Lakes and Freshwater Wetlands SWBAT explain the formation of freshwater lakes and wetlands; describe the process of eutophication; recognize the effects of human activity on lake development

Origins of Lakes Lake What are some ways lakes can form? A depression in the surface material of a landscape that collects and holds water What are some ways lakes can form? Oxbow lakes form when a river changes course, and streams can get blocked. Glaciers create lakes through gouging the land, moraines can create dams, cirque lakes form in mountains, and ice melting on an outwash plain creates kettle lakes.

Get your Lab notebook Title: Surface materials determine where a lake can form. Watch the demonstration and answer the following in complete sentences Create a 3 columned chart, and label the columns: Clay, Gravel, Sand Describe what happened to the 500 mL of water that was added to each container. How is this activity similar to what happens on Earth’s surface when a lake forms? What can you infer about the Earth materials in which lakes most commonly form?

Lakes Undergo Change Eutrophication Wetland Process by which lakes become rich in nutrients from the surrounding watershed, resulting in a change in the kind of organisms found in the lake Wetland Land area that is covered with water for a large part of the year

Wetland Environments Bogs Bogs are a wetland that gets its water from precipitation, not from streams. The soil is rich is sphagnum (peat moss). The soil also tends to be acidic and supports unusual plants such as Venus flytraps, pitcher plants, sundew.

Wetland Environments Marshes Marshes form along mouths of streams or delta areas. They have lush growth of grasses with shallow roots, which anchor silt deposits, slowing the water and expanding the marsh. Grasses, reeds, sedges, and rushes are commonly found here.

Wetland Environments Swamps Swamps are low-lying areas near streams. They develop from marshes that have filled in enough to support shrubs and trees.

Freshwater Wetlands How do wetlands help the environment? Wetlands improve the water quality by filtering pollutants, sediments, and bacteria. Wetlands also provide habitats for birds and other wildlife.

In your Groups Answer questions 1-4 on page 231 in complete sentences. Finish for homework.