Nutrient Deficiency and Coral Bleaching

A Coral-List Server Discussion Thread

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Date: Mon, 07 May 2001 14:21:20 -0300
To: coral-list@www.coral.noaa.gov
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Bleaching corals - are they food-starved?

Hi coral researchers,

Do you see a clear difference between what is happening with the "mass 
coral bleaching" and what you would expect to see if the corals were
nutrient-starved? It looks very similar to me.

Might the patchy availability of food for reef corals help explain the
oft-noted "patchiness" of bleaching episodes?

Lowering of the tolerance thresholds for light and heat (the thing that
appears to be happening?) is an expected result of food-starvation. As is
lowered immunity to infectious diseases. Do you suspect malnutrition as a
common underlying cause?

Have you considered fishing as an independent risk factor in mass bleaching
events (and emerging coral diseases)? Might fishing have had the cumulative
result of lowering the total biomass available for recycling, and therefore
ultimately caused food-starvation in corals?

I've just posted a fairly lengthy discussion of this issue on my website at
http://www.fisherycrisis.com/coral1.html and would greatly appreciate
feedback from any of you. The wider theme of the site, the possibility of
an overall "starving marine ecosystem," is summarized on the main page:
http://www.fisherycrisis.com

Thanks,
Debbie MacKenzie

Date: Thu, 10 May 2001 08:05:01 +1000
To: <debimack@auracom.com>
Cc: <coral-list@www.coral.noaa.gov>
From: "Ove Hoegh-Guldberg" <oveh@uq.edu.au>
Subject: Perhaps you need to do a bit more reading ...

Dear Debbie,

Much though I was amused by your article and proposal (that the "seas are
starving" and this is why reefs are experiencing mass bleaching), I feel that
you need to do a little more reading in the area of mass coral bleaching to
correct the many errors. My feeling is that you need to do more reading - a
fact indicated by your reference list - I feel this probably underpins why you
came to such odd conclusions. In contrast - extensive experimental and field
evidence (as opposed to weakly based conjecture) exists of temperature as the
primary factor (and light as an important secondary factor). Note that use of
word "secondary carefully" - it is just one of many errors you have made in
article posted to the web site: http://www.fisherycrisis.com/coral1.html.

I have sent you a copy of reviewed material that should help you in your
research. Perhaps this will help you understand the errors you have made. Till
then - feel free to come back to me with any questions you might have.

Best wishes,

Ove

Professor Ove Hoegh-Guldberg
Director, Centre for Marine Studies
University of Queensland
St Lucia, 4072, QLD

Phone: +61 07 3365 4333
Fax: +61 07 3365 4755
Email: oveh@uq.edu.au
http://www.marine.uq.edu.au/ohg/index.htm

Date: Thu, 10 May 2001 12:03:22 -0300
To: coral-list@www.coral.noaa.gov
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Re: Perhaps you need to do a bit more reading ...

Hi Ove,

Thanks for responding to my post. Glad you were amused! 

At 08:05 AM 5/10/01 +1000, you wrote:
>Dear Debbie,
>
>Much though I was amused by your article and proposal (that the "seas are
>starving" and this is why reefs are experiencing mass bleaching), I feel that
>you need to do a little more reading in the area of mass coral bleaching to
>correct the many errors. My feeling is that you need to do more reading - a
>fact indicated by your reference list - I feel this probably underpins why
you
>came to such odd conclusions. 

The length of my reference list? Since when has that been the measure of
whether or not an idea is interesting and well thought out? I've read
umpteen things on the declining "condition"(fat content), and growth rates
of marine life overall, everything from marine mammals to all-groundfish,
large pelagics, small pelagics, etc. - and I obviously didn't list them all
there - but that's the pattern. (And it looks like the corals may be
developing the same problem.) Declining abundance and condition factor
simultaneously - contrary to "expectations" based on previous "knowledge"
(in fish, the one used to predictably go up when the other went down, now
they both go down together.) It all points to the very real likelihood that
the overall marine biomass has been depleted (and not entirely by "warm
water" ;>)

"The many errors?" - I wish you'd been more precise. Is it an error by
definition to ask new questions? - to make new observations or
interpretations?

What I would like to read, but have been unable to find - maybe you can
help me - is research done on the possibility of undernutrition as a
contributing factor in mass coral bleaching. Experiments that provide
supplemental feeding to test corals, to check whether or not the possession
of increased stored reserves confers any advantage in resisting "warm water
coral bleaching." Has this been done? 

And how do you explain the "patchiness" of bleaching occurring on a given
reef? Relating it to feeding success is maybe a plausible idea, since
corals are immobile and at the mercy of the random availability of the
"patchy" food that may come their way - all similar corals will therefore
not necessarily have equal feeding success or energy stores for the lean
(warm) times. 

In contrast - extensive experimental and field
>evidence (as opposed to weakly based conjecture) exists of temperature as the
>primary factor (and light as an important secondary factor). 

Yes, believe it or not I've read a fair amount of that. The fact that
bleaching is strongly associated with warm water spells is not inconsistent
with the idea that an important factor could be low nutritional stores. The
predominance of events in warmer water would be expected. It's all in where
your suspicions lie - and there's been a lot of attention to the suspicion
of warm water as cause - but, as they say, "you'll find what you look for,"
which is true to quite an extent, and you won't find what you don't look
for. If you're going to cover all the bases in making the complete correct
diagnosis, you need to consider the possibility of food-starvation. It
should be relatively easy to rule out - no? Maybe it's an unnecessary test,
but it's in the best interest of the patient to run all the tests anyhow,
"just in case." "Unlikely" maybe, but I thnk it's best to rule it out, and
I've yet to see where it has been considered.

>I have sent you a copy of reviewed material that should help you in your
>research. Perhaps this will help you understand the errors you have made.
Till
>then - feel free to come back to me with any questions you might have.
>

Yes, thanks, I've read it already. And I have another question. Figure 10,
your long-term sea surface temp data, shows the thermal thresholds for
corals in the 3 regions of the Great BArrier Reef : south approx 28.2 C,
central approx 29.2, and north approx 30. And corals in all three areas
have been recently affected by the warm-water bleaching, the difference in
their tolerances is due to each being acclimatized to the normal temps
where they are. It looks like the mean temp in the central area has
recently risen from about 27 to almost 28, and that area is not hitting the
"30 threshold" at all, the temp limit that the northern cousins can't take.
But the northern ones lived quite comfortably in the past at a mean temp of
28. Have you tried transplanting any corals to more southerly locations,
where conditions might now match what they were used to for so long? It
would be interesting to see if the naturally more heat acclimatized ones
would have better survival these days if moved a bit south. If so, it
strengthens the "temp threshold" theory, you've spared them from the temp
peak that they cannot tolerate...if not, it might point to the possibility
of the "starvation" theory.

Earlier you wrote:

>I find the idea pretty hard to rationalise over the extent of areas seen
in the
>1997-98 bleaching cycle. While it may contribute to a varying threshold like
>other factors, I doubt whether it is the cause. Warming oceans is the main
>factor.
>
>

"Doubt?" "hard to rationalize?" -- OK, sure, it's hard to "get your head
around the possibility" -- but it's not something that will be particularly
hard to test for. 

The temperature-based research was probably stimulated by an observation
like "There seems to be a lot of unusually high temperatures lately, it's
getting warmer, I wonder if that's hurting these corals." Where I'm
"coming from," however, is noting what looks like poor feeding, slowed
growth and reduced fat content and reproductive success in a very wide
range of organisms throughout the ailing ocean -- so for me, coral
bleaching prompted the question "I wonder if the sick corals are
experiencing feeding difficulties as well?"

Another question: Do you believe that the sewage, etc., that we've poured
into the rivers literally serves as an effective replacement,
nutrient-wise, for the fish that we've removed? Or, do you think that it
doesn't matter...that "there's lots of other fish in the sea?"

And one of my other "odd conclusions" - "the importance of solid vs liquid
nutrients" - what do you think about that one? I think that the reefs
cannot tolerate high levels of "liquid nutrient," but clearly tolerated
high levels of "solid nutrient" prior to fishing...and would incorporate
solid nutrients into their food web today in a non-damaging way, if such
nutrients were made available. 

Cheers,
Debbie MacKenzie
http://www.fisherycrisis.com

Date: Thu, 10 May 2001 13:28:10 EDT
To: debimack@auracom.com, coral-list@www.coral.noaa.gov
From: EricHugo@aol.com
Subject: Re: Perhaps you need to do a bit more reading ...

Hi Debbie and list:

I read your post, your paper, and Ove's comments.

I must say I question your choice to take on Ove in this, of all, subjects 
;-) But if I might offer a few comments? I trust the list members will 
correct me if I am mistaken, as I am not actually pulling the many papers 
from which the following are drawn:

First, the lipid content of coral mesenteries can vary greatly not only 
because of environmental conditions, but also due to species physiology 
(mesentery size, respiration rate, etc.), with some corals able to exist on 
stored lipid content up to 100 days, if I recall correctly. Second, warming 
water tends to encourage reproduction, and spawnings happen during the warmer 
months...this includes many animals forming the plankton that corals feed 
on...Much, if not most, of the plankton on coral reefs is produced and dwells 
in, and migrates upward nightly on the reef, and is not pelagic. The pelagic 
plankton is a component, but probably is significantly lost by fish grazing 
on the fore-reef slope. Other planktonic inputs come from nearshore areas 
being flushed outward by tidal changes.

Corals are also mixotrophic (polytrophic) and do not depend on single 
heterotrophic sources. They can absorb significant amounts of DOM ("liquid 
nutrients" as you put it). Further, many feed on detritus (coral mucus, 
algal debris, bacteria, agglomerations of other microorganism, etc.) This is 
a rich food source well documented in the literature. Some corals may even 
obtain their largest percentage of energy obtained by feeding from this 
source, including the soft corals that also bleach. In the absence of one 
food source, they can shift to obtaining required energy from other food 
sources. Detritus, being formed of such material, especially N-rich bacteria 
and coral mucus, would, if anything, increase during warmer months.

Also, the energy obtained by light and zooxanthellae is carbon rich, mostly 
lost as mucus, whereas heterotrophic acquisition tends to be more weighted 
toward N and contributes towards growth and reproduction. If anything, high 
N would allow more to be excreted or to be present in a non-limiting N 
environment, perhaps even allowing the zooxanthellae to slow their synthesis 
and translocation of glycerol and other photosynthate and using it to produce 
proteins, resulting in unbalanced growth, and perhaps even exacerbating a 
potential bleaching situation by overly high densities within the 
gastrodermis. 

Also, your understanding of the bleaching mechanism, literature on the 
subject, and the results of free oxygen, peroxide, etc. in the bleaching 
response are not shown by your web page. In terms of growth, warmer temps 
increase calcification up to point, and corals live optimally up to near a 
few degrees of their upper thermal limit, So reduced growth is not really 
the case. Also, warming waters are involved in coral spawning and gonad 
maturation, so the comment on decreased reproduction is not quite right 
either.

The patchiness of bleaching was discussed on the list a while back, and 
stagnant areas due to flow dynamics even around a coral colony can result in 
local conditions that exacerbate bleaching. 

Finally, the web page sort of reads in a sensationalist manner, in my 
opinion, that I don't think adds to its credibility. 

Just my thoughts,

Eric Borneman

Date: Thu, 10 May 2001 19:48:07 +0200
To: coral-list@www.coral.noaa.gov
From: "christine.schoenberg" <christine.schoenberg@mail.uni-oldenburg.de>
Subject: nutrient deficiency and bleaching

Dear Debbie,

a compliment up front: I like the way you defend your idea. We always need
to ask new questions, sometimes daring ones. The most difficult paths to
follow are against well-trodden ones, i.e. the ones everybody believes in.
However, we need to test the merit of such new ideas. I have some thoughts
re your question whether bleaching could be caused by nutrient depletion,
however, I am afraid they take Ove's side.

How come that bleaching is usually more severe nearshore, where nutrients
are enhanced to levels, which in turn can become detrimental to many coral
reef organisms, which are highly adapted to exist in oligotrophic
conditions? Could that maybe relate to some patchiness, too: too much
'food' and maybe toxic substances?

You reason that corals may not think that the stuff we pour into the seas
are edible. But some species certainly benefit from our disposals (see eg.
KRN Anthony 1999. Coral suspension feeding on fine particulate matter.
JEMBE 232: 85-106 and KRN Anthony 1999. A tank system for studying benthic
aquartic organisms at predictable levels of turbidity and sedimentation:
case study examining coral growth. Limnol Oceanogr 44(6): 1415-1422.).

I have another angle to look at your question: a different organism group.
I work on bioeroding sponges, some of which also contain zooxanthellae.
Sponges have been shown to be great biomonitors for nutrient conditions and
some species just love human waste materials and especially the bacteria
growing on them. The bioeroding sponge I worked with bleached under
nutrient-rich conditions, but did very well in less rich environments.

Sorry to be a spoil-sport...

Cheers, Christine

Dr. Christine Schoenberg, PhD
Dept. of Zoosystematics & Morphology
Fachbereich 7 - Biology, Geo- & Environmental Sciences
Carl von Ossietzky University Oldenburg
26111 OLDENBURG
GERMANY
ph +49-441-7983373
fax +49-441-7983162
email christine.schoenberg@mail.uni-oldenburg.de
internet http://www.uni-oldenburg.de/zoomorphology/Whoiswho.html

Date: Sat, 12 May 2001 13:06:51 -0300
To: coral-list@www.coral.noaa.gov
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Re: nutrient deficiency and bleaching -and- Perhaps you need to do a bit more reading ... 

Hi Christine, Eric, coral-list,

Christine, you wrote:

>I have some thoughts
>re your question whether bleaching could be caused by nutrient depletion,
>however, I am afraid they take Ove's side.
>

I would just like to clarify exactly what it is that Ove and I seem to
disagree on. It certainly is not the obvious fact that the majority of
coral bleaching events are "thermally induced," or at least are strongly
associated with times of warmer water. Regarding whether thermally induced
bleaching "could be caused by nutrient depletion" - my impression was that
Ove agreed with me that it could, he just thinks it's unlikely. He
certainly did not claim to have disproved it. So if we disagree, I'm
thinking it's basically on the importance of this particular idea, and
whether or not it warrants investigation. Considering the shocking extent
of the coral bleaching problem and the dire predictions that are being made
for their future by scientists like Ove, I think that any possibility,
however remote, ought to be fully investigated.

also:

>How come that bleaching is usually more severe nearshore, where nutrients
>are enhanced to levels, which in turn can become detrimental to many coral
>reef organisms, which are highly adapted to exist in oligotrophic
>conditions? Could that maybe relate to some patchiness, too: too much
>'food' and maybe toxic substances?
>

It's my impression that "thermal stress" is apt to be higher nearshore. But
you are right that those kinds of pictures are complicated by the effects
of multiple stressors, heat, pollution and fishing, so it's very difficult,
maybe impossible, to pinpoint the exact effects of each. That's why I think
that their relative impacts will be best sorted out in areas not receiving
terrestrial runoff. Especially if one wants to isolate the effects of
fishing/biomass removal alone on the health of corals.

But before you investigate the effects of too-low "nutrient" levels on
corals, I think you need to re-examine the meaning of the word "nutrient."
I discussed this in a fair amount of detail in my (admittedly too long)
essay ( http://www.fisherycrisis.com/coral1.html ). In the oligotrophic
waters that are normally found on coral reefs, the absolute level of
dissolved nutrients found there only represents the limit of the efficiency
of the organisms in removing them from the water. The nutrient recycling
patterns on the reefs (and elsewhere in aquatic systems, although to
varying degrees) conserve the nutrients in solid form and many circular
routes can be completed without the individual nutrients passing through
the "dissolved" stage. Fishing removals can therefore result in the effects
of "nutrient" depletion being felt despite apparently unchanging absolute
levels of nutrients in dissolved form.

>From "Life and Death of Coral Reefs" Birkeland (ed), 1997, a snapshot of
the (underrated in my opinion) "downside" of the food web:

"Fish feces have been observed to be fed upon by corals (McCloskey and
Chesher, 1971) and Tovertson (1982) deduced that some fecal material from
fishes may be eaten and recycled through five fishes before it reaches the
seafloor to be consumed by corals or other invertebrates." (p 416)

....and "corals or other invertebrates" are consumed by reef fish, some
portion of "nutrients" therefore coming full circle without passing through
the "liquid" phase. So, your measurements and thinking on "nutrient levels"
needs to be expanded somehow to reflect the presence or absence of FISH, IMO.

>From the same source, p 415, 

"On coral reefs...the movements of fishes may cause enough movement of
nutrients in coral-reef ecosystems to influence the growth of corals (Meyer
et al 1983), and overfishing can have large-scale ecosystem-level effects."

Unfortunately, however, chap 10, "Effects of Reef Fishes on Corals and
Algae" notes that "the role of fish feces fertilizing the reef" represents
a "potentially important interaction between fishes and reefs" but the
author omits it from the discussion. Beyond fish feces, ammonia excreted
from the gills of fish is available for uptake and use by corals.

One person commented to me off-list: "Ove can tell you that following
bleaching a good blast of N & P will help stimulate recovery." A "blast
of N & P" helps corals recover? No surprise...but might that "blast" have
been given naturally when standing stocks of reef fish were higher? And the
starved state of the bleached corals is not unexpected since we know that
they lost their main food-providers when the zooks left -- but it would be
very interesting to see whether or not a "blast of N & P" given
prophylactically might help. Could the susceptibility to bleaching be
lessened in this way? Maybe when the Hotspot program indicates that
bleaching risk is rising, experimental "blasts" of N & P could be tried
here and there to see if the availability of these nutrients might prevent
the expulsion of the zooks in the first place.

Eric wrote:

>The patchiness of bleaching was discussed on the list a while back, and 
>stagnant areas due to flow dynamics even around a coral colony can result
in 
>local conditions that exacerbate bleaching. 
>

That sounds reasonable, but which feature of "local conditions" is most
affected by stagnant flow, "nutrient" levels or water temperature? My hunch
is that still water would be more prone to becoming extremely
nutrient-depleted rather than extremely warm, but I DO NOT KNOW! Do you?

>Finally, the web page sort of reads in a sensationalist manner, in my 
>opinion, that I don't think adds to its credibility. 
>

I realize that, it's because "you can't please all of the people all of the
time." I have been trying to discuss this issue with scientists, but at the
same time I try to write so that my fisherman-neighbours and the general
public just might get interested and be able to plough through an article.
Sorry, but most of your scientific literature is essentially unavailable to
them, they just can't read it. 

And Ove chose to rename this discussion "Perhaps you need to do a bit more
reading..."

That's OK, of course I will, but I'll never know half of what this group
knows about corals. But I would like to point out that I MAY have done "a
bit more reading" than many in this group on the finer points of other
marine-ecosystems-in-trouble. The declining abundance and stunted growth of
fish everywhere is very worrisome. In some places the declining
productivity is blamed on decreased top-to-bottom mixing patterns - yet we
have a large area in the Northwest Atlantic (Bay of Fundy, Georges Bank)
that is constantly mixed by TIDAL action - which has not changed - but the
"productivity" and growth of fish is way down. And the certainty that fish
were in trouble solely because of changes in water temperature - that's
appealing, but it's falling apart in a lot of instances. For example, a
decade ago in Atlantic Canada we had unusually cold water which caused our
cod to feed poorly and grow very slowly (all cod papers predicted that when
the water warmed up the fish would feed better and grow more quickly).
However, in recent years the water has warmed to a point above the
long-term mean...and growth of cod is still inexplicably dropping. And
declining growth has been noted in our deep water fish stocks, living down
on the "slope" where temperature variations are in hundredths of degrees
rather than tenths...and no-one tries to stretch it far enough to blame the
slow down of those fish (exploited and unexploited) on water temperature.
It's recognized as "biomass depletion" in that case - fishing resulting in
food shortage for marine life.

I'm concerned that the coral scientists as well will belatedly discover
that the problems are not solely driven by the effects of changing water
temperature - I'm convinced that there is an "environmental impact" of
fishing that's not been recognized, and it's a generalized food shortage.

What concerns me is not just coral bleaching or coral diseases, but the
larger diagnostic problem of a whole ocean in trouble. I see a theme, a
generalized slowing of feeding and growth, and suspect it's because of
fishing-induced biomass depletion. The possibility of fishing removals
adversely impacting the "base" of the food web is adamantly denied by
(most) scientists I've corresponded with regarding the northern
fish....they try to reassure me with measurements of chlorophyll
levels....but if the corals turn out to be "hungry" because of
fishing-induced biomass depletion, it really strengthens my argument. It's
rather a huge topic though, very hard to pull it all together in one piece
of work (and I've found that most scientists are very specialized,
struggling with only one piece of the overall puzzle - that adds to the
frustration). For a bit more detail on some of the things that I have read,
and emerging themes that I think I see, check out "The Marine Nutrient
Cycle" http://www.fisherycrisis.com/motherocean.html

Thanks for your interest,
Debbie MacKenzie
http://www.fisherycrisis.com

Date: Sat, 12 May 2001 16:11:11 -0400
From: "Alina M. Szmant" <szmanta@uncwil.edu>
Subject: Re: nutrient deficiency and bleaching
To: Debbie MacKenzie <debimack@auracom.com>, coral-list@www.coral.noaa.gov

Hello Debbie and others:

I have been following with interest the debate about whether bleaching in
reef corals could be at least partially due to coral starvation that could
result from ovrefishing. I guess I'd like to add my 2 cents to the
argument. 

I've had a chance to scan thru your web papers, and I want to add my voice
to those of others concerned about the VERY serious effect overfishing is
having on coral reef health. This has become my "band-wagon" as of late
(as some of you know), and is also expressed in my Panama Symp paper
(Szmant, A.M. 1997. Nutrient effects on coral reefs: the importance of
topographic and trophic complexity on nutrient dynamics. Proc. 8th
Internat. Coral Reef Symp., Panama, June 1996. Vol. 2: 1527-1532), in
which in fact I express concern for the effects of overfshing on coral reef
trophic dynamics and nutrient cycling. There is no doubt that fish
excretion and defecation is important to nutrient cycling on coral reefs
(Szmant-Froelich, A. 1983. Functional aspects of nutrient cycling on coral
reefs. In: The Ecology of Deep and Shallow Coral Reefs. Symp. Ser.
Undersea Res. NOAA Undersea Res. Prog., Vol. 1: 133-139.) just as similar
activities by larger vertebrates are important to trophic dynamics and
nutrient cycling in terrestrial systems. 

However, I do not think that it is a factor in coral bleaching. I have
done experiments in which I starved corals in the lab for weeks and months
and did not observe any change in zooxanthellae density. I did however
induce severe bleaching of corals in the lab of corals maintained for only
2-3 weeks at 30 oC while controls at 28 oC were fine. 

And while I do not have any data to support or refute that coral nutrition
is or is not affected by overfishing, I do think that the nutrient-related
effects of overfishing are happening more at other levels (effects on algal
dynamics, lack of herbivory, population explosions of corallivores, etc).
Further, in comparing tissue biochemical characteristics (C, N, C/N ratios
etc) of corals from reefs with more and fewer fishes (e.g. Glovers Reef and
Bahamas back in the '80s before bleaching was such a problem) we did not
find any difference that correlated with fish communities (we were looking
for differences associated with nutrient environment).

But I also agree with your statements about the important of "solid"
nutrients (see Szmant 1997), and have played around with corals eating fish
feces (they do if they are from planktivores but not herbivores). But
Florida corals have bleached and died just as much as Caribbean corals that
are much more overfished, and Florida corals have a high tissue N content
compared to some other areas where fish are more depleted. I do not think
that Florida reefs are anthropogenically nutrified (Szmant, A.M. and A.
Forrester. 1996. Water column and sediment nitrogen and phosphorus
distribution patterns in the Florida Keys, and potential relationships to
past and present coral reef development. Coral Reefs. 15: 21-41.) but but
there is plenty of particulate matter in the water there has been no
consistent difference between the bleaching of corals offshore (lower
nutrients, more fishes) and closer to shore (more nutrients and
particulates, fewer fishes). 

And my best set of evidence for disbelieving the fish
presence-nutrition-bleaching hypothesis you propose is that some of the
most bleached corals in the Florida Keys during the 1998 bleaching event
were on a nearshore patch reef where the snappers and grunts literally
formed a think layer over the corals all day long (little other shelter
around) and the corals (other than bleached) appeared to be very healthy.
This patch reef had an incredible amount of algae on any non-coral
substrate wherever the fishes hung out (few herbivores on this reef), which
I attributed to the fish excretion. The corals recovered very well from
the bleaching as soon as the water temperatures started to drop in late
summer. Thus, high fish abundance and fish excretion and defecation did
not prevent these corals from suffering from bleaching when temperatures
exceeded 30 oC, but who knows, they may have helped the corals recover
quicker.

Thank you for initiating an interesting debate. Over-fishing is a terrible
thing for coral reefs, and in fact, we don't know all the ways its effects
can cascade down thru the reef community. I do not doubt that coral
nutrition is affected at some level, but in my opinion not enough to be a
contributor to bleaching.

Alina Szmant

Date: Sun, 13 May 2001 10:41:27 +0300
From: CRCP <crcp@africaonline.co.ke>
Reply-To: crcp@africaonline.co.ke
Organization: Coral Reef Conservation Project
To: coral-list@www.coral.noaa.gov
Cc: "Alina M. Szmant" <szmanta@uncwil.edu>,
Debbie MacKenzie <debimack@auracom.com>
Subject: Nutrient deficiency and bleaching


Debbie, Alina and co.

One interesting observation of the 98 bleaching in western Indian Ocean was
that the marine parks, which have a high biomass of fish, experienced the
highest mortality through bleaching (McClanahan et al. 2001). This is largely
attributable to the fact that Acropora is more abundant in the parks where as
it seems to be damaged by nets, coral collection and other things outside of
the park. Also the the very pristine and unfished Maldives and Chagos Islands
experienced terrible bleaching in 98 (Goreau et al. 2000, McClanahan 2000,
Sheppard 1999). So, these findings would support Alina's contention that
fishing and bleaching effects are not influenced by fish abundance through any
nutrient interactions, but that fishing does affect coral abudance through
direct damage (breaking, collecting..) but also through predator-prey
interactions that influence bleaching by influencing the abundance of
bleaching and non-bleaching sensitive corals. Branching corals are most
susceptible to bleaching and also from damage and collection, consequently
parks can increase the abundance of these species and produce the most
dramatic losses when bleaching occurs.


Goreau, T., T. McClanahan, R. Hayes, and A. Strong. 2000. Conservation of
coral reefs after the 1998 global bleaching event. Conservation Biology
14:5-15.

McClanahan, T.R. 2000. Bleaching damage and recovery potential of Maldivian
coral reefs. Marine Pollution Bulletin 40:587-597.

McClanahan, T.R., Muthiga, N.A., Mangi, S. 2001. Coral and algal changes
after the 1998 coral bleaching and mortality: interaction with reef management
and herbivores on Kenyan reefs. Coral Reefs 19: 380-391

Sheppard, C.R.C. 1999. Coral decline and weather patterns over 20 years in the
Chagos Archipelago, Central Indian Ocean. Ambio 28:472-478.


Tim McClanahan
Coral Reef Conservation Project
The Wildlife Conservation Society
Kibaki Flats #12
Kenyatta Beach, Bamburi
P.O. Box 99470
Mombasa, Kenya
email: crcp@africaonline.co.ke
Tel O: 254 11 485570
Tel H: 486549

Date: Sat, 12 May 2001 15:26:15 -0400
From: Les Kaufman <lesk@bu.edu>
To: Debbie MacKenzie <debimack@auracom.com>
CC: coral-list@www.coral.noaa.gov
Subject: Re: nutrient deficiency and bleaching -and- Perhaps you needto do a bit more reading ...
Sender: owner-coral-list@aoml.noaa.gov


Debbie, I suspect you might find that nutrient pulses aid reef recovery
where herbivore densities are still adequate to offset macrophyte growth. 
In other words, on a reef thick with macrophytes and/or thin on
herbivorous fishes, urchins, etc. (arthropods and molluscs are "etc."),
macrophytes might flush from the nutrients and cause problems for the
corals. On a well-grazed reef, the corals will get the bennies without
the bullying. It might appear, however, that the removal of the fishes
compromised the resiliency of the reef for reasons other than some of them
being herbivores: i.e., your hypothesis about nutrient limitation.
Of course, even this is a bit simplistic. Some folks think that the
very high densities achieved by Diadema antillarum on some Caribbean
reefs were the result of low predation by fishes (porgies, hogfishes,
and queen triggerfish are similarly delicious to people). Via that
route, overfishing could actually help the corals. Of course, the
urchin plague took care of that for a while in the west Atlantic, but
things are turning around a bit now. You want to see all the
possibilities, and then judge which is the most likely (and worth
actually testing) for any given place or situation. On the whole yes,
reefs are in trouble in many places. If we were to stop overfishing it
would probably help. If we were to stem runoff and eutrophication, that
would probably help too. 

-- 
Les Kaufman
Biology Department
Boston University
5 Cummington St.
Boston, MA 02215
schwartz@bu.edu
617-353-5560 office
617-353-6965 lab
617-353-6340 fax

and

BUMP
7 MBL St.
Woods Hole, MA 02543
508-289-7579 office
508-289-7950 fax

Note: Kaufman had MacKenzie's whole message in his original message. MacKenzie's message  is already displayed above.

Date: Mon, 14 May 2001 23:43:10 -0300
To: coral-list@www.coral.noaa.gov
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Re: Nutrient deficiency and bleaching 


Hi Coral-list,

Thanks very much for your feedback. You are convincing me that, in all
likelihood, no simple correlation exists between standing stock of reef
fish and susceptibility of corals to bleaching. (Although it's possible
that the presence of fish might aid recovery, according to Alina's example
- but, maybe, maybe not?)

Tim wrote:
>One interesting observation of the 98 bleaching in western Indian Ocean was
>that the marine parks, which have a high biomass of fish, experienced the
>highest mortality through bleaching (McClanahan et al. 2001). This is
largely
>attributable to the fact that Acropora is more abundant in the parks where as
>it seems to be damaged by nets, coral collection and other things outside of
>the park. Also the the very pristine and unfished Maldives and Chagos
Islands
>experienced terrible bleaching in 98 (Goreau et al. 2000, McClanahan 2000,
>Sheppard 1999). So, these findings would support Alina's contention that
>fishing and bleaching effects are not influenced by fish abundance through
any
>nutrient interactions,

Ove wrote:
>Both fished and non-fished areas bleached extensive in 1997-98. One Tree
>Island (a total preserve - not ever fished) bleached a greater levels than
other
>non-fished areas.
>

Mark wrote:
>I studied the reef fish populations in the southern Seychelles during the
bleaching in 1998, and have just returned from the Chagos Archipelago. In
both places (representing over 2% of the world's coral reefs) 80-90% of the
coral died from the bleaching. These also represent reefs with remarkably
low levels of fishing (or other environmental impacts), they had, and
actually still have, abundant and diverse reef fish populations. This would
appear to counter any corellation between nutrient mining and the impacts
of the bleaching. While you might choose to link it to a "wider ocean in
trouble" scenario, Chagos in particular is thought to have existed in
considerable isolation and with highly oligotrophic waters all around over
considerable timescales.
>

80-90% mortality!? - That must be very depressing to witness.

And of course severe bleaching also occurred in areas where standing stocks
of reef fish were very low. So, I guess that's not it. 

"While you might choose to link it to a 'wider ocean in trouble' scenario.."

Well, that actually is my concern, since the "wider ocean" does appear to
be in trouble by all indications. Steep drops in zooplankton levels have
been documented in some open ocean areas. One Pacific study recorded a 70%
drop since 1950. In the Bering Sea, a study on the baleen of
(plankton-feeding) bowhead whales indicates that they have been
experiencing a steadily decreasing rate of feeding success over the last 40
years. In the Northwest Atlantic, records also indicate a significant
decline in zooplankton over the last 40 years. For some reason there seems
to be less krill in the waters of Antarctica, and minke whales are getting
thinner. This leaves me wondering about the zooplankton levels in the
tropical waters - do you have any time-series data on the abundance of those?

What is the cause of these declines in other areas of the world ocean? If
it's "nutrient mining"/fishing, or some other environmental factor...might
it not be affecting the tropical ocean as well? After all, the currents in
the "wider ocean" range pretty far...

"If" the tropical open ocean zooplankton levels are also significantly less
than they once were, what effect would you expect that to have on the coral
reefs? I've read repeatedly that corals consume zooplankton washed over the
reef by ocean water (in addition to consuming the resident type), and that
a certain amount of dissolved nutrient is unavoidably lost by the reef to
the ocean water as well. What is the actual magnitude of these sorts of
exchanges? 

The impression I've gotten from what I've read is that the zooplankton
input from the open ocean represents a net nutrient gain for the coral
reef. But that would depend on the abundance of the zooplankton - obviously
it could potentially drop below a point where the contribution of nutrients
was outweighed by the dissolved nutrients that are washed off the reef.
(The latter would not change since the same volume of water could be
expected to pass over - so if zooplankton drop below a certain threshold
the balance will be tipped, and being bathed in open ocean water, normally
a benefit to the corals, could turn into a liability.) 

Alina expressed the opinion that "overfishing" is having a very serious
effect on coral reef health. She recognizes the importance of fish in
nutrient recycling - yet she's not getting the impression that fishing as
such on an individual reef, is having the kind of direct detrimental
nutrient impact that I suspected. There's got to be a good reason for her
conclusion. It seems that the consensus here is that coral bleaching is
being induced by something "environmental," a feature of the seawater
itself - and temperature appears to be blatantly obvious as the #1
enviro-trigger. But is there another one?

The lack of "fishing effect on coral nutrition" on the local scale of a
given reef -- really should not surprise me, it's reminiscent of the lack
of "fishing effect" elsewhere on individual fish stocks. Downturns in
fisheries everywhere are frequently giving the impression that they are
being caused by environmental factors - factors that invariably cause
decreased growth, but also there are dramatic species shifts - and changing
temperatures alone cannot possibly explain all these. (Nor can pollution,
nutrient or chemical.) The changes give the impression that they are being
driven by something affecting the whole ecosystem - my question is "could
that 'something' be overall biomass depletion?" Could that be a systemic
effect of fishing?

I have another question regarding the bleached corals -- Why do you suppose
that the faster growing species are the most susceptible to the bleaching?
(Of course, my simplistic view is that faster growing ones need more food
to be available, therefore they feel the pinch first. But maybe there's
something else about their metabolism that makes them more susceptible to
higher temperatures. Have you investigated this question?)

Now I'm repeating myself, but a couple of days ago I wrote:

>Eric wrote:
>
>>The patchiness of bleaching was discussed on the list a while back, and 
>>stagnant areas due to flow dynamics even around a coral colony can
result in 
>>local conditions that exacerbate bleaching. 
>>
>
>That sounds reasonable, but which feature of "local conditions" is most
affected by stagnant flow, "nutrient" levels or water temperature? My hunch
is that still water would be more prone to becoming extremely
nutrient-depleted rather than extremely warm, but I DO NOT KNOW! Do you?
>
>

I'd like to read your discussion of the reasons for the patchiness of
bleaching, but couldn't locate it in the list archives. When was it, and
are the messages sorted by thread anywhere? It seems to me that there has
to be a very important clue in the details of the "patchy" pattern, and
also in the order in which corals fall ill during the course of a bleaching
event. What is it that allows some coral colonies to resist the effects of
warmer water longer than others?

Alina wrote:

>I have
>done experiments in which I starved corals in the lab for weeks and months
>and did not observe any change in zooxanthellae density. I did however
>induce severe bleaching of corals in the lab of corals maintained for only
>2-3 weeks at 30 oC while controls at 28 oC were fine. 
>

Did you starve them till the point of death? I've read that food starvation
does cause loss of zooxanthellae in similar manner to what is observed in
mass bleaching events (as do several other stressors, of which you all know
more than I do...my only point being that simple food starvation is one
thing that "could" cause the observed phenomenon, including reduced thermal
threshold.) And if you starve them in an aquarium, do you change the water,
to simulate the washing away of nutrients that occurs on the reefs? If not,
maybe they'll last a lot longer in your experiment than they will in the
wild. 

And the bleaching that occurred at 30 C after 2-3 weeks, did you get the
impression that they had run out of fuel? Or what? - what changed? How
could they tolerate the elevated temperature for a few weeks, if it's a
temperature that they cannot stand? What allowed them to survive it for as
long as they did? Technically, I doubt if it could be called "heatstroke,"
which would normally cause organisms to sicken in hours rather than weeks.
Have you tried varying the amount of food available to the corals
undergoing these temperature trials?

I realize that if it helped at all, food could only do so much to raise the
thermal threshold, these organisms obviously have a temperature ceiling
that's getting them in trouble (...but I'm still bugged by the question of
whether or not they're feeling the added effects of a nutritional threshold
as well...do any of you get the impression that their heat tolerance must
have been higher in the past?) And I asked Ove the other day if he'd
considered transplanting some corals on the Great Barrier Reef to slightly
higher latitudes where today's temperatures might match their normals of a
couple of decades ago - I think that could be an interesting test also, it
might help reveal what, if any, other secondary environmental factors are
at play.

Debbie MacKenzie
http://www.fisherycrisis.com 

Date: Mon, 14 May 2001 22:46:01 -0700
From: Gregor Hodgson <gregorh@ucla.edu>
To: Debbie MacKenzie <debimack@auracom.com>
CC: "coral-list@www.coral.noaa.gov" <coral-list@www.coral.noaa.gov>
Subject: Bleaching, nutrients and recovery

Debbie,

I bet you are correct that nutrients will be more important than suspected so far
in the bleaching/mortality/recovery story, but maybe not in the bleaching end as
you first suggested. A search for an important role of nutrients might be more
likely to bear fruit if it were aimed at the post-bleaching mortality and/or
recovery processes and focused on the interactions among nutrient availability,
bacterial activity on dying corals, hypoxia, algal recruitment and growth, the
ability of damaged coral tissue to recover and new larvae to settle. Michael
Risk and colleagues have made interesting discoveries about the synergistic
effects of nutrients and sediment.

Since 1997, the results of Reef Check have clearly confirmed on a pan-tropical
basis what John Munro suspected in the late 1950s in Jamaica and Tim McClanahan
showed experimentally in the 1990s in Kenya -- that overfishing on reefs (and
not just of fish) is one of the most serious threats to their health.

On the other hand, observations of bleaching events around the world suggest
that the "fish poop theory" will not be supported the data. To confirm this, the
results of Reef Check and other datasets such as the AIMS long-term monitoring
program could be used to show that reefs with high populations of various guilds
of reef fish were often more heavily bleached than reefs with lower populations
-- as noted by Alina and others. Good examples for this lack of correlation may
be found by comparing well-managed, no-take MPAs such as reefs at Orpheus Island,
Australia with fished reefs nearby which bleached equally or less badly in 1998.

The pattern of bleaching follows a consistent trend globally that suggests that
following bleaching events, reefs located in areas with less water column mixing
are usually the worst affected. Typically these are inshore reefs where both
nutrient flux and absolute levels of nutrients are likely higher than outer
reefs. Obvious large scale examples are Australia (GBR), Fiji, Okinawa. One
reason that the Acropora go first is simply that the water usually heats from
shallow to deep, thus it is the common shallow water corals that get nailed first
-- such as Acropora. Experiments in the early 20th century in Australia, Hawaii
and Japan also have documented species-specific tolerance levels for a variety of
physical stressors including hot water.

No doubt if more people looked at the starving basking shark story at the bottom
of your homepage http://www.fisherycrisis.com, they would better understand your
views.
Greg

McClanahan, T. R. 1995. A coral reef ecosystem-fisheries model: Impacts of
fishing intensity and catch selection on reef structure and processes. Ecological
Modeling 80(1):1.

Hodgson, G. 1999. A global assessment of human effects on coral reefs. Marine
Pollution Bulletin. 38 (5) 345-355.

Edinger, E. N., Limmon, G. V., Jompa, J. Widjatmoko, W., Risk, M. J. The Janus
effect: are coral growth rates good indicators of healthy coral reefs? Coral
Reefs. (in press)
--
Gregor Hodgson, PhD
Director, Reef Check Foundation
Professor (Visiting), Institute of the Environment
1652 Hershey Hall 149607
University of California at Los Angeles
Los Angeles, CA 90095-1496 USA

Office Tel: 310-794-4985 Fax: 310-825-0758 or 310-825-9663
Email: gregorh@ucla.edu Web: www.ReefCheck.org

Date: Tue, 15 May 2001 09:56:12 -0400 (EDT)
From: Jim Hendee <hendee@aoml.noaa.gov>
To: Debbie MacKenzie <debimack@auracom.com>
cc: coral-list@www.coral.noaa.gov
Subject: Re: Nutrient deficiency and bleaching 

Debbie,

In response to your question concerning list threads, I'm
compiling the thread that has developed from your original question, and
there are threads for other subjects (see the CHAMP page for these
threads, currently at http://www.coral.noaa.gov/themes/themes.html, but
soon to be moved to the coral-list archives area).

In response to your question regarding other causes for coral
bleaching, as you are by now no doubt aware, coral bleaching is a response
to stress of many different types. In addition to high sea temperatures,
you may want to investigate the effect of ultraviolet in the works of M.
Lesser, G. Wellington, S. Coles and P. Jokiel, among others. As you can
imagine, it is a complex phenomenon. Here are some good starting refs
which also of course have good literature citations therein:

Coles, S.L. & Jokiel, P.L. (1978). Synergistic effects of temperature,
salinity and light on the hermatypic coral Montipora verrucosa. Marine
Biology 49: 187-195.

Gleason, D.F. & Wellington, G.M. (1993). Ultraviolet radiation and coral
bleaching. Nature 365: 837-838.

Gleason, D.F. & Wellington, G.M. (1995). Variation in UVB sensitivity of
planula larvae of the coral Agaricia agaricites along a depth gradient.
Marine Biology 123: 693-703. 

Lesser, M.P. (2000). Depth-dependent photoacclimatization to solar
ultraviolet radiation in teh Caribbean coral Montastraea faveolata. Mar
Ecol Prog Series 192: 137-151.

Lesser, M.P.; Stochaj, W.R.; Tapley, D.W. & Shick, J.M. (1990). Bleaching
in coral reef anthozoans: effects of irradiance, ultraviolet radiation,
and temperature on the activities of protective enzymes against active
oxygen. Coral Reefs 8: 225-232.

~~~~~~~

You may also want to visit the online coral literature abstracts on the
CHAMP site for other references pertaining to bleaching.

Cheers,
Jim

Date: Mon, 14 May 2001 09:59:08 +0100
From: "Mark Spalding" <Mark.Spalding@unep-wcmc.org>
To: <debimack@auracom.com>, <coral-list@www.coral.noaa.gov>
Subject: Nutrient deficiency and bleaching

I'm not going to claim high expertise in all the critical areas of energy flow and coral nutrition, but (aside from points already mentioned) I would also have one fairly practical objection, to your proposal, which applies at the macro scale.

I studied the reef fish populations in the southern Seychelles during the bleaching in 1998, and have just returned from the Chagos Archipelago. In both places (representing over 2% of the world's coral reefs) 80-90% of the coral died from the bleaching. These also represent reefs with remarkably low levels of fishing (or other environmental impacts), they had, and actually still have, abundant and diverse reef fish populations. This would appear to counter any corellation between nutrient mining and the impacts of the bleaching. While you might choose to link it to a "wider ocean in trouble" scenario, Chagos in particular is thought to have existed in considerable isolation and with highly oligotrophic waters all around over considerable timescales.

Best wishes

Mark



__________________________________________

Mark Spalding, PhD
Senior Marine Ecologist 
UNEP-World Conservation Monitoring Centre www.unep-wcmc.org
219 Huntingdon Road Tel: +44 (0)1223 277314
Cambridge, CB3 0DL Fax: +44 (0)1223 277136
UK e-mail:mark.spalding@unep-wcmc.org
or
Research Associate
Cambridge Coastal Research Unit
Department of Geography
Downing St
Cambridge
UK 

Date: Tue, 15 May 2001 13:09:14 -0400
From: John Ware <jware@erols.com>
Reply-To: jware@erols.com
Organization: SeaServices, Inc.
To: "coral-list@www.coral.noaa.gov" <coral-list@www.coral.noaa.gov>
Subject: Causes of bleaching

Dear List and Debbie,

As long as we're talking about causes of bleaching, I am surprised that
nobody has mentioned disease as a possible causative or contributive
factor:

Kushmaro,A; Loya,Y; Fine,M; Rosenberg,E (1996): Bacterial infection and
coral bleaching. Nature 380, 396.

Rosenberg,E; Loya,Y (1999): Vibrio shiloi is the etiological (causative)
agent of Oculina patagonica bleaching: general implications. Reef
Encounter. 25(July), 8-10.

John
-- 
*************************************************************
* *
* John R. Ware, PhD *
* President *
* SeaServices, Inc. *
* 19572 Club House Road *
* Montgomery Village, MD, 20886 *
* 301 987-8507 *
* jware@erols.com *
* seaservices.org *
* fax: 301 987-8531 *
**************************************************************

Date: Tue, 15 May 2001 22:37:40 -0400
From: McCarty and Peters <McCarty_and_Peters@compuserve.com>
Subject: More Bleaching Agents
To: Coral Reef List Server <coral-list@www.coral.noaa.gov>

Dear All,

In addition to increases in temperature, UV, and vibrios (bacteria, see
also K.B. Ritchie and G.W. Smith, 1998, Type II white band disease, Rev.
Trop. Biol. 46 Suppl. 5:199-203), bleaching of reef corals has also been
associated with (citing only a few studies):

Cold water

Steen, R.G., and L. Muscatine. 1987. Low temperature evokes rapid
exocytosis of symbiotic algae by a sea anemone. Biol. Bull. 172:246-263.

Turbidity and sedimentation

Rogers, C.S. 1979. The effect of shading on coral reef structure and
function. J. Exp. Mar. Biol. Ecol. 41:269-288.

Rogers, C.S. 1983. Sublethal and lethal effects of sediments applied to
common Caribbean reef corals in the field. Mar. Pollut. Bull. 14:378-382.

Reduced salinity

Goreau, T.F. 1964. Mass expulsion of zooxanthellae from Jamaican reef
communities after Hurricane Flora. Science 145:383-386.

and

Protozoan infections

Upton, S.J. and E.C. Peters. 1986. A new and unusual species of coccidium
(Apicomplexa: Agammococcidorida) from Caribbean scleractinian corals. J.
Invertebr. Pathol. 47:184-193. [And continuing unpublished observations]

Bleaching might be the result of exposure to extreme physical conditions,
pollutants, parasites, or pathogens, in which the symbiotic relationship is
disturbed and the algae are released from the gastrodermal cells by
exocytosis or the algal pigments are damaged in situ. Bleaching might also
occur by sloughing of the gastrodermal epithelium, as observed in:

Gates, R.D., G. Baghdasarian, and L. Muscatine. 1992. Temperature stress
causes host cell detachment in symbiotic cnidarians: implications for coral
bleaching. Biol. Bull. 182:324-332.

Each case of bleaching should be evaluated to determine which causal agent
and mechanism is affecting the condition of the host.

Esther Peters

From: "Ove Hoegh-Guldberg" <oveh@uq.edu.au>
To: "'Coral Reef List Server'" <coral-list@www.coral.noaa.gov>
Cc: "'McCarty and Peters'" <McCarty_and_Peters@compuserve.com>
Subject: RE: More Bleaching Agents
Date: Wed, 16 May 2001 14:35:34 +1000

Good discussion so far. Can I suggest we also keep distinct agents that cause
"bleaching" (many) and agents that cause "mass coral bleaching" (a subset of the
former)? We should also keep in mind the distinction between primary agents
(directly causal) and those that are secondary (aggravating). In this way,
thermal events (primary) that trigger mass coral bleaching events are often
aggravated by secondary factors like high PAR light, UVR, hypoxia due to reduced
water movement, perhaps starvation and other factors that might not have been
the primary trigger.

Congratulations Debbie - a useful thread has developed.

Cheers,

Ove

Professor Ove Hoegh-Guldberg
Director, Centre for Marine Studies
University of Queensland
St Lucia, 4072, QLD

Phone: +61 07 3365 4333
Fax: +61 07 3365 4755
Email: oveh@uq.edu.au
http://www.marine.uq.edu.au/ohg/index.htm

Note: Hoegh-Guldberg had Peter's whole message in his original message. Peter's message  is already displayed above.

Date: Wed, 16 May 2001 12:33:43 -0300
To: coral-list@www.coral.noaa.gov, Debbie MacKenzie <<debimack@auracom.com>
From: Bernard THOMASSIN <Bernard.Thomassin@com.univ-mrs.fr>
Subject: Re: nutrient deficiency and bleaching -and- Perhaps you need to do a bit more reading ...

Dear Debbie and all colleagues interested by coral bleaching,

To the comment:

> How come that bleaching is usually more severe nearshore, where
> nutrients are enhanced to levels, which in turn can become detrimental
> to many coral reef organisms, which are highly adapted to exist in
> oligotrophic conditions? Could that maybe relate to some patchiness,
> too: too much 'food' and maybe toxic substances?

I don't agree with this opinion taking as example that occured around
Mayotte Island in the North of the Mozambique Channel, SW Indian Ocean,
where I studied since 1983 several bleachings of various intensity.

Here the huge bleaching event of the April-June 1998 (when an warmer
mass of oceanic seawater coming from the North reached this SW Indian
Oc. area) -the bleaching was undubfully caused by the seawater
temperature increase : T=B0 C reached up to 32=B0 C in ocean open sea and
stayed as during near 3 months, it was the corals from the outer slopes
of the barrier reefs (187 km long) that bleached and then died, mainly
in the shallow depths (3m down to 15-20m - but encrusting corals at
down 30m also bleached -) : all the tabular and branched Acroporids,
all the Pocillopora, some Diploastrea, some massive Porites (but on
some of them parts were kept alive, if most of the colonies died). Even
Sarcophyton and Sinularia bleached, as well as the large sea-anemones
as Heterotactis magnifica, and some Tridacnids. So, consequently, the
barrier reef slope coral communities were destroyed at more than 85
percent.

On the slopes of lagoonal reefs, as well as on the slope of the
fringing reefs, also the bleaching occured, but on the fringing reefs
in muddy environments of deep coastal bays, most of the corals
survived.

My opinion (exposed in one of our Bali's Conf. posters) is that corals
living in clear oceanic waters on the barrier reef slopes or lagoonal
reef slopes near large passages, live in oceanic seawaters showing more
constant parameters (according to the seawater temperature they are
more "stenothermes"). In contrary, corals living in nearshore
environments where seawater parameters are more variable (increase of
temperature due to closed environments, or decrease of temperature due
to cool groundwater seepages ; salinity variations due to rainfalls and
river flows ; variation of the turbidity due to alluvial inputs
associated with rainfalls or to phytoplankton blooms ; bacterial
attacks from terrigeneous materials ; etc...).=20

In fact coastal populations of corals (for the same species) are more
resistant to all the possible stresses that coral populations living in
more stable and constant seawater conditions.

In this conditions I disagree with your opinion.

But be very carefull with the biology/physiology of corals. I begin to
believe that the same species of corals have not the same biology (and
physiology) in region located fare away. So extrapolations of results
from one area to another one are not possible. This is true for the
biologists and ecologists, but also for our paleo-geologist
colleagues.

This can explain the opposite views between different researchers!

Have a good day.

Sincerely yours.

Bernard

Bernard A. THOMASSIN
CNRS-UMR 6540 "Dimar",
Centre d'Oc=E9anologie de Marseille,
Station marine d'Endoume,
Chemin de la batterie des Lions,
13007 Marseille,
France

(33) 04 91 04 16 17 (ligne directe)
(33) 04 91 04 16 00 (standart)
mobile (33) 06 63 14 91 78
fax (33) 04 91 04 16 35 (=E0 l'attention de....)

Date: Wed, 16 May 2001 09:20:34 -1000
To: Bernard THOMASSIN <Bernard.Thomassin@com.univ-mrs.fr>,
coral-list@www.coral.noaa.gov
From: Bruce Carlson <carlson@waquarium.org>
Subject: Nearshore vs. offshore bleaching 


RE: Offshore vs nearshore bleaching

Bernard Thomassin disagreed with the general statement that bleaching is 
usually more severe nearshore. I concur.

The other day, Gregor posted a message that "The pattern of bleaching 
follows a consistent trend globally that suggests that following bleaching 
events, reefs located in areas with less water column mixing are usually 
the worst affected. Typically these are inshore reefs where both nutrient 
flux and absolute levels of nutrients are likely higher than outer reefs."

I wrote to Gregor saying that my data indicate that both nearshore and 
offshore reefs in Fiji (south of Viti Levu) suffered significant bleaching 
last year. When I revisited my transects this year I found that both areas 
suffered high mortality (>95% Acropora dead), but I also found significant 
regrowth ("phoenix" corals) and significant recruitment in the lagoons 
(Acropora spp.), whereas the remote offshore barrier reef showed virturally 
no survival and no new recruitment (the "virtually" means that whereas last 
year I counted on average over 100 acroporid colonies per 30 x 1 meter belt 
transect, this year I found only one tiny survivor on one transect and one 
tiny recruit on the other transect). The nearshore patchreefs and barrier 
reef where recovery is good, are located near the mouth of a large river 
and the water in this lagoon area is typically turbid most of the 
time. The remote barrier reef is typically in a pristine ocean 
environment, often crystal clear, and subjected to large open ocean swells 
much of the year.

Gregor wrote back to me and qualified his statement:

"What I was referring to was that in "moderate" bleaching events, when 
there was less than say 50% mortality, the inner reefs typically showed 
higher mortality than the outer reefs due to mixing at the outer reefs..... 
When it is a" bad" event there is little difference as you have seen in 
mortality. But your observations of faster recovery on the inner reefs are 
interesting and one wonders if this has more to do with a higher number of 
nearby parent colonies, water retention in those areas which facilitated 
recruitment, rather than with the nutrients being a beneficial stimulus. 
But all these are open questions deserving of more research."

So what is the "global trend"? Do nearshore reefs or remote barrier reefs 
suffer higher mortality and lower recovery rates? Or should we even try to 
make such a generalization with so many unique factors at each locality?

Aloha
Bruce


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Date: Wed, 16 May 2001 11:02:31 -1000
From: "John Naughton" <John.Naughton@noaa.gov>
To: Bruce Carlson <carlson@waquarium.org>
CC: Bernard THOMASSIN <Bernard.Thomassin@com.univ-mrs.fr>,
coral-list@www.coral.noaa.gov
Subject: Re: Nearshore vs. offshore bleaching

To add to the mix, I concur with Bruce's statements below. During the recent
severe bleaching event in Palau, we noted that corals in the lagoon close to
the main island of Babeldaob were basically not impacted, while much of the
coral (particularly Acropora) on the barrier reef was hammered. Could this be
attributed to the possible lowering of nearshore water temps from runoff?

Mahalo, John

John Naughton
NMFS, Pacific Islands Area Office
Honolulu, HI

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Date: Wed, 16 May 2001 17:36:50 -0500
From: "Bob Buddemeier" <buddrw@kgs.ukans.edu>
Organization: KGS
To: John Naughton <John.Naughton@noaa.gov>
CC: Bruce Carlson <carlson@waquarium.org>,
Bernard THOMASSIN <Bernard.Thomassin@com.univ-mrs.fr>,
coral-list@www.coral.noaa.gov
Subject: Re: Nearshore vs. offshore bleaching

On the basis of evidence available at the time we (Buddemeier, R. W. and Fautin,
D. G., 1993, Coral Bleaching as an Adaptive Mechanism, Bioscience 43:320-326)
observed that:
"There are consistent habitat differences in bleaching resistance at a given
locale; corals in habitats that are more variable or more prone to stresses of
various sorts, including thermal (such as shallow water or fringing reefs), tend
to be less bleached than those in more normally equable environments."

Apparently the field observational patterns are more consistent than attention to
the literature.

The reasons can be described as aclimatization, adaptation, or different
'ecospecies' occupying the different habitat niches, but they all boil down to the
fact that both 'corals' and their microenvironments exhibit systematic differences
over rather small scales.

Bob Buddemeier

--
Dr. Robert W. Buddemeier
Kansas Geological Survey
University of Kansas
1930 Constant Avenue
Lawrence, KS 66047 USA
Ph (1) (785) 864-2112
Fax (1) (785) 864-5317
e-mail: buddrw@kgs.ukans.edu

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From: "peter Houk" <p_houk@hotmail.com>
To: coral-list@www.coral.noaa.gov
Subject: Re: Nearshore vs. offshore bleaching
Date: Thu, 17 May 2001 01:09:27 

Dear All,
I was finishing up field work on my M.S. thesis at the time of the 
bleaching event in Palau. My work was conducted in the Iwayama Bay, 
secluded lagoon waters nearshore Koror. I noticed that the large beds of 
Anacropora were not impacted nearly as much if they were situated along a 
channel (where runoff enters). My data shows this as well.

Best Regards,
Peter Houk
CNMI DEQ Office

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Date: Wed, 16 May 2001 22:32:41 -0400
From: "Alan E Strong" <Alan.E.Strong@noaa.gov>
Organization: NOAA NESDIS/ORA
To: peter Houk <p_houk@hotmail.com>
CC: coral-list@www.coral.noaa.gov
Subject: Re: Nearshore vs. offshore bleaching

...and tidal currents are stronger promoting increased mixing....

Cheers,
Al Strong

--
AES...<><.........<><.........<><.........<><........<><..........AES
Alan E. Strong
Physical Oceanographer & Team Leader
NOAA/NESDIS/ORA
Oceanic Research & Applications Division (ORAD)
Marine Applications Science Team
NOAA Science Center -- Rm 711
5200 Auth Road
Camp Springs, MD 20746
Phone: 301-763-8102 x170
FAX: 301-763-8108
Alan.E.Strong@noaa.gov
http://orbit-net.nesdis.noaa.gov/orad
AES...<><.........<><.........<><.........<><........<><..........AES
.

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Date: Thu, 17 May 2001 11:12:57 +0100
To: coral-list@www.coral.noaa.gov
From: Jacques Laborel <rutabaga@pacwan.fr>
Subject: bleaching and erosion

Dear coral listers
I follow with great interest the debate upon coral bleaching.
Last october I could survey Gaidoo atoll, one of the innumerable "virgin"
maldivian atolls that was more or less completely destroyed by the 1998
event. Like Bernard Thomassin and others I found that bleaching had been
more severe on the outer ocean facing subvertical slope of the reef (about
100% from surface down to about 35 metres deep) than in the lagoon. In fact
the less affected zone we observed was a wide patch reef between 3 and 15
m deep in the shallower part of the lagoon with "only" 50 to 60%
destruction. This was the only place on that atoll where Mussids and some
Faviids were still alive.
In fact the place were young colonies were more abundant were small reefs
near the city-island of Mal=E9, and subject to pollution and man
disturbance...In Gaidoo, however, all branching species had beeen wiped
out. More resistant genus were Goniopora and Diploastrea.
This is already well known. But there is something that stunned me : it
was the absence of sea urchins, either out on the reef or hiding in coral
thickets: during our three week stay I saw exactly 3 Diadema !.
I had already surveyed sea-urchin depleted reefs in the carribean during
the big Diadema disease of 1984-85 and had been struck by the immediate
development of brown algae, Sargassum, Turbinaria and the like, immediately
capping coral colonies; but here, there were NO macrophytes at all (the
only Caulerpas found were on sand). Filamentous algae were abundant on
dead coral inside the lagoon but the outer slope was a white graveyard of
coral colonies, gouged and abraded by what seemed to be parrotfish action.
Some branches of Acropora palifera had lost about 6 cm in two years (raw
evaluation) and appeared pure white except for a small development of
Corallines on their base. This seemed to me a perfect example of
overgrazing. Unfortunately no night dives were possible. I am afraid fish
fauna is beginning to suffer from the disappearing of corals.
Best wishes to all

Jacques Laborel
La Ciotat France

Jacques & Francoise Laborel
Chemin des grands Bassins,13600 La Ciotat, France
tel. (33) 04 42 83 60 32
fax. (33) 04 42 71 81 68
e-mail : rutabaga@pacwan.fr
visitez nous sur
http://www.jardinesperance.org

From: James Wiseman <james@winmarconsulting.com>
To: coral-list@www.coral.noaa.gov
Subject: Nearshore bleaching photos - Fiji
Date: Thu, 17 May 2001 10:52:24 -0500

Ladies and gentlemen,

I have posted some photos of nearshore bleaching from a recent trip to Fiji.
I decided to post them to a webpage yesterday as I think they are worth
discussing as part of this recent "Factors in coral bleaching - nearshore
vs. offshore reefs" discussion.

The website (It is NOT commercial) shows ONLY the pictures and location map
and some of my comments (temperature, some observations, etc). Here is the
URL:

http://www.reefhabilitation.com/fiji/bleaching/index.htm


Of particular interest to me are some of the photos showing "unusual"
bleaching patterns. Any feedback on these is much appreciated - as I would
like to better understand coral bleaching.

For example: 
Photo 1596 shows an Acropora sp. bleaching from the center out. Why is
this? 
Photos 1594 and 1595 show a monospecific stand of acropora. I would expect
either the whole colony to bleach, or perhaps the tops of branches - however
the coral is only bleached in large "patches." Why is this? 
Some of the photos show many different colonies in one patch reef. Why is
one coral bleached, and it appears that an identical species next to it is
not (1599 and 1600). Why did one coral bleach, and the other did not? 

The areas I dove in Fiji were in the North (Somosomo Straits and reefs
around Savusavu and Namenala Isl.) and I did not observe any bleaching below
20 foot water depth.

Please feel free to use these photos for non-commercial use and high
resolution digital photos are available upon request.

James Wiseman
Project Engineer
Winmar Consulting Services
www.winmarconsulting.com

From: "Andy Hipkiss" <andy@andy-hipkiss.co.uk>
To: <coral-list@www.coral.noaa.gov>
Subject: RE: Nearshore bleaching photos - Fiji
Date: Thu, 17 May 2001 18:51:19 +0100

James,

Another non-technical viewpoint ... but my divemaster whilst in the Maldives
"drift diving", noted that in '98, what WAS a drift dive in previous years
became the hardest drifting he'd ever done!

Even at 30m he was getting little flow and temperatures of 30-31C. The
question is, did the temperature cause the shift in flow patterns or vice
versa?

I mention this in relation to your centre out bleaching photo ... the inner
areas of the colony would be even more affected by decreased flow than the
outer margins I would presume.

Cheers
Andy
--
http://www.andy-hipkiss.co.uk

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Date: Fri, 18 May 2001 13:12:14 +0900
From: Rob van Woesik <b984138@sci.u-ryukyu.ac.jp>
Organization: University of the Ryukyus, Japan
To: coral-list@www.coral.noaa.gov
Subject: Coral bleaching and flow

Dear all,

indeed, water-flow rates influence the extent of coral bleaching.
Increases in water-flow speed enhances the shear stress on a benthic
organism by its square. Shear stress in turn allows the passive
diffusion (i.e., not involving energy) of metabolites (i.e., mass
transfer) or heat across the boundary between the organism and the
ambient environment. As the shear stress increases, resistance to
passive diffusion progressively decreases; thus forced convection
enhances mass transfer. Below, gives reference to a recent paper where
we outline this theory and test whether coral colonies growing in
high-flow habitats are more resistant to high SSTs than colonies in
low-flow habitats. Field evidence, as many of you have also found, shows
higher survival on reefs, or in habitats, with strong currents. We argue
that this is because flow rate will determine the rate of removal of
photosynethic byproducts, or heat, that accumulate under stress (i.e.,
during high SSTs). Obviously, these ideas need further experiments, but
the biophysics and what saw happen on the reefs in 1998 agree.

See Marine Ecology Progress Series 212: 301-304
Nakamura T and Van Woesik R (2001) Water-flow rates and passive
diffusion partially explain differential survival of corals during the
1998 bleaching event.

To download a PDF version see:
http://www.int-res.com/abstracts/meps/v212/index.html

Best Regards

Rob van Woesik

*******************************************
Dr. Robert van Woesik
Associate Professor
Department of Marine Sciences
University of the Ryukyus
Nishihara, Okinawa 903-0123
JAPAN

E-mail: b984138@sci.u-ryukyu.ac.jp
Website: http://www.cc.u-ryukyu.ac.jp/~b984138/

Ph: (81) 098 895 8564
Fax: (81) 098 895 8552

******************************************

From: "Ove Hoegh-Guldberg" <oveh@uq.edu.au>
To: "'James Wiseman'" <james@winmarconsulting.com>,
<coral-list@www.coral.noaa.gov>
Subject: RE: Nearshore bleaching photos - Fiji
Date: Fri, 18 May 2001 06:26:51 +1000

Dear James,

Interesting, useful photos. Without knowing the precise oceanographic
conditions of the area at the time, the suggestions below will be speculations
at best. But, however, here goes (my two cents worth):


Your question - Photo 1596 shows an Acropora sp. bleaching from the center out.
Why is this?

I would suspect that the secondary variables light and flow (perhaps trapped by
the morphology of this flat Acropora colony) have conspired to increased the
effect of the warmer than normal conditions. We should also be mindful that
most of the growth occurs on the outer edges (that are less affected), and that
the number of zooxanthellae are lower there as well. The latter might mean
less oxidative stress per host cell and hence less bleaching.


Photos 1594 and 1595 show a monospecific stand of Acropora. I would expect
either the whole colony to bleach, or perhaps the tops of branches - however
the coral is only bleached in large "patches." Why is this?

Two interpretations: (1) One is that there are clonal (genetic) differences
either in the host or the zooxanthellae that create slightly different
temperature thresholds for bleaching stress (see paper by Pete Edmunds) OR (2)
slight variations in flow have interacted with the effects of temperature -
producing different patches.

Some of the photos show many different colonies in one patch reef. Why is one
coral bleached, and it appears that an identical species next to it is
not (1599 and 1600). Why did one coral bleach, and the other did not?

As above: Either it is genetics or it is local secondary factors that vary
across the reef. History - feeding, reproductive condition, interspecies
aggression etc) might also play a role in determining behaviour under thermal
stress.


Cheers,

Ove

Professor Ove Hoegh-Guldberg
Director, Centre for Marine Studies
University of Queensland
St Lucia, 4072, QLD

Phone: +61 07 3365 4333
Fax: +61 07 3365 4755
Email: oveh@uq.edu.au

Date: Thu, 17 May 2001 13:03:45 -0300
To: coral-list@www.coral.noaa.gov
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Re: Nearshore vs. offshore bleaching 

Dear Coral-list,

Here's what I'm thinking now: To be healthy corals need access to their
normal supply of zooplankton from open ocean water. Without it, they'll
live for a while, but their resistance to an array of
malnutrition-aggravated conditions drops. Corals can derive limited benefit
from land-source nutrient input and fish poop, but all will feel the ill
effects of a dropping supply of oceanic zooplankton...."IF" this is now a
fact of their existence.

This may help explain why corals have done so badly in some of the pristine
open ocean locations. In addition to missing the open ocean zooplankton,
they are deprived of any benefit they might have derived from land source
nutrients, so their position becomes doubly precarious (and possibly worse
yet again if the fish poop feeding option has also been removed...although
Alina made an interesting observation that corals prefer to consume the
feces of planktivores vs. herbivores...plankton clearly still being on the
the "keys.")

If you will permit me to compare codfish and corals briefly, I'd like to
point out that the "better inshore/worse offshore" trend in nutritional
success is predicted by the "overall marine biomass depletion" theory, and
is very well demonstrated in the condition of Canadian groundfish stocks
and other marine animals. It is a common theme that I've noted repeatedly
in the "starving ocean," and it pops up quite often on my website.
Basically, natural processes in the sea do not work quickly enough to
counteract the nutrient loss incurred by fishing, so input sources from
outside the system become increasingly important. Nutrients in terrestrial
runoff provide only low-grade nourishment for the coastal system, but this
does confer a survival advantage (when it does not kill). The other coastal
nutritional advantage is in the productivity that occurs in the intertidal
zone - might that help explain the slight advantage enjoyed by the corals
inside the lagoons? - and, doesn't the water actually get hotter in the
lagoons? I guess, I don't know.)

Your detailed observations of the coral bleaching pattern are very
interesting. It seems to me that they might be reasonably consistent with
my interpretation - what do you think?

Bernard concluded that:

>In fact coastal populations of corals (for the same species) are more
resistant to all the possible stresses that coral populations living in
more stable and constant seawater conditions.
>
(The same is clearly true for our groundfish stocks, their resiliency to
various stressors, i.e. fishing pressure and climate change, is much higher
when they are located nearer to outflows of major rivers or mainland
shorelines. So is their growth rates, this is well documented...the
connection to enhanced feeding opportunities is rather hard to deny.)

Bruce wrote:

>my data indicate that both nearshore and
>offshore reefs in Fiji (south of Viti Levu) suffered significant bleaching
>last year. When I revisited my transects this year I found that both areas
>suffered high mortality (>95% Acropora dead), but I also found significant
>regrowth ("phoenix" corals) and significant recruitment in the lagoons
>(Acropora spp.), whereas the remote offshore barrier reef showed virturally
>no survival and no new recruitment (the "virtually" means that whereas last
>year I counted on average over 100 acroporid colonies per 30 x 1 meter belt
>transect, this year I found only one tiny survivor on one transect and one
>tiny recruit on the other transect). The nearshore patchreefs and barrier
>reef where recovery is good, are located near the mouth of a large river
>and the water in this lagoon area is typically turbid most of the
>time. The remote barrier reef is typically in a pristine ocean
>environment, often crystal clear, and subjected to large open ocean swells
>much of the year.
>

As I mentioned a few days ago, lacking the normal degree of zooplankton
contribution, "large ocean swells" would become a nutritional liability to
corals, as dissolved nutrients would continue to be washed away. Might the
water have become "too clean?"

John wrote:

>During the recent
>severe bleaching event in Palau, we noted that corals in the lagoon close to
>the main island of Babeldaob were basically not impacted, while much of the
>coral (particularly Acropora) on the barrier reef was hammered. Could
this be
>attributed to the possible lowering of nearshore water temps from runoff?
>

Does runoff have the effect of lowering the water temperature? I don't
know, but it does have the unarguable effect of raising the level of
dissolved and particulate "nutrients" in the water - no?

Bob wrote:

>"There are consistent habitat differences in bleaching resistance at a given
>locale; corals in habitats that are more variable or more prone to
stresses of
>various sorts, including thermal (such as shallow water or fringing
reefs), tend
>to be less bleached than those in more normally equable environments."
>

...which sounds like the shallows are warmer. Thermal stress higher, yet
resistance to bleaching higher also??

Peter wrote:

>My work was conducted in the Iwayama Bay,
>> secluded lagoon waters nearshore Koror. I noticed that the large beds of
>> Anacropora were not impacted nearly as much if they were situated alone a
>> channel (where runoff enters).

Jacques wrote:

>Like Bernard Thomassin and others I found that bleaching had been
>more severe on the outer ocean facing subvertical slope of the reef (about
>100% from surface down to about 35 metres deep) than in the lagoon. In fact
>the less affected zone we observed was a wide patch reef between 3 and 
>m deep in the shallower part of the lagoon with "only" 50 to 60%
>destruction. This was the only place on that atoll where Mussids and some
>Faviids were still alive.
>In fact the place were young colonies were more abundant were small reefs
>near the city-island of Mal=E9, and subject to pollution and man
>disturbance...In Gaidoo, however, all branching species had beeen wiped
>out.

For corals, the best survival odds were nearer the source of pollution? And
the worse were facing the open ocean? As I have repeatedly pointed out (to
others) regarding the groundfish picture, a decreasing survival gradient as
one moves away from the shoreline seems to reflect the disadvantage
associated with decreasing availability of coastal-source nutrients much
better than a temperature gradient.

I'm also interested in the reason for the heightened susceptibility of the
branching corals (they have also been heavily impacted by infectious
diseases as well as bleaching, have they not?)

Gregor wrote:

>One
>reason that the Acropora go first is simply that the water usually heats from
>shallow to deep, thus it is the common shallow water corals that get
nailed first
>-- such as Acropora.

Does the water usually heat from shallow to deep? The temperature
connection can get confusing.

Does Acropora typically live in the warmest spots? Or is their
vulnerability related to the possibility that they naturally rely more
heavily on the zooplankton nutrition provided by the seawater? Looking at
pictures of Acropora, the branching design seems to be meant to maximize
the feeding benefit derived from the passing seawater, since contact with
the water seems to be maximized. If the passing water didn't contribute the
usual amount of zooplankton, yet washed away the usual amount of nutrients,
the fast-growing, branching coral might find itself in the worst trouble.
Their strategy of maximizing exposure to the passing water, one that
previously allowed their dominance - has it lately backfired? Have you
considered the problem from this angle?

So, bottom line, last question: where are the time-series data on tropical
ocean zooplankton levels?

Debbie MacKenzie
http://www.fisherycrisis.com

Date: Fri, 18 May 2001 12:42:01 -0300
To: debimack@auracom.com, coral-list@www.coral.noaa.gov
From: Bernard THOMASSIN <Bernard.Thomassin@com.univ-mrs.fr>
Subject: Re: Nearshore vs. offshore bleaching

>Debbie and all interested colleagues

>Taking in account my remark :
> >In fact coastal populations of corals (for the same species) are more
>resistant to all the possible stresses that coral populations living in
>more stable and constant seawater conditions.
> >

You say :

>(The same is clearly true for our groundfish stocks, their resiliency to
>various stressors, i.e. fishing pressure and climate change, is much higher
>when they are located nearer to outflows of major rivers or mainland
>shorelines. So is their growth rates, this is well documented...the
>connection to enhanced feeding opportunities is rather hard to deny.)
>
>
>About growth rates from massive corals (Porites lutea, and P. 
>lobata) our idea is supported also by results about the coral 
>calcification from Mayotte I. and SW Madagascar area (Tulear), both 
>sites being in the Mozambique Channel but separated by about 10 
>latitudinal degrees (13° S for Mayotte, 23° S for Tulear region) 
>(results from Kathrin PRIESS thesis, see PRIESS et al., 1997 ; from 
>TESTREEF Program with W.C. DULLO, L. MONTAGGIONI, T. EISENHAUER, G. 
>HEISS, etc..):

massive Porites living:
- in "oceanic" waters on outer barrier reef slopes, or near large 
passages, growth more quickly but with a less dense skeleton,
- those living in coastal "neritic" waters grow more slowly but with 
a more dense skeleton than the first.

Unfortunatly we have not yet results for the metabolism rates and 
feeding rates.

Interesting debate you opened. this is Science.

Cheers,

Bernard

Bernard A. THOMASSIN
Dir. recherches CNRS
Centre d'Océanologie de Marseille,
Station marine d'Endoume,
Chemin de la batterie des Lions,
13007 Marseille,
France
&
G.I.S. "LAG-MAY"
"Environnement marin & littoral de
l'île de Mayotte"
tél. (33) 04 91 04 16 17 (ligne directe)
(33) 04 91 04 16 00 (standart)
mobile (33) 06 63 14 91 78
fax (33) 04 91 04 16 35 (à l'attention de....)

Date: Fri, 18 May 2001 11:16:38 -0400
From: "Billy Causey" <Billy.Causey@noaa.gov>
Reply-To: billy.causey@noaa.gov
Organization: NOAA FKNMS
To: Alan E Strong <Alan.E.Strong@noaa.gov>
CC: peter Houk <p_houk@hotmail.com>, coral-list@www.coral.noaa.gov
Subject: Re: Nearshore vs. offshore bleaching

Al,
Our field observations and monitoring supports your comments and Peter's
observations. Water movement and circulation seems to play a major role in the
intensification of the bleaching event in specific areas. Billy

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Date: Fri, 18 May 2001 19:16:24 -0400
From: "Billy Causey" <Billy.Causey@noaa.gov>
Reply-To: billy.causey@noaa.gov
Organization: NOAA FKNMS
To: Jacques Laborel <rutabaga@pacwan.fr>
CC: coral-list@www.coral.noaa.gov
Subject: Re: bleaching and erosion

Dear Jacques,
Thank you for sharing these observations of coral bleaching. For some time now
I have suspected and have been reporting at some meetings, that I have observed
a steady intensification of coral bleaching in the Florida Keys since 1980
(minor event) until the more recent 1997-98 back-to-back coral bleaching events
when our reefs remained in some degree of bleaching from July 1997 to the
winter of 1998. While the bleaching was originally restricted to the outer
reefs (1983 and 1987).... coral bleaching began to occur in the shallow,
nearshore waters affecting the nearshore patch reefs and isolated coral
formations (1990, 1997, and 1998). Soon, I hope we will have the water
temperature data compiled from 27 thermographs installed by Sanctuary
Biologists Harold Hudson and Bill Goodwin throughout the FKNMS that will show
the pattern. However, at this time I suspect we have seen the inshore coral
that had historically acclimated to a broader range of physical parameters
(i.e. water temperature) now being pushed to the upper limit or threshold of
their tolerance to warm or hot water temperatures.

Whereas, during the earlier bleaching episodes (1980, 83, and 87) ... the outer
reefs, which had previously existed in a more narrower range of physical
conditions were first pushed to their upper threshold of tolerance.

But let me stress, I am by no means promoting temperature as the sole causative
factor of bleaching.
So .... I suggest you watch the corals in the lagoon and see if they bleach in
future episodes.

Cheers, Billy

--
Billy D. Causey, Superintendent
Florida Keys National Marine Sanctuary
PO Box 500368
Marathon, FL 33050
(305) 743-2437 phone
(305) 743-2357 Fax
billy.causey@noaa.gov
http://www.fknms.nos.noaa.gov/

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Date: Sat, 19 May 2001 17:21:07 +0200
To: James Wiseman <james@winmarconsulting.com>
From: Arnfried Antonius <arnfried.antonius@univie.ac.at>
Subject: Re: Nearshore bleaching photos - Fiji
Cc: <coral-list@www.coral.noaa.gov>

Dear James,

you already got useful suggestions to the Fiji bleaching problem.
Let me add one more:
over at least 2 decades I have observed blue-green algae to trigger 
White Band Disease (e.g. Proc. 4th Int. Coral Reef Symp., 2: 7-14 
(1981). P.S.Z.N.I: Marine Ecology, 6(3):197-218 (1985). Proc. 6th 
Int. Cor.Reef Symp.2: 293-298 (1988)).
I think its quite possible that cyanophytes could also play a role in 
bleaching. Perhaps they can trigger the process, or enhance it when 
conditions are right. (there is considerable algal overgrowth 
visible in some of your fotos: 1578, 1583, 85, 86, 87, 93, etc.)
Thus, patchiness of occurrence of cyanophytes might account for 
patchiness of bleaching. In foto 1596, bleaching has apparently (and 
typically!) crept up from the base of the colony where cyanophytes 
lurk. This explains why the center is bleached but the margins not 
(yet).

Very nice photographs you made. Good luck for future work !

Arnfried

From: "Peter J Mumby" <p.j.mumby@ncl.ac.uk>
To: <coral-list@www.coral.noaa.gov>
Subject: bleaching and cloud cover
Date: Sat, 19 May 2001 00:05:57 +0100

Following the interesting discussion on spatial patterns of bleaching, I 
thought I'd mention our observations from the Society Islands, French
Polynesia. In 1998, the incidence of mass bleaching was patchy at scales
of 10s - 100s km. Interestingly, bleaching was minor in Tahiti and 
Moorea despite positive SST anomalies being of similar magnitude and
duration to previous years in which mass bleaching occurred. 
Meteorological data also revealed that wind speeds were exceedingly low
which is usually consistent with the onset of mass bleaching. However, 
although sea temperatures were elevated and the conditions were calm,
cloud cover was very significantly greater than that associated with 
mass bleaching events (or other years for that matter). We used data on 
SST, wind speed and cloud cover to create a discriminant function that 
hindcasted the onset of mass bleaching in the area. Predictions for 1998 
(i.e. minor bleaching) were only correct if cloud cover was explicitly 
incorporated into the analysis (i.e. in addition to temperature).

Laboratory studies have shown that bleaching can occur on a scale of 
seconds or minutes under conditions of solar stress, but how do such 
responses reconcile with the large spatial scale of mass bleaching 
events? Although high cloud cover reduced overall levels of solar 
radiation at a large (island) scale, we have no biophysical 
understanding of the interaction between solar irradiance, cloud cover 
and bleaching. Measurements of cloud cover are unable to reveal the 
intensity and duration of incident irradiance so if high cloud cover did 
help prevent bleaching, we don't know whether it was because overall 
light budgets were reduced or whether the frequency of intense episodic 
bursts of irradiance was reduced. Anyway, food for thought...

More details are available in Mumby PJ, Chisholm JRM, Edwards AJ, 
Andrefouet S, Jaubert J (2001) Cloudy weather may have saved Society 
Island reef corals during the 1998 ENSO event. Marine Ecology Progress 
Series (in press)

Sorry if this was a bit long.

Cheers

Pete

Dr Peter J. Mumby
Royal Society University Research Fellow

Centre for Tropical Coastal Management Studies
Department of Marine Science and Coastal Management
Ridley Building
The University
Newcastle upon Tyne
NE1 7RU
UK
tel: +44 (0)191 222 6228
fax: +44 (0)191 222 7891
email: p.j.mumby@ncl.ac.uk
http://www.ncl.ac.uk/tcmweb/ctcms/mumby.shtml

Date: Sat, 19 May 2001 15:51:47 -0400
From: "Billy Causey" <Billy.Causey@noaa.gov>
Reply-To: billy.causey@noaa.gov
Organization: NOAA FKNMS
To: Bob Buddemeier <buddrw@kgs.ukans.edu>,
coral list <coral-list@www.coral.noaa.gov>
Subject: Re: Nearshore vs. offshore bleaching

Bob,
I wish I had seen your excellent response before I sent mine yesterday.
Unfortunately I am making my way down a list of hundreds of back-logged messages and
just came to your comments. Excellent! Billy
--
Billy D. Causey, Superintendent
Florida Keys National Marine Sanctuary
PO Box 500368
Marathon, FL 33050
(305) 743-2437 phone
(305) 743-2357 Fax
billy.causey@noaa.gov
http://www.fknms.nos.noaa.gov/

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From: "Ove Hoegh-Guldberg" <oveh@uq.edu.au>
To: "'Peter J Mumby'" <p.j.mumby@ncl.ac.uk>, <coral-list@www.coral.noaa.gov>
Subject: RE: bleaching and cloud cover
Date: Mon, 21 May 2001 08:49:45 +1000

A great case of secondary factors affecting the outcome of a primary factor.
Supported by the observation that the initial impact on photosynthesis is damage
to the dark reactions of photosynthesis. Decreasing light levels decrease the
impact.

Ove

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From: "Ove Hoegh-Guldberg" <oveh@uq.edu.au>
To: <billy.causey@noaa.gov>, "'Bob Buddemeier'" <buddrw@kgs.ukans.edu>,
"'coral list'" <coral-list@www.coral.noaa.gov>
Subject: RE: Nearshore vs. offshore bleaching
Date: Mon, 21 May 2001 08:46:47 +1000

Bob B and co are probably correct in saying that "both 'corals' and their
microenvironments exhibit systematic differences over rather small scales." I
suspect that we differ in how certain we would be of the causes of these
differences (real?, genetic?, phenotypic?). There are many observations that
would also seemingly contrast conclusions that inshore, presumably more stressed
corals bleach less (e.g. HG and Salvat 1995, Berkelmann and Oliver 1999 - just
two off the cuff cases in which inshore sites were more than often more bleached
in 1998 etc. ... from the literature too!)

As many have been indicating, much is speculative and little is locked down at
this point. I still feel that we have to be very careful in distinguishing
between good, untested ideas (that should be tested) and ideas that have been
verified by solid experimental methods and field observations etc. The former
category (no criticism intended) would characterise much of our discussion so
far. The latter category has few lines to it.

Ove

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Date: Sat, 19 May 2001 09:43:30 -0400
From: Peter_Craig@nps.gov (Peter Craig)
Subject: Bleaching & dissolved oxygen
To: coral-list@www.coral.noaa.gov

Coral list,

In discussions of bleaching, low levels of dissolved oxygen (DO) are 
occasionally mentioned, but I have been surprised by the tolerance of some 
nearshore corals in American Samoa to extreme ranges of DO. 

At one site, a diverse and healthy-looking assemblage of 52 coral species 
tolerated DO's ranging from 15 to 233% saturation, with negligible bleaching 
(about 1%). (The DO instrument was still in calibration after these 
measurements were taken and the data were similar to those of a second 
instrument.)

The study site is a large and 'pristine' backreef moat on a fringing reef. At 
low tide, the 1-meter deep moat is isolated from ocean flushing, thus it is 
subject to wide daily fluctuations in temperature, brief exposures (hours) to 
very high temperatures, extreme fluctuations in DO saturation (15% at night, 
233% daytime), and changes in pH (7.9-8.5). During the daytime, steady streams 
of oxygen bubbles float to the surface (so some supersaturation seems 
reasonable) although there is little macroalgae present.

I am aware of only a little literature on naturally occurring DO levels in 
tropical reefs (eg, Kinsey & Kinsey 1977, Tytler & Davis 1984), or its 
relationship to bleaching or effects on coral reef organisms, so comments would 
be welcome.

Peter Craig
National Park of American Samoa 

Date: Mon, 21 May 2001 14:09:09 +0800
To: coral-list@www.coral.noaa.gov
From: Anya Salih <anya@emu.usyd.edu.au>
Subject: Re: Nearshore bleaching photos - Fiji
Sender: owner-coral-list@aoml.noaa.gov

James,

Had a look at your excellent photos and here's another possible difference
for the observed inter- and intraspecific variation in coral bleaching so
far not mentioned in the feedback - the degree of fluorescent pigmentation
in sp and morphs of the same species. For several years now I have been
researching the function of fluorescent pigmentation in corals and have
accumulated a lot of experimental and ecological evidence for at least one
function being that of photoprotection.

Given that temperature related bleaching involves light, corals with
sunscreening fluorescent pigmentation can be more resistant to bleaching. I
found this to be so in experiments where fluorescent and non fluorescent
species were exposed to high light and temperature, as well as when
temperature-induced bleaching of fluro- and non-fluorescent morphs of the
same species was compared. Similarly, during 1998 mass bleaching on Great
Barrier Reef in the majority of cases fluorescent morphs were unbleached or
partially bleached, while non fluorescent ones growing near-by, were
completely bleached (Salih et al 2000, Fluorescent pigments in corals are
photoprotective, Nature 408: 850-853).

>Photo 1596 shows an Acropora sp. bleaching from the center out. Why is
>this?

The distribution of fluorescent pigmentation in any one colony is often
uneven; frequently the edges of colonies are more pigmented than the
center. This may be one reason for the observed difference in your photo

>Photos 1594 and 1595 show a monospecific stand of acropora. I would expect
>either the whole colony to bleach, or perhaps the tops of branches - however
>the coral is only bleached in large "patches." Why is this?

I found that monospecific stands of Acropora are frequently composed of
patches of fluorescent and non-fluorescent morphs eg intertidal lagoon,
reef front and slope of Heron and One Tree Islands, mid-shelf reefs such as
Cayley, Feather, Coats of Great Barrier Reef and also Red Sea reefs in
Hurghada, Egypt. In all these sites, patchy distribution of bleaching as
shown in your photos was correlated with concentration of fluorescent
pigmentation in Acropora colonies.

>Some of the photos show many different colonies in one patch reef. Why is
>one coral bleached, and it appears that an identical species next to it is
>not (1599 and 1600). Why did one coral bleach, and the other did not?

Similarly, some of the species in your photo may be fluorescently pigmented
while others are not. The easiest way to find out whether or not corals are
fluorescent is to look for the greenish tinge in their coloration. However
fluoresce is not always apparent in daylight. A reliable quick method is to
illuminate them with UV or blue light at night, for example using Charlie
Mazel's underwater torches (mentioned previously on this list) or more
simply, by covering a torch with a blue plastic filter. At present I am
conducting large scale surveys of distribution of fluorescent pigmented
corals on Great Barrier Reef and found them to be very abundant, in some
reef parts being more common than non fluorescent corals. It may be
speculated that reefs with highly fluorescent corals may be on the whole
much less susceptible than reefs with largely non fluorescent morphs.

I will be very interested to hear how these observations compare to records
of coral bleaching elsewhere.

regards

Anya Salih

Anya Salih Email: anya@emu.usyd.edu.au
Electron Microscope Unit Telephone: 02-93517540
Madsen Building FO9 Facsimile: 02-93517682
The University of Sydney
Sydney, 2006, AUSTRALIA

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Date: Mon, 21 May 2001 09:12:04 -0400
From: Simon Wilson <106422.2221@compuserve.com>
Subject: Bleaching & dissolved oxygen
To: Peter Craig <Peter_Craig@nps.gov>
Cc: Coral List <coral-list@www.coral.noaa.gov>

Dear Peter

Corals in Oman also experience low oxygen concentrations periodically, not
caused by respiration at night but because of upwelling of water that
contains very little oxygen. So far oxygen concentrations can only be
inferred from open water oceanographic measurements, but I would expect
values of less than 0.2mg/l at times. I saw the effect on the benthos of a
strong upwelling in the Gulf of Oman last year that killed several hundred
tons of fish. Mortality to invertebrates in reef areas was also high,
particularly for worms, sipunculids, gastropods and echinoderms. Hard
corals were more resiliant than soft corals, but they were also killed. The
tissue of hard coral became necrotic and then sloughed off revealing white
skeleton underneath, but I didn't see any signs of bleaching then or on
subsequent days.

Any references on the tolerance of coral to low oxygen concentrations would
be welcome.

All the best
Simon

***********************************************************
Simon Wilson
PO Box 2531
CPO 111
SEEB
Sultanate of OMAN

Tel & Fax: 00 968 736260
Mobile: 00 968 9358053
E-mail: 106422.2221@compuserve.com
*********************************************************** 

Date: Mon, 28 May 2001 13:07:12 -0300
To: buddrw@kgs.ukans.edu
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Re: Biomass depletion in the big picture
Cc: coral-list@www.coral.noaa.gov

Hi Bob,

Thanks for your reply.

At 05:34 PM 5/25/01 -0500, you wrote:
>1. Fossil fuel emissions:
>"Since 1751 over 270 billion tons of carbon have been released to the
>atmosphere from the consumption of fossil fuels and cement production.
Half of
>these emissions have occurred since the mid 1970s. The 1997 estimate for
global
>CO2 emissions, 6601 million metric tons of carbon, is
>the highest fossil-fuel emission estimate ever."
>(http://cdiac.esd.ornl.gov/trends/emis/tre_glob.htm)
>

Yes, very big numbers, which may or may not be accurate. Regardless, they
are not particularly useful as long as the other half of the terrestrial
carbon equation remains unknown. The capacity of terrestrial systems to act
as carbon sinks is just starting to be realized.
http://www.eurekalert.org/releases/cu-naacda.html
And the very fact of the "missing sink" - approx. 30% of the carbon
"airborne fraction" going "missing" - this reflects the crudeness of our
understanding and probably our calculations. All of this obviously has a
huge margin of error.

Also, why was not "the highest fossil-fuel emission estimate ever"
accompanied by the "highest jump in global CO2 ever?" (And why did not
"half of the CO2 rise" also occur since the mid 1970s, if that's the time
period during which "half of these emissions" occurred? These observations
weaken the direct cause and effect that is commonly believed: "rising
emissions = rising CO2 levels")

>2. Global fishery production is cited by McGinn (1998) in Worldwatch
Paper 142
>as rising from 20 million tons in 1950 to about 120 million tons in the mid
>1990s. This is in tons of wet weight biomass, which is typically on the
order
>of 1% carbon. Even with a generous estimate of 5% C/wet weight, annual
fishery
>removal from the sea is <0.1% of the annual fossil fuel input to the
>atmosphere.
>

120 million tons - that's including aquaculture production - for the farm
fish that are fed fish meal are you counting the same wild fish twice? One
when you caught him and then again after he was incorporated into the flesh
of the farm fish? Regardless, annual wild fishery yields rose for a long
time but stabilized in the vicinity of 90 million tons about a decade ago.
And the average trophic level of what makes up the 90 million tons is
dropping...contrary to the expectations of "conventional wisdom" which hold
that as the trophic level drops in the system, the overall biomass at those
levels should increase significantly. (Some thinking has it increasing by a
factor of 10 for each trophic level dropped.) Why has the yield not
increased as the trophic level has dropped? It's because one key ingredient
for building fish is in short supply - fixed Nitrogen.

It's not clear to me why you would compare the carbon content of fishery
removals with that in fossil fuel emissions. Carbon does not appear to be
in short supply. It's the link between the carbon and nitrogen cycles that
is most important in assessing the effect of fishing on CO2.

And a simple calculation of tonnage is unlikely to tell the tale. As you
know, fixed nitrogen is (most times) the limiting nutrient in marine
ecosystems. (Actually another scientist did the math for me one time - dry
weight of nitrogen removed by fisheries is only a small fraction of the
nitrogen "put back" by humans via nutrient-enriched terrestrial runoff.
However, the sea knows how to get rid of that - sedimentation,
denitrification...and therefore very little becomes incorporated into the
living web, since it's "given back" in inappropriate form, amount and
location. Stunted growth of fish in an "overnourished" ocean presents a
bizarre paradox, IMO.) 

Nitrogen is the limiting nutrient factor in marine food webs, therefore the
availability of nitrogen determines the strength of the biological pump.
The "biological pump" contains two sections, each of which relies on the
presence of nitrogen, but in slightly different ways. The "organic pump"
delivers carbon to the deep water by sinking organic particles, and
nitrogen is a necessary part of their makeup. Therefore, it's via the
"limiting nutrient" route that nitrogen affects the strength of the organic
pump. 

The other part of the biological pump, however, the "carbonate pump," may
be the more significant side, since besides consigning carbon to the deep
carbonate pool, it sequesters it in sediment, sand, limestone, skeletons of
coral reefs, seashells, etc. Nitrogen functions as a "catalyst" rather than
a key participating element in the carbonate pump. It allows the reaction
to proceed without being consumed by the reaction itself.

Visualize a scenario: 

phytoplankton uses ammonia from seawater as the critical N source for
production/carbon fixation -> a shell-forming marine organism consumes the
phytoplankton, incorporating 10% of the nitrogen into its flesh and
excreting 90% back into the seawater in a form usable by the phytoplankton
-> a small fish consumes the shell-former, the fish also keeps 10% and
excretes 90% of the N (in two short steps, 99% of the N has therefore been
returned to the phytoplankton), the fish excretes the carbonate shell since
it's nutrient content is too low and its indigestible (it's mineral, ends
up making sand)...

This cycle goes round and round, efficiently recycling the N but constantly
shunting more C into long-term storage in mineral and deep sea carbonate
pools. Building the shells uses only minute amounts of N, but N is the
"catalyst" for shell formation since the living shell-building organisms
will not exist without it. No molluscs and corals -> no shells...no N -> no
molluscs and corals... Therefore, although N is not a catalyst in the
chemical sense for the carbonate pump, it is so in the functional sense. 

So how could you calculate the effect on the carbon cycle of removing one
mole of N from the marine ecosystem? From the "biological pump" point of
view you've not only removed a building block, but an essential catalyst as
well. (The math will be very tough, a far cry from a linear relationship...)

>3. If one assumes that most of the biomass extraction is at least two
steps up
>the food chain from the primary producers, the "factor of 10 per trophic
level"
>rule of thumb suggests that fisheries deplete total marine biomass by no more
>than 1%. This is probably a significant overestimate.
>

As suggested above, that rule of thumb seems not to be working in the real
world. "When theory conflicts with reality, reality always wins" - no?

>4. Human acceleration of nutrient cycles has led to major eutrophication in
>many coastal areas (which are disproportionately important to the total
marine
>productivity) -- this is production of EXCESS marine biomass at the most
basic
>and quantitatively dominant level.
>

Now this is a dangerous myth. EXCESS phytoplankton in polluted estuaries
maybe, but this does not translate into EXCESS marine biomass. Ask any
fisherman...or any fish. We've made some very crude adjustments to what was
once a finely balanced system...Polluting the water does not produce fish,
it produces what you said, "major eutrophication." That means that the
waterway is now functioning as a septic system, accelerated sedimentation
and denitrification are the main things going on there. 

>5. A review of the carbon cycle literature shows that the biggest scientific
>challenge is the identity of a "missing" carbon sink. If fishery depletion
>were actually making an unrecognized contribution to the atmospheric CO2,
this
>would be a missing source, not a sink.
>

You've got it!

>I hope that counterarguments will be put forward quantitatively, in terms of
>the extensive literature on global carbon inventories and dynamics.
>

OK, sure, so do I. BTW, did you read my article:
http://www.fisherycrisis.com/strangelove.html , or did you just react to
the abstract that I posted?

Debbie MacKenzie

From: "Bob Buddemeier" <buddrw@kgs.ukans.edu>
To: "Debbie MacKenzie" <debimack@auracom.com>
Cc: <coral-list@www.coral.noaa.gov>
Subject: Re: Biomass depletion in the big picture
Date: Mon, 28 May 2001 22:06:45 -0500


Debbie,

I will resume the discussion when you can come up with a testable hypothesis
that is based on:
1. valid biogeochemical equations;
2. valid mass-balance algebraic equations;
3. supporting citations from the peer-reviewed scientific literature;
and/or
4. data or well-formulated logical arguments refuting the published
findings you wish to ignore.

In the meantime, recommended reading:

Field, C.B., Behrenfeld, M.J., Randerson, J.T., and Falkowski, P., 1998,
Primary production of the biosphere: Integrating terrestrial and oceanic
components: Science, v. 281, p. 237-240.
--- Message -- Oceanic net primary production is approx 50 PgC/yr, (=5E16
g) phytoplankton turnover time is 2-6 days, so standing biomass averages
about 5E14gC. Annual fisheries harvest is around 5E11 gC (as previously
discussed), or 0.1% of primary producer (not total) biomass. Whether
expressed as C or N, this extraction is trivial compared to the overall
inventory, the measurement uncertainties, and both intra-annual and
interannual natural fluctuations.

Pahlow, M., and Riebesell, U., 2000, Temporal trends in deep ocean Redfield
ratios: Science, v. 287, p. 831-833.
--- Message -- Measurements of deepwater chemistry over time show a rising
N:P ratio in the N. Atlantic, and increased export production in the N.
Pacific (which incidentally, is identified as Fe- rather than N-limited).
Neither lends much support to the idea of productivity limitation by N
reduction.

Keeling, C.D., Whorf, T.P., Wahlen, M., and van der Plicht, J., 1995,
Interannual extremes in the rate of rise of atmospheric carbon dioxide:
Nature, v. 375, p. 666-670.
--- Message -- Compare curves of atmospheric CO2 and fossil fuel emissions
(over nearly half a century). Not only is there a correspondence that
defies classification as coincidence, but the anomalies show that biotic
effects have also been quite consistent , and rather minor in variability
(certainly with no evidence for a systematically increasing offset as
fisheries harvest increased).

Kleypas, J.A., Buddemeier, R.W., Archer, D., Gattuso, J.-P., Langdon, C.,
and Opdyke, B.N., 1999, Geochemical consequences of increased atmospheric
carbon dioxide on coral reefs: Science, v. 284, p. 118-120.
And
Ware, J.R., Smith, S.V., and Reaka-Kudla, M.L., 1992, Coral reefs: sources
or sinks of atmospheric CO2?: Coral Reefs, v. 11, p. 127-130.
--- Message -- Calcium carbonate production is a sink for carbon (extracted
from the marine DIC reservoir) but a source of atmospheric CO2. And, for
obligate shallow-water calcifiers, carbonate ion may be or soon become a
limiting nutrient.

Moffat, A.S., 1998, Global nitrogen overload problem grows critical:
Science, v. 279, p. 988-989.
--- Message -- (with references) Mobilization of fixed N to the ocean has
dramatically increased, particularly in coastal regions (which supply most
of the world fisheries harvest).

Bob Buddemeier

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Date: Wed, 30 May 2001 14:45:06 -0300
To: coral-list@www.coral.noaa.gov
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Re: Biomass depletion in the big picture 

Bob,

At 10:06 PM 5/28/01 -0500, you wrote:
>
>Debbie,
>
>I will resume the discussion when you can come up with a testable hypothesis
>that is based on:
>1. valid biogeochemical equations;
>2. valid mass-balance algebraic equations;
>3. supporting citations from the peer-reviewed scientific literature;
>and/or
>4. data or well-formulated logical arguments refuting the published
>findings you wish to ignore.
>

Your third and fourth conditions are the ones that I thought that I had met
in my article: http://www.fisherycrisis.com/strangelove 

Have you taken the time to read it yet? 

What do you make of the concidental timing of the CO2 rise and the
progression of the fishing industry? And the theory that supports the
contention that a decrease in marine biota will cause an ocean-atmosphere
readjustment involving an increase in atmospheric CO2? (not my idea, backed
up by published, peer-reviewed references, if you read it.) Also, the key
question that the whole theory hinges on, is whether or not the total
marine biomass has been diminished over the course of the history of human
fishing. The references that you pointed me to do not address this
question, and this question is critical. To disprove my hypothesis, there
needs to be evidence somewhere that the overall marine productivity has NOT
been falling. I offered published evidence that it has been dropping, for
instance the record from the baleen of the bowhead whales. 

>In the meantime, recommended reading:
>
>Field, C.B., Behrenfeld, M.J., Randerson, J.T., and Falkowski, P., 1998,
>Primary production of the biosphere: Integrating terrestrial and oceanic
>components: Science, v. 281, p. 237-240.
>--- Message -- Oceanic net primary production is approx 50 PgC/yr, (=5E16
>g) phytoplankton turnover time is 2-6 days, so standing biomass averages
>about 5E14gC. Annual fisheries harvest is around 5E11 gC (as previously
>discussed), or 0.1% of primary producer (not total) biomass. Whether
>expressed as C or N, this extraction is trivial compared to the overall
>inventory, the measurement uncertainties, and both intra-annual and
>interannual natural fluctuations.
>

A quote from the article: "Our results based on time-averaged data are
likely to charcterize typical NPP from this time period but certainly miss
key anomalies such as ENSO, as well as progressive global changes."

Therefore no trend in NPP has been revealed in this work. Here are 2 more
quotes from that article: 

"In terrestrial ecosystems, it is relatively straightforward, in principle,
to determine NPP from incremental increases in biomass..."

"Because of the rapid turnover of oceanic plant biomass, even large
increases in ocean NPP will not result in substantial carbon storage
through changes in phytoplankton standing stock."

They measure accumulation of plant tissue (trunks, branches, roots) that
are not involved in photosynthesis, when trying to determine terrestrial
NPP. And this is considered a valid approach. Yet when assessing the marine
system, they only look at the phytoplankton segment/biomass, since that
represents "the plants." They are looking for phytoplankton to accomplish
"carbon storage" by amassing more phytoplankton. However, the phytoplankton
are analogous only to the leaves on the terrestrial trees (the actual
photosynthesizing units), the analogy to growth of trunks, roots, etc., in
the sea is the accumulation of standing stocks of fish. That's where the
photosynthesizing units in the sea store their carbon...as opposed to the
treetrunks on land.

And I do not see where those authors tried to compare their NPP estimates
to a mass-balance with fisheries removals. And regarding your mass-balance
observation, what did you think of my comments to the effect that nitrogen
functions as building block and catalyst both for the organic pump?

>Pahlow, M., and Riebesell, U., 2000, Temporal trends in deep ocean Redfield
>ratios: Science, v. 287, p. 831-833.
>--- Message -- Measurements of deepwater chemistry over time show a rising
>N:P ratio in the N. Atlantic, and increased export production in the N.
>Pacific (which incidentally, is identified as Fe- rather than N-limited).
>Neither lends much support to the idea of productivity limitation by N
>reduction.
>

One key message from this work: "These findings imply that the biological
part of the marine carbon cycle currently is NOT in steady state."
(consistent with my points - no? Today's carbon cycle models assume the
opposite, that it IS in a steady state.)

Also, the possible reasons for the rising N:P ratio (without increasing
AOU, "apparent oxygen utilization," which would be expected if enhanced
N-fertilized primary productivity was the cause), in the North Atlantic
Ocean included "any process weakening export production, such as reduced
nutrient transport to the surface ocean due to declining vertical
mixing..." (the development of the open ocean N-shortage that I suspect,
would predictably "weaken export production") I can imagine that the N:P
ratio could rise as a result of fishing depletion since fishing removes
both N and P. The ocean has an active mechanism, albeit slow, to restore N
(nitrogen-fixation), but no means to actively restore P ... therefore
rising N:P ratio is quite plausibe and consistent with my ideas, it seems
to me.

This study did NOT report rising N-CONTENT in the deep ocean.

>Keeling, C.D., Whorf, T.P., Wahlen, M., and van der Plicht, J., 1995,
>Interannual extremes in the rate of rise of atmospheric carbon dioxide:
>Nature, v. 375, p. 666-670.
>--- Message -- Compare curves of atmospheric CO2 and fossil fuel emissions
>(over nearly half a century). Not only is there a correspondence that
>defies classification as coincidence, but the anomalies show that biotic
>effects have also been quite consistent , and rather minor in variability
>(certainly with no evidence for a systematically increasing offset as
>fisheries harvest increased).
>

This requires a convoluted explanation to account for the fact that the
first 20 years of the data fit with the fossil fuel emission data in one
way (seemingly 55.9% of airborne CO2 fraction accumulated in the atmosphere
each year)..and the second 20 years did not. 

"Our double-deconvolution calculation suggests that the oceans typically
are a larger sink for atmospheric CO2 during El Nino event than
otherwise..." This agrees with my statements that the atmosphere is
acutely sensitive to changes in ocean currents and accompanying
"outgassing" of CO2. Regarding the ocean becoming a "larger sink" during El
Nino...that's strange because it's rather well known that fish production
tends to drop at those times. Rather than becoming a "larger sink" the
ocean more likely becomes a "smaller source" during El Ninos.

"In summary, the slowing down of the rate of rise of atmospheric CO2 from
1989 to 1993, seen in our data and confirmed by other measurements, is
partially explained (about 30%) by the reduction in growth rate of
industrial CO2 emissions that occurred after 1979. We further propose that
warming of surface water in advance of this slowdown caused an anomalous
rise in atmospheric CO2, accentuating the subsequent slowdown, while the
terrestrial biosphere, perhaps by sequestering carbon in a delayed response
to the same warming, caused most of the slowdown itself."

This is what I mean by a "convoluted explanation." There are some large lag
times between cause and effect there, for example 10 years between reducing
the growth rate of emissions and slowing the rise rate of CO2. Also the
warming that caused a see-saw (first caused CO2 to go up, then a delayed
reaction by terr. plants brought it down) is a bit of a stretch. My take on
it: the rate of rise in atmospheric CO2 slowed down beginning in 1989 - the
same year that wild fishery yields peaked (and have stabilized thereafter)
- so the slowdown in rate of marine biomass removal nicely coincides with
the slowdown in rising atmospheric CO2 levels.

>Kleypas, J.A., Buddemeier, R.W., Archer, D., Gattuso, J.-P., Langdon, C.,
>and Opdyke, B.N., 1999, Geochemical consequences of increased atmospheric
>carbon dioxide on coral reefs: Science, v. 284, p. 118-120.
>And
>Ware, J.R., Smith, S.V., and Reaka-Kudla, M.L., 1992, Coral reefs: sources
>or sinks of atmospheric CO2?: Coral Reefs, v. 11, p. 127-130.
>--- Message -- Calcium carbonate production is a sink for carbon (extracted
>from the marine DIC reservoir) but a source of atmospheric CO2. And, for
>obligate shallow-water calcifiers, carbonate ion may be or soon become a
>limiting nutrient.
>

These concerns about the effects of rising CO2 on seawater pH, carbonate
saturation, and ease of calcification for marine organisms....I do not
dispute. This work still does not question the SOURCE of the rising CO2,
which is what I'm trying to get at. These scenarios would be the same
whether the CO2 came from terrestrial emissions or ocean-atmosphere carbon
imbalance, IMO.


>Moffat, A.S., 1998, Global nitrogen overload problem grows critical:
>Science, v. 279, p. 988-989.
>--- Message -- (with references) Mobilization of fixed N to the ocean has
>dramatically increased, particularly in coastal regions (which supply most
>of the world fisheries harvest).
>

A brief intro, really, to this work that Moffat recommends:

Human Alteration of the Global Nitrogen Cycle: Causes and Consequence. by
Peter M. Vitousek, Chair, John Aber, Robert W. Howarth, Gene E. Likens,
Pamela A. Matson,
David W. Schindler, William H. Schlesinger, and G. David Tilman
online at: http://esa.sdsc.edu/tilman.htm

>From Vitousek et al. "In large river basins, the majority of nitrogen that
arrives is probably broken down by denitrifying bacteria and released to
the atmosphere as nitrogen gas or nitrous oxide." (i.e. it doesn't
translate into more fish)

Also, this is another nice one: Oceanic Sources and Sinks
(Fred Mackenzie, Karen von Damm, Dave DeMaster, Tom Church, Billy Moore) 
http://www.joss.ucar.edu/joss_psg/project/oce_workshop/focus/progress/paper_
two.html

>From this article: "Water flux times the riverine composition cannot be
simply translated into net oceanic source terms without intimate knowledge
of biogeochemical and exchange reactions either at the transient saline
boundary of a river plume, or within the more permanent mixing zone of a
confined estuary and attendant sinks." And this intimate knowledge is
seriously lacking. 

Another interesting observation from Fred Mackenzie et at. "The Atlantic
Ocean accumulates much more calcium carbonate than the Pacific because the
Atlantic deep waters have a higher pH (i.e. less corrosive to CaCO3) than
those in the Pacific..." (That helps to convince me that the cessation of
North Atlantic fishing during WWII allowed a partial recovery of the marine
biota, and consequently a significant global CO2 drawdown. Perhaps the
Atlantic marine biota represents a stronger "biological carbon pump" than
the Pacific?) 

Debbie MacKenzie

Date: Wed, 30 May 2001 21:37:44 -0400
To: coral-list@www.coral.noaa.gov
From: "James M. Cervino" <cnidaria@pop.earthlink.net>
Subject: Carbon Dioxide: The Plot Thickens.

Hi Debbie,

Here are some other helpful sources:

1) Falkowski, P. R.J. Scholes, E. Boyle, J. Canadell, D. Canfield, J. 
Elser, N. Gruber, K. Hibbard, P.Hogberg, S. Linder. F.T.Mackenzie, B. 
MooreIII, T. Pendersen, Y. Rosenthal, S. Seitzinger, V. Smetacek, 
W.Steffen, The Global Carbon Cycle: A Test of Our Knowledge of Earth 
as a System 2000 Oct. 13 Science Vol 290, pp 291-295.

Farooq Azam, 1998, Microbial Control of Oceanic Carbon Flux: The Plot 
Thickens. Science Vol. 280 pp. 694-696.

An Introduction To The Chemistry Of The Sea, Michael E. Pilson 
Prentice Hall Inc. Simon & Schuster. ISBN 0-13-258971-0. Pilson is 
at the Graduate School Of Oceanography University of Rode Island 
Narragansett, RI.

Also an interesting article in Oceanus The Rain of Ocean Particles 
and the Earths Carbon Cycle. 1997,Fall/Winter by Susumu Honjo.

James
-- 

************************************
James M Cervino
PhD. Candidate
Marine Science Dept.
University of South Carolina
(803) 996-6470
e-mail:cnidaria@earthlink.net
*************************************

Date: Wed, 30 May 2001 18:40:40 -0300
To: coral-list@www.coral.noaa.gov
From: Debbie MacKenzie <debimack@auracom.com>
Subject: Re: Biomass depletion in the big picture 

Coral list,

Very sorry, typed the URL into my last post minus-".html"
oops :>(
Here it is: http://www.fisherycrisis.com/strangelove.html

Debbie MacKenize

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