Reading - Part 3

Coral reefs are large underwater structures composed of the skeletons of coral. There are hundreds of different species of coral. Coral reefs have a surprising array of shapes and colours, ranging from round, folded brain corals named for their resemblance to a human brain to tall, elegant sea whips and sea fans that look like brightly coloured trees or plants. Fringing reefs are the most commonly seen coral reefs, and they grow near coastlines. Barrier reefs are separated from the coastlines by deeper, wider lagoons.

Corals are found all over the world's oceans, from the Aleutian Islands off the coast of Alaska to the warm tropical waters of the Caribbean Sea. The biggest coral reefs are found in the clear, shallow waters of the tropics and subtropics. The largest of these coral reef systems is the Great Barrier Reef in Australia. It is more than 2,400 kilometres long. Scientists have explored only about 20 percent of the ocean's floor, and they continue to find previously unknown coral reefs that have likely existed for hundreds of years.

The corals that build reefs are known as hard or reef-building corals. Soft corals, such as sea fans and sea whips, do not produce reefs. The calcium carbonate that is created by hard corals provides a foundation for baby corals to settle upon. And if the reef breaks to create reefs are limited, then the corals will build up over time and create healthy, vibrant coral reef. Other types of animals and plants also contribute to the structure of reefs. For example, algae, seaweed, and sponges add to the architecture of coral reefs.

The largest coral reef in the world, the Great Barrier Reef, is home to at least 400 individual species of coral and thousands of different species of fish, molluscs, sea snakes, sea turtles, whales, dolphins, birds and more. As with the other coral reefs of the world, this incredible ecological hotspot is under threat. A heat wave in 2016 caused a large percentage of the corals in the Great Barrier Reef to undergo severe bleaching and death. Even in the deeper, less-exposed areas of the reef, nearly 40 percent of the corals had partial bleaching.

Healthy reefs lead to healthy oceans, and healthy oceans are vital to all life on the planet. The destruction facing not only the Great Barrier Reef, but also every reef around the world, can lead to the extinction of thousands of species of marine life. In turn, coastlines that are currently protected by reefs would more readily be flooded during storms. Some islands and low-lying countries would vanish under the water. Moreover, the highly important and profitable industry that coral reefs provide could collapse.

The Australian government has put forth a long-term plan to sustain the Great Barrier Reef. The plan outlines efforts to reduce and eventually eliminate dumping materials and chemicals, reduce fishing and poaching, and monitor the water quality. There are also many attempts to rebuild the reef. Scientists are working to breed stronger species of coral that are less sensitive to warmer waters. Another group of ecologists are experimenting with growing corals on steel frames placed over the old parts of the reef.