[Coral-List] FW: RE: What is a coral reef and where is it's edge?

Robert Bourke rbourke at OCEANIT.COM
Mon Aug 26 14:16:55 EDT 2013

In nature, is a coral colony always a subset of a coral community, and is a coral community always a subset of a coral reef?

Because "coral reefs" are defined by federal regulation as a "Special Aquatic Site" they are provided special consideration during permitting.  99-percent of the time this is a very good thing.  However, it can lead to some absurd and costly rulings for little environmental gain when the regulation is enforced because of isolated corals growing on unusual substrates such as navigation structures, harbor facilities, or other structures not associated with the reef.  The special aquatic site regulations define a coral reef, using the word "reef" to describe itself:

"Coral reefs consist of the skeletal deposit, usually of calcareous or silicaceous materials, produced by the vital activities of anthozoan polyps or other invertebrate organisms present in growing portions of the reef." (emphasis added).

This would seem to infer that a pre-existing "reef" is required if a "coral reef" is to exist.

>From a nautical perspective a "reef " is a hard typically abrupt physical uprising of the seafloor that ships can run aground on and is similar to a "shoal" which connotes a broader often soft bottom uprising of the seafloor.  Coral reefs are reefs built by hermatypic corals and associated organisms.. Deeper 3-D structures built by corals or other organisms (algae, worms, whatever...) are bioherms because they are neither associated with reefs or shoals.  It's unfortunate that "bioherm" doesn't bring to the mind the same romantic images as "coral reef."

But the above definition eliminates many ecosystems that we all "know" are coral reefs from consideration as true coral reefs.  For me, the extensive deep Porites reefs off the Kona Coast that grow across the lava substrate at depths of 30-80 feet are definitely ecosystems worth protecting, but are not true reefs in the nautical sense or according to the definition under the special aquatic sites regulation.

The EPA has recently come out with a method for slicing and dicing ecosystem types and services provided through the us of a numerical classification approach (Landers, et al, 2013  Ecosystem Services:  http://ecosystemcommons.org/document/final-ecosystem-goods-and-services-classification-system-july-2013 )  I challenge The List to develop an approach to "coral reef" classification that, similar to wetland classification systems or this new EPA approach, can allow any two scientists to arrive at the same classification of the same reef to better define its extend, boundaries, and quality.  More importantly it will allow all of us to use a common ruler to gauge the types, functions and values of reefs distributed across the world.
Bob Bourke
Environmental Scientist

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