“Wetlands are a pivotal part of the natural system, providing tremendous benefits for coastal ecosystems and communities. They provide us with clean water, flood protection, abundant fisheries, and more.”
NOAA
We have at least five types of coastal wetlands – each differs due to its water regime, landscape, vegetation, soils, climate, and more. These coastal inhabitants are too valuable to lose. Unfortunately, they are currently disappearing three times faster than forests.
They host some of the richest biodiversity on the planet. Salt marshes, seagrass beds, and mangrove forests are refuges for wildlife and nurseries for juvenile fish, including commercially important species such as groupers and snappers.
What do we get from coastal wetlands, what are their benefits to humans, and what you can do to save them. Let’s drive through the important aspects of these five common wetlands.
Mangrove Swamps
- Key Feature: Mangrove trees that grow above the shoreline
- Impact on the Environment: 3 to 5 times more efficient carbon sinks than tropical forests
Like all coastal wetlands, mangroves are saturated with water, and plants that tolerate wet soils and low oxygen levels characterize them.
A significant feature of these swamps is the tangled, clumped roots of mangrove trees that grow above the shorelines. They enable the wetlands to buffer coastlines successfully from currents, waves, storm surges, and tides. At the same time, these plants provide the most suitable nursery grounds for some shark species, groupers, and snappers.
If that’s not enough, imagine how much the tangled, clumped roots protect small fish from predators. Besides being some of the best coastal wetlands, mangrove swamps are 3 to 5 times more efficient carbon sinks than tropical forests.
Seagrass Wet Meadows
- Key Feature: Seagrass growing underwater
- Impact on the Environment: Absorbs about 10% of the carbon sequestered in the ocean
There are many types of wet meadows, and seagrass meadows are one of the most common ones – it’s characterized by seagrass- another plant with a high ability to tolerate moist soils and low Oxygen levels.
Seagrass grows underwater, creating an ecosystem that serves as a suitable nursery ground for wildlife and fish species. Like mangrove swamps, these meadows also help minimize the adverse impact of climate change and reduce soil erosion.
Moreover, the wetland absorbs approximately 10% of the carbon sequestered in the ocean.
Salt Marshes
- Key Feature: Saltwater that floods as tides come in
- Impact on the Environment: Absorb plenty of water and extract carbon from the atmosphere.
Salt marshes are one of the five common types of coastal wetlands found worldwide, particularly in temperate regions. As tides come in, saltwater floods them.
Salt marshes are home to plenty of birds, invertebrates, and fish, making them an outstanding contributor to local economies and fisheries.
The unique ability of salt marshes to absorb plenty of water is one of the reasons it has made it into the list of the five common types of wetlands. This reduces flooding in the coastal areas, thereby protecting the local communities from disasters.
Moreover, like seagrass beds and mangrove swamps, salt marshes extract carbon from the atmosphere and store it safely.
Freshwater Marshes
- Key Feature: Shallow water and mineral soils
- Impact on the Environment: Protect the coastal lines from flooding and storms
According to the National Oceanic and Fisheries Administration (NOAA), freshwater marshes feature among the five common types of coastal wetlands. Periodic or permanent shallow water and mineral soils characterize these coastal wetlands.
Freshwater marshes typically get most of their supplies from surface water, including runoffs from the ocean and floods. However, they derive some water from underground sources as well.
Plants and animals that aren’t tolerant to salt thrive in these wetlands. Besides offering an essential nursery and rich feeding ground for numerous marine species, they protect the coastal lines from flooding and storms.
Forested Swamps
- Key Feature: Trees or other woody vegetation that tolerate permanent to semipermanent flooding
- Impact on the Environment: Regulate the regional climate, affecting the carbon sequestration and oxygen in the environment through plant respiration and photosynthesis , provide water conservation, such as water storage and purification, runoff regulation, and flood interception and maintain species diversity acting as the intersections between forests and swamps
Forested swamps are found in north temperate regions, with enormous ecological functions. The Great Xing’an Mountains of Northeastern China contain rich forest swamps in a cold temperate forested region.
Birds like Canada Warbler, Prothonotary Warbler, Red-headed Woodpecker, Louisiana Waterthrush dominate these coastal wetlands.
Forested swamps have trees that are large, vigorous skunk cabbage of richer forested swamps. They have areas of exposed black mucky soil.
4 Benefits of Coastal Wetlands
We’ve discussed the benefits of the five common types of coastal wetlands under each category above to make comparisons easy. In this section, we’ll dive into the unique benefits into a bit more detail.
Here are some of the top benefits:
- Support sustainable fisheries: Your favorite seafood considers wetlands the safest places to feed, reproduce, and live. In 2018, the US contributed $238 billion in sales and supported 1.7 million jobs. Without wetlands, there would be no fish in the ocean.
- Clean water: Coastal wetlands are natural water purifiers. They trap and filter impurities from runoff and agricultural activities. That’s how wetlands can help you to maintain beautiful beaches.
- Store coastal blue carbon: Most coastal wetlands remove greenhouse gases like carbon dioxide from the atmosphere and store them in the soil and plants. By doing this, they minimize the harmful effects of pollution.
- Carbon Sequestration: Certain coastal wetland ecosystems (such as salt marshes and mangroves) can sequester and store large amounts of carbon due to their rapid growth rates and slow decomposition rates.
Wetland Losses
Nearly 80,000 acres of coastal wetlands are lost in the United States each year to development, draining, erosion, and sinkage. That’s close to seven football fields every hour.
Wetlands have historically been drained for human activities, significantly impacting greenhouse gas emissions, flood control, nutrient cycling, and biodiversity. However, the global scale of natural wetland loss remains uncertain. By integrating national and subnational records of drainage and conversion with land-use maps and simulated wetland extents, it is estimated that 3.4 million km² of inland wetlands have been lost since 1700, primarily to cropland conversion. This net loss of 21% of the global wetland area is lower than previous estimates based on data from regions with high wetland loss.
Wetland loss has been most pronounced in Europe, the United States, and China, with rapid expansion occurring in the mid-20th century. For instance, Michigan has approximately 275,748 acres of Great Lakes coastal wetlands. This equates to about 50% of the coastal wetlands that existed in Michigan prior to European settlement. In some locations, such as the Detroit River, losses are as high as 90%.
Wetland Restoration
We have seen why the five types of coastal wetlands are too valuable to lose. So, what should we do to stop these coastal habitats from disappearing three times faster than forests?
The NOAA Fisheries Office of Habitat Conservation works to protect and restore our coastal wetlands and the benefits they provide. With the help of partners, they have restored nearly 50,000 acres of wetland habitat since 2008. Their work helps boost fish populations, recover threatened and endangered species, and support resilient coastal ecosystems and communities.
Wetland restoration involves altering the physical, chemical, or biological characteristics of a former or degraded wetland to restore its natural functions. Restoration practices include:
- Re-establishment: Rebuilding a former wetland.
- Rehabilitation: Repairing the functions of a degraded wetland (US EPA, 2007a)
Wetlands Reserve Easements (WRE) also help private and tribal landowners protect, restore, and enhance wetlands that have been previously degraded due to agricultural uses.
That said, wetland restoration is, of course, a complex issue that requires holistic intervention, including addressing pollution and consciously utilizing wetlands and the benefits they offer.
Something you can do as an individual is to spread the word about the importance of wetlands, the threats they face, and what people can do to help conserve these important habitats!
Learn more about wetlands near you by visiting the National Wetlands Inventory Program’s Wetlands Mapper.
Ocean Insights: Hear From Our Experts
By Rida Nasir
Researcher and Conservationist, with an MSc in Environmental Science
Wetlands are natural infrastructures that provide resilience to natural hazards like floods, drought, fire, storms, landslides and erosion. According to the World Bank (2004), investments in preventative measures, including in maintaining healthy ecosystems, are seven times more effective than the costs incurred by disasters. According to my research, coastal wetlands are the buffers for climate variations. Mangroves protect the coast by absorbing the energy of storm-driven waves and wind. The only two yachts undamaged by Cyclone Tracy in Darwin in 1974 were sheltered in a mangrove creek. In 2006, mangroves protected vessels and the coastline during Cyclone Larry in far north Queensland. The damage bill would have been much higher if it wasn’t for the existence of intact mangrove forests. Coastal Wetlands also provide clean drinking water, flood protection, recreational opportunities, and more. They are important in maintaining the biodiversity and ecosystem sustainability. Wetlands provide protection from floods that saves vulnerable coastal communities $23 billion each year. As an environmental scientist I advocate for conservation of these important landscape feature of our planet.
FAQs
What are wetlands?
Wetlands are distinct ecosystems that are permanently or seasonally saturated with water. All types of wetlands are characterized by plants that tolerate low oxygen levels and wet soils. Coastal wetlands are found in the region in which tidal streams drain to the inland seas or the ocean. Salt marshes, seagrass beds, freshwater marshes, and mangrove swamps are some of the most common coastal wetlands.
What are the challenges that the five common types of coastal wetlands face today?
One of the main challenges the five common types of coastal wetlands face today is habitat loss. Most coastal watersheds lose vast chunks of land to erosion, drainage, development, sea-level rise, and subsistence. The next major one is human activities. Humans alter coastal habitats for selfish reasons, and this trend has led to the degradation, disappearance, and disconnection of many wetlands worldwide. The effects of climate change also pose a significant threat to these resources.
Can wetlands purify wastewater?
Wetlands can treat wastewater in some instances. When water flows through a wetland, the tangled, clumped roots of the growing plants remove large plastics and other unwanted materials from the water. This process helps to keep the ocean plastic-free. However, unless more is done, coastal wetlands can’t remove some pollutants and nutrients naturally from the water.
How do wetlands protect coastal lands from flooding?
Plants that grow in coastal wetlands can efficiently hold back some flood waters or reduce the speed at which they enter the ocean. Thus, they are good at reducing the severity of soil erosion and downstream flooding. Statistics show that flood peaks may increase to 80% in some watersheds where wetlands have been lost.
Why are salt marshes marshy?
Salt marshes are marshy because the soils are often peat and deep mud. Saltwater marshes are also called saltwater wetlands. To know more about these wetlands and why they are marshy, please remember that ocean tides bring the salt water that floods and drains them, and the floods can collect soil from anywhere, including the deep mud.
