[Coral-List] Coral immortality

Eugene Shinn eshinn at marine.usf.edu
Fri Mar 18 14:04:05 EDT 2011

Good! We got to express ourselves about technical aspects of corals 
and reefs. The subject received two kinds of responses. Those that 
agreed that corals die of old age (mainly off-line) and those that 
disagreed (all on-line). I would like to propose another question for 
discussion. What if all the bamboo on earth began to die at the same 
time? Would there be finger pointing and accusations as to who, and 
what, caused it? I think there would be if it were not for the 
Chinese who have been watching such events for centuries. Bamboo is a 
major construction material in Asia and also the main food for 
Pandas. Do some Google searching and you will find that one species 
dies worldwide at the same time about every 125 years (associated 
with flowering). Other species die on shorter time scales and one in 
northern India flowers and bears fruit once every 40 years leading to 
a plague of rats that consume much of the rice crops leading to 
famine. Now before you say bamboo is in no way related to coral I ask 
how do we know that corals do not naturally go through similar boom 
and bust cycles. Who was diving and paying attention to corals and 
coral recruitment 100 years ago? Unfortunately even the geologic 
record is of little direct help. It is only because of the Chinese 
historical records that we know about bamboo cycles that prevents us 
from becoming hysterical.
      As for Doug Fenners remarks about sea level he is correct, 
Massive corals in shallow water do reach the surface and can grow no 
more. That can be seen on patch reefs in the Florida Keys. In 
addition sea levels fluctuates and corals are killed when the sea 
goes down. However, for the vast majority of the reef tract bordering 
the clear blue Gulf stream the water is 20 to-30-ft deep and there 
are hundreds of widely scattered heads that are less than 200 years 
old. Coals there have had at least 6,000 years to grow! Why are they 
all about the same size? And why is the reef accumulation no more 
than 1 meter thick over the vast extent of the reef tract? Head coral 
growth-rate is much faster than the known rise in sea level so why 
did they not keep pace and make coral heads 20 ft high? Either, like 
bamboo, various species died synchronously on some schedule we are 
unaware of, or they were killed by some environmental factor i.e. 
Hurricanes, disease, cold fronts and/or warming evens. Either way it 
is clear that many non anthropogenic events have kept the Florida 
reef tact from outpacing the well-known rise in sea level since the 
last glacial maximum when sea level was more than the length of a 
foot ball field below present I contend that many mysteries remain! 
If only we were doing the science/research aimed at understanding non 
anthropogenic causes of coral death. In stead we keep hammering away 
at the "usual suspects" that is driven by NGOs and other funding 
      The remarks concerning Enewetak demonstrate that the Atoll has 
been able to keep pace with the many sea level fluctuations that have 
occurred over the past 65 million years. I spent 2 months there 
involved in drilling and diving. Unfortunately there are many atolls 
that did not respond well or could not keep up with subsidence. They 
now lie hundreds of meters below sea level and are called guyots.
      A Clarification: I certainly was not suggesting that corals are 
immortal. Just the opposite! Just needed a snappy title. Also, most 
organisms do not die of old age. They die of any number of diseases 
when they become weakened by old age. Could that be what we are 
seeing today? It is interesting that A. cervicornis "sticks" exposed 
in deep trenches made by ship groundings and other causes are more 
robust and often 2 to 3 times the diameter of those that died 
recently. In our paper (Shinn et. Al., 2003) we carbon 14-dated 39 
randomly collected, (actually hap-hazard), fossil sticks in reef sand 
over a hundred mile long stretch of the Florida reef tract, We found 
specimens that dated from 6,000 years old to the present (all near 
the surface). What was most interesting was a convincing 500 year 
absence of Staghorn centered at 4,500 years ago and another less 
convincing 500 year absence centered at around 3,000 years. The 
4,500-year interval correlates well with a period of inferred ice 
rafting determined from deep sea sediment cores. There were probably 
many climate episodes during the Holocene. Gene

Reference: Shinn, E. A., Reich, C. D., Hickey, T. D., and Lidz, B. 
H., 2003, Staghorn tempestites in the Florida Keys, Coral Reefs, 22: 


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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