Mangrove Tree Roots – Mangrove Information And Mangrove Types


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 Information

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.

Mangrove Types

There are three definitive types of mangrove.

  • Red mangrove, which grows along shorelines, is the hardiest of the three major mangrove plant types. It is recognized by its mass of tangled red roots that extend 3 feet (.9 m.) or more above the soil, giving the plant its alternate name of walking tree.
  • Black mangrove is named for its dark bark. It grows at slightly higher elevations than red mangrove and has access to more oxygen because the roots are more exposed.
  • White mangrove grows at higher elevations than red and black. Although no aerial roots are generally seen, this mangrove plant can develop peg roots when oxygen is depleted due to flood. White mangrove excretes salt through glands at the base of pale green leaves.

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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  • Mangrove
  • Mangrove forests
  • Fringed
  • Brackish
  • Prop roots
  • Propagules
  • Detritus
  • Dredging
  • The United States Mint kids website (www.usmint.gov/kids), including the following pages:
    • www.usmint.gov/learn/kids/library/america-the-beautiful-quarters/salt-river-bay
    • www.usmint.gov/coins/coin-medal-programs/america-the-beautiful-quarters/salt-river-bay-national-historical-park-and-ecological-preserve
  • Appropriate websites, texts, videos, and other resources for researching mangrove forests:
    • NPS Salt River Bay National Historical Park and Ecological Preserve: www.nps.gov/sari/index.htm
    • NPS Mangrove and Salt Marshes: www.nps.gov/subjects/oceans/mangroves.htm
    • NPS Red Mangroves: www.nps.gov/bicy/learn/nature/red-mangrove.htm
    • NPS Video, "Success at Salt River Bay NHP&EP planting red mangroves with STEM students: one year later": www.youtube.com/watch?v=G_xI7xJXC7A
  • Access to internet and/or computer(s) for student-conducted research
  • Access to SmartBoard, projector, or virtual presentation for multimedia presentations (i.e., display images, play video)
  • Copies of the following worksheets about Salt River Bay and mangrove forests:
    • Making Predictions Graphic Organizer worksheet
    • Benefits Leaf Template worksheet
    • Mangrove Maze Game worksheet
    • Reflection Activity worksheet
  • Coins (one per every two students)
  • Small tokens or toys to serve as game pieces
  • Craft supplies (e.g., pipe cleaners, large brown paper bags, aluminum foil, paper mache, paint, tissue paper, glue, tape, white paper, construction paper, crayons, colored pencils, scissors, newspaper, paper towel rolls/tubes, etc.)

Mangrove Meet-up: Sharing ideas, perspectives and experiences

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.


Mangrove

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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.

© CI/Russell A. Mittermeier

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.

© Trond Larsen

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.

© Kyle Obermann

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.

© Keith A. Ellenbogen

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.​​​


Session One

Essential Questions: What is a mangrove? Where do mangroves grow? What are some characteristics of mangroves?

  1. Show students the quarter design, including the reverse or tails side, found on the U.S. Mint's website: www.usmint.gov/coins/coin-medal-programs/america-the-beautiful-quarters/salt-river-bay-national-historical-park-and-ecological-preserve. Explain that as part of the America the Beautiful Quarters® Program, the U.S. Mint features national parks and historical sites on quarters that are specific to a state, territory, or district. In 2020, the U.S. Virgin Islands quarter highlights the Salt River Bay National Historical Park and Ecological Preserve. The park is located on St. Croix in the U.S. Virgin Islands.
  2. Ask students to guess which type of plant is featured on the coin. Explain that this is a mangrove tree. Many trees that grow together are known as mangrove forests. They play a very important part in the coastal ecosystem in the U.S. Virgin Islands. The Salt River Bay National Historical Park and Ecological Preserve holds some of the largest remaining mangrove forests in the Virgin Islands.
  3. Explain to students that they are going to learn all about mangrove forests and the services they provide.
  4. Show students additional pictures of mangroves from the NPS website for Salt River Bay National Historical Park and Ecological Preserve (www.nps.gov/sari/index.htm) Mangrove and Salt Marshes (www.nps.gov/subjects/oceans/mangroves.htm) Red Mangroves (www.nps.gov/bicy/learn/nature/red-mangrove.htm) or other online sources. Point out interesting characteristics about mangroves to help guide students' thinking (i.e., where it grows, what the roots look like, what type of water it grows in, etc.).
  5. As a warmup activity, ask students to make predictions about mangroves based on their observations.
    • If teaching in person, have students write their predictions in the Predictions column of the "Making Predictions Graphic Organizer" worksheet.
    • If teaching remotely, have students create their own graphic organizer in a journal or notebook using the Graphic Organizer worksheet as a guide. After writing their predictions, allow students to share their predictions.
  6. Show the NPS video, "Success at Salt River Bay NHP&EP planting red mangroves with STEM students: one year later": www.youtube.com/watch?v=G_xI7xJXC7A. Ask students to share what they learned about mangroves.
  7. Explain that mangrove trees that grow together are called mangrove forests. Mangrove forests play an important role in a coastal ecosystem. Review the following information with students:
    • A mangrove is a small tree or shrub that grows in shallow water along the coastlines in warm, tropical climates.
    • Mangrove forests grow in tropical or subtropical regions all over the world, including the U.S. Virgin Islands. On St. Croix, Salt River Bay is fringed – or bordered – by mangrove forests. There are 3 main species in Salt River Bay: red mangroves, white mangroves, and black mangroves. The quarter features a red mangrove tree.
    • Mangroves can grow in saline water (saltwater) or brackish water (a mixture of fresh water from any source like a river and salt water from the sea).
    • Mangroves are "landbuilder communities" – they extend the shoreline through their system of roots, called "prop roots".
    • The roots of mangroves are special. Like other plants, they need oxygen to survive, but there is no oxygen in the mud or soil where the roots are. So, mangroves have developed roots that grow from the ground upwards and even beyond the surface of the sea. This allows them to breathe and get the oxygen they need.
    • Mangrove seeds are also unique. The seeds develop into a seedling with leaves and roots while still on the mature mangrove tree. The seedlings – called propagules – will stay on the adult tree and grow to a certain size. Then, they drop into the water and float until they reach water that is shallow enough for the roots to penetrate the mud. These seedlings can travel far distances and survive waves and tide changes.
    • Mangrove forests provide many benefits:
      • Provide a habitat for hatchling sea turtles or a "nursery" for vulnerable young fish, shrimp, and crustaceans that later move out to coral reefs or to sea
      • Provide food for tiny marine animals (i.e., leaves and twigs are broken down and eaten by small organisms)
      • Provide nesting areas and shelter for coastal birds
      • Prevent coastline erosion
      • Clean the water (i.e., trap and cycle pollutants and chemicals)
      • Protect uplands from storms, winds, waves, and floods
  8. Using the Making Predictions Graphic Organizer worksheet or their own journal/notebook entry, have students check their original predictions and fill in the "Fact Check" column with new information they learned. Ask for students to share whether their predictions were correct and what they learned.
  9. Next, each student will create their own mangrove tree. Using the Salt River Bay National Historical Park and Ecological Preserve quarter design and mangrove images as a guide, demonstrate to students how to create a model of a mangrove tree using craft materials available. The model should show its roots, trunk, leaves, and canopy. If students get done early, have students research and create models of some of the animals that live in, on, or around the mangrove tree (e.g., fish, shrimp, algae, bees, birds, etc.).
    • If teaching in person, have students make their mangrove model using various craft supplies (e.g., pipe cleaners, construction paper, paper towel rolls, tissue paper, glue, tape, scissors, paper mache, brown/black/white paint, etc.).
    • If teaching remotely, have students find materials around their house that they can use (e.g., cardboard tubes from paper towel or toilet paper rolls, straws, napkins, building blocks, play dough, paper, cardboard, newspaper, etc.).
  10. Once students complete their mangrove tree model, have them create another model of a tree that is located near their house or neighborhood. Ask the students to explain how the models are similar and how they are different.

Session Two

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?

  1. Review with students what a mangrove is and the key characteristics of mangrove forests.
  2. Create a T-chart on a projector, smartboard, whiteboard and/or via a digital presentation. On side of the T-chart, write "Environmental Benefits". On the other side, write "Human Benefits". Explain to students that mangrove forests play a very important role in the environment as well as human communities. They provide food, shelter, and protection for animals and humans.
  3. Re-watch the NPS video, "Success at Salt River Bay NHP&EP planting red mangroves with STEM students: one year later": www.youtube.com/watch?v=G_xI7xJXC7A. Ask students to name some of the benefits of mangroves that were discussed in the video (listed below) or from what they learned in Session One. After each benefit is listed, ask if it is a human benefit or an environmental benefit. Write each benefit under the correct column in the T-chart. Examples of responses can include:
    • Environmental Benefits
      • Roots provide habitats or a "nursery" for young fish, shrimp, and crustaceans that later move out to coral reefs or to sea
      • Leaves and branches provide habitats for birds, bees, insects, and other wildlife
      • Decayed leaves and/or twigs – called detritus – are broken down and eaten by small organisms, which in turn, become food for larger organisms
      • Protects the coastlines from storms, erosion, and floods
      • Controls stormwater / runoff from the land by capturing sediment and/or pollutants to help clean the water
      • Protects coral reefs from too much sediment from runoff
    • Human Benefits
      • Protects areas of human settlement from heavy storm surge (e.g., winds, waves) from seasonal hurricanes
      • Protects areas of human settlement from erosion
      • Provide a rich source of fishery products (e.g., fish, shellfish)
  4. Let the students know that they will be creating a "Mighty Mangrove" tree diagram. Use the pictures and/or coin design as a guide.
    • If teaching in person, break students into small groups. Allow them to draw the roots, trunk, and branches of a mangrove tree on a large sheet of paper or poster.
    • If teaching remotely, instruct students to draw their own roots, trunk, and branches of a mangrove tree on a piece of paper or another medium (e.g., a large brown paper grocery bag).
  5. Using the T-chart as a guide, instruct students to choose a benefit that they think is important. Using the Benefits Leaf Template worksheet as a guide, model for students how to write a sentence explaining why mangrove forests are important using the benefit they selected.
    • If teaching in person, have students cut out a leaf from construction paper and re-write their sentence on the leaf.
    • If teaching remotely, have students draw a leaf on a piece of paper, re-write their sentence, then cut it out and color it.
  6. Instruct students to either tape or glue their leaves onto the tree branches. Allow students to continue to create more leaves that describe additional benefits to fill out the tree more.
    • If teaching in person, take turns presenting each group's tree to the class.
    • If teaching remotely, have students show their tree to an adult and/or virtually.

Session Three

Essential Questions: What threats do mangrove forests face? What can I do to help protect and preserve mangrove forests?


The Critical Importance Of Mangroves To Ocean Life

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"

Authors:
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.

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Materials provided by American Geophysical Union. Note: Content may be edited for style and length.


Watch the video: Mangroves - Definition: Habitat: Types: Adaptations: Stresses: Economic Value: mangrove forest Uses


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