Name
Class
Date
6.3 Aquatic Ecosystems
Key Concepts
Ecologists classify aquatic ecosystems according to criteria such as salinity, depth, and
whether the water is flowing or standing.
Standing freshwater ecosystems include ponds, lakes, inland seas, and wetlands. Flowing
freshwater ecosystems include rivers and streams.
Estuaries are home to diverse ecosystems that prevent soil erosion and flooding.
The ocean can be divided into three zones based on their distance from shore: intertidal,
neritic, and open ocean.
Vocabulary Preview
Define each vocabulary term in your own words. Then, write yourself a quick note on
how you will remember each. One term has been done for you.
Term
Definition
How I Remember
Salinity
Photic zone
Aphotic zone
The layer below the photic zone
where no sunlight penetrates and
photosynthesis cannot occur
Benthic zone
104
I know the prefix a– can mean “without,”
so aphotic must mean “without
light.”
Name
Term
Class
Definition
Date
How I Remember
Littoral zone
Limnetic zone
Wetland
Flood plain
Estuary
Upwelling
Describing Aquatic Ecosystems
1. Identify three factors that characterize aquatic systems.
2. Explain why a freshwater fish cannot survive in salt water.
3. Give one reason why there tends to be more organisms in the photic zone than in the
aphotic zone.
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Name
4.
Class
Date
Complete the table below to summarize the general
characteristics of flowing and standing water ecosystems.
Type of Ecosystem
Characteristics
Example
Flowing-water ecosystem
Standing-water ecosystem
Freshwater Ecosystems
5.
Draw and label a diagram that shows the five aquatic zones in
freshwater ecosystems. Add plants and other organisms to your diagram.
6. Provide two reasons to support the following statement: Wetlands have significant
ecological importance.
7. Why are flood plain soils particularly fertile?
106
Name
Class
Date
Estuaries
For Questions 8–12, complete each statement by writing the correct word or words.
8. Where fresh and salt water mix in coastal estuaries, they form
ecosystems.
9. Freshwater estuaries tend to be diverse ecosystems with a mix of river and
organisms.
10. Salt marshes stabilize shorelines against
.
11. In
silty coasts.
latitudes, mangrove forests are found along gently sloping,
12. The largest
in America are in Florida’s Everglades region.
13. State the ecological importance of estuaries.
The Oceans
14. Explain the effect salinity and temperature have on water density.
15. Why are upwellings important to ocean ecosystems?
16. Identify three major ocean ecosystems.
17. Compare and contrast kelp forests and coral reefs.
18. Why is microscopic phytoplankton very important as a food source?
10