I'm not completely convinced that this is a great idea

Suffolk Life Newspapers - William Floyd Students Work To Save Forge River

Students from Liz Bedell's environmental class and Amy Meyer's Environmental Club, both at William Floyd High School, and fourth-graders from Michele DeNicolo's class at Tangier Smith Elementary School, are launching bio-haven floating islands into East Mill Pond. This initiative is being coordinated between Save the Forge River, Inc. and the school district.
Bio-haven floating islands, made from 100% recycled materials from plastic drink bottles, are buoyant mats, planted much like a garden, and contain plants native to Long Island that have been grown in the students' classrooms, then launched onto the water. Layers of material are bonded together with foam, where the floating islands are intended to reduce nitrogen levels in the water system by supporting the growth of microbes and plants.