SAN JUAN, Puerto Rico (AP) — Scientists in Puerto Rico have attached some 4,800 live oysters to mangroves along a popular lagoon in the capital of San Juan to help purify its waters.

The nonprofit San Juan Bay Estuary Program says volunteers and researchers will monitor water conditions monthly in the yearlong experiment. The oysters are capable of filtering up to 40 gallons (151 liters) of water a day.

The Condado Lagoon is popular with paddle boarders and has hosted several triathlons, including two Ironman events.