An invasive plant species has taken over Tibbetts Brook in Van Cortlandt Park.

High school students are voluntarily getting into the water to remove the plant known as water chestnuts.

The plant blocks sunlight from reaching the water's surface, which harms other plant life.

Water chestnuts are not easy to remove, but employee Yoseph Kamran says to pull from the roots in order to prevent the plant from regrowing.

The plant also dies all at once, which takes all of the dissolved oxygen out of the water, making it impossible for other plants to live there.

Every year, interns remove the seeds, making it harder for the species to come back.