By: Mary H. Dyer, Credentialed Garden Writer
What are mangroves? Experts believe this fascinating and ancient family of trees originated in Southeast Asia. The plants traveled to tropical, marine environments around the world via the buoyant seeds, which floated on ocean currents before lodging in wet sand where they took root. As the mangrove plants established and mud gathered around the roots, the trees developed into large, very important ecosystems. Keep reading for more mangrove information, including the adaptations that allow mangrove plants to survive in the saltwater zones between water and land.
Mangrove forests serve a critical role by stabilizing shorelands and protecting them from erosion by the constant pounding of waves and tides. The storm buffering capability of the mangrove forests have saved property and countless lives around the world. As sand gathers around the roots, new land is created.
Additionally, mangrove forests are home to a vast number of living organisms including crabs, lobsters, snakes, otters, raccoons, hundreds of thousands of bats, a vast variety of fish and bird species, to name just a few.
Mangrove plants have several unique adaptations that allow them to survive in harsh environment. Some types filter salt through the roots, and others through glands in the leaves. Others secrete salt into the bark, which the tree eventually sheds.
The plants store water in thick, succulent leaves similar to desert plants. A waxy coating minimizes evaporation, and small hairs minimize moisture loss through sunlight and wind.
There are three definitive types of mangrove.
Mangrove environments are threatened, due in large part to clearing of land for shrimp farms in Latin America and Southeast Asia. Climate change, land development and tourism also affect the future of the mangrove plant.
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By MAP Volunteer Intern, Emma McDowell
March 9th was another sweltering day in southern Thailand. The air was almost wet with humidity, the sun beat down from overhead, and the relentless heat hung around like a blanket. However, the midday temperature did not stop the seven villagers from Ban Thung Yor, Klong Thom, Krabi Province who were exploring the mangrove restoration site at Ban Nai Nang. This was the second stop on a two-day tour of three villages affiliated with Mangrove Action Project (MAP) and funded through Synchronicity Earth of the UK. The tour was set up to highlight the experiences of MAPs participants and share ideas of how to successfully restore their own mangrove area.
Earlier that day they had explored the site at Ban Lang Da- a reclaimed shrimp pond area where the abundant green mangroves showed the success of the Community Based Ecological Mangrove Restoration project (CBEMR) started in 2008. The site was restored back to mangrove forest, after it had been converted into a shrimp pond and then abandoned for more than 10 years. Village leader Mr. Bandon Mad-osot showed the sites’ foliage and reestablished fish, crab and bird populations to the villagers from Ban Thung Yor. He spoke of his community’s experience working with MAP and ended his tour by saying, “I don’t have very much more to say. Just do it! You will see so many benefits for your community.” The villagers asked many questions and were excited to see how the area has reestablished the mangroves over time. “It is beautiful,” spoke the village chief of Thung Yor, “so much green everywhere.”
Our group posing for a picture in front of the bee and rubber garden at Ban Nai Nang. March 8th, 2017
The second stop of the day brought the villagers to the heat of mid-day and to the eco village of Ban Nai Nang. Villagers got to meet Mr. Sutee Pankwan the chairperson of the villages apiculture group, and discussed how the village has many different groups (crab bank, ecotourism, and apiculture product production) and that allwork together and contribute their profits to the conservation group that aids the preservation of the mangroves. Sutee Pankwan highlighted the need to learn and work together and share knowledge to be successful, and told the group that, “working together is the key to our success. We all have different groups in the village, but we always make sure that some of the money we make, goes into the conservation fund. Without natre, our projects would be pointless.” He also shared that the village was trying to register as a community forest, and that they have plans to work on rehabilitating the mangrove area in the coming month. After trying some of the delicious honey and touring the mangrove site, the villagers embarked on the final step of their trip.
Two participants showing off their own handmade Batik prints made at Ban Talae Nok. March 9th, 2017.
The tour concluded with an overnight visit to the village of Ban Talae Nok. Villagers here have worked for years to reestablish their mangrove area, and have divided it into two sections- one left to restore naturally, and another with the addition of the planning of Nypa plants that the villagers use for thatch roofs, cigarette rollers, food, and daily life. Villagers of Ban Thung Yor were invited to learn to make batik fabric prints and were taken on a tour of the mangrove area, which has grown a considerable amount since the last time it was visited. “Our biggest problem was hydrology of the site,” spoke Mr. Ekakarat Cheangyang, “once we got the hydrology fixed, the area grew back quite quickly, and is still growing.” Indeed, the lush green leaves and myriad of crabs, birds, and monkeys are a sure sign of the sites success.
A group “selfie” in the Mangrove Restoration Site at Ban Talae Nok. March 9th, 2017.
Upon saying goodbye, and arriving back in Ban Thung Yor, the participants were left with a lot of information and knowledge. Thung Yor village chief, Mr. Raksa Komodkhan said, “Thank you so much for taking us on this trip. We have a lot to think about now and will raise these ideas with our community.” Hopefully after some reflection, they will decide to join the MAP network and make their site the latest addition to the restoration areas directed by MAP.
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Mangrove, any of certain shrubs and trees that belong primarily to the families Rhizophoraceae, Acanthaceae, Lythraceae, Combretaceae, and Arecaceae that grow in dense thickets or forests along tidal estuaries, in salt marshes, and on muddy coasts and that characteristically have prop roots—i.e., exposed supporting roots. The term mangrove also applies to thickets and forests of such plants. Respiratory or knee roots ( pneumatophores) are characteristic of many species they project above the mud and have small openings (lenticels) through which air enters, passing through the soft spongy tissue to the roots beneath the mud.
Mangroves are extremely important to the coastal ecosystems they inhabit. Physically, they serve as a buffer between marine and terrestrial communities and protect shorelines from damaging winds, waves, and floods. Mangrove thickets improve water quality by filtering pollutants and trapping sediments from the land, and they reduce coastal erosion. Ecologically, they provide habitat for a diverse array of terrestrial organisms, and many species of coastal and offshore fish and shellfish rely exclusively on mangroves as their breeding, spawning, and hatching grounds. Because of their high salt tolerance, mangroves are often among the first species to colonize mud and sandbanks flooded by seawater, but an increase in coastal development and altered land use led to a decline in global populations. Several species are listed as vulnerable or endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.
Mangrove flora along the Atlantic coast of tropical America and along the coast of the Gulf of Mexico to Florida consists chiefly of the common, or red, mangrove (Rhizophora mangle) of the family Rhizophoraceae and the black mangroves (usually Avicennia nitida, sometimes A. marina) of the family Acanthaceae. Mangrove formations in Southeast Asia also include Sonneratia of the family Lythraceae and the nipa palm (Nypa fruticans) of the family Arecaceae. The trunks and branches of most mangrove species constantly produce adventitious roots, which, descending in arched fashion, strike at some distance from the parent stem and send up new trunks.
The common mangrove grows to about 9 metres (30 feet) tall. The leaves are 5 to 15 cm (2 to 6 inches) long, opposite, oval or elliptic, and smooth-edged they are thick, have leathery surfaces, and are borne on short stems. The flowers are pale yellow. While the fruit is still attached to the parent branch, the long embryonic root emerges from the seed and grows rapidly downward. When this propagule falls, the young root is in the correct position to be driven into the mud the plant being thus rooted, the shoot makes its appearance. The young root may grow to such a length that it becomes fixed in the mud before the fruit separates from the parent tree.
Florida mangroves prefer the southern coast.
The United States has roughly 2,500 square kilometers (about 1,500 square miles) of mangroves — an area about the size of Luxembourg — located almost entirely in southern Florida.
Mangroves have (carbon) hoarding issues.
Blue carbon ecosystems (mangroves, sea grasses and salt marshes) can be up to 10 times more efficient than terrestrial ecosystems at absorbing and storing carbon long term, making them a critical solution in the fight against climate change.
Mangroves can help keep people safe.
Mangrove forests — specifically, their thick, impenetrable roots — are vital to shoreline communities as natural buffers against storm surges, an increasing threat in a changing global climate with rising sea levels.
There’s trouble in Myanmar.
Mangroves are under threat nearly everywhere, but the problem is particularly acute in Myanmar, where the rate of deforestation is four times the global average.
Shrimping is a jumbo problem.
In Thailand, Mexico and Indonesia, mangroves are often cut down to make room for temporary shrimp pens. But once the pens have been removed, the accumulated biowaste renders the water too toxic for most forms of life.
It’s better to revitalize than replant.
Mangroves’ dense root systems inhibit the flow of tidal water and encourage the deposition of nutrient-rich sediments. But once lost, mangroves are very difficult to replant due to shifts in the very sediments the roots helped keep in place.
Essential Questions: What is a mangrove? Where do mangroves grow? What are some characteristics of mangroves?
Essential Questions: What role do mangrove forests play in the ecosystem of the U.S. Virgin Islands? Why are they important to preserve and protect?
Essential Questions: What threats do mangrove forests face? What can I do to help protect and preserve mangrove forests?
Mangroves, the backbone of the tropical ocean coastlines, are far more important to the global ocean's biosphere than previously thought. And while the foul-smelling muddy forests may not have the scientific allure of tropical reefs or rain forests, a team of researchers has noted that the woody coastline-dwelling plants provide more than 10 percent of essential dissolved organic carbon that is supplied to the global ocean from land, according to a report to be published 21 February in Global Biogeochemical Cycles, a publication of the American Geophysical Union.
Thorsten Dittmar at Florida State University in Tallahassee reports that mangrove plants, whose finger-like roots are known to protect coastal wetlands against the ocean and as important fish habitats, cover less than 0.1 percent of the global land surface yet account for a tenth of the dissolved organic carbon (DOC) that flows from land to the ocean. Dittmar and his colleagues at several German research institutions analyzed the carbon output from a large mangrove forest in Brazil and suggest that the plants are one of the main sources of dissolved organic matter in the ocean.
The researchers note that the organic matter that is dissolved in the world oceans contains a similar amount of carbon as is stored in the skies as atmospheric carbon dioxide, an important greenhouse gas. Dissolved organic matter is an important player in the global carbon cycle that regulates atmospheric carbon dioxide and climate.
"To understand global biogeochemical cycles it is crucial to quantify the sources of marine dissolved organic carbon," Dittmar writes. "Here we show that mangroves play an unexpected role in the global carbon cycle."
Dittmar reports that the mangrove root system slows carbon-rich leaf litter running from continental land and allows it to settle into shallow sediment, where dissolved organic matter is leached in large quantities into the coastal waters. The daily rise and fall of the tides then flushes the dissolved carbon into the open ocean (like a teabag being dipped in an out a cup). Once in the ocean, however, the intense tropical sunlight destroys some of the most delicate dissolved organic carbon molecules. But more than half of the dissolved organic matter survives the attack from sunlight or bacteria.
The authors measured the chemical signature in water samples from the massive mangrove forest in northern Brazil, using natural carbon isotopes and nuclear magnetic resonance spectroscopy--an established and common technique for determining the structure of organic compounds--to determine that mangroves are indeed a main source of dissolved organic carbon in the open ocean. In total, they concluded that the carbon exported from mangroves is approximately 2.2 trillion moles of carbon per year [2.2 x 10(12), similar to the annual Amazon River discharge], nearly triple the amount estimated from previous smaller-scale estimates of the carbon released into the ocean.
Mangrove foliage, however, has declined by nearly half over the past several decades because of increasing coastal development and damage to its habitat. As the habitat has changed, ever-smaller quantities of mangrove-derived detritus are available for formation and export of dissolved organic matter to the ocean. The researchers speculate that the rapid decline in mangrove extent threatens the delicate balance and may eventually shut off the important link between the land and ocean, with potential consequences for atmospheric composition and climate.
Title: "Mangroves, a major source of dissolved organic carbon to the oceans"
Thorsten Dittmar, Florida State University, Tallahassee, Florida
Norbert Hertkorn, GSF-National Research Centre for Environment and Health, Institute of Ecological Chemistry, Neuherberg, Germany
Gerhard Kattner, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
Ruben J. Lara, Center for Tropical Marine Ecology, Bremen, Germany.
Citation: Dittmar, Thorsten, et al., (2006), Mangroves, a major source of dissolved organic carbon to the oceans, Global Biogeochem. Cycles, Vol. 20, No. 1, GB101210, doi: 10.1029/2005GB002570, 2006.
Materials provided by American Geophysical Union. Note: Content may be edited for style and length.