If you live in the Northeast, Midwest, or along the Pacific coast, don’t be surprised if you see small ponds or lakes appear suddenly in your neighborhood during the spring. These are vernal pools – wet areas that form in low-lying zones where water collects in winter and spring. By summer the water evaporates, leaving the site damp or dry through autumn.
Vernal pools are seasonal wetlands, but many other types occur year-round across North America. Wetlands are areas where the soil is always or usually saturated with water, so they support plants and animals that are adapted to moist conditions. Bogs, marshes, mud flats, swamps, and estuaries are all forms of wetlands.
They don’t always look impressive (that’s one reason why many wetlands have been filled in or paved over), but wetlands play important ecological roles. They serve as nurseries and feeding grounds for many types of fish, mammals, and birds; filter pollutants and sediments out of water; and protect coastlines from the impact of storms.
To put wetlands into context, unit 8 of The Habitable Planet describes Earth’s water resources, how they move through the global water cycle, and threats to fresh water. Section 3 shows how the world’s freshwater resources are distributed between ground and surface waters. Section 8 discusses how pollutants–including biological organisms, chemicals, and sediments–impair water quality.
Wetlands can serve as settings for biology, ecology, or chemistry classes. In Journey North, learn how wetlands are especially important feeding and nesting zones for whooping cranes. Read about what the birds eat, track their migration stops, and discuss how human actions are affecting the wetlands that these birds use. For a biology or chemistry class, see unit 4, section 7 of Rediscovering Biology, “Microbial Diversity,” for a discussion of how archaea break down carbon in swamps. And the interactive on “Garbage – Solutions for Sewage” offers a case study of Arcata, California’s wastewater management system, which includes artificial (constructed) wetlands that improve water quality through physical and chemical processes.
And if you live in a region where vernal pools form, the Association of State Wetland Managers has news, videos, and links to additional materials about these seasonal spring wetlands and the many species that live in them.
Look for post #2 next Wednesday (April 23) with more ideas for teaching about wetlands during American Wetlands Month in May!