Outforia Quicktake: Key Takeaways
- Marshes are permanent wetlands where herbaceous plants, such as grasses and reeds, flourish and they can be classified into three types: Tidal Salt Marshes, Tidal Freshwater Marshes, and Inland Freshwater Marshes.
- The formation of marshes can be attributed to various phenomena like rising sea or river levels, glacial or earthquake activities, human activities like dam or highway construction, or even beaver activities.
- Marshes provide habitat to a plethora of plant and animal species, contributing to the overall biodiversity of the ecosystem. Their ecosystem is driven by a complex food web that, if disrupted, can lead to the ecosystem’s collapse.
- Marshes are under threat from pollution, invasive species, climate change, and development activities like draining marshes for farming and buildings.
- Marshes also have cultural significance, featuring in various myths, legends and folklore across different cultures.
Water is life, and this is very apparent in a wetland such as a marsh. A marsh is a permanent wetland where herbaceous plants such as reeds and grasses grow.
Marshes have shallow water, where trees are not present, or at least not in the dominant flora. Marshes can be composed of salt, fresh water, or a mixture of both.
Marshes can be fun to explore, as long as you have the right equipment and gear. It also helps to have a good map. Marshes have historically been mysterious places where will-o’-the-wisps and phantoms have lured travelers.
Human industries such as farming, fishing, and basket making have shaped our relationship with wetlands today.
Intrigued? Read on to discover the secret life of marshes.
How is a Marsh Formed?
Marshes can be formed in several ways:
- By rising sea or river levels.
- By a glacier or earthquake damming a river, causing water to flood over the surrounding landscape.
- Gradually, as a river erodes the landscape and deposits sediment,
- By sinkholes dissolving bedrock and leaving depressions.
- Human activity such as dam or highway construction
- Beavers are damming rivers.
When any of these factors create a floodplain of shallow water and sediment, herbaceous plants and grasses begin to grow and spread. As these establish, they form permanent areas of boggy grassland.
So some marshes can be created in a matter of months, like those made from human dam construction. Some have taken thousands of years to establish, such as those made by rivers gradually eroding the landscape.
Where Can You Find Marshes?
They are most often found in lowland areas, where water flows more slowly and rivers create floodplains. The reduced force of the water allows sediment to drop and build up enough for plants to grow.
Tidal marshes can be found where there is a natural barrier to wave action, such as an island or peninsula. The reduced force of the tide allows sediment to form, and a marsh wetland is created.
Here is a delta on the Yukon River in Alaska.
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Types Of Marshes
There are three types of marshes found worldwide:
- Tidal Salt Marshes: coastal marshes that are flooded with sea water, most often by tides
- Tidal Freshwater Marshes: marshes fed by freshwater streams but affected by tides
- Inland Freshwater Marshes: marshes fed by inland water from a river, spring, or lake
Above is a tidal marsh in the Marismas de Santoña, Victoria y Joyel Natural Park of Cantabria, in Spain.
Marshes Around The World
Here are just some of the well-known marshes around the world: Many of them are vital to the biodiversity of their respective countries. They are important economically to the people who live in and near them.
The Pantanal, Brazil
The Pantanal is the largest wetland on earth. It encompasses over 140,000 square kilometers. 131,000 of its 140,000 sq km area is flooded annually.
Some of the Pantanal is marsh, and some of it is swamp. There are even regions of dry forest within it.
It is home to 2,000 species of plants and almost 700 species of birds, plus hundreds of species of mammals, insects, reptiles, and amphibians.
It’s a UNESCO World Heritage Site and the largest tropical wetland in the world. These capybara are just one of the mammal species that thrive in the Pantanal.
The Camargue area of France is famous for its galloping wild horses and flamingos. It contains one of the 25 major flamingo nesting sites worldwide.
The Camague is a patchwork of pink salt flats, marshes, rice paddies, and beaches. Local cowboys called “gardians” tend the Camargue’s prized black bulls and horses.
It is home to 400 species of birds, as well as flamingos.
Finland’s Boreal Peatlands
One third of Finland’s land area is boggy terrain. This is composed of decomposing mosses and sedges from the last Ice age, 12,000 years ago.
Finland has drained half of its wetlands for forestry, leaving 4 million hectares undrained.
Now, with government funding, 28,000 of the 50,000 hectares of wetland in Finland’s 40 national parks have been restored.
One such peatland is Leivonmäki National Park. This contains forests, marshes, and lakes. There are lots of hiking trails and duckboard trails.
Sungei Buloh Wetland Reserve, Singapore
Asia contains very large wetlands that feed off the Indus, Ganges, Chao Praya, Mekong, and Red rivers.
One such place is the Sungei Buloh Wetland Reserve in Singapore. It was created in 1993 and officially recognized as a nature reserve in 2002.
It contains mangroves, mudflats, forests, and ponds. It is home to animals such as mudskippers, water snakes, crabs, and spiders, as well as many bird species like kingfishers and sunbirds.
It is recognized as a site of international importance for migrating birds. The picture shows a kingfisher pod, where visitors can watch kingfishers from a sculptural hide located on an aerial walkway.
Meet some classic marsh plants that you may find on a visit to marshes all over the world. These plants have adapted to a life of being semi-submerged.
Their roots play a vital role in wetland ecosystems, keeping the sediment in place. They provide food and habitat for wetland animals.
Reedmace (Typha latifolia)
This tall, stately grass has a brown seed head that looks like a hot dog. Earlier in the season, you will see clouds of yellow pollen from the male parts of the flowers. Reedmace is highly invasive, spreading by seed and rhizome.
It’s edible and can be used for basketry and phytoremediation (removing toxins such as heavy metals from water).
Watercress (Nasturtium officinale)
Watercress is a cabbage family plant native to Europe and Asia. It grows in areas of very shallow, flowing water. It is a delicious edible if you like peppery flavors. It is cultivated in many countries and is expensive to buy.
Watercress has white, four-petaled flowers. It can harbor liver fluke parasites, so only the aerial parts should be eaten raw. It is very nutritious.
Egyptian Paper Rush (Cyperus papyrus)
Endemic to the Nile River in Egypt, papyrus has a long history. It was used as writing paper by the ancient Egyptians. The part used was the inner pith. Papyrus belongs to the Sedge family of grasses.
Papyrus can reach 5 m (16.4 ft) in height. It has a spray of brown flowers. It needs saturated soil or shallow freshwater to grow. It supports a rich and fertile ecosystem populated with birds, fish, crocodiles, and hippopotamuses.
Water Hyacinth (Pontederia crassipes)
Water Hyacinth is also regarded as highly invasive in its native South America. So much so that it is now found in most countries across the world that are not too cold. It is the most invasive water plant in the world.
It is a mat-forming aquatic plant with tiny pockets of air trapped in bulb-like growths on the stalks. The purple roots hang down in the open water. The flowers are violet. It can be used as a salad, as biofuel, and even to ‘grow’ new floating islands for impoverished people.
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Of all the thousands of species of marsh animals, here are just a few of the most fascinating.
Hippopotamus (Hippopotamus amphibius)
The hippo is a classic of children’s storybooks. However friendly they look with their big stumpy teeth and short legs, hippopotamus are dangerous animals. They live in sub-Saharan Africa, staying in the cool of the river by day and feeding at night.
They weigh up to 8,000 pounds (3,629 kg). They feed on short grasses and fallen fruit.
Hippos secrete a white “suntan lotion” from pores in their skin. This protects their skin from sunlight. They will also cover themselves in mud to ward off biting insects.
Mudskipper (Periophthalmus sp.)
Mudskippers are charming-looking bony fish in the Goby family. They have adapted to a life half in and half out of water. They represent the missing link between fish and amphibians.
Mudskippers can trap bubbles of water in their gills. This enables them to breathe air for up to two days. They also have specially adapted eyes and fins that are able to propel them on land by ‘jumping’. Hence the name ‘mudskipper’.
Bittern (Botaurus stellaris)
This stripy, shy heron is found in the UK. It has a pattern of bars and stripes in browns and tans, which makes it hard to see amongst the reeds. It feeds on fish, amphibians, and insects in marshland and wetlands.
The bittern has a mellow, booming call. It’s the male that makes this far-reaching call in the spring. It is an Amber List species, which means it is rare but not endangered.
Listen to its call below.
Beavers (Castor fiber)
Beavers capture the popular imagination with their chubby bodies and powerful incisors. Their teeth are actually orange due to the high levels of iron in the enamel. This makes their teeth strong enough to bite through wood.
Beavers are known for their dam-building abilities. They are so good at this that they have a large impact on waterways. They can be beneficial in the right places, slowing the flow of rivers and mitigating flood damage.
The Eurasian beaver used to have a wide range, from the UK to Siberia, but now 85% of Eurasian beavers are found in Europe. The American beaver can be found all over North America.
The Marsh Ecosystem
The unique conditions found in a salt marsh, for example, favor salt-tolerant water plants. Mammals and insects both eat them. Crustaceans feed on fish, which in turn are eaten by birds. Birds also feed directly on fish. Crabs may scavenge a dead bird’s corpse.
This complex chain of life is known as a food web.
Here’s an example of a salt marsh food web:
- Worms are fed on by bay goby fish
- Egrets feed on bay goby fish.
- Egrets also feed on crabs
- Crabs feed on dead egret
- Dead egrets release nutrients into mud, which are fed on by salt marsh plants.
A freshwater food web in a Hudson River (US) marsh might look like this:
- Algae eaten by snails or worms
- Snails eaten by marsh wrens and redwing blackbirds
- Cattails and reeds eaten by muskrats and mice
- Mice eaten by snapping turtles
- Mice eaten by herons
The reliance of each living thing on other living things means these food webs can be fragile. Removing one link from the web can cause the entire ecosystem to collapse.
Even removing an apex (top) predator like the snapping turtle can unbalance the food web, causing a population boom in mice. The mice would then eat too much reedmace and cause a food shortage.
Marsh vs Swamp: What’s the Difference?
A marsh is a region of shallow water dominated by grasses and soft-stemmed plants.
A swamp is a region of shallow water dominated by trees. That’s it in a nutshell.
Marshes and swamps can be found in the same wetland regions, such as certain areas of New Zealand or the Pantanal in Brazil.
Below is an example of a cypress swamp by Lake Martin in Louisiana, US. Notice how the trees have developed aerial root systems so they don’t drown.
Why are Marshes Threatened?
One-third of the world’s wetlands have disappeared since 1970. 85% of the world’s freshwater wetland species are in decline. What factors are causing this to happen?
Marshes are threatened by:
- Pollution: Wetlands act as sinks for fertilizer runoff, sewage, heavy metals, and factory chemicals. They do have the ability to filter toxins from water. Reedmace is used for removing heavy metals from water.
- Invasive species: This includes water hyacinth, killer shrimp, and signal crayfish, which outcompete native species for resources. They can also spread disease.
- Climate change: Drought and floods can unbalance marsh ecosystems.
- Development: draining marshes for farming and buildings.
American Signal Crayfish are bigger than the UK’s native White Clawed Crayfish. They have caused the almost total extinction of this species. If you catch one, it is illegal to return it to the water.
Myths and Legends of the Marshes
There are some real mysteries and spooky stories concerning wetlands and marshes.
Will-o’-the-wisps are said to be malevolent spirits that are dead but doomed to wander the marshes of Europe.
In some legends, the wisp is a dead blacksmith. The wisp lures travelers into the marshes with a magic light or lantern. When he blows out the light, they are stranded and sink into the marsh to their doom.
Bolotnik is the Master of Marshes in Slavic folklore. He appears as an old man covered with weed and fish scales. He pretends to be a stepping stone, which then gives way under a traveler’s foot. They fall to their deaths in the water and mud.
The Essex Serpent was apparently inspired by 17th-century legends of evil serpents and “wyrms” living in the marshes near Essex, UK. This is how the village of Wormington got its name.
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What to Take with You When Exploring a Marsh
If you haven’t been scared off by the legends and still want to explore a marsh, here are some good ideas as to how to do it and what to take.
The best ways to explore marshes are on foot, by canoe, or by snorkel.
If you are going by foot, get a tide timetable. Only go exploring at low tide, and leave in good time before the tide comes in.
People have died by being trapped by incoming tides, which cut them off from land. This is what happened to the cockle pickers at Morecambe Bay.
You may need:
- Tide timetable (print off from local authority website or ask in local shops)
- Long waders, high boots, sturdy sandals, or wet shoes
- A local OS map
- Mobile phone
- Waterproofs and swimwear underneath
- Plastic pocket to keep valuables safe.
Canoeing (or another flat-bottomed boat like a punt) is a great way to explore a marsh. Go at high tide, or you could get stuck on a sandbar.
Canoes have such a shallow draft that you can get right into places you could never reach otherwise. They are so quiet, you can get near the birds.
You may need:
- A canoe or punt. These can be hired or bought.
- A paddle
- Local OS map
- Water and snacks
- Life jacket
- Tide timetable
Swimming with a snorkel
Snorkeling is a really immersive experience if you are a strong swimmer. If you like seeing fish and underwater creatures, go snorkeling.
It doesn’t cost a lot to get a snorkel and goggles. Plus, it’s a good way to stay cool on a hot day.
If you are feeling competitive, try the Welsh Bog Snorkeling Championships. You can race others through a muddy bog.
You may need:
- Snorkel and goggles
- Wetsuit or drysuit if the water is cold
- Tow float; you can cling to this if you get tired or get cramps. Some have waterproof pockets to store valuables.
What Is A Marsh FAQs
How much wetland is there worldwide?
There are 7 to 9 million km2 (2.7 to 3.5 million m2) of wetlands worldwide. This equates to 4–6% of the Earth’s land surface.
Out of this total, 56% is located in tropical and subtropical regions, while 2.7 million km2 (1.04 million m2) are wetland areas in polar and boreal regions. Rice paddies account for the remaining 1.5 million km2 (0.58 million m2) of the total.
Do marshes contain salt or freshwater?
Marshes can be either saltwater or freshwater marshes, or a mixture of both. They can be tidal, containing sea water, or inland marshes, containing fresh water.
Can marshes help in the fight against climate change?
Marshes lock in carbon when in their natural wetland state. This means they can be used as carbon sinks. When they are dried out for agriculture or by climate change, they release carbon into the atmosphere. This is why it is important to keep wetlands wet.
What is bog snorkeling?
Bog snorkeling is an event held in Wales every year. Competitors swim through a ditch cut through a muddy bog, wearing snorkels.