When Jasmine Jeffers was 7 years old, she used to spend peaceful afternoons at Oleta River State Park in North Miami Beach.
But with all the development and construction around the park, her quiet getaway has become threatened.
''It's a piece of Old Florida surrounded by Florida International University and all this booming development,'' Jeffers said. ``Urbanization is threatening the park's tranquility and a lot of other state parks.''
Jeffers, of Plantation, didn't just sit back and watch the park deteriorate.
As part of her environmental science and Everglades restoration magnet program at South Plantation High School, Jeffers, along with three classmates, created concrete ``reef balls.''
At the inlet off Oleta River State Park and just off Golden Beach, they deployed the reef balls, which look like big sponges. The balls attach themselves to the existing coral reef to help it grow, despite pollution, poor boating practices and dredging.
Jeffers, 17, was awarded a $400 prize by Action for Nature, a nonprofit organization in San Francisco that honors young people ages 8 to 16 who take key steps to solve environmental problems. She was one of eight recipients this year.
The project also had an educational component. The students held outreach events where they would take a small group of kids -- sometimes Girl Scouts -- snorkeling so they could see the reefs and collect water samples for chemical testing.
''They taught some teachers in elementary and middle schools about the project and gave them ideas for activities . . . in class,'' said Allan Phipps, Jeffers' Advance Placement environmental science teacher at South Plantation. ``They educated the community how humans impact coral reefs, what to do when you are swimming by coral, and that your activities on land affect the ocean.''
The judges were impressed with Jeffers' eagerness to share what she had learned.
''We were interested in her because of her interest in educating others and persuading others to change the way they are doing things,'' said Beryl Kay, an organizer for the event. ``She did an inspiring thing that tells people to get involved.''
The money will come in handy for Jeffers as she heads to Princeton University, where she plans to study political -- and environmental -- science. Eventually she would like to practice environmental law.
''What's good for people isn't usually good for the environment,'' Jeffers said. ``As a lawyer, I'd like to ensure that the people responsible for polluting the site are held responsible. Unfortunately, the environment has become political over the years.''
Securing the permits to submerge the balls in the water was not easy, but Jeffers' group persisted and worked with the Miami-Dade Department of Environmental Resource Management.
Phipps said the curriculum they created will be used at the high school. Jeffers would like to see more reef balls dropped in the Florida Keys, Biscayne Bay and off Fort Lauderdale.
''Our project just shows people that kids can make a difference,'' Jeffers said. ``You don't need a high-powered official or someone in government to help the environment.''
Applications and guidelines will be posted on the website www.actionfor nature.org in September. The deadline to submit applications is Feb. 28.