1. Chapter 10
Freshwater Biomes

2. 10.1 Aquatic Biomes Objective:
Describe the factors that characterize the various types of aquatic biomes

3. 10.1 Aquatic Biomes
An aquatic habitat is one in which the organisms live in or on water.
Aquatic biomes are scattered and are determined by depth not location

4. 10.1 Aquatic Biomes
Aquatic biomes can be divided into two main groups: Freshwater and Saltwater

5. 10.1 Aquatic Biomes All bodies of water contain some dissolved salts
The amount of dissolved salts in a sample of water is called salinity

6. 10.1 Aquatic Biomes
Most of the water in lakes, ponds, and rivers is freshwater
Most of the water in oceans is saltwater

7. 10.1 Depth Bodies of water can be divided into depth zones
Photic zone: The top layer of water that receives enough sunlight for photosynthesis to occur
Aphotic zone: Part where no sunlight reaches. Only deep lakes and the ocean have aphotic zones.
Benthic zone: The floor of a body of water

8. 10.2 Standing-Water Ecosystems
Objectives:
Identify the characteristics of different types of standing water ecosystems.
Explain the value of wetlands and the reasons for their decline.

9. Types of Freshwater Biomes
Two main types:
Standing-Water Ecosystems
Flowing-water Ecosystems
Lakes and ponds are most common of standing-water ecosystems.
May also include: wetlands (bogs), prairie potholes, swamps, and freshwater marshes.
No net flow exists, but there is circulation.

10. Abiotic Factors
Lake: Deepest type of standing water. Usually fed by underground aquifers.
Pond: Fed mostly by rainfall; may be seasonal.
Marsh: Very shallow with exposed land; soil is saturated; may be freshwater, saltwater, or brackish; often tidal; Florida Everglades is largest Freshwater Marsh in US.
Swamp: Land soaked because of poor drainage; found along streambeds and flatlands; mangrove swamps found are salty and along coastlines.
Bog: Inland wetland with little inflow or outflow; soil is acidic; decay is slow; also called fen or moor.

11. Biotic Factors
Lake: Main producers are floating algae in the photic zone and benthic plants on shoreline; complex food webs.
Pond: Main producers are plants and algae that grow on bottom; food web simpler than lakes.
Marsh: Plants have roots under water, but leaves are above the water; mostly grasses.
Swamp: Dominated by large trees and shrubs; plants are adapted to grow in muddy, oxygen-poor soil; cypress common in south; willow and dogwood common in north.
Bog: Sphagnum moss is dominant organism; partly decayed moss accumulates as peat.

12. Standing-water Organisms
Organisms that live in upper levels are different from those in lower levels.
Top level supports the plankton community because more sunlight is allowed in at the surface.
Plankton that carry out photosynthesis are called phytoplankton.
Those that do not are zooplankton.
Small fish feed on plankton and insects on surface.
Large fish feed on Small fish.
Many deep water organisms are scavengers as they feed on descending organic material from the surface.

13. Wetlands
Wetlands are ecosystems in which the roots of plants are submerged under water for at least part of the year ex) marshes, swamps, bogs
Most are standing water that is fresh or brackish
Wetlands act as efficient filters detoxifying chemicals in the water
They are also important breeding grounds for many different types of animals
Wetlands are being destroyed by humans for many different reasons
they are found unattractive
they are breeding grounds for mosquitos
they give off unpleasant odors due to the methane released from decomposing organisms in the muddy, oxygen free soil
used as landfill sites and filled in for building sites

14. The Florida Everglades
Were once a swampy marsh that spanned 160m from Lake Okeechobee to the tip of Florida
There is a wet season from May through October followed by a dry season
During the dry season many organisms survive by living in gator holes - large depressions in the ground scooped out by alligators forming pools
The wetlands were drained when water from the lake was channeled away to create farmland, putting the ecosystem in danger
Since 1947, people have been working to save the Everglades

15. 10.3 Flowing Water Ecosystems
Objectives: Describe how abiotic factors of gravity, erosion, and sedimentation affect stream ecosystems.

16. Stream Organisms
Organisms that live in flowing-water habitats are adapted to the rate of the water’s movement.
Organisms that have adapted to life in freshwater streams are the fish of the salmon and trout families.

17. Stream Organisms
When salmon are mature and ready to breed, they swim upstream to the exact location where they hatched.
They find this exact spot by “smelling” tiny amounts of chemicals in the water.

18. Stream Flow
Most streams begin at high altitude, often from the runoff of melting snow on the tops of mountains.
The place where the stream begins is the source, or head, of the stream. Water near the source is called headwater.
Headwaters tend to flow too rapidly for most organisms to live in the water.

19. Stream Flow
Streams may cause erosion with their flow over time, for example curves in a stream could become more pronounced.
Human activity to a stream could potentially damage many delicate ecosystems.