This lesson asks students to consider whether artificial reefs (human-made objects in the ocean or sea) are good for marine ecosystems. Students will look at pictures of artificial reefs and read articles describing the pros and cons of these structures. They will conclude by writing paragraphs explaining whether they think a new artificial reef should be created in Florida waters.

Geography, life science

Standard 8: "The characteristics and spatial distribution of ecosystems on Earth's surface"

Two hours

• Computer with Internet access

Students will

• hypothesize whether human-made objects in the water can provide good habitats for marine animals;
• view pictures of human-made marine habitats, and discuss what they see;
• make charts hypothesizing the pros and cons of artificial reefs;
• read and answer questions about two articles concerning artificial reefs; and
• write paragraphs on the pros and cons of sinking a ship off the Florida coast to create an artificial reef.

Pose this question to the class: "Can human-made objects, such as sunken ships or oil rigs, provide good habitats for marine animals?"

Ask students to think about the question for a minute, and spend about five minutes discussing their initial ideas.

Make sure the students know that coral reefs are barriers and ridges created by the limestone remains of tiny coral polyps, and that they attract a wide variety of marine animals. Define the term "artificial reef" as a human-made structure in the ocean or sea. Explain that, like coral reefs, artificial reefs frequently attract marine animals from the surrounding ocean areas.

Have students look at the pictures at these Web sites to see some examples of artificial reefs. Discuss the different types of structures they see and the types of animals and plants they see living on or around the structures:

Artificial Reefs Worldwide
Rigs-to-Reefs Information
South Carolina Department of Natural Resources: Marine Artificial Reefs

Ask students to make "pros and cons" charts that hypothesize the positive and negative impacts of artificial reefs on the marine ecosystem. They can make their charts individually, in small groups, or as a class, but be sure to discuss the charts as a class.

Have students read the National Geographic News article, Artificial Reefs: Trash to Treasure, either individually or as a class. Ask them to answer the following questions as they read:

• Why are marine organisms attracted to a sunken ship?
• When a ship sinks and turns into an artificial reef, does it matter how it is shaped or what it is made of? Why?
• Over time, do artificial reefs become very similar to or very different from natural reefs?
• How might a sunken ship help a nearby natural coral reef?

Have students do further research and answer these questions:

• How might artificial reefs "fool" fishermen into thinking there are more fish than before the artificial reef existed?
• What are the ecological arguments against artificial reefs?

Have students make new "pros and cons" lists based on the information they have gathered.

Discuss students' new lists as a class. Overall, do they think artificial reefs are a good idea? Under what circumstances might they be more damaging than beneficial?

Have students consider the pros and cons of creating a new artificial reef by deliberately sinking a ship off the west coast of Florida. There are already a number of artificial reefs in this area, as shown on this map of Pinellas County. Ask them to write paragraphs explaining the pros and cons of sinking the ship and to provide their own opinions about what should be done.

• Present students with this scenario:
  
  The country of Denmark has signed the Kyoto Agreement, agreeing to reduce its carbon dioxide emissions. This is good news for air quality, global warming, and many animal and plant species. In the process of reducing emissions, Denmark has built sea-based windmill parks to harness energy from the wind. The question remains as to how these windmill structures, which rise out of the sea, will affect the marine ecosystem. Will seals and porpoises be disturbed by these structures? How might other parts of the marine ecosystem be affected by these windmills, and how might impacts on invertebrates and fish affect marine mammals?
  
  Ask students to write paragraphs predicting the effects of the Danish windmills on the marine ecosystem. They should base their predictions on what they have already learned about artificial reefs and on additional research into artificial reefs and the behaviors and habitats of seals and porpoises.

• Have students imagine that they are fishermen or divers who are planning an excursion to explore artificial reefs off the west central coast of Florida (Pinellas County). Have them gather information at these Web pages and write an itinerary for their trip. Their itinerary should include three stops and explain why they have chosen each site and what they expect to see at each one.
  
  Pinellas County, Florida Artificial Reefs Guide
  Map of Pinellas County Artificial Reefs

Artificial Reefs of the Keys
Rigs-to-Reefs Information
South Carolina Department of Natural Resources: Marine Artificial Reefs