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Reading Passage: Protecting Coral Reefs

Coral reefs are some of the most productive and varied ecosystems on the planet, rivaled only by the rainforests for diversity. They comprise less than ¼ of 1 percent of the total marine environment, but account for more than 25 percent of known fish species. These habitats are teeming with life and provide homes for fish, rays, sharks, lobsters, dolphins, crabs, turtles, and anemones. Certainly, reefs are admired for both their abundance and their beauty. However, they are not only beautiful but useful as well. Reefs act as barriers preventing shore erosion, attract tourists, and provide valuable resources for the fishing industry. Yet, many reefs are endangered by both natural and human causes, and the many benefits of the reefs may soon be lost if further steps are not taken to protect them.

Image courtesy of
Reef Relief


Reefs are very fragile and grow over long periods of time. The reefs in Florida developed slowly sometime between five and seven thousand years ago. Different species of coral can grow at different rates. Some may grow as little as half an inch per year, while others may extend as much as seven inches in the same amount of time. The growth is caused by organisms called coral polyps. Polyps gather calcium from the surrounding sea water and then excrete a hard exoskeleton, or shell. After time, the skeletons of dead coral compound to form the huge limestone reefs. Coral reef development requires many particular features. First, coral must have a solid foundation on which to grow. Plus, coral can grow only in warm and predictable waters, with stable salinity, clear water, and moderate wave movement. In addition, coral needs certain nutrient levels; too much phosphate or nitrogen can actually be damaging. Overloading nutrients can cause eutrophication, an imbalance in the ecosystem where some plants grow out of control, killing off other wildlife.
3 The limits to how fast and where coral can grow make it all the more precious and its conservation all the more difficult. Already, scientists predict that 30 percent of all existing coral reefs are damaged. Anchors, boat groundings, diver/snorkeler damage, hurricanes, and diseases can all harm the delicate coral reefs. However, the primary cause of damage to coral reefs is overdevelopment and poor sewage management, particularly in Florida.  Budding coastal cities often dump waste that is high in nutrients that muddy the waters and disrupt the natural balance of the ecosystem.  In the Florida Keys most of the coral reefs have decreased in size. In the graph below, taken from Teaching Issues and Experiments in Ecology, three areas of the Keys are shown. The black bar represents the percent of sites where growth decreased significantly, the white area is where growth increased, and the gray bar is where growth remained relatively stable. Clearly most sites in the Keys are suffering significant growth loss. 

figure 1a
Image courtesy of Teaching Issues and Experiments in Ecology


If an effort is not made to preserve the reefs, many of their valuable services will be lost. For instance, without barrier reefs, shore erosion would be a much greater problem in many areas. Furthermore, the reefs, like the ones found in the Florida Keys, attract thousands of tourists each year.  Worldwide these benefits alone are worth an estimated $375 billion a year. This is excluding the money that is made each year harvesting fish from these regions. This is also a multi-billion dollar industry. Additionally, the potential that reefs provide for medical and chemical research make it an enticing and lucrative area for the pharmaceutical business as well.
5 Some efforts are being made to correct the problem.  In one area of the Florida Keys where a large boat accidentally grounded and shattered coral reefs, the owners spent $3 million on a special new underwater concrete to restore the foundation of the coral.  The boat's owners collaborated with scientists from the Florida Keys National Marine Sanctuary to coordinate the first ever reef rebuilding project.  Another organization, Reef Relief is working to ensure that cruise ships and boats respect the No Discharge Zone around the Florida Keys, where dumping waste can severely damage the reefs.
6 Coral Reefs are truly intricate and delicate environments. They are full of life that developed slowly over many thousands of years. Thus, their delicate nature and slow recovery rate make them vulnerable to human interference. Pollution and other human factors all negatively impact this environment. Its loss would deprive future generations of an unsurpassed beauty and the economy of billions of dollars each year. Organizations are just starting to make headway in the effort to preserve our precious reefs.  New technology like special underwater concrete and stricter regulations are already starting to undo some of the damage we have already caused.

General Questions

What role does the nutrient calcium play in developing corals?

According to the passage, which of the following statements is not true?

Look at the graph (Fig. 1A). In the Upper Keys, the percent of sites increasing and decreasing in population differ by approximately what percent?

Look at the graph (Fig. 1A). Approximately what is the largest percentage of sites decreasing in growth in the Upper Keys, Middle Keys, and Lower Keys?

What is the approximate difference of the smallest percentage of sites increasing in growth and the largest percentage of sites increasing in growth in the Upper Keys, Middle Keys, and Lower Keys?

“This is also a multi-billion dollar industry.” What or who does this refer to?

Which statement best expresses the main idea of the article?

Which of the following is a result of eutrophication?

The author’s perspective indicates

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