Chapter 20, Section 3Freshwater Ecosystems

• Vocabulary• Tributary• Littoral zone• Open-water zone• Deep-water zone• Wetland• Marsh• Swamp

Chapter 20, Section 3Freshwater Ecosystems

• Turn to page 486 of your text and define the vocabulary words.

Chapter 20, Section 3Freshwater Ecosystems

• Brooks, Streams and Rivers

• Ecosystems based on moving water

• Comes from melting ice, snow or from an underground spring.

• Each stream of water that joins another stream is considered a tributary.

• As many streams join together, they form a river.

Chapter 20, Section 3Freshwater Ecosystems

• Moving Water

• Organisms that live in moving water require special adaptations

• Algae and moss cling to rocks

• Insect larvae live under rocks

• Tadpoles use suction disks to hold themselves to rocks

Chapter 20, Section 3Freshwater Ecosystems

• Slowing down

• As rivers grow wider they meander or flow back and forth.

• The more meanders the older the river!

Chapter 20, Section 3Freshwater Ecosystems

• Ponds and lakes have different ecosystems than do streams and rivers.

• Lake Superior, the largest lake in the world, has more in common with a beaver pond than a stream or river.

• The ecosystem of a lake or pond looks like this:• 1. Littoral Zone: This is where the water meets

the land. Characterized by many plants and animals. The plants in this area provide a home for many small animals, such as, insect larvae, snails, clams, frogs, salamanders and turtles.

Chapter 20, Section 3Freshwater Ecosystems

2. Open Water Zone: This area extends from the littoral zone across the top of the water. It is characterized by sunlight penetration and phytoplankton. It is home to such animals as bass, blue gills and trout.

• 3. Deep Water Zone: This zone is located below the open water zone, where no light reaches. Catfish, carp, fungi and bacteria live in this area.

Chapter 20, Section 3Freshwater Ecosystems

• Wetlands Marshes and Swamps.• 1. Wetlands. Here, the water level is near

or above the surface of the ground. They play an important role in flood control. During heavy rains or snow melting in spring they soak up large amounts of water. Wetland water also seeps into the ground, replenishing underground water supplies.

Chapter 20, Section 3Freshwater Ecosystems

• 2. Marshes. This is a treeless wetland ecosystem. These can be both freshwater and saltwater systems. Turtles, frogs, and redwing blackbirds can be found in marshes.

• 3. Swamps. This is a wetland ecosystem where trees and vines grow. They provide a home for a variety of wildlife, such as, fish, snakes and birds.

Chapter 20, Section 3Freshwater Ecosystems

• From lake to Forest. • 1. Water entering usually carries with it

sediments.• 2. These materials settle on the bottom.• 3. Dead leaves, plants, and animals, also settle

on the bottom.• 4. Gradually, the pond fills in.• 5. Plants grow in the newly filled areas and with

time, the body of water becomes a marsh.• 6. Eventually the marsh becomes a forest.