[Coral-List] Heat;light, food, and bleaching, continued

Thomas Goreau goreau at bestweb.net
Wed May 31 22:58:15 EDT 2006

Heat, light, food, and bleaching, continued.

I will be unable to respond from my regular email as I
will be completely out of reach in the field in many
countries almost all the time from now to at least the
end to July, and likely well beyond, so I can't
respond to list server enquiries directly for a long
time. Could you please post these comments on the list
server for me? Thanks!

I'm a little sorry to have raised such fundamental
issues and then have to effectively drop out before
replying to the legitimate questions my post has
raised . So I'd like to make some clarifying explanations
here in response to the first thoughtful replies to my previous posting.

It is a serious error to assume that oxygen mass
balance  tells you the carbon mass balance in a
reciprocal way. The fact that corals are autotropic in
carbon goes back to oxygen titrations by Afred Mayor
and by Thomas F. Goreau's whole reef oxygen and carbon
metabolism studies at Bikini Atoll in 1947
(unpublished but I have all the data), and of course
supported by later oxygen respirometry mentioned

The fundamental error is to assume that the carbon
fixed by the zooxanthellae and translocsted to the coral
is in fact retained by the coral. In fact it is almost
all used to make biochemical precursors for mucus
synthesis and very rapidly excreted. This was shown in
a long series of classic papers on coral physiology by
Thomas F. Goreau and Nora I. Goreau in the 1950s, that
pioneered the use of Carbon-14 and Calcium-45 tracers
in marine biology. These findings were later supported
by others, including Trench, Cooksey and Cooksey, and by Jim
Battey. So the fixed carbon has long been known to
make a minor to negligible contribution to coral nutrition.
Yet because so few people bother to read the primary
literature, this simple minded error of reciprocally
conflating oxygen and carbon balances has been
endlessly repeated and even taught as dogma by people
and textbooks that should know better.

The role of zooplankton feeding was pioneered by Sir
Maurice Yonge during the Cambridge University Great
Barrier Reef Expedition in the 1920s, and followed
through by Thomas F. Goreau and Nora I. Goreau. The
definitive paper on coral nutrition by Goreau, Goreau,
and Yonge, shows the extremely diverse
multi-trophic pathways of corals, acting as primary
producer, herbivore, canrnivore, detritus feeder, and
dissolved organic carbon scavenger, simultaneously,
but arguing from
the experimental physiology, enzymology, and functional anatomy
that zooplankton feeding is the primary mode of carbon
nutrition of the stony corals.

Naturally, this must
involve sub specialization of different corals on
different components of zooplankton and other
resources, as indicated by Jim Porter's work on
trophic niche separation in corals as a function of
polyp size and Ken Sebens and other's
work on zooplankton capture. You can see this clearly
by the different responses of different species to
zooplankton at night. The role of feeding on survival
from bleaching is therefore trivially obvious and
readily seen in diffferential survival in the field in
sites with higher and lower zooplankton availability
and capture ability.

Andrea Grottolli's point that thermal bleaching is different
than dark bleaching is correct. It is thermal stress
that kills heat shocked corals rather than bleaching per se, and
feeding is able to counteract this in a
species-specific manner that depends on local
zooplankton availability, depending on the severity
of heat shock.

There is much more to be done by building on the shoulders
of the giants who have prceceded us intstead of
uncritically following shallow analogical errors, fads, and
false claims of novelty. Yet the recent literature is
riddled with the latter flaws. In my view every coral reef
paper published in Science or Nature in the past 15
years except for two by Mike Risk and
colleagues have jargon-filled bogus claims of
novelty that simply ignore the previous literature. This indicates
a sitiuation much more serious than widespread
ignorance of past knowledge by current researchers. It
indicates a massive failure of competence by the
"peer" "review" "system", and why there is little
point even playing their game.

While some won't appreciate my comments, they are certified free of  
No Risk® to circulate them on the server!

Best wishes,

Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net


Message: 4
Date: Tue, 30 May 2006 15:32:44 -0400
From: Charles Booth <booth at easternct.edu>
Subject: Re: [Coral-List] Thomas Goreau's comments
	coral-zooxanthellae	symbiosis
To: "coral-list at coral.aoml.noaa.gov"
<coral-list at coral.aoml.noaa.gov>
Message-ID: <C0A2161C.8904%booth at easternct.edu>
Content-Type: text/plain;	charset="ISO-8859-1"

Thomas Goreau wrote:

?The fact that corals don't get their carbon from
zooxanthellae is also very
old knowledge, but for decades people have
ignored the old literature and have mistaken the net
oxygen balance to
assume that corals are also autotrophic in carbon.
This recent error has
become dogma, despite being wrong, because nowadays
people don't read the
literature or ask those who know it. The first
radiocarbon tracer
experiments, done by Thomas F. Goreau and Nora I.
Goreau more than 50
years ago showed that very little zooxanthella carbon
contributed to coral carbon, and that corals relied on
zooplankton for the
vast bulk of their carbon needs.?

I plead ignorance here as I?m not a coral specialist.
But, it has been my
understanding that zooxanthellae do make a significant
contribution to the
carbon requirements of the coral polyp, and I have
been relating this ?fact?
to my students for many years. My sources of
information have been various
textbooks and review articles, and, occasionally,
original research
articles, such as the following:

  Falkowski et al (1984, BioScience 34: 705-709)
described energy budgets for
Stylophora pistillata based on O2 fluxes and relative
biomasses of
zooxanthellae and coral tissue, and concluded that
?carbon fixation and
translocation by zooxanthellae contributes, on
average, 140% of the coral
animal?s daily carbon requirement for maintenance
[The original data were published by Dubinsky,
Falkowsky, Muscatine et al; I
presume these values, which were derived from net O2
production, are the
ones Dr. Goreau suggests have been interpreted
incorrectly. However, I have
not come across any published criticism of this method
and the results;
rather, the data appear to have been widely cited by
various authors, such

B.G. Hatcher (1988, Trends in Ecology and Evolution,
3: 106-111), who wrote
?...zooxanthellar production is able to meet the
animal?s carbon
requirements for growth as well as respiration.
Shade-adapted corals fix
less carbon..., and must depend on heterotrophy to
make up the difference
(refs: McCloskey et al, 1985, Proc. Fifth Int. Coral
Reef Congr, vol. 4,
Delesalle, B. ed, pp. 527-529; Muscatine, et al, 1984,
Proc. R. Soc. London
Ser. B. 222: 181-222).

Even if the O2 flux-derived values for energy/carbon
translocation are
incorrect, subsequent studies using 14-CO2 tracer
methods appear [to me, at
least] to support a significant role of
zooxanthellae-derived carbon for
coral biomass production:

In Barnes, R.S.K and K.H. Mann, eds., Fundamentals of
Aquatic Ecology
(Oxford/Blackwell, publication date was early 90s, I
think ? I?m relying on
a photocopy of the relevant pages) R.N. Hughes wrote
(Chapter 11, p. 217)
  ?Incubation with 14-CO2 has shown that as much as 50%
of the carbon-14
fixed daily by photosynthesis becomes incorporated
into coral tissue, mostly
as lipid and protein (Muscatine and Cernichiari, 1969,
Biol. Bull. 137:
506-523; Kellogg and Patton, 1983, Mar. Biol. 75:

In Barnes, R.S.K. and R.N. Hughes, An Introduction to
Marine Ecology (3rd
ed. Blackwell Science; published ~2000, as I recall-
again, I?m relying on a
photocopy w/o the publication date), the author(s)
wrote (Chapter 6, p. 137)
?Estimating these proportions [of zooplankton- vs.
energy] is not easy and data are rather uncertain, but
the proportions of
energy ultimately derived from photosynthesis ranges
from over 95% in the
?autotrophic? corals down to somewhat over 50% in the
more extreme
?heterotrophic? species....Incubation of Pocillopora
damicornis with 14-CO2
on the reef has shown that up to 50% of the 14-C fixed
by the zooxanthellae
during 24 h ends up in the coral tissue, mostly as
lipid and protein.
Evidently, the glycerol released by the algae is used
by the animal in lipid
synthesis.? [I presume the latter statements refer to
the work by Muscatine,
Cernichiari, Kellogg, and Patton cited above]

More recently still, Lesser et al (2004, Science 305:
997-1000) wrote (p.
  ?...it [glycerol] is the major carbon compound
translocated from the
symbiotic zooxanthellae to the host tissues (Muscatine
, L. 1990, in Coral
Reefs, Ecosystems of the World, Z. Dubinsky, ed.,

I may well be guilty of a cursory reading of the
primary literature and an
uncritical acceptance of secondary sources ? if so, I
would like to bring
myself up to date. Perhaps Dr. Goreau, or someone
else, can direct me to the
relevant literature that clarifies the current
understanding of the role of
zooxanthellae in the nutrition of coral polyps.

Chuck Booth

*   *   *   *   *   *   *
Dr. Charles E. Booth
Dept. of Biology
Eastern Connecticut State University
Willimantic, CT  06226

Ph: 860-465-5260
Email: booth at easternct.edu
FAX:  860-465-5213


Message: 5
Date: Tue, 30 May 2006 15:37:10 -0400
From: Andr?a Grottoli <grottoli.1 at osu.edu>
Subject: [Coral-List] coral bleaching: response to
To: coral-list at coral.aoml.noaa.gov, goreau at bestweb.net
< at osu.edu>
Content-Type: text/plain; charset="iso-8859-1";

Dear Tom,

I read your contribution on the coral list about
coral bleaching with interest.  As the lead
author of the recent Nature paper on
heterotrophic plasticity in bleached corals, I
would like to comment.  You stated:

"The recent paper that claims to have discovered "for
the first time"
that corals eat zooplankton and can survive bleaching
better if fed is
not new either. The fact that corals don't get their
carbon from
zooxanthellae is also very old knowledge, but for
decades people have
ignored the old literature and have mistaken the net
oxygen balance to
assume that corals are also autotrophic in carbon.
This recent error has
become dogma, despite being wrong, because nowadays
people don't read
the literature or ask those who know it. The first
radiocarbon tracer
experiments, done by Thomas F. Goreau and Nora I.
Goreau more than 50
years ago showed that very little zooxanthella carbon
contributed to coral carbon, and that corals relied on
zooplankton for
the vast bulk of their carbon needs. They kept corals
bleached in the dark for years, feeding them on
zooplankton. So survival
of bleached fed corals has been known for over half a
century and is not
a "new discovery" at all. Like so much else in the
current literature."

I would like to point out that our paper showed
that only one species, Montipora capitata,
consumed enough zooplankton to meet all of its
metabolic demand heterotrophically when
bleached.   When healthy, M. capitata met less
than 15% of its metabolic demand
heterotrophically.  The other two species we
studied, Porites compressa and Porites lobata,
only met 21-35% of their daily metabolic demand
heterotrophically when they were either healthy
or bleached.   In all cases, our corals were
exposed to naturally occurring zooplankton on the
reef.  Thus under natural reef conditions, not
all bleached corals can meet all of their
metabolic needs heterotrophically.  Under
artificially fed conditions (i.e., coral exposed
to higher than ambient concentrations of
zooplankton or brine shrimp in tanks), things can
be quite different.   As you pointed out, the
fact that corals do get some fixed carbon from
zooplankton has been know for a very long
time.  However, the fact that when bleached at
least one species can  increase heterotrophic
feeding to meet all of its metabolic needs while
two others could not, is novel.  Our results
suggest that not all species of corals would be
able to meet their metabolic demand when
maintained in the dark under natural
concentrations and abundance of zooplankton (i.e,
P compress and P lobata probably could not get
all of their energy needs met heterotrophically
when bleached under darkness... but this would
need to be specifically tested).   In addition,
bleaching induced by keeping corals in the dark
is not necessarily the same as
temperature-induced bleaching.  The chain of
physiological stress responses that occur under
high temperature include free radical and stress
protein production, making any heterotrophic
responses under tempreature-induced bleaching
possibly quite different than hetertrophic
responses under sustained darkness.


Andrea Grottoli

Andr?a G. Grottoli, Assistant Professor
Ohio State University
Department of Geological Sciences
125 South Oval Mall
Columbus, OH 43210-1398
office:  614-292-5782
lab: 614-292-7415
fax: 614-292-7688
email: grottoli.1 at osu.edu
web: www.geology.ohio-state.edu/~grottoli
Office location: 329 Mendenhall Labs



Message: 6
Date: Tue, 30 May 2006 21:13:33 -0700 (PDT)
From: shashank Keshavmurthy <iamshanky15 at yahoo.com>
Subject: Re: [Coral-List] coral bleaching: response to
To: "Andréa" Grottoli <grottoli.1 at osu.edu>,
	coral-list at coral.aoml.noaa.gov, goreau at bestweb.net
<20060531041333.31960.qmail at web31810.mail.mud.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

Dear Listers
It is interesting to see that finally the debate
on the coral energy aquisition has surfaced...

most of the resarch papers till now say that
there is major contribution of Carbon form
zooxanthellae to corals....but, when in need the
corals can adapt to the carbon aquisition

We all need to get lots of information from
aquarists around the world....

If you will see the book written by "Julian
Spring" on the aquarium corals...it gives the
mode of nutrition as autotrophy and heterotrophy
to most of the corals described in his book....

we as researchers may just dont know what really
is happening out there....

here i agree totally with Tom....we still need to
get lots work done so as to understand the true
feeding habits of corals...

Recent paper by "Palardy et al, MEPS (2005) 300:
79-89, Effects of upwelling, depth, morphology
and polyp size on feeding in three species of
Panamanian corals"...looks at what corals are

Collaboration with aquarists is needed to really
understand about the energy aquisition in corals
in more detail...

more and more people are looking at zooxanthellae
since it is believed to be "the source of Carbon"
and "the factor for/of coral bleaching

question is how much is the symbiotic dependency?
there are many studies showing that the corals
can survive without the presence of
zooxanthellae...it may not be for long time and
may not be see in natural enviroment....but we do
see many sea anemones in coral reefs, bleached
and still surviving....

i think it is like, do corals want to feed on
zooplankton when they loose zooxanthellae?
does it take some time to switch between the
modes of nutrition acquisition?
combination of stress factors may be disturbing
the switching between the modes

for instance, when kept in aquarium tank in
dark..it is only one stress and corals can
survive with the zooplankton being fed...that
means  they are able to switch between the

hmm...its pretty complex out there..and coral
physiology is more and more challenging...this is
my view...


"the role of infinitely small in nature is infinitely
large"-Louis Pasteur

Keshavmurthy Shashank
phD candidate
Kochi University, Graduate School of Kuroshio Science
Laboratory of Environmental Conservation
Otsu 200, Monobe, Nankoku-shi
783-8502, Kochi, Japan
alt. id: shashank at cc.kochi-u.ac.jp
phone: 81 080 3925 3889

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