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The Great Barrier Reef's Ecosystem

The Great Barrier Reef, located off the coast of Queensland, Australia, is the world's largest coral reef system. Composed of over 2,900 individual reefs and 900 islands, it stretches for over 2,300 kilometers and is one of the most biodiverse ecosystems on Earth. The reef's structure is built by billions of tiny organisms known as coral polyps. These polyps secrete calcium carbonate to form a hard skeleton, which accumulates over generations to create the massive formations we see today.

The reef supports an extraordinary diversity of life. It is home to more than 1,500 species of fish, 400 types of coral, and thousands of species of mollusks and other invertebrates. This rich biodiversity is possible because of the symbiotic relationship between coral polyps and algae called zooxanthellae. The algae live within the coral's tissues, providing the coral with up to 90 percent of its energy through photosynthesis. In return, the coral provides the algae with a protected environment and the compounds they need for photosynthesis. This relationship is vital for the reef's survival.

The ecosystem of the Great Barrier Reef is a complex and fragile web of interdependence. For example, many fish species, like the parrotfish, graze on algae, which helps prevent it from overgrowing and smothering the coral. Sea turtles use the reef for feeding and nesting, while sharks, as apex predators, help maintain the health of fish populations. The delicate balance of this ecosystem highlights its vulnerability to environmental changes.