SUBSTRATE: Dominantly sandy with beds of clay, phosphatic mudstone, and peat; usually underlain by limestone.

TOPOGRAPHY/HYDROLOGY: Most Florida lakes formed by dissolution of limestone bedrock, subsequent groundwater flow into subterranean caverns, and collapse of surface layers. 7800 lakes greater than 1 acre; most are small, shallow, and in central, sandy ridge part of state; Okeechobee produced by an uplifted sea-floor depression, is by far the largest.

VEGETATION/ALGAE: Density and diversity of microalgal species dependant on trophic level; aquatic plants, macroalgae, mosses, and floating flowering plants particularly important in Florida's numerous shallow lakes.

FAUNA: Molluscs, crustaceans, larval and adult insects common; about 40 species of native fishes.

PROCESSES/DYNAMICS/ABIOTIC FACTORS: Trophic (nutrient) status varies; most lakes are poorly to moderately supplied with nitrogen and phosphorus nutrients and have low to medium densities of microalgae and aquatic plants.

HUMAN IMPACTS: Discharge of nutrients and other pollutants from human activities; siltation from forest clearing; exotic plant species, such as water hyacinth and hydrilla, clog waterbodies and change their chemical composition; native fish experience competition from 21 established exotic fish species.

ANIMALS AND PLANTS NATIVE TO ECOSYSTEM: List of selectable animals and plants native to the Lakes ecosystem, with detailed descriptions and pictures on each.