By focusing on source reductions, nutrient pollutants and their adverse effects can sometimes be
reversed. In Tampa Bay, Florida, nitrogen loads from high population growth and industrial developments
in the 1960s and 1970s resulted in rapid algal growth and a depletion of native seagrass
populations. By 1972, 72 percent of the seagrass populations had been lost compared to earlier
estimates. Strategies that began in 1980 to reduce nutrients were effective in reducing nitrogen
inputs from sewage treatment plants by 50 percent. Within five years, algal concentrations in Tampa
Bay began to decrease and the seagrass populations slowly began to return. In more recent years,
the increased fossil fuel combustion from increased population in Florida has been contributing
nitrogen from the atmosphere, again threatening water quality.