Category: General Article
Reefs can be constructed of different materials including rock, sand or coral. Others can be artificially or accidentally created, such as a sunken aircraft or ship. They can be the result of underwater geography laid down by natural processes million of years ago; or built up over shorter periods by the accumulation of materials carried on the water or created by living organisms. Below are three examples of three different kinds of reefs from around the world.
Oregon’s waters do not have a great diversity of hard and soft coral species when compared to tropical areas, but the volcanic geography of the coast did create numerous rocky reefs. One of the best known is the Orford Reef, located several miles offshore from Port Orford on the South Coast. In the dark valleys of the reef grow vast forests of bull kelp, their long fronds stretching as much as 100 feet (30 m) to the sunlit surface. Sea birds may perch on these floating mats of kelp, using them as platforms to hunt the fish schooling below. Further down, rockfish are also using the reef as a hunting ground. The fish will use barbs on their fins to anchor themselves to the rocky walls, waiting patiently for something tasty to swim by before they attack. Likewise, some of Oregon’s larger predators – including the Great White Shark and the Orca – may prowl the reefs in search of food like Harbor Seals and Steller Sea Lions.
Other reefs are formed by the actions of living organisms, or what is called a biotic process. When most people think about reefs, they probably imagine sprawling coral forests teeming with brightly colored tropical fish. These reefs are excellent examples of those formed through a biotic process since coral is a rocky secretion produced by marine animals called coelenterates.
Stretching over 1,500 miles (2,414 km), this is the world’s largest and best known coral reef. It is located in the Coral Sea near Australia and is home to thousands of species of animals. The name may be a little misleading, however, as this is not a single unbroken reef but a collection of over two thousand individual coral colonies and hundreds of islands. The reef is home to many species now threatened by climate change and marine pollution, including sea turtles, salt-water crocodiles, and dozens of species of sharks and whales. To help protect these animals, a large part of the reef is a marine park where human uses such as fishing and tourism are very limited.
A third form a reef is completely artificial – or created by human beings and then deposited in the ocean. Some of the best examples of an artificial reef are sunken ships where the very body of the vessel becomes a haven for all kinds of marine life. In most cases, these ships find their way onto the ocean floor due to accident, natural disaster or war. More recently, however, ships may be intentionally scuttled to create a new reef for ocean life.
Chuuk Lagoon is a tiny spot in the middle of a collection of islands in the South Pacific. The lagoon is partially sheltered by a natural coral reef, but it’s also the site of one of the most extensive artificial reefs in the world. Sadly, this reef of sunken ships and aircraft were created in one terrible day in 1944, the result of an aerial attack by American forces against the Japanese fleet harbored here. When the smoke cleared, sixty ships and nearly 300 aircraft were resting on the bottom of the lagoon. In the nearly seventy years since the battle, marine life have reclaimed these human artifacts. Sharks, turtles and rays swim through the mass of twisted metal – often joined by SCUBA divers who consider Chuuk Lagoon one of the best diving spots on earth! New corals have formed large colonies on the hulls of the warships and the darkened holds provide shelter to almost three hundred species of fish. Although the circumstances around this reef’s creation are tragic, Chuuk Lagoon is a great example of how nature has the ability to reclaim almost anything.
Related Information: Life in Ruins
Photo credits: NOAA.