Mangrove forest

Mangrove forests, also called mangrove swamps, thickets or mangals, are special wetlands found in warm places where the land meets the ocean. These forests grow in areas where the water moves slowly and the soil has very little oxygen. They can only live in warm climates because they cannot survive in cold temperatures.

The trees in mangrove forests have unique stilt-like roots that help them stay standing in the water. These roots slow down the moving water and help build up the land by trapping tiny bits of dirt. They also protect the coast from erosion and provide a home for many animals.

Mangrove forests are very important for the environment. They help control the climate by storing a lot of carbon in the soil under the water. They also help keep the water clean and provide food and shelter for many sea creatures. Scientists are still learning more about how these forests work and how they help the world.

Today, there are about 15.9 million hectares of mangrove forests around the world. Asia has the most, with Indonesia having the largest area. Other countries with big mangrove forests include Brazil, Australia, Nigeria, and Mexico.

Overview

Mangrove forests are special wetlands found in warm places near the coast where the water often goes in and out with the tides. There are about 80 different kinds of mangrove trees, and they all live in areas where the water moves slowly and leaves behind rich soil that doesn’t have much oxygen. These trees can’t survive in cold places, so they only grow in warm climates.

The trees have unique root systems that look like stilts, helping them stay upright in muddy water. These roots slow down the water, which helps build up land and protects the coast from big waves and storms. The roots also give a safe home to many sea creatures, including young fish that grow up to be important for fishing and fun.

Distribution

Main article: Mangrove tree distribution

Further information: List of mangrove ecoregions

There are about 80 kinds of mangrove trees found along coastlines around the world. Most of these special trees grow between where the ocean meets the land, where the water level changes with the tides. They used to cover much of the world's warm coastlines, especially in Southeast Asia. Some are small bushes, while others grow very tall, up to 60 meters. These trees live in different places depending on how much water they can handle and how salty the soil is.

Mangroves grow in 118 different countries in warm parts of the world, mostly near the equator. Asia has the most mangrove forests, followed by Latin America and Africa. The biggest mangrove forest is in the Sundarbans, located where the Bay of Bengal meets rivers from India and Bangladesh. This huge forest is home to many animals, including the Bengal tiger, and it helps protect nearby communities from strong storms.

Ecosystem

Mangrove forests provide a special home for many small sea creatures. Their tangled roots shelter algae, barnacles, oysters, sponges, and bryozoa, which need a hard surface to live. Shrimp and mud lobsters live in the muddy areas below, while mangrove crabs eat the leaves and help feed other animals.

In places like Puerto Rico, different kinds of mangroves grow in different spots, each storing different amounts of carbon. These forests play a big role in storing carbon, helping protect coastlines from strong storms. Over time, mangrove material can turn into peat, locking away carbon in the soil.

Biodiversity

Mangrove forests are special places for many kinds of animals, especially birds and fish. Birds like mangrove kingfishers and brown pelicans live in these forests and use them as safe places to find food. The forests change with the tides, so birds need to be flexible to survive.

Fish also love mangrove forests. The roots of the trees give shelter to baby fish and food to grown fish. Crabs, like fiddler crabs, help keep the soil healthy by moving it around and providing food for other creatures. These tiny animals work with tiny organisms to recycle nutrients, making the forest a rich home for many living things.

Biogeochemistry

Further information: Marine biogeochemistry

Carbon cycle

Mangrove forests are some of the most productive marine environments in the world. They produce a lot of plant material each year, about 208 Tg C yr⁻¹. As these forests grow, they keep a balance between older trees dying and new trees growing. This means that the amount of carbon stored in the forest stays about the same. The carbon from these forests can stay in the trees, get buried in the mud, or move to nearby areas as small bits of plants and other materials.

One idea is that mangroves help feed nearby ocean areas by sending out carbon. This carbon can support tiny animals and plants in those areas. Studies show that mangroves usually produce more carbon than they keep, which supports this idea. However, how much carbon they send out can change depending on the shape of the coast, tides, and how much fresh water flows into the area.

In the 1990s, scientists thought mangroves produced about 218 ± 72 million tons C each year. They later found that about half of this carbon was sent out into the water. Recent studies in Australia support these ideas, though some scientists think the amount sent out might be a bit less.

Nitrogen assimilation

Mangrove forests and coastal marshes often lack enough nitrogen, which plants need to grow. Because of this, mangrove plants are very good at using the nitrogen they can find in the soil. Different kinds of mangrove trees can use nitrogen at different speeds, even though they use it in similar ways. Scientists have measured how fast mangrove plants take in nitrogen and found it can vary a lot depending on how much nitrogen is available.

The environment can also change how fast mangroves take in nitrogen. Salt in the water can make it harder for plants to use nitrogen, which slows down their growth.

Exploitation and conservation

Mangrove forests have faced significant destruction, with about 35% of them lost since data collection began. Each year, around 2% of mangrove areas continue to disappear. One major cause is shrimp farming, which destroys large parts of these forests. However, efforts to protect mangroves are growing. Communities are finding ways to earn money without harming mangroves, such as by producing honey or collecting natural materials.

Mangroves also help protect coastal areas from strong storms and floods. For example, a village in Tamil Nadu planted many trees, which helped protect it during a big tsunami in 2004.

Biogeochemical implications of conservation

Mangroves help store carbon, which is important for the environment. When mangroves are lost, this storage decreases. Some places, like the Niger Delta in Nigeria, Gazi Bay in Kenya, and Trapeang Sangkae in Cambodia, have started projects to protect and restore mangroves. These projects help local communities and the environment.

Ocean deoxygenation

Mangrove areas sometimes have less oxygen in the water, which can harm sea life. Human activities, like building shrimp farms, make this problem worse by polluting the water. Protecting mangroves helps keep water quality better and supports local fish populations.

Reforestation

Main article: Mangrove restoration

In some places, people are working to plant new mangrove trees. Red mangroves are often chosen because they are popular in special water setups called marine aquariums. They help keep the water clean by removing certain substances.

One project in Arkiko, Eritrea, tries to grow new mangroves. Early attempts didn’t work well, but scientists learned that mangroves need nutrients from the water to grow. They developed a special way to plant the seeds, using old steel cans and adding nutrients to help them grow. Today, hundreds of thousands of mangroves are growing there, providing food for animals and homes for fish and crabs.

Another way to plant mangroves is by using drones. These drones can carry and drop seed pods quickly and cheaply compared to traditional methods.

In Java, Indonesia, many mangrove forests were lost, which used to protect the land from flooding. A group called Wetlands International helped villages rebuild these forests. They built barriers from bamboo and later PVC pipes to catch sediment and mangrove seeds. Over time, these barriers help new mangroves grow and protect the coast. By 2018, they had built many kilometers of these barriers to help restore the mangroves. However, there are worries that sometimes reforestation might not always work perfectly and could even harm the mangroves in the long run.

National and international studies

Studies show that Belize has lost only a small amount of its mangrove forests over the past 30 years. Between 1980 and 2010, less than 16 square kilometers of mangroves were cleared. This slow loss rate suggests that Belize's rules to protect mangroves are working well. However, protecting these important forests is still very important because they help the country's economy.

In Tanzania, a scientist named Adelaida K. Semesi started one of the first plans to manage mangrove forests. In 2019, NASA used satellites to create new maps of mangrove forests around the world. These maps show that mangrove forests help remove carbon dioxide from the air, making them very important for our planet.