have extremely high biodiversity.
Figure 13.16: Chesapeake Bay, surrounded by Maryland and Virginia, is the largest estuary
in the United States. ( 11 )
Ecological Role of Wetlands
As mentioned above, wetlands are homes to many different species of organisms. Though
they make up only 5% of the area of the United States, wetlands contain more than 30% of
the plant types found in the United States. Many endangered species live in wetlands, and
therefore many wetlands are protected from human use.
Wetlands also play a key biological role by removing pollutants from water. For example,
they can trap and use fertilizer that has rushed off a farmer’s fields, and therefore prevent
that fertilizer from contaminating another body of water. Since wetlands naturally purify
water, preserving wetlands also helps to maintain clean supplies of water.
Floods
Floods are a natural part of the water cycle, but they can be terrifying forces of destruction.
Put most simply, a flood is an overflow of water in one place. Floods can occur for a variety