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Wetlands and Their Importance
Marshes, swamps, bogs, and their ecosystem services
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Wetlands are ecosystems where water covers the soil or stays near the surface long enough to shape the plants, animals, and chemical processes there. Marshes, swamps, bogs, fens, mangroves, and floodplain wetlands all provide habitat for organisms adapted to saturated conditions. They matter because they protect biodiversity, improve water quality, reduce flooding, and store carbon. Although wetlands may look like quiet patches of water and plants, they are among the most productive ecosystems on Earth.
A wetland works through the close connection between water, soil, plants, microbes, and wildlife. Slow-moving water allows sediment to settle, while plant roots and microorganisms help trap nutrients and break down pollutants. Wetland soils are often low in oxygen, which changes how carbon, nitrogen, and other elements cycle through the ecosystem. These processes make wetlands valuable natural infrastructure for communities, especially in areas facing storms, erosion, and water pollution.
Key Facts
- A wetland is defined by hydrology, hydric soil, and water-tolerant vegetation.
- Wetlands act like natural filters by trapping sediment, nutrients, and some pollutants before water reaches rivers, lakes, or coasts.
- Flood storage can be estimated by V = A d, where V is water volume, A is wetland area, and d is average water depth.
- Wetlands store carbon in waterlogged soils because low oxygen slows decomposition.
- Food webs in wetlands often begin with photosynthesis: 6CO2 + 6H2O + light energy = C6H12O6 + 6O2.
- Wetland loss reduces habitat, increases flood risk, lowers water quality, and can release stored carbon to the atmosphere.
Vocabulary
- Wetland
- A wetland is an ecosystem where soil is saturated or covered by water long enough to support water-adapted plants and special soil conditions.
- Hydric soil
- Hydric soil is soil that forms under saturated, low-oxygen conditions and often has chemical signs of prolonged wetness.
- Biodiversity
- Biodiversity is the variety of living organisms in an ecosystem, including plants, animals, fungi, and microorganisms.
- Nutrient cycling
- Nutrient cycling is the movement and transformation of elements such as nitrogen, phosphorus, and carbon through living organisms, water, soil, and air.
- Ecosystem service
- An ecosystem service is a benefit that people receive from nature, such as flood protection, clean water, habitat, or carbon storage.
Common Mistakes to Avoid
- Thinking wetlands are just wastelands is wrong because they provide major ecosystem services such as flood control, water filtration, habitat, and carbon storage.
- Assuming all wetlands are the same is wrong because marshes, swamps, bogs, fens, and mangroves differ in water source, plant life, soil chemistry, and location.
- Ignoring microorganisms is wrong because bacteria and other microbes drive many wetland processes, including decomposition, nitrogen cycling, and pollutant breakdown.
- Draining a wetland without considering downstream effects is wrong because it can increase flooding, reduce water quality, destroy habitat, and release stored carbon.
Practice Questions
- 1 A wetland has an area of 12,000 m2 and stores floodwater to an average depth of 0.45 m. Use V = A d to calculate the volume of water stored.
- 2 A restored wetland removes 35% of nitrate from water flowing through it. If 80 kg of nitrate enters the wetland in one week, how many kilograms are removed and how many kilograms leave the wetland?
- 3 Explain why wetland soils often store large amounts of carbon even though wetlands contain many decomposers.