A reef is any physical structure which lies no more than 20 feet (6 m) below the ocean surface. Reefs can be composed of many different things, but most are formed through abiotic processes where naturally occurring chemical or physical factors combine to create these structures. For example, natural wave and tidal actions may build up sand masses or break down rock formations to create reefs.

  • Comparing Reefs From Around The World

    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. Compare three famous reefs from around the world.

  • Small Animals, Big Results

    Category: Fun Fact

    Can you imagine a structure so large it can be seen from space – and human beings had nothing to do with it? Can you guess what it is?

  • Tracking Sharks on the Great Barrier Reef

    Category: General Article

    Join Dr. Michelle Heupel of the Australian Institute of Marine Science for this week-long look at her research tracking sharks on the Great Barrier Reef. Features include daily blogs, videos, slideshows, downloadable educational materials and much more.

  • Phoenix Islands Chain Deep Dive

    Category: General Article

    They are one of the deepest, most pristine coral reefs on Earth. Venture to the Phoenix Islands Chain with Schmidt Ocean Institute for a first glimpse at these unseen ecosystems.

Slideshow: Reefs

  • Reef6

    All of Oregon's reefs are volcanic in nature, constructed of the same rock as much of the coastline.

  • Reef7

    Reefs can be artificial in nature, such as this sunken World War II aircraft now covered in marine life. (NOAA Photo)

  • Reef1

    Reefs can be constructed of different materials. Coral reefs like this one are confined to warmer waters. (NOAA Photo)

  • Reef2

    Rockfish are a common species in Oregon's rocky reefs which provides them with vital habitat. (NOAA Photo)

  • Reef3

    Exploring reefs is popular among SCUBA divers and a growing form of tourism. (NOAA Photo)

  • Reef4

    Reefs can provide food and habitat for a variety of species, including fish and invertebrates. (NOAA Photo)

  • Reef5

    Sebastian Reef is one of Oregon's best known. The exposed areas are a well-known haul-out for pinnipeds.