reef

     

In nautical terminology, a reef is a rock, sanbar, or other feature lying beneath the surface of the water yet shallow enough to be a hazard to ships. Many reefs result from abiotic processes—deposition of sand, wave erosion planning down rock outcrops, and other natural processes—but the best-known reefs are the coral reefs of tropical waters developed through biotic processes dominated by corals and calcareous algae.

Trivia about reef

  • In 1996 the destroyed HMCS Columbia was sunk to make an artificial one of these for divers
  • (Jon of the Clue Crew wriggles through a small cave opening at Carlsbad Caverns Nat'l Park, New Mexico.) Carlsbad is part of an ancient one of these structures, on the edge of an inland sea; it was mostly formed by the remains of algae & sponges, not coral