How Much Do You Know About World Reef Awareness Day? Quiz

Coral reefs are often called the “rainforests of the sea” because they support a staggering level of biodiversity, similar to how rainforests support life on land. Despite covering less than 1% of the ocean floor, reefs are home to over 25% of all marine life. Their intricate ecosystems host fish, invertebrates, and plant species, many of which rely on coral for shelter, food, or breeding. This comparison isn't just poetic—it’s an ecological fact that highlights the richness and complexity of reef systems, and why their protection is as vital as preserving rainforests.

Climate change is the primary driver of coral bleaching due to its effect on sea temperature. As ocean waters warm even slightly, the stress causes corals to expel the symbiotic algae (zooxanthellae) living in their tissues. Without these algae, corals lose both color and a major energy source. While overfishing and tourism contribute to reef degradation, rising sea temperatures are by far the most widespread and devastating impact globally, making climate change the leading cause behind coral bleaching events and subsequent reef die-offs.

World Reef Awareness Day is observed every year on June 1. This day is dedicated to raising awareness about the fragile condition of coral reefs and the urgent actions needed to protect them. June 1 serves as a global call to individuals, governments, scientists, and businesses to recognize how interconnected human activities are with marine ecosystems. It is strategically placed early in the month to coincide with other ocean-related events like World Oceans Day (June 8), amplifying momentum and driving sustained ecological attention during a critical time.

More than 25% of all marine species depend on coral reefs at some point in their life cycles. That includes thousands of species of fish, mollusks, crustaceans, and even marine mammals. Reefs act as nurseries, feeding grounds, and shelter zones. This statistic underlines why their loss would result in a catastrophic collapse of marine biodiversity. Unlike niche ecosystems, reefs serve as a foundational support system for ocean life, and their destruction has ripple effects that extend far beyond the visible coral itself into global food chains and economies.

The hard skeleton of corals is made primarily of calcium carbonate (CaCO₃). Corals secrete this compound to form protective limestone-like structures that build the reef's physical foundation over thousands of years. These calcium carbonate structures provide the architectural complexity needed for fish and other marine species to inhabit and thrive. However, calcium carbonate formation is highly sensitive to ocean acidity, and with increased CO₂ absorption, ocean acidification is weakening coral skeletons, making them more vulnerable to erosion and breakage, thereby threatening the entire reef ecosystem.

El Niño, a global climate phenomenon marked by the warming of surface waters in the central and eastern Pacific Ocean, triggers mass coral bleaching. It disrupts normal weather patterns and raises sea temperatures across large regions, stressing coral systems worldwide. During strong El Niño years, reefs in areas from the Indian Ocean to the Caribbean have suffered unprecedented bleaching events. El Niño is especially dangerous because it affects reefs that are already dealing with local stressors like pollution or overfishing, pushing ecosystems beyond their capacity to recover.

Corals bleach because they lose symbiotic algae called zooxanthellae, which live in their tissues. These algae provide up to 90% of a coral’s energy through photosynthesis and give them their vibrant color. When stressed—mainly by elevated sea temperatures—corals expel these algae, revealing their white calcium carbonate skeletons. This makes them more vulnerable to disease, starvation, and eventual death if the stressful conditions persist. The relationship is so critical that even temporary loss of these algae significantly weakens corals and their survival chances.

Many regular sunscreens contain chemicals like oxybenzone and octinoxate that are toxic to coral reefs even in small amounts. These substances can cause coral DNA damage, hinder reproduction, and increase coral bleaching. When swimmers use such sunscreen and enter the ocean, these chemicals wash off and linger in reef areas. Over time, the cumulative effect contributes to reef degradation. That’s why “reef-safe” sunscreens—those free from harmful chemicals—are increasingly recommended in reef-sensitive regions, especially around protected marine parks and tourist beaches.

Coral reefs act as natural barriers, absorbing wave energy and protecting coastlines from erosion, storm surges, and flooding. In countries vulnerable to hurricanes and typhoons, healthy reefs reduce the impact of extreme weather by buffering wave action. Their complex structures break up waves and lower their destructive power before they reach shorelines. Without reefs, coastal communities would face increased vulnerability to disasters and would need to invest heavily in man-made defenses like sea walls, which are costlier and less sustainable long-term.

The Great Barrier Reef in Australia is the world’s largest coral reef system, stretching over 2,300 kilometers and visible from space. It comprises thousands of individual reefs and islands and is home to an incredible diversity of life including 600 types of coral, 1,500 species of fish, and 30 types of marine mammals. Recognized as a UNESCO World Heritage Site, the Great Barrier Reef is both a scientific marvel and a critical natural resource. Unfortunately, it is also one of the most endangered due to repeated bleaching, climate change, and human interference.