ISLAMORADA — A “flotilla of cattails” turned stagnant fresh water clear and earned Aiden Pegues the first-place prize for his aquatic project at last week’s Science Fair at Treasure Village Montessori Charter School.

Lake Okeechobee water brought in for Pegues’ project “was full of pesticides and fertilizers,” said the eighth-grader. “Sitting there [in above-ground pools], the water turned more toxic every day.”

Then Pegues built floating containers — plastic crates and buoys lashed together with zip-ties — to hold cattails and see if the water plants would have an effect within a few weeks. They did.

“It cleared the water completely. There were lily pads and flowers everywhere,” Pegues said. Pollutants that were first measured at 30 parts per million dropped to 8 parts per million.

About six dozen Science Fair projects were entered by sixth- to eighth-graders at Treasure Village Montessori on Plantation Key.

Florida Bay Forever, a local conservation group, suggested a theme that focused on protecting and restoring local waters through innovative experiments. Many students took up the challenge, but work in health, engineering and other science fields were performed, too.

“Students could enter anything under the sun as long as it’s something that might make a difference in how people live in the world,” fair coordinator Bobbi Burson, a school math and science teacher, said.

Pasqual Weisberger, a seventh-grader, compared the breakdown of “bioplastic” materials, made of biodegradable starches, to common petroleum-based plastics that wind up in Keys waters.

He placed materials in saltwater tubs, ponds and a dock area, measuring the effects of light and wave action. The bioplastic bags broke down more readily. Weisberger concluded the bioplastic bags “could be a practical solution to help reduce the amount of plastic items going into our marine environment.”

Eighth-grader Marshall Newman experimented with three types of material to hold roots of seagrass planted in damage-restoration efforts. Cardboard bathroom-tissue tubes won out, closely followed by cheesecloth, he reported.

Judges from the community and environmental groups helped rate the entered projects.

In addition to Pegues’ top honor, awards went to:

• Aidan Austin’s “Webtastic,” creating an artificial web as strong as an actual spider web;

• “Tribo Electrical Effect” by Jordan Lubis, on using static electricity to produce power;

• “Electronics While Eating,” a survey by Tommy Cheung on how phone use affects food consumption;

• Alice Dangel’s “Left Vs. Right Memory,” a comparison between the left-handed and right-handed; and

• “Eco-friendly 3-D Printing” by Zack Woltanski.

Treasure Village’s top science projects will advance to the countywide science fair, with a berth in the state competition at stake.