Aquatic ecology and Biodiversity

Unit 10- Coastal ecosystems

10.4.1. Mangrove habitat

Mangrove distribution is determined primarily by sea level and its fluctuations and secondarily by air temperature, salinity, ocean currents, storms, shore slope, and soil substrate. Most mangroves mostly live on muddy soils, but they can also grow on sand, peat and coral rocks. Zonation often characterizes mangrove forests. Some mangrove species occur close to the shores, fringing islands, and sheltered bays. Others are found further inland in the estuaries influenced by tidal action.
Mangroves vary in height according to species and environment from shrubs to tall trees. The roots of some mangrove species such as Rhizophora spp. (red mangrove) contain the pneumataphores- the unique breathing roots and Avicennia spp. (black mangrove) contain many small "breathing" pores, called "lenticels." These allow oxygen to diffuse into the plant and down to the underground roots by means of air space tissue in the cortex, called "parenchyma." The lenticels are inactive during high tide. Certain species of mangroves exclude salt from their systems while, others actually excrete the salt via their leaves, roots, or branches.