1. Section 3: Aquatic Ecosystems
Aquatic ecosystems are grouped based on abiotic factors such as water flow, depth, distance from shore, salinity, and latitude.

2. Essential Questions
What are the major abiotic factors that determine the aquatic ecosystems?
What are transitional aquatic ecosystems and why are they important?
What are the zones of marine ecosystems?
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Aquatic Ecosystems

3. Vocabulary Review New continued New salinity wetlands estuary
sediment
littoral zone
limnetic zone
plankton
profundal zone
New continued
wetlands
estuary
intertidal zone
photic zone
aphotic zone
benthic zone
abyssal zone
Aquatic Ecosystems
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4. The Water on Earth
Aquatic environments are divided into freshwater and marine ecosystems.
Only about 2.5 percent of the water on Earth is freshwater.
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Aquatic Ecosystems

5. Freshwater Ecosystems
Rivers and streams
Water in rivers and streams flow in one direction.
The slope of the landscape determines the direction and speed of the water.
Sediment is the material that is deposited by water, wind, or glaciers.
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Aquatic Ecosystems

6. Freshwater Ecosystems
Rivers and streams
Interactions between land and water result in differences in erosion, nutrient availability, and species composition and diversity along the course of the water.
Fast moving water: less sediment and organic matter; fewer species
Slow moving water: sediment is deposited as mud, silt, and sand; supports a diversity of plant and animal species
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Aquatic Ecosystems

7. Freshwater Ecosystems
Lakes and ponds
An inland body of standing water is called a lake or pond.
The temperature of lakes and ponds varies depending on the season.
Turnover in lake water circulates nutrients and oxygen between water depths
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Aquatic Ecosystems

8. Freshwater Ecosystems
Lakes and ponds
Lakes and ponds are divided into three zones based on the amount of sunlight that penetrates the water.
The littoral zone is closest to shore, shallow, and sunlight reaches the bottom.
The littoral zone is a highly productive area, with numerous producers.
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Aquatic Ecosystems

9. Freshwater Ecosystems
Lakes and ponds
The limnetic zone is an open water area that is well lit.
Production is dominated by plankton, free-floating autotrophs
Home to many freshwater fish
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Aquatic Ecosystems

10. Freshwater Ecosystems
Lakes and ponds
The profundal zone is the deepest part of a lake or pond.
Little light penetrates through the limnetic layer
Colder and lower in oxygen
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Aquatic Ecosystems

11. Transitional Aquatic Ecosystems
Wetlands
Areas of land such as marshes, swamps, and bogs that are saturated with water and that support aquatic plants are called wetlands.
Wetlands have high levels of species diversity.
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Aquatic Ecosystems

12. Transitional Aquatic Ecosystems
Estuaries
An estuary is where freshwater from a stream or river meets saltwater from the ocean.
Estuaries can support a variety of habitats, such as mangrove forests or salt marshes.
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Aquatic Ecosystems

13. Marine Ecosystems Intertidal zone
The intertidal zone is a narrow band where the ocean meets land.
Organisms must adapt to daily changes in tides and wave action.
The intertidal zone is further divided into vertical zones.
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Aquatic Ecosystems

14. Marine Ecosystems Open ocean ecosystems
The open ocean is divided into three zones: pelagic, abyssal, and benthic.
The pelagic zone is further divided into two zones
The photic zone is shallow enough that sunlight is able to penetrate.
The aphotic zone is an area that sunlight is unable to penetrate.
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Aquatic Ecosystems

15. Marine Ecosystems Open ocean ecosystems
The benthic zone is the area along the ocean floor.
In shallow areas, the benthic zone receives sunlight, as depth increases, light and temperature decrease.
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Aquatic Ecosystems

16. Marine Ecosystems Open ocean ecosystems
The deepest region of the ocean is called the abyssal zone.
Water is very cold, and there is no light penetration
Organisms depend on food materials that sink from the surface
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Aquatic Ecosystems

17. Marine Ecosystems Coastal ocean and coral reefs
Coral reefs are one of the most diverse ecosystems on Earth.
Widely distributed in warm shallow marine waters
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Aquatic Ecosystems