Environmental Science 3(3+0)

iii. Estuaries

 

• Estuaries are areas where freshwater streams or rivers merge with the ocean. This mixing of waters with such different salt concentrations creates a very interesting and unique ecosystem. Microflora like algae, and macroflora, such as seaweeds, marsh grasses, and mangrove trees (only in the tropics), can be found here. Estuaries support a diverse fauna, including a variety of worms, oysters, crabs, and waterfowl.

• Physical alteration and the destruction of habitats are now considered one of the most significant threats to coastal areas. Half of the world’s wetlands, and even more of its mangrove forests, have been lost over the past century to physical alterations, the major causes being accelerating social and economic development and poor-planning (UNEP, 2002). There are currently about one billion people living in coastal urban areas. It is estimated that almost 50% of the world’s coasts are threatened by development-related activities. The intense pressure on coastal ecosystems calls for preventive and protective action at all levels - local, national, regional and global.