1. Objectives Chapter 21 Section 2 Aquatic Ecosystems
Describe the major aquatic ecosystems.
Identify major biotic and abiotic factors associated with different aquatic ecosystems.
Compare the ocean and freshwater zones.

2. Ocean Zones Photic zone in the ocean receives light (top 100 m)
Section 2 Aquatic Ecosystems
Chapter 21
Ocean Zones
Photic zone in the ocean receives light (top 100 m)
Water absorbs light
Aphotic zone does not
Most of the ocean
Photosynthesis does not occur
Other zones of the ocean are defined based on their relative locations.

4. Ocean Zones, continued The Intertidal Zone Chapter 21
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Ocean Zones, continued
The Intertidal Zone
Area of shoreline covered in water at high tide and exposed during low tide.
Organisms must be able to tolerate drying and pounding by waves.
Crabs, clams, mussels, oysters, sea anemones, sea stars

5. Section 2 Aquatic Ecosystems
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Intertidal Zone

6. Ocean Zones, continued The Neritic Zone Chapter 21
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The Neritic Zone
The neritic zone receives nutrients from the bottom of the ocean and from land. It is the ocean’s richest zone in terms of the number of species and individuals.
Plankton, fish, sea turtles

8. Section 2 Aquatic Ecosystems
Chapter 21
Neritic Zone

9. Ocean Zones, continued The Oceanic Zone Chapter 21
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Ocean Zones, continued
The Oceanic Zone
Deepest parts of the ocean with fewer species.
Production in the oceanic zone is limited by a shortage of nutrients.
Photic zone producers: protists, bacteria, plants, invertebrates.
Photic zone consumers: fish, mammals such as whales, large invertebrates.
Aphotic producers: chemosynthetic bacteria (feed tubeworms)
Aphotic consumers: squid, fish

10. Adaptations:
Large eyes
Sensitive vision
Barbed arms with photophores
webbing

11. Section 2 Aquatic Ecosystems
Chapter 21
Oceanic Zone

12. Ocean Zones, continued Estuaries Chapter 21
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Estuaries
Estuaries are very productive areas where rivers and streams flow into the sea.
Variations in temperature and salinity
Impacted by tide changes

13. Freshwater Zones Lakes and Ponds Chapter 21
Section 2 Aquatic Ecosystems
Chapter 21
Freshwater Zones
Lakes and Ponds
Oligotrophic lakes are clear and lacking in nutrients.
Eutrophic lakes are rich in nutrients and are often murky.
Both contain fish, otter, muskrat, ducks, loons, turtles, snakes, salamanders, frogs.

14. Section 2 Aquatic Ecosystems
Chapter 21
Three Lake Zones

15. Freshwater Zones, continued
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Rivers and Streams
Rivers and streams are bodies of water that flow down an elevation gradient within a watershed.
Insect larvae attach to rocks, fish adapted to swim upstream against powerful currents.
Stream River

16. Freshwater Zones, continued
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Freshwater Zones, continued
Freshwater Wetlands
Freshwater wetlands are areas of land, such as marshes and swamps, that are covered with fresh water for at least part of each year.
Marshes: nonwoody plants (cattails)
Swamp: woody plants
Most productive freshwater ecosystem.
Birds, fish, mammals, amphibians, invertebrates, reptiles.
US wetlands have large predators like American alligator, American crocodile, the Florida panther, the whooping crane.

17. Section 2 Aquatic Ecosystems
Chapter 21
Freshwater Biomes

18. Freshwater Wetlands Significance Stopover for migrating birds
Protect spawning organisms like fish
Filter pollutants out of water
Flood control
Everglades National Park

20. Chapter 21
Standardized Test Prep
Multiple Choice
1. Why are estuaries more productive than most other biomes? A. Estuaries contain vast coniferous forests. B. Estuaries have shallow, nutrient-laden water. C. Estuaries get more sunlight than other biomes. D. The majority of land on Earth is covered by estuaries.

21. Multiple Choice, continued
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Multiple Choice, continued
1. Why are estuaries more productive than most other biomes? A. Estuaries contain vast coniferous forests. B. Estuaries have shallow, nutrient-laden water. C. Estuaries get more sunlight than other biomes. D. The majority of land on Earth is covered by estuaries.

22. Multiple Choice, continued
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2. Which of the following characterizes the neritic zone of the ocean? F. It receives little sunlight. G. It supports very few species. H. It is exposed to the air by low tide. J. It receives nutrients washed from land.

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2. Which of the following characterizes the neritic zone of the ocean? F. It receives little sunlight. G. It supports very few species. H. It is exposed to the air by low tide. J. It receives nutrients washed from land.

24. Multiple Choice, continued
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3. Which of the following is true of temperate deciduous forests? A. They are found near the equator. B. They have the lowest rainfall of any biome. C. They undergo seasonal changes in temperature. D. They have the highest species richness of any biome.

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3. Which of the following is true of temperate deciduous forests? A. They are found near the equator. B. They have the lowest rainfall of any biome. C. They undergo seasonal changes in temperature. D. They have the highest species richness of any biome.

26. Multiple Choice, continued
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Multiple Choice, continued
4. Which of the following best describes the water of all eutrophic lakes? F. cold G. salty H. murky J. lifeless

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Multiple Choice, continued
4. Which of the following best describes the water of all eutrophic lakes? F. cold G. salty H. murky J. lifeless

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Multiple Choice, continued
Use the graph below to answer question 5. The graph shows the relative temperature, precipitation, and soil nutrient content in a specific biome.

29. Multiple Choice, continued
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Multiple Choice, continued
5. Which of the following biomes is best represented by this graph? A. tundra B. desert C. tropical rain forest D. temperate grassland

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Multiple Choice, continued
5. Which of the following biomes is best represented by this graph? A. tundra B. desert C. tropical rain forest D. temperate grassland

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Complete the following analogy: 6. grasses : savanna :: coniferous trees : F. taiga G. tundra H. desert J. temperate deciduous forest

32. Multiple Choice, continued
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Complete the following analogy: 6. grasses : savanna :: coniferous trees : F. taiga G. tundra H. desert J. temperate deciduous forest

33. Multiple Choice, continued
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Use the graph below to answer question 7. The graph ranks several types of biomes in terms of their relative productivity.

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Multiple Choice, continued
7. If a scientist needed to add a bar representing the temperate grassland biome to this graph, where should the bar be placed? A. to the left of desert B. between savanna and estuary C. between estuary and tropical rain forest D. to the right of tropical rain forest

35. Multiple Choice, continued
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Standardized Test Prep
Multiple Choice, continued
7. If a scientist needed to add a bar representing the temperate grassland biome to this graph, where should the bar be placed? A. to the left of desert B. between savanna and estuary C. between estuary and tropical rain forest D. to the right of tropical rain forest

36. Short Response Chapter 21
Standardized Test Prep
Short Response
Biomes are very large terrestrial ecosystems that contain a number of smaller but related ecosystems.
Describe how the major biomes are characterized.

37. Short Response, continued
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Short Response, continued
Biomes are very large terrestrial ecosystems that contain a number of smaller but related ecosystems.
Describe how the major biomes are characterized.
Answer: The major biomes are distinguished by abiotic factors and by the presence of characteristic plants and animals.

38. Extended Response Chapter 21
Standardized Test Prep
Extended Response
Base your answers to parts A & B on the information below. Ecologists recognize the following ecological zones in the ocean: photic, aphotic, intertidal, neritic, oceanic, pelagic, and benthic. Part A Describe the factors used as a basis for distinguishing the zones. Part B Relate these factors to the types of organisms that inhabit each zone.

39. Extended Response, continued
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Standardized Test Prep
Extended Response, continued
Answer: Part A Factors used as a basis for distinguishing the ecological zones of the ocean are depth, distance from shore, and penetration of sunlight. Part B Student responses should explain that the ocean can be divided into zones along a vertical axis on the basis of light penetration (photic and aphotic zones) or nearness to the bottom (benthic and pelagic zones), or along a horizontal axis on the basis of distance from shorelines (intertidal, neritic, and oceanic zones). Responses should also describe typical organisms and adaptations for each of these zones.