[Coral-List] Coral Immortality
Bill Raymond
billraymond10 at yahoo.com
Thu Mar 17 16:38:26 EDT 2011
I'm thinking that it means the growth-death cycle is shorter than we think.They
don't die of old age, they die from environmental causes. When I dived in sand
borrow pits while monitoring beach restoration projects and at Macintyre &
Lighty's Pompano outfall trench through the third reef, I saw cervicornis pieces
over two inches thick, and brain coral 6 to 8 feet across (all dead and buried,
of course). I figured growing conditions were better then, but, like you say,
why couldn't they be much larger?
________________________________
From: Eugene Shinn <eshinn at marine.usf.edu>
To: coral-list at coral.aoml.noaa.gov
Sent: Tue, March 15, 2011 1:12:48 PM
Subject: [Coral-List] Coral Immortality
Dear Coral-Listers, Here is a stimulating break from the incessant
job advertisements. See
<http://planetearth.nerc.ac.uk/news/story.aspx?id=907> It is
interesting because the vast majority of head corals in the Florida
Keys suffered mortality over the past 35 years, especially during the
1980s at places like once-thriving Carysfort reef where there were
hundreds in the 200 to 300 year-old range. More than a dozen of the
living Montastrea sp heads there were cored and their growth rates
measure and published by Hudson (1981). In addition brain corals also
perished or are hanging on by a thread (see
<http://gallery.usgs.gov/videos/334>). It is interesting to note that
similar head corals grew during the Pleistocene and built the Florida
keys when sea level was more than 20 ft higher than today.
Interestingly those heads that built the reef grew no larger than
those that recently died in the Florida Keys. Why do we not see head
corals that grew 15 to-20-feet in height (or even 50 ft) back when
there were no anthropomorphic influences? Does it mean corals are not
immortal? Could it mean that corals die of old age like all other
organisms on earth and we just happen to be living at the right time
to observe the current age class of geriatrics demise? Is that why
more than 95 percent of what we call the Florida reef tract is less
than 1 meter thick when it had the past 6 to 7,000 years to grow? I'm
sure there are those who think today's corals should be immortal but
why weren't they immortal in the past? Just something to think about!
Gene
Reference: Hudson, J. H., 1981, Growth rates in Montastraea
annularis, a record of environmental change in the Key Largo Coral
Reef Marine Sanctuary, Florida. Bulletin of Marine Science, v. 31,
pp. 444-459
--
No Rocks, No Water, No Ecosystem (EAS)
------------------------------------ -----------------------------------
E. A. Shinn, Courtesy Professor
University of South Florida
Marine Science Center (room 204)
140 Seventh Avenue South
St. Petersburg, FL 33701
<eshinn at marine.usf.edu>
Tel 727 553-1158----------------------------------
-----------------------------------
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