[Coral-List] Coral immortality (and Youtube)
Dean Jacobson
atolldino at yahoo.com
Tue Mar 22 20:20:08 EDT 2011
Listers:
It seems obvious to me (as a coral newbie, with ten years Majuro field experience)) that there must be r vs K differences among coral. Acropora have a limited life span (large cytherea tables collapse from their own weight around 20 years in age, even if storms don't remove them). Pocillopora is another fast recruiting and short-lived species here. However, certain massive species (including some in the genus Porites, Pavona and Leptoria) are able to continue growing in the pink of health over hundreds of years. (I guess we have little data on fecundity over such long time spans!) Leptoria, a locally uncommon species, grows to a dimension of 2 x 3 x 3.5 meters on an unpolluted atoll (Arno) but the only two Leptoria colonies on all of polluted Majuro (an I have swum, at the optimal depth of 2-3 meters, many km of shoreline in search of them) are only a meter across and not very tall. Further, one of these two colonies is infected by multiple,
actively expanding disease lesions (as is the case with most of the other massive colonies in the area). Clearly, disease is causing a massive amount of premature death.
You can see images of these colonies on Youtube. My files, out of sheer ineptness, are confusingly named: Pt 1 and 2 are RMI coraldisease1.mov and RMI coral disease2, while part 3 is JacobsonPt4, and part 4 is RMI coral disease5. (No part 5 after all... brilliant).
Thanks for the kind and much appreciated comments so far!
Cheers,
Dean Jacobson
College of the Marshall Islands
--- On Tue, 3/22/11, Delbeek, Charles <CDelbeek at calacademy.org> wrote:
> From: Delbeek, Charles <CDelbeek at calacademy.org>
> Subject: Re: [Coral-List] Coral immortality
> To: "Mark Spalding" <mark at mdspalding.co.uk>, "coral-list at coral.aoml.noaa.gov" <coral-list at coral.aoml.noaa.gov>
> Date: Tuesday, March 22, 2011, 8:21 AM
> Is there anything to suggest that
> these massive corals slow in growth rate once they reach a
> certain size as is seen in Tridacna clams?
>
> I seem to recall reading somewhere that Pocillopora
> meandrina in Hawaii have a limited life space of about 10
> years, which would explain why you do not see them above a
> certain size and why you often find dead specimens encrusted
> with corallines at about the same size..
>
> Best regards,
> Charles
>
> J. Charles Delbeek, M.Sc.
> Assistant Curator, Steinhart Aquarium
> California Academy of Sciences
>
> p 415.379.5303
> f. 415.379.5304
> cdelbeek at calacademy.org
> www.calacademy.org
>
> 55 Music Concourse Dr.
> Golden Gate Park
> San Francisco CA 94118
>
> The world's only aquarium-planetarium-rainforest-living
> museum.
>
>
> -----Original Message-----
> From: coral-list-bounces at coral.aoml.noaa.gov
> [mailto:coral-list-bounces at coral.aoml.noaa.gov]
> On Behalf Of Mark Spalding
> Sent: Monday, March 21, 2011 3:23 PM
> To: coral-list at coral.aoml.noaa.gov
> Subject: [Coral-List] Coral immortality
>
> I commend Gene Shinn once again for getting us all
> thinking. Of course the
> suggestion that that a polyphyletic group such as corals
> might all suddenly
> die in a natural cycle of events rather like bamboos is a
> bit bizarre, and
> the original paper (Perry and Smithers) he referred us to
> does not begin to
> suggest that this is what is happening. We all know that
> corals die, and I
> suppose we could also talk about reefs "dying" (in the
> sense only that
> periods of active reef growth are interspersed with periods
> of non-growth or
> even erosion). Most authors then look for indicators of
> cause, rather than
> claiming old age. And throughout geological history there
> have been many
> causes.
>
> But I agree with Gene that we need to be a little more
> critical and avoid
> bandwagons. When diving in the "dying" reefs of the
> Southern Seychelles
> during the 1998 coral bleaching I remember noticing the
> lack of any large
> corals whatsoever on the out reef slopes. Here there were
> lots of massive
> corals (mostly bleached or recently dead), but none in
> colonies larger than
> about 60-80cm diameter. (There were much bigger ones in the
> lagoons.) I
> remember commenting that maybe this sort of coral die-off
> happens more
> regularly than we think. Most of those reefs have made good
> recoveries, but
> the individual corals died. An obvious and interesting
> study would be a very
> large-scale analysis of maximum sizes of corals. My guess
> is that an old-age
> hypothesis would produce a nice simple tailing off
> size-frequency curve, but
> that if there are big global or regional events we might
> see some nice
> breaks in those curves, with major drops in the numbers
> above certain sizes
> indicating such events. (Maybe someone's already done
> that?).
>
> That gets at the dying corals (regular natural or human
> induced
> perturbance), but dying reefs need some level of sustained
> perturbance. I
> have to admit that it worries me when a geologist says
> "don't worry, it'll
> get better again". When exactly? Perhaps they've spent too
> long studying
> near-immortality to realise that most people care about
> now, next year and
> the next generation.
>
> And just because some things happen naturally doesn't mean
> that we should
> relax if we produce the same impact by human actions.
> Whether compounding
> threats are synergistic or just mildly additive it's not a
> clever response
> to say let's not worry, its happened before. Giant panda's
> survived
> innumerable cycles of bamboo flowering, but not
> surprisingly now face
> extinction because we added to the problem, mostly through
> habitat loss.
> Think about it!
>
> Mark
> ____________________________
>
> Mark D Spalding, PhD
> Senior Marine Scientist, Global Marine Team
> The Nature Conservancy
> and
> Conservation Science Group, University of Cambridge
>
> Reefs at Risk Revisited - www.wri.org/reefs
> Recent books: The World's Protected Areas; The Atlas of
> Global Conservation
> www.ucpress.edu
> World Atlas of Mangroves - www.earthscan.co.uk
>
> >>>>__________________________________________________________________
> Date: Fri, 18 Mar 2011 14:04:05 -0400
> From: Eugene Shinn <eshinn at marine.usf.edu>
> Subject: Re: [Coral-List] Coral immortality
> To: coral-list at coral.aoml.noaa.gov
> Message-ID:
> <a06230903c9a94e76aa1b@[131.247.137.127]>
> Content-Type: text/plain; charset="us-ascii"
> ; format="flowed"
>
> 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
> sources.
> 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:
> 91-97.
>
> --
>
>
> 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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