1 of 4 Sea Days to Melbourne - Day 47

Coral is alive… it is easy to think of coral as the same as a rock or a plant. But coral is an invertebrate creature. This colony of countless tiny animals known as polyps is alive. Coral originate when swimming larvae attached themselves to rocks that line a cove or rest in shallow waters. Over time the polyps and coral reproduce and secrete calcium carbonate, which hardens into a skeleton and gives the reef its shape. The reef can grow to comprise many miles and attract myriad species of fish.
Even then, the coral does not sit passively. Though difficult to discern during a snorkeling expedition, this vibrant ecosystem is constantly changing. Surprisingly on alert for tiny fish and plankton they deploy minuscule stinging cells to catch their prey and engulf them deep in their nutrients much like plants do, from a process similar to photosynthesis. These species thrive in clear, shallow water where sunlight is plentiful.
Coral may appear in three reef configurations. Fringing reefs grow directly from a shoreline in shallow water and may even be exposed at low tide. Barrier reefs are located farther from the shore; its coral therefore remain underwater. An atoll reef, also called coral atoll, completely or partially encircles a shallow lagoon. Whatever its form, coral is an integral part if marine life and comprises some of the oceans’ most colorful and thriving ecosystems.もっと詳しく