Restoration of The Everglades - Water Quality

Water Quality

Attention to water quality was focused in South Florida in 1986 when a widespread algal bloom occurred in one-fifth of Lake Okeechobee. The bloom was discovered to be the result of fertilizers from the Everglades Agricultural Area. Although laws stated in 1979 that the chemicals used in the EAA should not be deposited into the lake, they were flushed into the canals that fed the Everglades Water Conservation Areas, and eventually pumped into the lake. Microbiologists discovered that, although phosphorus assists plant growth, it destroys periphyton, one of the basic building blocks of marl in the Everglades. Marl is one of two types of Everglades soil, along with peat; it is found where parts of the Everglades are flooded for shorter periods of time as layers of periphyton dry. Most of the phosphorus compounds also rid peat of dissolved oxygen and promote algae growth, causing native invertebrates to die, and sawgrass to be replaced with invasive cattails that grow too tall and thick for birds and alligators to nest in. Tested water showed 500 parts per billion (ppb) of phosphorus near sugarcane fields. State legislation in 1987 mandated a 40% reduction of phosphorus by 1992.

Attempts to correct phosphorus levels in the Everglades met with resistance. The sugarcane industry, dominated by two companies named U.S. Sugar and Flo-Sun, was responsible for more than half of the crop in the EAA. They were well represented in state and federal governments by lobbyists who enthusiastically protected their interests. According to the Audubon Society, the sugar industry, nicknamed "Big Sugar", donated more money to political parties and candidates than General Motors. The sugar industry attempted to block government-funded studies of polluted water, and when the federal prosecutor in Miami faulted the sugar industry in legal action to protect Everglades National Park, Big Sugar tried to get the lawsuit withdrawn and the prosecutor fired. A costly legal battle ensued from 1988 to 1992 between the State of Florida, the U.S. government, and the sugar industry to resolve who was responsible for water quality standards, the maintenance of Everglades National Park and the Arthur R. Marshall Loxahatchee National Wildlife Refuge.

A different concern about water quality arose when mercury was discovered in fish during the 1980s. Because mercury is damaging to humans, warnings were posted for fishermen that cautioned against eating fish caught in South Florida, and scientists became alarmed when a Florida panther was found dead near Shark River Slough with mercury levels high enough to be fatal to humans. When mercury is ingested it adversely affects the central nervous system, and can cause brain damage and birth defects. Studies of mercury levels found that it is bioaccumulated through the food chain: animals that are lower on the chain have decreased amounts, but as larger animals eat them, the amount of mercury is multiplied. The dead panther's diet consisted of small animals, including raccoons and young alligators. The source of the mercury was found to be waste incinerators and fossil fuel power plants that expelled the element in the atmosphere, which precipitated with rain, or in the dry season, dust. Naturally occurring bacteria in the Everglades that function to reduce sulfur also transform mercury deposits into methylmercury. This process was more dramatic in areas where flooding was not as prevalent. Because of requirements that reduced power plant and incinerator emissions, the levels of mercury found in larger animals decreased as well: approximately a 60% decrease in fish and a 70% decrease in birds, though some levels still remain a health concern for people.