[Coral-List] Coral immortality/senescence

Lescinsky, Halard L HLescinsky at otterbein.edu
Mon Mar 21 16:01:04 EDT 2011


Dear List, 

Philosophical musings on natural cycles aside, this should be a pretty easy question to answer empirically:  Do corals show inherent colony senescence?  There are many huge coral heads out there, and I know I have seen branching colonies persist for 3+ m of outcrop height in the Pleistocene of Curacao, and 4-5m of outcrop height in the Holocene PNG record.  Clearly these corals are very long lived.  But the best data set would be from long cores taken from giant coral heads.  Does someone know the data on these?  Is there a significant decline in growth rate/annual band thickness over a coral head's several hundred year record?  I don't think I have ever seen this suggested, but perhaps someone with firsthand experience could weigh in. 

Hal Lescinsky

-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov [mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Martin Moe
Sent: Monday, March 21, 2011 2:26 PM
To: vassil zlatarski; Coral -List
Subject: Re: [Coral-List] Coral immortality/senescence

Dear list, 

Immortality is impossible. In this universe, everything that has a beginning, 
has an end. And in the shorter run, everything that lives on our little Earth, 
also has an ending. Death is programmed into the genome of complex animals and 
plants, if it were not then the species itself could not change with sexual 
reproduction and evolve to survive changing ecological and environmental 
conditions. The continued existence of a species depends on the death, sooner or 
later, of individuals and the continuous change and renewal of the genome of 
that species. (Humans, by the way, are no exception, and extinction is not 
impossible.)
 
Semantics aside, great longevity of individual organisms, measured in thousands 
of years is very rare, but possible. I think that the longevity of coral 
colonies is more dependent on the continuous existence of environmental factors 
that favor growth and survival then internal mechanisms that might induce the 
simultaneous death of coral colonies of many species at intervals of a great 
many years over vast tracks of ocean habitat.. Reproductive success in corals is 
dependent upon simultaneous spawning on an annual basis, but I can’t see how 
simultaneous death after many long years of cyclic sexual reproductive activity 
would contribute to survival of the species. Corals can reproduce sexually and 
asexually, providing both evolutionary flexibility and colonial longevity. But 
neither the genome of a coral species, although granted longevity through 
colonial growth and fragmentation, nor individual colonies whose term of 
existence is determined by the limits of growth as influenced by ecological and 
climateological conditions, are immortal.
 
We have much yet to learn about the biology and longevity of corals, but at this 
point we need to find ways to enhance the existence of our coral reefs and keep 
them with us for as long as possible in the hopes that they will be able to 
survive the insults humanity is heaping upon them.

My two cents worth.

 
Martin Moe




________________________________
From: vassil zlatarski <vzlatarski at yahoo.com>
To: Coral -List <coral-list at coral.aoml.noaa.gov>
Sent: Mon, March 21, 2011 10:58:30 AM
Subject: [Coral-List] Coral immortality/senescence

Dear colleagues,

The question of coral immortality is related to the knowledge about their 
senescence.  Unfortunately, our understanding concerning coral senescence in 
shallow water habitat is poor.  The data about the ontogeny, generation time and 
whole life history for the mesophotic zone and deep sea are even less.  One 
constructive appeal of the current discussion will be to start projects focused 
on these issues.

Cheers,

Vassil 

Vassil Zlatarski
D.Sc. (Biology), Ph.D. (Geology)
131 Fales Rd., Bristol, RI 02809, USA;  tel.: +1-401-254-5121





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