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1
Reef Life of the Andaman (full marine biology documentary)
Reef Life of the Andaman (full marine biology documentary)
::2012/11/01::
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2
BBC Great Barrier Reef II 2012 HD الحيوانات بالريف الافضل وثائقي HD
BBC Great Barrier Reef II 2012 HD الحيوانات بالريف الافضل وثائقي HD
::2013/08/04::
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3
reef *new album* Lucky #5
reef *new album* Lucky #5
::2013/01/23::
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4
Miss Reef 2015
Miss Reef 2015
::2014/11/04::
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5
Adventure coral reef under the sea of Egypt
Adventure coral reef under the sea of Egypt
::2014/01/26::
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6
Compassing // a film by cyrus sutton x reef // free download at Reef.com
Compassing // a film by cyrus sutton x reef // free download at Reef.com
::2013/09/03::
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7
Great Barrier Reef  Nature
Great Barrier Reef Nature's Miracles Nature Documentary
::2013/11/28::
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8
Exploring Oceans: Great Barrier Reef
Exploring Oceans: Great Barrier Reef
::2009/03/30::
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9
Coral Reef Adventure 1-4 HD 720p
Coral Reef Adventure 1-4 HD 720p
::2011/06/15::
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10
Great Barrier Reef Documentary
Great Barrier Reef Documentary
::2014/02/01::
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11
Building The Ultimate Reef Tank!!
Building The Ultimate Reef Tank!!
::2014/04/05::
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12
Matt
Matt's Reef Tank | Episode 1 | Tank Construction
::2014/04/27::
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13
Dormero Rotes Ross Reef Aquarium June 2013
Dormero Rotes Ross Reef Aquarium June 2013
::2013/06/07::
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14
Finalistas Miss Reef 2014
Finalistas Miss Reef 2014
::2014/02/18::
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15
The 2011 Miss Reef Calendar
The 2011 Miss Reef Calendar
::2010/09/30::
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16
Minecraft PC - The-Reef.EU - Cloudy Combat
Minecraft PC - The-Reef.EU - Cloudy Combat
::2014/05/11::
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17
How to setup simple cheap reef tank!
How to setup simple cheap reef tank!
::2012/06/21::
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18
The Reef  (The Heart Pounding Ending) HQ
The Reef (The Heart Pounding Ending) HQ
::2014/06/21::
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19
Largest Private Reef Aquarium
Largest Private Reef Aquarium
::2014/02/25::
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20
Slippery Survival and Cloudy Combat | The Reef Minecraft Mini-games
Slippery Survival and Cloudy Combat | The Reef Minecraft Mini-games
::2014/05/06::
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21
Reef  - Set the Record Straight
Reef - Set the Record Straight
::2009/12/27::
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22
Reef The Lost Cauze - Moonshine prod. by Haj of Dumhi
Reef The Lost Cauze - Moonshine prod. by Haj of Dumhi
::2013/05/13::
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23
The Reef : Welcome to the server! - Ep 1
The Reef : Welcome to the server! - Ep 1
::2014/05/22::
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24
The Ultimate Reef Tank Lighting - AmericanReef Saltwater Tank ReefKeeping Video
The Ultimate Reef Tank Lighting - AmericanReef Saltwater Tank ReefKeeping Video
::2014/01/06::
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25
Spearfishing the Great Barrier Reef
Spearfishing the Great Barrier Reef
::2012/07/02::
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26
Bogan Loves the Great Barrier Reef
Bogan Loves the Great Barrier Reef
::2014/08/20::
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27
Nature
Nature's wonders: Coral reefs in HD
::2010/05/21::
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28
Minecraft PC - Sky Wars/Bow Battle - The-Reef.eu
Minecraft PC - Sky Wars/Bow Battle - The-Reef.eu
::2014/05/18::
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29
Payne Triumphs at High-Flying Reef Hawaiian Pro
Payne Triumphs at High-Flying Reef Hawaiian Pro
::2014/11/15::
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30
Don
Don's High-Tech Custom Reef Tank
::2013/05/02::
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31
Wild Kratts Rocket Jaw Rescuer of The Reef
Wild Kratts Rocket Jaw Rescuer of The Reef
::2014/07/22::
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32
The Reef (2010)
The Reef (2010)
::2014/04/10::
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33
Reef Hawaiian Pro: Wipeout Montage
Reef Hawaiian Pro: Wipeout Montage
::2014/11/15::
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34
Minecraft: Cloudy Combat - iBallisticSquid Trick Shot! (The-Reef.EU server)
Minecraft: Cloudy Combat - iBallisticSquid Trick Shot! (The-Reef.EU server)
::2014/05/18::
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35
Destiny Walkthrough Part 10 - The Reef (Let
Destiny Walkthrough Part 10 - The Reef (Let's Play Commentary)
::2014/09/10::
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36
Reef Doctors Episode 1 (Full Episode)
Reef Doctors Episode 1 (Full Episode)
::2013/07/12::
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37
REEF TANK ADDICTION Season 1 Episode 1
REEF TANK ADDICTION Season 1 Episode 1
::2014/09/28::
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38
Reef Roids Plankton Coral Feeding
Reef Roids Plankton Coral Feeding
::2013/10/29::
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39
Great Barrier Reef - Reef to Rainforest (s01e02)
Great Barrier Reef - Reef to Rainforest (s01e02)
::2012/01/10::
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40
Sonic & Knuckles Music: Lava Reef Zone Act 1 [extended]
Sonic & Knuckles Music: Lava Reef Zone Act 1 [extended]
::2008/12/15::
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41
Haleiwa Pumps, Teen Shines at Reef Hawaiian Pro
Haleiwa Pumps, Teen Shines at Reef Hawaiian Pro
::2014/11/13::
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42
The Reef (2010) - Official Trailer
The Reef (2010) - Official Trailer
::2011/01/10::
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43
Spearfishing the Swains Reefs- Southern Great Barrier Reef 2014
Spearfishing the Swains Reefs- Southern Great Barrier Reef 2014
::2014/04/06::
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44
Eleogram
Eleogram's Reef Pro Tube-Time Scores Perfect 10
::2014/11/12::
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45
Shallow Reef Suring | HD
Shallow Reef Suring | HD
::2013/01/15::
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46
Crystal Reef - Animal Jam Journey Book Cheat Guide
Crystal Reef - Animal Jam Journey Book Cheat Guide
::2013/03/20::
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47
the great barrier reef documentary
the great barrier reef documentary
::2014/03/16::
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48
Selecting Fish for a New Reef Tank - EP 1: Fish and Corals
Selecting Fish for a New Reef Tank - EP 1: Fish and Corals
::2013/04/09::
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49
REEF - The Path of the Modern Gypsy
REEF - The Path of the Modern Gypsy
::2011/05/28::
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Great Barrier Reef
Great Barrier Reef
::2012/12/16::
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From Wikipedia, the free encyclopedia
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For other uses, see Reef (disambiguation).
Pamalican island with surrounding reef, Sulu Sea, Philippines.
A reef surrounding an islet.

A reef is a rock, sandbar, or other feature lying beneath the surface of the water (80 meters or less beneath low water).

Many reefs result from abiotic processes—deposition of sand, wave erosion planing 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. Artificial reefs such as shipwrecks are sometimes created to enhance physical complexity on generally featureless sand bottoms in order to attract a diverse assemblage of organisms, especially fish.

Biotic reef[edit]

There is a variety of biotic reef types, including oyster reefs, but the most massive and widely distributed are tropical coral reefs. Although corals are major contributors to the framework and bulk material comprising a coral reef, the organisms most responsible for reef growth against the constant assault from ocean waves are calcareous algae, especially, although not entirely, species of coralline algae.

These biotic reef types take on additional names depending upon how the reef lies in relation to the land, if any. Reef types include fringing reef, barrier reefs, as well as atolls. A fringing reef is a reef that is attached to an island. A barrier reef forms a calcareous barrier around an island resulting in a lagoon between the shore and the reef. An atoll is a ring reef with no land present. The reef front (ocean side) is a high energy locale whereas the internal lagoon will be at a lower energy with fine grained sediments.

Geologic reef[edit]

Definition[edit]

Archeocyathids, the first reef building organisms, from the Poleta formation in the Death Valley area

Geologists define reefs and related terms (for example, bioherm, biostrome, carbonate mound, pseudo-atoll) using the factors of depositional relief, internal structure, and biotic composition. There is no consensus on one universally applicable definition. A useful definition distinguishes reefs from mounds as follows. Both are considered to be varieties of organosedimentary buildups: sedimentary features, built by the interaction of organisms and their environment, that have synoptic relief and whose biotic composition differs from that found on and beneath the surrounding sea floor. Reefs are held up by a macroscopic skeletal framework. Coral reefs are an excellent example of this kind. Corals and calcareous algae grow on top of one another and form a three-dimensional framework that is modified in various ways by other organisms and inorganic processes. By contrast, mounds lack a macroscopic skeletal framework. Mounds are built by microorganisms or by organisms that don't grow a skeletal framework. A microbial mound might be built exclusively or primarily by cyanobacteria. Excellent examples of biostromes formed by cyanobacteria occur in the Great Salt Lake of Utah (USA), and in Shark Bay, Western Australia.

Cyanobacteria do not have skeletons and individuals are microscopic. Cyanobacteria encourage the precipitation or accumulation of calcium carbonate and can produce distinct sediment bodies in composition that have relief on the seafloor. Cyanobacterial mounds were most abundant before the evolution of shelly macroscopic organisms, but they still exist today (stromatolites are microbial mounds with a laminated internal structure). Bryozoans and crinoids, common contributors to marine sediments during the Mississippian (for example), produced a very different kind of mound. Bryozoans are small and the skeletons of crinoids disintegrate. However, bryozoan and crinoid meadows can persist over time and produce compositionally distinct bodies of sediment with depositional relief.

The Proterozoic Belt Supergroup contains evidence of possible microbial mat and dome structures similar to stromatolite reef complexes.[1]

Geologic reef structures[edit]

Reefs off Vanatinai in the Louisiade Archipelago.

Ancient reefs buried within stratigraphic sections are of considerable interest to geologists because they provide paleo-environmental information about the location in Earth's history. In addition, reef structures within a sequence of sedimentary rocks provide a discontinuity which may serve as a trap or conduit for fossil fuels or mineralizing fluids to form petroleum or ore deposits.

Corals, including some major extinct groups Rugosa and Tabulata, have been important reef builders through much of the Phanerozoic since the Ordovician Period. However, other organism groups, such as calcifying algae, especially members of the red algae Rhodophyta, and molluscs (especially the rudist bivalves during the Cretaceous Period) have created massive structures at various times. During the Cambrian Period, the conical or tubular skeletons of Archaeocyatha, an extinct group of uncertain affinities (possibly sponges), built reefs. Other groups, such as the Bryozoa have been important interstitial organisms, living between the framework builders. The corals which build reefs today, the Scleractinia, arose after the Permian–Triassic extinction event that wiped out the earlier rugose corals (as well as many other groups), and became increasingly important reef builders throughout the Mesozoic Era. They may have arisen from a rugose coral ancestor. Rugose corals built their skeletons of calcite and have a different symmetry from that of the scleractinian corals, whose skeletons are aragonite. However, there are some unusual examples of well preserved aragonitic rugose corals in the late Permian. In addition, calcite has been reported in the initial post-larval calcification in a few scleractinian corals. Nevertheless, scleractinian corals (which arose in the middle Triassic) may have arisen from a non-calcifying ancestor independent of the rugosan corals (which disappeared in the late Permian).

See also[edit]

Notes[edit]

References[edit]

  • Shears N.T. (2007) Biogeography, community structure and biological habitat types of subtidal reefs on the South Island West Coast, New Zealand. Science for Conservation 281. p 53. Department of Conservation, New Zealand. [1]

External links[edit]

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