Why are swamps and marshes among Earth’s most productive ecosystems?

Swamps and marshes are considered among Earth’s most productive ecosystems because they function as vital transition zones that excel at nutrient cycling and energy production. Their high productivity is driven by several key factors:1

• Nutrient Availability: These wetlands often act as sinks for inorganic nutrients, which are supplied by water flowing into the system from surrounding drainage basins. This steady influx of nutrient-rich sediment creates a fertile environment that supports rapid plant growth.12
• Primary Production: Through photosynthesis, these ecosystems convert inorganic materials into energy-rich biomass at exceptionally high rates. In some instances, such as in tall stands of Spartina alterniflora in salt marshes, productivity levels can rival the highest yields achieved in industrial agriculture.32
• Ecosystem Services: By collecting, filtering, and storing water, these wetlands maintain the chemical and physical processes necessary for high biological activity. Their role as "the kidneys of the landscape" allows them to process organic materials efficiently, supporting diverse habitats for plants, animals, and waterfowl.1

Because they combine attributes of both terrestrial and aquatic environments, these wetland ecosystems sustain high levels of biodiversity and play a critical role in the global biosphere.14