DarwinsTheory: Difference between revisions
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= Darwin's Theory = | = Darwin's Theory = | ||
Darwin grouped coral reefs into three distinct types: barrier, fringing, and atolls. He believed that each reef type was really a separate stage of reef development around a slowly sinking volcanic island. | Darwin grouped coral reefs into three distinct types: barrier, fringing, and atolls. He believed that each reef type was really a separate stage of reef development around a slowly sinking volcanic island.<ref> Strykowski and Bonem, p. 19-20 </ref> | ||
==Stage 1 - Fringing Reef== | ==Stage 1 - Fringing Reef== | ||
A submarine volcano forms an island rising from the sea floor. Corals begin to grow in the shallow regions off the coast of the island. As the island gradually sinks, the reef grows upward in order to stay within a sunlit range. A fringing reef is a reef encircling this volcanic island while it first begins to sink.<ref> Strykowski and Bonem, p. 20 </ref> | |||
==Stage 2 - Barrier Reef== | ==Stage 2 - Barrier Reef== | ||
As the volcanic island continues to sink, a lagoon begins to form between the reef and the exposed island. In this phase, the reef is a barrier reef.<ref> Strykowski and Bonem, p. 20-1 </ref> | |||
==Stage 3 - Atoll== | ==Stage 3 - Atoll== | ||
Once the volcanic island is fully submerged, the reef is known as an atoll. The reef outline is circular with a central lagoon.<ref> Strykowski and Bonem, p. 21 </ref> | |||
==Evidence== | ==Evidence== | ||
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==Notes== | ==Notes== | ||
<references/> | |||
==References== | ==References== | ||
*Strykowski, Joe and Rena M. Bonem. Palaces Under the Sea. Crystal River, FL: Star Thrower Foundation, 1993, p. 19-26. Print. | |||
Revision as of 20:50, 30 December 2012
Darwin's Theory
Darwin grouped coral reefs into three distinct types: barrier, fringing, and atolls. He believed that each reef type was really a separate stage of reef development around a slowly sinking volcanic island.[1]
Stage 1 - Fringing Reef
A submarine volcano forms an island rising from the sea floor. Corals begin to grow in the shallow regions off the coast of the island. As the island gradually sinks, the reef grows upward in order to stay within a sunlit range. A fringing reef is a reef encircling this volcanic island while it first begins to sink.[2]
Stage 2 - Barrier Reef
As the volcanic island continues to sink, a lagoon begins to form between the reef and the exposed island. In this phase, the reef is a barrier reef.[3]
Stage 3 - Atoll
Once the volcanic island is fully submerged, the reef is known as an atoll. The reef outline is circular with a central lagoon.[4]
Evidence
Notes
References
- Strykowski, Joe and Rena M. Bonem. Palaces Under the Sea. Crystal River, FL: Star Thrower Foundation, 1993, p. 19-26. Print.