[Coral-List] Impact of listing 66 coral species on coral research
Eugene Shinn
eshinn at marine.usf.edu
Wed Dec 12 12:27:43 EST 2012
Thanks Mike and Lisa, I was beginning to feel hung out to dry. As
you suggested, I will pick up on the bioerosion issue. There is a
very interesting paper in the October 2012 issue of GEOLOGY. The
thrust of the paper, based on a lot C14 data and observation, is that
Australian reefs in muddy water areas near shore are accreting faster
than those offshore in clear water. Seems to be that way in the Keys
as well except that those reefs as susceptible to periodic cold
snaps. What this paper shows, in a nutshell, is that sedimentation of
mud on dead corals protects them from bioeroders. As Mike noted Terry
Scoffin and others, showed long ago that the rate of bioerosion is
approximately equal to coral growth rate. Simply said, a coral head
that took 100 years to reach a meter in height can be bioeroded down
flat in 100 years once it dies. Of course if there is too much
sediment the live tissue cannot grow. It is a Goldilocks situation. I
remember there were 24 papers on muddy water reefs off Australia
presented at the Mali International coral reef meeting in 2002. Those
papers countered the prevailing coral reef paradigm so that
information has been ignored. I call it the "cone of silence." I
pointed this out on the coral-list a few months ago and a very nice
person sent me a photo of healthy looking staghorn coral exposed at
low tide and surrounded by water that looked like coffee with cream.
It is in Indonesia. The water there is simply too muddy for
underwater photography!
I might add that Lisa Greer in her coral-list post was referring
to a place in the mountains of the Dominican Republic that I visited
with Dennis Hubbard. Anyone glued to the existing paradigm (the usual
suspects I call it) would have said corals could never have grown
there. It is a blind-end narrow valley between mountains that was
open to the sea at one end. Staghorn piled on staghorn reaching 30 to
40ft high are beautifully exposed in vertical outcrops cut by
seasonal streams. All the usual Caribbean coral species are also
preserved there as well. All had died 7,000 years ago when the
entrance to the valley was sealed by a river delta and the water
evaporated exposing the fringing reefs. Clearly C02 had nothing to do
with its demise but for sure there was a water quality crisis! That
trip changed my view of coral reef requirements forever. More coral
scientists should visit that area.
Mike mentioned the 500-m-thick Permian reef that I have scrambled
over many times. He is right the inland sea where it grew dried up
leaving hundreds of feet of banded gypsum and sea salts: a real water
quality crisis. I might also mention the 1,200-mile long Lower
Cretaceous reefs (hundreds of feet thick) that extend from outcrops
in Mexico to the subsurface of Texas and Louisiana and into south
Florida. I spent a few years studying that reef because it produces
oil and gas, if one can just find the sweet spots. What one notices
most about these rocks (they were constructed by both Rudistid
gastropods and corals) is the amount of fine-grained sediment that
filled voids while it was growing. Is that what allowed these reefs
to accrete and be preserved? I don't know. In conclusion there is a
lot we need to learn abut coral reefs and their requirements. Listing
all those species (why no list all corals??) is going to retard
research needed to learn more about coal reefs. Ask anyone who has
ever worked on a listed species of any kind. Gene
--
No Rocks, No Water, No Ecosystem (EAS)
------------------------------------ -----------------------------------
E. A. Shinn, Courtesy Professor
University of South Florida
College of Marine Science Room 221A
140 Seventh Avenue South
St. Petersburg, FL 33701
<eshinn at marine.usf.edu>
Tel 727 553-1158----------------------------------
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