. Coming in direct contact with toxic algae through boating, swimming or water skiing may cause rashes, itchy eyes or sore throat. Ingesting contaminated water can cause diarrhea, nausea, vomiting and stomach pain. Animals can become extremely sick and may even die after ingesting the toxins in the algae.

Hoping to bring an end to the problem, the Corps of Engineers has reduced the amount of water being released from Lake Okeechobee into local waterways and estuaries. The Army Corps said $514.2 million will be spent to repair Herbert Hoover dike, which will allow the lake to hold more water, reports Sun Sentinel. Then, less water would be released into surrounding rivers and hopefully lessen the growth of algae bloom.

To see just how widespread this year's algae bloom, watch this video from University of Florida's Florida Sea Grant program.

Editor's note: This story has been updated since it was originally published in July 2016.

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.