People and pets warned of blue-green algae at Prospect Park Lake in Brooklyn

There is a warning about a danger to dogs in New York City's second largest park.

A lake in Prospect Park is closed because of algae that could make pets sick.

"She likes to come look at the animals, and you can see there's a lot, it is green here," said Ravi Ramaswamy, a father.

That greenish tint and scum on the surface of Prospect Park Lake is called "blue-green algae" and it can be toxic. The Prospect Park Alliance has signs up to warn park-goers.

"We avoid that whole area with the trees in the algae area," said Ramon King, a boater.

King thought it was kind of gross, but he didn't know it posed a danger.

"Now that I know it's toxic I'll definitely keep the kids away from it," King said.

It turns out that kids and pets are more vulnerable to the effects, which can cause rashes and irritate the eyes.

It can produce Asthma like symptoms if inhaled and gastrointestinal and neurological symptoms from being swallowed.

So while fishing there is catch and release, it's best to be careful when handling the fish.

Dog owners are advised to head to "Dog Beach" where the water is not affected, that's where Daisy loves to play, but her owner would like to see the park take more steps when it comes to the algae.

"I think more signs or more ways to notify park-goers about what the algae does to dogs and humans and how it impacts the environment," said Ruby Koch, a dog owner.

Behind the scenes, environmental scientist Jennifer Cherrier is leading up a nearly $400,000 state funded project aimed at stopping the algae problem.

She has designed an eco-friendly sponge to remove excessive amounts of phosphates that cause the algae growth.

"We've created a system that is like a filter but we're giving it a little bit of a boost to make sure that we get as much phosphorous out as possible," Cherrier said.

She hopes to start work in the fall, but it could take several years before the algae stops taking over.