View from the mountains of the north-west coast of Tahiti with Moorea island in background, French Polynesia, south Pacific ocean
Divers have found a new coral reef near the island of Tahiti in the Pacific Ocean. The reef is more than 200 feet wide and stretches for almost two miles. Having grown in water between 100 and 200 feet deep, this new reef is one of the largest ever found at this depth.
Coral reefs are formed by small, soft ocean animals called polyps. The polyps grow together in large colonies and feed on plankton and other organisms in the surrounding water. The skeletons of polyps form the hard, rock-like substances that most people envision when they think of coral reefs. Coral polyps also depend on algae for food, and algae is what gives coral reefs their color. Since algae needs sunlight to grow, most coral reefs are found in warmer, shallower waters up to about 80 feet deep where sunlight can penetrate more easily. The new reef found near Tahiti is unusual because it lies at a depth that gets much less sunlight. One reason the new reef may be thriving at a greater depth is because it is in a part of the ocean that is far from land and has less sediment.
In recent years, many coral reefs have become endangered because of climate change, pollution, and overfishing. Some reefs in shallow waters have experienced coral bleaching, a stress response that can occur during heat waves. When ocean water heats up too much, a reef’s coral polyps may reject algae. Without algae the coral loses color and all that remains are the white, bleached skeletons. If bleaching continues too long it can kill the coral.
In the past 15 years, about 30 percent of Earth’s coral reefs have died. Australia’s Great Barrier Reef has suffered bleaching of up to 80 percent of its coral since 2016. This is alarming because coral reefs are critical to marine biodiversity. About 25 percent of all ocean animals live in and around coral reefs. If warming trends aren’t reversed, some scientists warn that all coral reefs will disappear by the year 2100.
The divers who found the new coral reef in Tahiti describe it as pristine. It seems to be unaffected by climate change, and the deeper location of the reef may offer it some protection. Scientists want to study this new reef and the animals that live there to better protect other coral reefs. Since only about 20 percent of the world’s ocean floors have been mapped, they are also hopeful that there are many more reefs that have yet to be discovered.
Image credit: ©Damsea/Shutterstock
Sources
- Rare, pristine coral reef found off Tahiti coast
(Source: AP News; accessed February 1, 2022) - Giant pristine coral reef discovered off Tahiti
(Source: BBC News; accessed February 1, 2022) - This huge coral reef has only just been discovered, and it’s undamaged by climate change
(Source: CBC Radio-Canada; accessed February 1, 2022) - Sprawling Coral Reef Resembling Roses is Discovered Off Tahiti
(Source: The New York Times; accessed February 1, 2022) - “Magical” massive coral reef discovered deep below surface in Tahiti “twilight zone”
(Source: CBS News; accessed February 1, 2022) - What Are Corals?
(Source: National Park Service; accessed February 1, 2022) - What is a Coral Reef?
(Source: Ocean Conservancy; accessed February 1, 2022) - What is coral bleaching?
(Source: National Ocean Service; accessed February 1, 2022)