[Coral-List] Poor terminology in coral reef research 2: Spur andGroove

Szmant, Alina szmanta at uncw.edu
Mon Nov 6 10:30:43 EST 2006

Dear Tom:

I disagree with your post about the term "spur and groove".  The term
"spur and groove" has been used for decades as a purely descriptive term
that does not include causative mechanisms (e.g. as used by Wiens (1962)
Atoll Environment and Ecology, Yale Univ. Press, pgs. 254 to 256), or
Milliman, Stoddart, Ladd and a number of early coral reef scientists,
mostly geologists; thumb through chapters in Biology and Geology of
Coral Reefs, Vol 1(1973), Geology 1, ed. by Jones and Endean). Peter
Glynn taught me these descriptive terms as commonly used today back in
1964. As you state, the grooves can be erosional, or the spurs can be
constructive, and there are places where both activities co-occur. In
many places corals have accreted to features (grooves) formed during
lower or changing stands of sea level. The grooves are also commonly
called surge channels in shallower water, but on deeper, drowned reefs
there isn't much surge through these relic features anymore (e.g. deeper
grooves along PR and USVI shelf edge reefs).  The spurs have also been
referred to as buttresses (e.g Wiens above).  While in Goreau (1956)
there may have been an attempt to differentiate among the processes and
different terms be used for erosional vs constructional reef features,
that suggestion has not been widely accepted, and is not how the spur
and groove, buttresses and surge channel terms have been used over the
past 40 years.  Just by looking at one of these features, one cannot
determine the exact mechanisms of formation.  



Dr. Alina M. Szmant
Coral Reef Research Group
UNCW-Center for Marine Science 
5600 Marvin K. Moss Ln
Wilmington NC 28409
Tel: (910)962-2362 & Fax:  (910)962-2410
Cell:  (910)200-3913
email:  szmanta at uncw.edu
Web Page:  http://people.uncw.edu/szmanta

-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Thomas
Sent: Friday, November 03, 2006 1:18 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Poor terminology in coral reef research 2: Spur

Many coral reef researchers are still incorrectly using the term  
"SPUR AND GROOVE" more than 50 years after this error was identified  
in the first work on coral species zonation (T. F. Goreau, 1956, A  
Study of the Biology and Histochemistry of Corals, Yale).

True Spur and Groove is the result of erosion, with the grooves  
incised into older hard rock, with little live coral coverage, and  
with erosion rounded boulders, not sand, in the grooves. This is what  
Mike Risk has recently described on the list server on the outer  
reefs of Mauritius, and is especially common in the Pacific, where it  
was first described in the 1947 studies at Bikini Atoll. It is very  
rare in the Caribbean, but true Spur and Groove can be found on the  
northern Barrier Reefs in the Turks and Caicos Islands (T. J. Goreau,  
T. Fisher, F. Perez, and K. Lockhart, 2006, Turks and Caicos Islands  
Coral Reef Assessment and Management and Restoration Strategy,  
Department of Environment and Coastal Resources, in press).

However almost all of what is now being called "Spur and Groove", at  
least in the Caribbean, has a completely different origin, the result  
of growth by living corals. These are CONSTRUCTIONAL, not EROSIONAL  
features. The  canyon sides were (originally) almost completely  
covered by live corals, and the bottom covered with reef sand flowing  
episodically down slope. The correct term for these formations is  
"Buttress and Canyon", with the heights of the growing coral  
buttresses above the canyons ranging from as little as inches to as  
much as 30 meters or more in the kinds of exceptionally healthy reefs  
we used to have in Jamaica. The fact that almost all the corals are  
now dead should not blind us to their very different origin by  
imprecise terminology that acts to confuse factors causing them, and  
it would be a good idea for people to again differentiate the origins  
of these superficially similar but very distinct morphological  
features by distinguishing them with the separate terms proposed half  
a century ago.

Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net

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