Ways to Make Coral Reefs

A coral reef is composed of the accumulation of the skeletal structures of corals--living organisms that protect themselves by creating a hard exoskeleton made primarily of calcium. Coral reefs provide homes for many species of tropical fish and plants and provide protection from erosion to many of the coastlines of Earth.

  1. An Endangered Ecosystem

    • Scientists estimate that it is possible that coral reefs provide homes, feeding areas and other necessities to up to 25 percent of all ocean life. However, climate change and various forms of habitat destruction including commercial fishing, pollution and sedimentation have placed the majority of the world's coral reefs at risk.
      The higher temperatures generated by global climate change are one of the greatest risks to coral reefs. Higher temperatures prevent the proper growth of algae on which the coral depend to survive. This lack of algae results in reefs that are bright white and non-functional, a process known as "bleaching." Higher temperatures can also result in the overgrowth of destructive surface algae (algae blooms) that prevent light and oxygen from reaching reefs, depriving them of vital nutrients.
      Although coral reefs provide homes to edible fish and crustaceans that make up the basis for 10 percent of the world's diet, destructive fishing and collection processes have also placed the world's reefs in danger. Although strongly constructed--some coral reefs have been accumulating and solidifying for millions of years--the reefs are no match for the use of dynamite by fishermen.
      Sedimentation, the deposits of sand and silt left on the sea floor due to erosion or human construction on coastlines, poses a similar danger to reefs. The buildup of sand and silt on the sea floor around coral reefs reduces the amount of space the reefs have to grow because corals need access to bare rock to attach to the sea floor. Large quantities of sand and silt may also create cloudy water around reefs and reduce the amount of sunlight that the corals can receive. In cases of large amounts of sedimentation, some reefs may even be buried and suffocated under the sand.

    Building New Reefs

    • Many methods are being studied to encourage natural reef-building. One of the most popular is to provide places for new reefs to form by sinking concrete or large metal structures that corals can attach to and begin the reef-building process. Many projects use concrete blocks or bricks made of Biorock, a mineral-rich substance that corals can attach to and grow. Reef-building and restoration efforts are going on all over the world, with some projects attempting to start new reefs and others to encourage expansion of existing endangered reefs.
      In 2009, the USNS Hoyt S. Vandenberg was sunk 7 miles off the coast of the Florida Keys to provide an artificial reef starter. It is hoped that the Vandenberg will provide a place for corals to anchor and contribute to Florida coastal reef restoration.