Florida
Enormous Lake Okeechobee serves as the headwaters for the Everglades and is half the size of Rhode Island. In May 2016, the lake was taken over by a blue-green algae bloom, visible here, which was blamed on high levels of chemicals in the water from agricultural runoff.
As the headwaters for the Everglades, Lake Okeechobee is immense—it holds more than a trillion gallons of water when full—but its average depth is only nine feet. From the air, it appears as a huge, roundish lake northwest of Miami, easily visible in satellite photographs.
Prior to about 6000 years ago, the area that is now the lake was a dry basin, sitting atop a region of compacted clay impermeable to water. Then the climate of south Florida started getting wetter, eventually giving rise to the vast wetlands that dominate southern Florida today. As the groundwater table became saturated, Lake Okeechobee took form, eventually filling an area half the size of Rhode Island.
From above, it’s sometimes possible to see that both Lake Okeechobee and the Everglades are in trouble. Development along the shores of the lake is obvious, with land divided up into both residential and agricultural sectors. Agriculture here is dominated by the sugarcane industry, which thrives in the dark, black muck of the Everglades Agricultural Area. But soil in south Florida is nutrient-poor and the fertilizer required to keep centuries-old fields productive has found its way into Lake Okeechobee.
In May 2016, a bloom of blue-green algae grew to cover thirty-plus square miles of Lake Okeechobee. The bloom was blamed on high levels of nitrogen and phosphorus in the lake, a result of fertilizer-permeated runoff from the sugarcane fields. The algae in turn produces toxins that can poison fish, destroy entire ecosystems, and negatively impact human health. High levels of arsenic, pesticides, and other pollutants have also been detected at alarming levels in the lake in recent years. In the absence of significant efforts to correct the degradation of southern Florida’s waters, Lake Okeechobee and the entire Everglades are quickly becoming one of the most endangered ecosystems in North America.
Lake Okeechobee covers 730 square miles and is the second-largest body of freshwater in the contiguous United States, although its average depth is only nine feet.
Trips by air to Miami, Tampa, or Key West, Florida, often offer an overhead view of Lake Okeechobee.
