Coral reef vibrant

Vibrant coral reefs host 25% of marine species but face threats from climate change and pollution.

About this subject

Coral reefs are underwater ecosystems built by polyps that secrete calcium carbonate, forming complex structures. Found in tropical regions, these reefs cover less than 0.1% of the ocean floor yet support a quarter of marine biodiversity, including fish, mollusks, and echinoderms. Australia hosts the world’s largest reef, the Great Barrier Reef, spanning 2,300 km and home to 30,000 associated species. Coral degradation from global warming and ocean acidification has placed 30% of reef-building corals at risk of extinction by 2050. Interestingly, corals also inspire medicine: extracts from living corals have led to the development of anesthetics and anti-inflammatory drugs.

Frequently Asked Questions

What causes coral bleaching?

Bleaching happens when corals expel symbiotic algae due to stressors like water temperature increases (>1°C above normal for months), pollution, or reduced salinity. The loss of these algae, which provide 90% of the coral's energy, leads to discoloration and can result in colony death.

How many species rely on coral reefs?

Approximately 25% of all marine species depend on coral reefs for survival. This includes 4,000 fish species plus crustaceans, echinoderms, and mollusks. In coastal regions, 500 million people rely on reefs for food, tourism, and storm protection.

How do corals contribute to medicine?

Coral research has identified compounds with antibiotic, anti-inflammatory, and anticancer properties. For example, corals in the Discodermia genus contain substances that inhibit tumor cell growth. Additionally, coral structures have been used in tissue engineering to regenerate human bones.