166 Continental Shelves and Neritic Zone
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CONTINENTAL SHELVES
AND THE NERITIC ZONE
Chapter Outline
CONTINENTAL SHELVES
Waves, Currents, and Light
Role of Sediments
BENTHIC COMMUNITIES
Patchiness in Soft-Bottom
Communities
Soft-Bottom Food Chains
Succession in Soft-Bottom
Chapter Objectives
• Describe the general characteristics of continental shelves, including the major
physical factors that shape the communities.
Key Terms
shear stress
epibenthic organisms
microphytoplankton
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Chapter Summary
1. Continental shelves vary in their characteristics depending on the geographic and
2. The number and kinds of organisms that can live on the bottom of continental
shelves is greatly influenced by sediment characteristics. Much of the food that
3. Kelps dominate in areas of the continental shelf where the bottom is hard, the water
is cold, and nutrients are readily available. These algae form complex, three-
4. Soft-bottom communities are dominated by burrowing organisms that are generally
suspension feeders or deposit feeders. The distribution of organisms in benthic
5. The neritic zone comprises the water that lies above continental shelves. The high
productivity of these regions is due to a combination of physical and biological
Chapter Outline
I. Continental Shelves
A. Waves, currents, and light.
B. Role of sediments.
II. Benthic Communities
A. Hard-bottom communities.
B. Kelp communities.
168 Continental Shelves and Neritic Zone
C. Rock reefs.
D. Soft-bottom communities.
1. Patchiness in soft-bottom communities.
2. Soft-bottom food chains.
3. Succession in soft-bottom communities.
III. Neritic Zone
A. Impact bubble: historical fisheries of the Atlantic and their future.
Suggestions for Presenting the Material
1. Show students photographs or preserved specimens of planktonic, benthic, and
2. Use Google Earth to view coastal waters where primary productivity is high, such as
3. Have students create a concept map using soft-bottom communities as the starting
4. Assign students to find out where in the world the major global fisheries are located,
Classroom Discussion Ideas
1. Contrast the typical fauna of hard- and soft-bottom communities in terms of the
feeding mechanisms of the dominant organisms. Explain how these mechanisms
relate to the physical characteristics of the habitat.
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Videos, Animations, and Websites
Videos
Wondrous Secrets of the Ocean Realm. (set of six DVDs, PBS, 1998)
The volume Cathedral in the Sea features the biota of Pacific kelp forests, shot by award-
Planet Earth: Shallow Seas: Kelp Forest. (set of five DVDs, BBC, 2007)
Spectacular time-lapse photography illustrates the behavior of benthic kelp forest
The Blue Planet: Seas of Life (Tidal Seas/Coasts). (set of five DVDs, BBC, 2002)
David Attenborough narrates this Emmy-award winning documentary examining
Animations
Virtual Dive Into Monterey Canyon.
An interactive animation on the habitats of Monterey Canyon, CA, from the Monterey
Websites
Monterey Bay Aquarium—Kelp Forest Exhibit.
An overview of kelp forest habitats with links to information about the individual kelp
Kelp Restoration by Algalita Research Foundation.
Bottom Watching: NOAA Coastal Monitoring and Observations.
NOAA lesson plan employing ArcExplorer Java GIS technology to analyze benthic data
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National Marine Sanctuaries Media Library.
Searchable database of photographs and video clips from America’s marine sanctuaries.
Monterey Bay Aquarium Live Underwater Kelp Cam.
Real-time web cam gives viewers around the globe a look into the main kelp forest tank
Suggested Answers to End of Chapter Questions
Multiple Choice
1. c. coastal seas
2. c. The sediments are silt and the water currents are slow.
3. a. hard bottoms
Matching
1. b.
Short Answer
1. What are the main sources of nutrient input into coastal seas?
Major sources of nutrient input into coastal areas are rivers delivering nutrient-rich
2. What factors affect the size of plankton populations?
Factors influencing the abundance of coastal plankton populations include:
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3. How do waves and currents affect the types of benthic organisms found on the
continental shelf?
Waves and currents affect continental shelf benthic organisms directly by
4. Name two important functions of bottom currents in benthic communities.
Bottom currents transport both organisms and their larvae, allowing colonization
5. Explain how the types of bottom sediments influence the diversity of life on the floor
of the continental shelf.
Sediments exposed to high current flow are coarse and harbor filter-feeding
6. List three explanations for the patchy distribution of organisms in soft-bottom
communities.
Patchy distribution of organisms in soft-bottom communities is a function of:
7. Explain how decreases in the size of lobster and cod populations have affected North
Atlantic kelp beds.
Reduction of North Atlantic lobster and cod has resulted in a 70 percent decline in
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8. Why are kelp beds frequently compared to terrestrial rainforests?
Reasons that kelp forests and rain forests are frequently compared may include:
9. Why is the neritic zone such a productive area?
The neritic zone is highly productive because of the high levels of nutrients—both
10. Diagram a simple food web for the continental shelf.
11. Describe the process of succession that occurs in soft-bottom communities that are
disturbed.
Succession in soft-bottom communities begins with a disturbance to the sediments,
12. What are two ecological roles for plankton in the neritic zone?
Key roles of neritic zone plankton are: serving as an essential link in the coastal
Thinking Critically
1. Currently there is concern about the possibility of global warming caused by the
greenhouse effect. How might this affect the productivity of coastal seas?
Global warming could have a variety of effects on coastal sea productivity. If
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2. Why do so many species of small fish found in coastal seas travel in large schools?
Schooling behavior confers a strong survival benefit. Small fish travel in schools as
3. Why do disturbances such as landslides have a greater impact on invertebrate
populations than on algal populations?
Undersea landslides can dislodge and bury epifaunal animals under thick
Suggested InfoTrac® Articles
“Larval Transport on the Atlantic Continental Shelf of North America: A Review.”
Epifanio, C.E. and R.W. Garvine. Estuarine, Coastal, and Shelf Science, (2001).