An overview of the ecology of the tidal marshes along the gulf coast of the United States is presented. The following topics are included: (1) the human impact on tidal marshes; (2) the geologic origins of tidal marshes; (3) a description of the physical characteristics and ecosystem of the marshlands; (4) a description of the marshland food chain and the resulting high yield in commercial animal species; and (5) the economic and aesthetic value of tidal marshes. Drawings and diagrams show how marshlands form, the animal and plant life they support, the spawning patterns of the brown shrimp, a simple example of a marsh-estuary food chain, and the life cycle of some of the animals and plants. References are included. (JW)