Each year off the west coast of Florida, a huge red algae bloom appears, closing beaches and causing chaos to wildlife of the area. The main reason is thought to be from phosphorus—algae thrive on the element—as the runoff flows through farms and lawns that use fertilizer, in which phosphorus is a main constituent. The year 2013 was no exception. The Caloosahatchee River, which runs through farmland and empties into the ocean at Fort Myers, is thought to have carried the phosphorus that fed the algae. The bloom was longer and more toxic, affecting humans, as the algae contain a nerve poison (brevetoxin) that is blown through the air when waves break; people can also become ill if they ingest local oysters and clams that absorb the brevetoxin. It also affects birds, dolphins, and other animals when they ingest the poison—as much of it clings to the ubiquitous sea grasses of the area. In fact, the toxin killed a record 241 (to date) manatees—animals that eat about 100 pounds (45.36 kilograms) of sea grass daily. Some scientists believe the algae were more virulent because a mild, semiwindless winter allowed the organisms to stay longer in 2012 and start earlier in 2013.