Reading Practice Question#4

Theme: Marine Ecology, Environmental Science, Conservation Biology, Climate Change, Sustainable Development

Reading Passage

Coral reefs are among the most diverse and valuable ecosystems on Earth, often referred to as the “rainforests of the sea.” These underwater structures are formed by colonies of tiny organisms called coral polyps, which secrete calcium carbonate to build their hard exoskeletons. Over time, these exoskeletons accumulate and form the large, complex reef structures that provide habitat for a vast array of marine life. Coral reefs cover less than 1% of the ocean floor, yet they support approximately 25% of all marine species, making them crucial to the health of the world’s oceans.

The importance of coral reefs extends beyond their ecological value. They provide essential services to human societies, including food, coastal protection, and income through tourism and fisheries. Coral reefs act as natural barriers that protect coastal areas from the effects of waves, storms, and erosion. This function is particularly vital for low-lying island nations and coastal communities, where the reefs help to prevent the loss of land and property. Moreover, coral reefs are a source of food for millions of people worldwide, particularly in tropical regions where fish from these ecosystems constitute a significant portion of the diet.

Despite their importance, coral reefs are facing unprecedented threats due to human activities. Climate change is one of the most significant challenges, as rising sea temperatures lead to a phenomenon known as coral bleaching. Coral bleaching occurs when corals, stressed by elevated water temperatures, expel the symbiotic algae (zooxanthellae) that live within their tissues. These algae provide the corals with nutrients and their vibrant colors. Without the algae, the corals turn white and, if the stress continues, they can die. Mass bleaching events have become more frequent and severe in recent years, putting entire reef systems at risk.

Ocean acidification, another consequence of climate change, also poses a serious threat to coral reefs. As the ocean absorbs more carbon dioxide from the atmosphere, the water becomes more acidic. This increase in acidity reduces the availability of calcium carbonate, which corals need to build their exoskeletons. As a result, coral growth slows, and the overall structural integrity of the reef diminishes. This weakening of coral reefs makes them more susceptible to damage from storms and other environmental stressors.

In addition to climate change, coral reefs are threatened by overfishing, pollution, and destructive fishing practices. Overfishing depletes key species that maintain the balance of the reef ecosystem, such as herbivorous fish that graze on algae. Without these fish, algae can overgrow and smother corals, disrupting the delicate balance of the reef environment. Pollution from agricultural runoff, sewage, and plastic waste also damages coral reefs by introducing harmful substances that can lead to disease and further stress the coral organisms.

To address these challenges, conservation efforts are underway worldwide. Marine protected areas (MPAs) have been established in many regions to limit human activities and allow reef ecosystems to recover. These protected areas can be effective in reducing the impacts of overfishing and pollution, but they are not immune to the effects of climate change. Additionally, some scientists are exploring more radical approaches, such as coral restoration and assisted evolution. Coral restoration involves growing corals in nurseries and then transplanting them to degraded reef areas. Assisted evolution, on the other hand, aims to enhance the resilience of corals by selectively breeding or genetically modifying them to withstand higher temperatures and acidic conditions.

Public awareness and global cooperation are also crucial to the preservation of coral reefs. Reducing greenhouse gas emissions, regulating fishing practices, and minimizing pollution are essential steps that require the collective effort of governments, industries, and individuals. As the challenges facing coral reefs continue to grow, the need for innovative solutions and sustained commitment becomes ever more urgent.

The future of coral reefs depends not only on our ability to mitigate the immediate threats but also on our willingness to address the underlying causes of these issues. The survival of these vital ecosystems will require a combination of traditional conservation methods, cutting-edge science, and a global commitment to environmental stewardship.

Questions

1. According to the passage, what is one of the primary reasons coral reefs are referred to as the “rainforests of the sea”?
   • (A) They are located in tropical regions.
   • (B) They support a high diversity of marine species.
   • (C) They provide wood for coastal communities.
   • (D) They are difficult to access and explore.
2. What is coral bleaching, as described in the passage?
   • (A) The process by which corals grow and expand.
   • (B) The result of corals expelling algae due to stress.
   • (C) The natural aging process of coral polyps.
   • (D) The formation of new coral colonies.
3. Which of the following is NOT mentioned as a threat to coral reefs in the passage?
   • (A) Climate change
   • (B) Tourism
   • (C) Pollution
   • (D) Overfishing
4. How does ocean acidification affect coral reefs, according to the passage?
   • (A) It speeds up the growth of coral exoskeletons.
   • (B) It increases the availability of calcium carbonate.
   • (C) It makes the water too cold for coral survival.
   • (D) It reduces the ability of corals to build their exoskeletons.
5. What is the purpose of Marine Protected Areas (MPAs) as mentioned in the passage?
   • (A) To promote tourism in coral reef regions
   • (B) To limit human activities and allow reefs to recover
   • (C) To encourage fishing in protected zones
   • (D) To increase the acidity of the ocean
6. What is one innovative approach to coral conservation mentioned in the passage?
   • (A) Coral restoration
   • (B) Increasing pollution levels
   • (C) Expanding urban development near reefs
   • (D) Promoting algae growth
7. Why is public awareness important for the preservation of coral reefs, according to the passage?
   • (A) It helps reduce the cost of coral restoration projects.
   • (B) It ensures that only scientists are involved in conservation efforts.
   • (C) It encourages global cooperation to address threats to reefs.
   • (D) It promotes the relocation of coastal communities.
8. What is the main idea of the passage?
   • (A) Coral reefs are declining due to natural processes beyond human control.
   • (B) Coral reefs are vital ecosystems that face multiple threats, requiring global conservation efforts.
   • (C) The tourism industry is the primary cause of coral reef degradation.
   • (D) Marine Protected Areas have completely solved the problem of coral reef decline.

Answers with Explanations

1. (B) They support a high diversity of marine species.
   The passage compares coral reefs to rainforests because they support a large variety of marine life, much like how rainforests support diverse terrestrial species.
2. (B) The result of corals expelling algae due to stress.
   Coral bleaching is described in the passage as the process where corals expel the symbiotic algae within their tissues due to stress from elevated water temperatures.
3. (B) Tourism
   Tourism is not listed as a threat to coral reefs in the passage, while climate change, pollution, and overfishing are mentioned as significant threats.
4. (D) It reduces the ability of corals to build their exoskeletons.
   Ocean acidification reduces the availability of calcium carbonate, which is essential for corals to build their exoskeletons, as mentioned in the passage.
5. (B) To limit human activities and allow reefs to recover
   MPAs are designed to limit human activities in order to give reef ecosystems a chance to recover from various stressors.
6. (A) Coral restoration
   The passage mentions coral restoration as an innovative approach to help restore degraded reef areas.
7. (C) It encourages global cooperation to address threats to reefs.
   Public awareness is important for mobilizing global efforts to reduce threats such as climate change, overfishing, and pollution, according to the passage.
8. (B) Coral reefs are vital ecosystems that face multiple threats, requiring global conservation efforts.
   The main idea of the passage is that coral reefs are critical ecosystems under threat, and that global efforts are needed to conserve them.