About mangroves

This is a broad overview to mangroves which are made reference to throughout the blog.

The name mangrove refers to the ecological grouping of a plants ability to grow under unfavourable conditions. These include areas of salt water, and freshwater, brackish water and areas of poor oxygen content. Mangroves therefore do not all belong to the same family.

In Florida there were there were three mangrove species which we came across on various occasions. White Mangrove (Laguncularia racemosa), Red Mangrove (Rhizophora mangle)Black Mangrove (Avicennia germinans) and Red Mangrove (Rhizophora mangle). These different species of mangrove generally follow a zonation pattern illustrated by the diagram below.

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Mangrove zonation pattern (Image)

White Mangrove:

  • The shortest of the three species of mangroves and generally grows in the shallowest furthest part of a mangrove swamp. This area is largely unaffected by tides.
  • Leaves are adapted to their salty environment by developing of glands which release salt onto the outer of the leaf. Therefore the leaves are speckled with salt crystals.

Black Mangrove:

  • This mangrove is characterised by its prop roots which vertically emerge from the water for oxygen exchange.
  • Black mangroves produce viviparous seeds or those that germinate while remaining attached to the tree.

Red Mangrove:

  • This mangrove is characterised by its prop and aerial roots which stabilise the trees as these are the most affected by tides.
  • The roots contain a waxy substance to reduce salt water affecting the tree. An adaptation to deal with the salt entering the plant includes the use of a sacrificial leaf. Salt will be deposited in a leaf which will shed away, releasing the salt from within the plant.

Importance of mangroves

  • Mangroves provide habitat for large numbers of species in particular acting as a nursery for juvenile individuals.
  • Mangroves also protect shorelines from erosion,  storms and hurricanes.  They also maintain water quality by filtering sediments which runoff from the land.
  • Carbon sequestration another feature of mangroves which is beneficial which is discussed during the Bill Mitsch talk on day 7 .