CORAL REEFS: THE RAINFORESTS OF THE SEA
Coral reefs are among the most diverse ecosystems on Earth despite occupying less than one per cent of the ocean floor. Built over thousands of years by tiny marine organisms known as coral polyps, reefs provide habitats for thousands of species of fish, crustaceans, molluscs and other marine life. Scientists regard healthy coral reefs as essential for maintaining biodiversity and supporting the ecological balance of tropical oceans.
Corals have a close relationship with microscopic algae called zooxanthellae, which live inside coral tissues. Through photosynthesis, these algae produce nutrients that supply much of the coral's energy requirements. In return, the coral provides the algae with protection and access to sunlight. This partnership enables coral reefs to thrive in nutrient-poor tropical waters.
One of the greatest threats facing coral reefs is coral bleaching. When ocean temperatures remain unusually high for extended periods, corals may expel their algae, causing them to lose colour and their primary source of nutrition. Although bleached corals are not immediately dead, prolonged periods without their algae greatly reduce their chances of survival. Researchers have observed that some reefs recover if environmental conditions improve, while others suffer long-term damage.
Scientists have also become increasingly concerned about ocean acidification. As the oceans absorb more carbon dioxide from the atmosphere, seawater becomes more acidic. This process may reduce the ability of corals to produce the calcium carbonate skeletons that form the foundation of reef structures. However, researchers continue to investigate how different coral species respond to changing ocean chemistry, as some appear more resistant than others.
Human activities create additional pressures on coral reef ecosystems. Overfishing, coastal development and pollution may weaken reef resilience by disrupting ecological relationships and reducing water quality. In response, many countries have established marine protected areas and introduced regulations to limit harmful activities. Nevertheless, scientists emphasise that local conservation measures alone are unlikely to eliminate every threat facing coral reefs.
Despite decades of research, many aspects of reef recovery remain poorly understood. Researchers continue to examine how genetic diversity, environmental conditions and species interactions influence the long-term survival of coral ecosystems.
Questions 1–12
Do the following statements agree with the information given in the passage?
Write
TRUE if the statement agrees with the passage
FALSE if the statement contradicts the passage
NOT GIVEN if there is no information in the passage.
1.Coral reefs occupy less than one per cent of the ocean floor.
2. Coral reefs support only a small number of marine species.
3. Zooxanthellae provide corals with nutrients through photosynthesis.
4. Corals protect algae from predators in exchange for nutrients.
5. Bleached corals die immediately after losing their algae.
6. Some coral reefs can recover if environmental conditions become favourable.
7. Scientists know exactly why certain coral species survive ocean acidification better than others.
8. Ocean acidification affects every coral species in exactly the same way.
9. Marine protected areas are one strategy used to help conserve coral reefs.
10. Australia's coral reefs recover more quickly than reefs in Southeast Asia.
11. Pollution always causes greater damage than overfishing.
12. Scientists first discovered coral bleaching in the twentieth century.
Summary
This IELTS reading passage explores the importance of coral reefs, often called the "Rainforests of the Sea," and their role in supporting marine biodiversity. It explains the symbiotic relationship between coral polyps and zooxanthellae algae, the causes and effects of coral bleaching, the impact of ocean acidification, and the threats posed by pollution, overfishing, and coastal development. The passage also discusses conservation efforts such as marine protected areas and ongoing scientific research into reef recovery. Twelve True, False, and Not Given questions are included to help learners improve their IELTS reading comprehension and analytical skills.