A view of Mangroves under water

Different species of Mangrove leaves

Red Mangroves

A View through a Red Mangrove Swamp

Healthy Mangroves on the Big Bend Coast

Links to web pages about Mangroves:

- USGS Mangroves Page

-Mangroves of Florida

-Mangroves of Singapore

- Queensland Government Mangrove Page

Mangroves

What are Mangroves?

Mangroves are groups of tropical trees or shrubs that grow in swampy ground along river banks, with branches that spread and send down roots, thus forming more trunks and causing growth. Mangroves are essentially the rainforest of the sea, and are unique in both the plant and animal life they support.

How did Mangroves originate?

Scientists theorize that the earliest mangrove species originated in the Indo-Malayan region 66 million years ago. Today there are far more mangrove species present in this region than anywhere else on earth. Mangroves unique floating propagules and seeds, caused ocean currents to spread the species westward towards India and East Africa, and eastward to Central and South America.

Where are Mangroves found?

Mangroves dominate coastal wetlands in tropical latitudes. These complex ecosystems are found between the latitudes of 32 degrees north and 38 degrees south along the tropical coasts of Africa, Australia, Asia, and North and South America. Although Mangroves are found all over the worlds coastline, the American, or red, mangrove is found along the muddy shores and in the everglades of the Florida peninsula Mangroves are specially adapted to in areas where there is continual flooding and salt water. They grow all along the Gulf coast of Florida, but because they are sensitive to cold temperatures, tend to be smaller and less abundant in the northern part of their range.

How do Mangroves work?

Mangroves function from their trunks by producing aerial roots that become embedded in mud and form a tangled network. This not only helps to stabilize the trees themselves, but serves as a means of aerating the root system. Such roots also form a base for the deposit of silt and other material carried by the tides, and thus land is built up which is gradually invaded by other vegetation.

How are Mangroves effected by the climate?

Near the area of Tampa Bay, Florida, mangroves are periodically killed by prolonged freezing winter temperatures. Mangroves are often replaced temporarily by smooth cordgrass until the trees recover.

It can take 5-10 years for mangroves to re-grow to their full potential again following severe freezes in this area.

dead mangroves and recovering mangroves

How do Mangroves relate to Geology?

Because Mangroves can filter silt out of water, they have overtime evolved so that they are able to survive not only in saltwater, but also in freshwater or brine. Some mangrove species form a broad network of roots above the surface of the water. Dense stands of mangroves dampen the effects of story weather and thus prevent coastal erosion. Mangroves have special aerial roots and salt-filtering tap roots that enable them to thrive in salt water and swamp lands. Mangrove ecosystems sheltered nursery and spawning grounds for much of the earths coastal marine life, They ensure rich nutrients for sea life; and needed protection of shorelines from erosion by waves and storm action. The strong holding roots of mangroves protect sea grasses and coral reefs from otherwise devastating deposits of silt. Mangrove forests, therefore, are essential habitats for many varieties of endangered species, such as rare birds, sea turtles, manatees, and dolphins.

How are Mangroves related to Coral Reefs?

In addition to providing protective areas and shelter for reef fish, crustaceans, and molluscs, their root systems also harbor organisms that trap and cycle nutrients, organic materials and other important chemicals. In addition, Mangroves also contribute to higher water quality by stabilizing bottom sediments, filtering water and protecting shorelines from erosion. They protect reefs from land runoff sedimentation, and are in return protected by the reefs from erosion during heavy storms and strong surf.

How can we protect Mangroves?

Mangrove forests are among one of the most threatened habitats in the world. They are disappearing at an alarming rate with little public notice or awareness. Lenticels in the exposed portions of mangrove roots are highly susceptible to clogging by crude oil and other pollutants, attacks by parasites, and prolonged flooding from artificial dikes or causeways, as well as costal development. Environmental stress can also damage or even kill large numbers of mangrove trees. In order to make sure that these precious trees stay protective, the government needs to enforce stricter local regulations and local communities must take action. Mangroves are essential to our ecosystem, and without them, coastal and marine life will be in potential peril.

Literature Cited

- Hogarth, Peter J.The biology of mangroves. New York : Oxford University Press, 1999

- Mangrove Action Project. <http://www.earthisland.org/map/mngim.htm>

-Tomlinson, Philip Barry.The botany of mangroves.New York : Cambridge University Press, 1986.

- USGS, Center for Costal Geology. <http://coastal.er.usgs.gov/wetlands/gallery/mangroves.html>

Images Credited by

Costal Ecosystems

<http://www.sfwmd.gov/org/wrp/wrp_ce2_wrp_ce_info/2_wrp_ce_photos7.html>

USGS, Center for Costal Geology. <http://coastal.er.usgs.gov/wetlands/gallery/mangroves.html>

Wetlands Photo Gallery

<http://www.ucmp.berkeley.edu/glossary/gloss5/biome/wetlands/wetlandsgallery.htm>

Link to other Student Webpages for 2004 Earlham Physical Geology

Copyright © 2004 Earlham College. Revised April 20, 2004 . Send corrections or comments to merwije@earlham.edu