Wetlands

Wetlands are lands that are significantly influenced by the presence of water. Although relatively rare, these fragile ecosystems, which occupy approximately 6% of Earth's surface, are found on every continent except Antarctica. Wetlands are found in most of the world's climatic zones, ranging from warm tropical climates to frigid arctic climates. They are present across a wide range of elevations around the world, from below sea level to mountaintops.

Wetlands are broadly classified according to topography and water salinity. Topographically, they may be present in either coastal areas or inland. When subdivided according to water salinity, they may range from saline (salinity > 30.0 parts per 1,000) to brackish (salinity 29–0.6 part per 1,000) to fresh (salinity < 0.5 part per 1,000). The salinity of coastal ...