ABSTRACT
Florida has many freshwater ponds, lakes, and streams, each containing interesting ecosystems. Because of the spring dry season and the summer rains, water levels naturally rise and fall, producing a broad margin with wetland plants where the land is only submerged part of the year. The alternating wet and dry conditions are important in many organisms' life cycles. Most ponds and lakes in Florida are eutrophic with the nutrients for photosynthesis because they drain phosphate rocks or receive nutrients from stormwater, farms, runoffs, and wastes from cities and industries. Oligotrophic lakes exist in some places in Florida where the drainage of water includes only rain water or runoff from poor superficial sandy soils—for example, sandhill lakes. As human settlements developed, enormous quantities of sewage, agricultural wastes, and highway debris have been running off the lands, making lakes very eutrophic. With increasing wastes in inflow, Lake Okeechobee has been getting more eutrophic and its value as a water supply is threatened.
