From the United States Geological Survey (USGS):
Coastal wetlands are among the most productive and valuable ecosystems in the world—comparable to even rainforests and coral reefs. They are often referred to as natural sponges or nature’s kidneys because they slow the flow of water across the watershed, filter out pollutants and excess nutrients, and even absorb and store large quantities of the greenhouse gas carbon dioxide.
These capabilities help protect coastal communities from storms and flooding, prevent erosion, improve water quality, and decrease the effects of climate change. Coastal wetlands also provide essential food, refuge, and nursery habitat for important species, as well as opportunities for recreation, like boating, hiking, and bird watching. Everyone benefits from the numerous critical services these ecosystems provide.
Learn more about the USGS at https://www.usgs.gov/.