What are coastal wetland ecosystems, what are their limits of distribution, and where dothey exist in the overall coastal landscape? There are several general definitions for wetlands,but the Ramsar definition is likely the most broadly encompassing (http://www.ramsar.org/), whereas others are more focused definitions tailored to country-specific protectionand management policies (Mitsch and Gosselink, 2006). We offer a very general approachrather than a precise definition: coastal wetlands are ecosystems that are found within anelevation gradient that ranges between subtidal depths where light penetrates to supportphotosynthesis of benthic plants to the landward edge where the sea passes its hydrologicinfluence to groundwater and atmospheric processes. At the seaward margin, biofilms,benthic algae, and seagrasses are representative biotic components. At the landward margin,vegetation boundaries range from those located on groundwater seeps or fens in humidclimates to relatively barren salt flats in arid climates.

Fil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Geología; Argentina

Fil: Wolanski, Eric. James Cook University; Australia. Australian Institute of Marine Science; Australia

Fil: Brinson, Mark M.. Brinson East Carolina University; Estados Unidos

Fil: Cahoon, Donald R.. United States Geological Survey; Estados Unidos

Fil: Hopkinson, Charles S.. University of Georgia; Estados Unidos