mangroves

mangroves, tropical trees that grow with their roots in salt and brackish water. Worldwide there are 65 species belonging to twenty different plant families. Mangroves grow in dense thickets along sheltered muddy shorelines, often in estuaries where the sea water is diluted and temperatures stay above 24 °C (75.2 °F). Mangrove forests probably once lined 75% of tropical coastlines, but over half have now been destroyed. Currently throughout the world, mangrove forests cover 180,000 square kilometres (69,498 sq. mls.). Mangroves are used for timber and to make charcoal. They are being cleared because of urbanization, and to make way for prawn farms. A square metre of mangrove swamp annually produces a kilogram of leaf litter, which attracts large numbers of animals, including seahorses. In northern Australia 75% of commercial fish spend some of their lives in mangrove swamps. As the large quantities of leaf litter rot, the oxygen in the mud is used up, so it becomes black and smelly. Mangroves have various adaptations to cope with this, ranging from aerial roots (in Avicennia) to stilt roots (in Rhizophora). Conserving healthy mangrove forests is important not only because of the rich diversity they support, but also because they provide protection against the destructive forces of tropical storms and tsunami.

See also marine plants.

http://www.ncl.ac.uk/tcmweb/tcm/mglinks. htm

M. V. Angel