coral reefs doomed -- and the ABH and carbonate saturation
Bob Buddemeier
buddrw at kgs.ukans.edu
Wed Sep 26 18:01:03 EDT 2001
Rick and not-quite captive audience –
I’ll answer your questions/comments in reverse order. As far as I know there is no
published/refereed statement of the putative effects of Mg-calcite on reef
calcification, so it will have to be what I think about what I think it is.
I. As I understand what I will call the Magnesium Salvation Theory (MST for a
convenient shorthand), it goes something like this:
1. There is a lot of magnesian calcite in the (low-latitude) carbonate sediments of
the world ocean.
2. High-Mg calcite is more soluble than aragonite.
3. As saturation state and pH of the surface ocean drop as a result of
anthropogenic CO2 additions (or for any other reason), high-Mg calcite will
dissolve before aragonite does, buffering the surface ocean carbonate saturation
state.
4. Therefore concerns about the effects of lowered carbonate saturation state on
calcification by corals and coralline algae are not warranted.
Points 1-2 are valid, point 3 is valid in principle but questionable in practice,
and the extension to point 4 isn’t valid. For the MST to work, two conditions
would have to obtain:
a. The saturation state at which the high-Mg calcite buffers the surface water
would have be high enough to avoid negative calcification effects, and
b. The equilibration (that is, dissolution kinetics) would have to be rapid on the
50-100 year time scale of anthropogenic CO2 additions.
Neither of these two conditions will be met.
Since Greek letters do not translate to text files, I use OM in place of Omega, the
saturation index (where 1 = solid-solution equilibrium, larger numbers =
supersaturation, and smaller numbers = undersaturation). OMh= saturation state of
high-Mg calcite, OMa= saturation state of aragonite. OMc= saturation state of
calcite.
1. Considering point a above:
Aragonite is more soluble than calcite and the ratio of their saturation states is
well-known: to 2 significant figures, OMc/OMa is 1.5. High-Mg calcite is a little
less precisely definable because it is not a well defined molecule, but rather a
range of solid solutions (0-30 mole % MgCO3 is stable, <8% has little or no effect
on calcite solubility, 11% has approximately the same solubility as aragonite), we
will be close enough to use the value of OMa/OMh = 1.3-1.5.
Essentially by definition, chemical dissolution does not occur at all above a value
of OM = 1. We can see that when high-Mg calcite would first start dissolving, OMa
would be 1.3-1.5 or less. If we consider the modeled results of Kleypas, J.A. et
al., 1999. Geochemical consequences of increased atmospheric carbon dioxide on
coral reefs. Science, 284(2 April 1999): 118-120 (figure 1C), we see that the most
extreme and extended prediction is for an average tropical surface ocean OMa of
>1.5 in the year 2100. It is this prediction on which the predictions of
calcification decline are based, and all of the projected calcification effects
occur before there could be any large-scale dissolution of high-Mg calcite – hence,
no salvation by magnesium.
2. Relevant to both points a and b:
Equilibrium is defined as the net balance between forward and back reactions (in
this case precipitation and dissolution). Not only the fact that the surface
oceans are strongly supersaturated with respect to calcite and aragonite, but also
a great deal of experimental work testify to the extremely limited occurrence of
inorganic (as opposed to biogenic) precipitation. Reaction kinetics are strongly
hindered and absolute rates are very slow, almost certainly due to the occlusion of
mineral surfaces by organics and/or less soluble mineral phases. Chemical symmetry
raises the question of why we would expect the surface ocean saturation state to be
controlled by mineral dissolution in the near future when it is not currently
controlled by mineral precipitation
This is probably the point to insert the qualifying comment that organisms are
constrained by environmental chemistry, but not absolutely controlled at the rates
and/or equilibria of inorganic chemistry (that is, they may be able to get around
some aspects of thermodynamics, but they are stuck with ultimate conservation of
mass and energy). The observations to date indicate that zooxanthellate corals and
coralline algae exhibit high rates of calcification at OMa >4, and that most
species show significant declines at levels that are still supersaturated but well
above 1.
3. Relevant to point b:
Apart from the micro-scale inhibition of dissolution and precipitation at the
carbonate surface, there are macro-scale advective issues that reduce potential
reaction rates. The large inventory of Mg-calcite in the world sediments is mostly
buried. Only the top few cm (in high energy environments) or mm (in low-energy
environments) is in any kind of well-exchanged contact with the overlying water.
Below that, pore water residence times rise exponentially. Interstitial pore water
in reef systems is normally (or at least often) controlled at the saturation state
of high-Mg calcite, with the help of biogenically mediated solution or
precipitation, but the volumetric exchange of this water with the overlying water
is extremely slow compared to both surface layer mixing and the physical and
biological processes acting in the open water and at the air-sea interface to
maintain the (super)saturation state there. Empirical evidence for this is that
the Holocene reef sediments (up to 8000 years in age) are neither flushed of
high-Mg calcite by dissolution, nor totally locked up by diagenetic cement
formation. And, there is no reason to expect a major change in pore water
residence times in the near future.
Another comment or two – the one place in the ocean where you do see reasonably
prompt responses of saturation equilibria is in the lysocline-carbonate
compensation depth region. This is far below the mixed layer, and is driven by
organic/carbonate ratios in the sedimentary rainout – all of which, in the pelagic
world, have much higher specific surface areas and therefore reaction rates than
the big, organic-rich lumps on a reef. The reason that the surface ocean can
maintain its saturation disequilibrium so well is that the mixed layer is rather
strongly compartmentalized in terms of its dissolved constitutents (as opposed to
particulates, which can fall through the pycnocline). And, since the exchangeable
carbon inventories of the mixed layer and the atmosphere are similar in size, and
air-sea exchange keeps them nearly in equilibrium, surface ocean response to CO2
input to the atmosphere is prompt and substantial.
Recommended or suggested reading (sorry if this seems egocentric, but obviously
it’s easiest for me to remember and judge relevance of what I’ve been involved in,
so there are a thoroughly disproportionate number of Buddemeier things):
Morse, J. W. and Mackenzie, F. T., 1990. Geochemistry of Sedimentary Carbonates.
Elsevier, Amsterdam, 707 pp.
Gattuso, J.P., Allemand, D. and Frankignoulle, M., 1999. Photosynthesis and
calcification at cellular, organismal and community levels in coral reefs: A review
on interactions and control by the carbonate chemistry. American Zoologist, 39(1):
160-183.
Kleypas, J.A. et al., 1999a. Geochemical consequences of increased atmospheric
carbon dioxide on coral reefs. Science, 284(2 April 1999): 118-120.
Kleypas, J.A., Buddemeier, R.W. and Gattuso, J.-P., 2001. Defining 'coral reef' for
the age of global change. International Journal of Earth Sciences, 90: 426-437.
Kleypas, J.A., McManus, J.W. and Menez, L.A.B., 1999b. Environmental limits to
coral reef development: Where do we draw the line? American Zoologist, 39(1):
146-159.
Tribble, G.W., Sansone, F.J., Buddemeier, R.W. and Li, Y.-H., 1992. Hydraulic
Exchange between a Coral Reef and Surface Seawater. Geological Society of America
Bulletin, 104: 1280-1291.
Buddemeier, R.W. and Oberdorfer, J.A., 1986. Internal Hydrology and Geochemistry of
Coral Reefs and Atoll Islands: Key to Diagenetic Variations. In: J.H.S.a.B.H.
Purser (Editor), Reef Diagenesis. Springer-Verlag, Heidelberg, pp. 91-111.
Buddemeier, R.W. and Oberdorfer, J.A., 1988. Hydrogeology and Hydrodynamics of
Coral Reef Pore Waters. In: J.H. Choate et al. (Editor), Proceedings, 6th Int.
Coral Reef Symp., Townsville, Australia, pp. 485-490.
Buddemeier, R.W., 1994. Symbiosis, calcification, and environmental Interactions.
In: F. Doumenge (Editor), Past and Present Biomineralization Processes. Musée
Océanographique, Monaco, pp. 119-137.
Buddemeier, R.W. and Fautin, D.G., 1996a. Global CO2 and evolution among the
Scleractinia. In: D. Allemand and J.-P. Cuif (Editors), Biomineralization '93, 7th
International Symposium on Biomineralization. Bulletin de l'Institut
oceanographique, Monaco, pp. 33-38.
Buddemeier, R.W. and Fautin, D.G., 1996b. Saturation state and the evolution and
biogeography of symbiotic calcification. In: D. Allemand and J.-P. Cuif (Editors),
Biomineralization '93, 7th International Symposium on Biomineralization. Bulletin
de l'Institute oceanographique, Monaco, Monaco, pp. 23-32.
II. ABH –
I think, and sincerely hope, that Daphne’s recent response will have clarified the
issues. Most of the so-called debate or criticism has consisted of other people
redefining or misinterpreting our statements and then claiming that there is
something wrong with the concept on the basis of their revision.
Related to your comments – one of reasons for proposing the existence of an
adaptively flexible multilateral symbiosis was precisely the points you make – long
taxon lifetimes in both corals and algae, in combination with an obligately
variable preferred habitat and no particular evidence of high extinction rates.
The ecospecies concept preserves the benefits of very rapid adaptation (of the
symbiotic combination) in the presence of the other features.
I thought it might be good to get the idea as close to a one-liner as possible – a
brief synopsis:
The question is: Can the application of stress (any stress or combination, not
just warm water) that results in a diminution of the pre-existing population of
endosymbionts (a.k.a. bleaching) lead to a change (from either endogenous or
exogenous sources) in the balance or nature of the symbiont types that results in
an increase in the fitness of the host-symbiont complex (ecospecies) with respect
to environmental stresses?
We hypothesized (on the basis of very real hard, if indirect evidence) that the
answer is yes, and proposed some tests. We consider both the indirect and the
direct evidence emerging since then to support, but certainly not to 'prove' the
hypothesis.
Bob Buddemeier
Richard Grigg wrote:
> Dear Bob,
>
> Thank you for shedding some more light on your adaptive bleaching
> hypothesis and as you point out, there is almost a complete absence of hard
> evidence either for or against the argument. In this regard, I don't have
> to remind you, that absence of evidence is not evidence of absence (of
> coral's adaptive abilities). Also, in this regard, I think we can infer
> more from the fossil record than most of us seem now willing to accept even
> though the adaptive responses have the benefit of thousand or even millions
> of years. BUT, over the millenia, there must have been some rapid bursts
> of sudden change such as the K-T event itself. Stephen J. Gould's view of
> evolution by punctuated equilibrium is, in fact, based on such bursts of
> change. And yet, we don't see much extinction in corals at least at the
> generic or Family level (Re: Veron's work). Doesn't this imply high
> adaptive ability? Perhaps we need to revisit the fossil record more often
> and pull in the views of John Pandolfi and Charley Veron (where are you
> guys?).
>
> Also, while I am at it, let me ask you to shed some of your
> exceptional knowledge and experience in marine geo-chemistry on the problem
> of decreasing carbonate saturation state in the world's oceans as a result
> of increasing co2 globally. I think there is an equally broad pool of
> misunderstanding about the degree to which existing carbonate sediments in
> the world's oceans, can serve as a buffer to this effect??? I for one
> would appreciate hearing your insights on this question. Hope this
> question does not pose to great a burden but I'm sure the coral reef
> community will appreciate your views.
>
> Rick Grigg
> Dept. of
> Oceanography
> University
> of Hawaii
>
> At 12:58 AM 9/18/01 -0500, buddrw wrote:
> >Coral-listers;
> >
> >I have received, in addition to this broadcast message from Ove, other
> >personal communications that indicate that there is a fairly broad pool of
> >misunderstanding about what the Adaptive Bleaching Hypothesis is and
> >isn't. The comments below address primarily things that it isn't, and I
> >have sent messages to Ove and others on an individual basis to try to get
> >this sorted out so that a productive discussion can ensue.
> >
> >In the meantime, I heartily recommend recourse to the original literature
> >as a source of primary information -- I, Daphne Fautin, and John Ware will
> >all be more than happy to answer questions or attempt to clear up
> >confusion.
> >
> >Bob Buddemeier
> >
> >PS: I stand by my original statements.
> >
> > >===== Original Message From <oveh at uq.edu.au> =====
> > >Dear Bob and others,
> > >
> > >I was triggered to respond by the inferences in your statement that some
> >"reef
> > >ecology and conservation" types have trouble with the Adaptive Bleaching
> > >Hypothesis. Any practicing experimental scientist would have an issue with
> >the
> > >state of play regarding support for this hypothesis. The basic problem at
> >this
> > >point is nothing to do with "culture" - it is more to do with hard evidence,
> > >which is almost completely lacking to support this still very soft and
> > >hypothetical explanation for why coral bleach. While experimental tests
> > have
> > >been coming in, they have had serious problems in terms of design and the
> > >conclusions they draw. Us "reef ecology and conservation types" still wait
> >for
> > >the definitive data that shows corals will bleach, get rid of one
> >dinoflagellate
> > >genotype and adopt another WHILE the thermal (or other) stress is still
> > being
> > >applied to the coral-dinoflagellate association. This has never been shown.
> > >Showing diversity in rDNA is interesting but irrelevant if diversity here
> >does
> > >not relate to relevant physiological differences. The recent paper by Baker
> > >(whom I greatly respect), for example, used light and could not prove (using
> > >RFLPs) that his corals had changed from one dinoflagellate genotype to
> >another
> > >(simply up-regulating one strain over another is not sufficient - that is
> > >acclimation and is not surprising). The experimental design was also
> >confounded
> > >by the fact that stressed corals were placed in the two contrasting and
> > >confounding (for the experiment) habitats (one, the deeper site, was at the
> > >extreme depth limit of the species concerned while the other was clearly
> > more
> > >optimal after photo acclimation). It is therefore not surprising that the
> >corals
> > >died more at deeper site - which has nothing to do with the fact that they
> >did
> > >not bleach!).
> > >
> > >Other issues abound and concern us "reef ecology and conservation types" -
> >the
> > >idea of range of expansion is limited (as outlined by several people so
> > far)
> >by
> > >the fact that light may be a more important limiting than temperature. I
> >also
> > >want to stress that the issue of the decline of reefs (as you, Bob, did
> >state)
> > >has nothing to do with the extinction of corals. As the "geo types"
> >(deliberate
> > >use here) tell us worse things have happened to corals and they have bounced
> > >back (but over thousands if not millions of years). The issue, however, is
> >the
> > >current human dependency on coral reef ecosystems - reefs disappearing for
> >even
> > >a few decades would present serious issues for several hundred million
> >people.
> > >The idea of finding out how reefs survived major extinction events is
> > >interesting but largely irrelevant to the current discussion.
> > >
> > >So - out I come on my old hobby horse - we still have no evidence of unusual
> > >adaptive abilities of corals that will match the fast rate of change. Us
> >reef
> > >ecology types keep looking. While looking for this evidence - perhaps we
> > also
> > >need to focus on how reefs will change and how we can "adapt" as human
> >societies
> > >to these changes. This research direction, if the projections of the
> > future
> >are
> > >correct, will assume a major significance as we enter the next few decades.
> > >
> > >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 at uq.edu.au
> > >http://www.marine.uq.edu.au/CMS_pro/www/staff.html
> > >
> > >
> > >-----Original Message-----
> > >From: owner-coral-list at coral.aoml.noaa.gov
> > >[mailto:owner-coral-list at coral.aoml.noaa.gov]On Behalf Of Bob Buddemeier
> > >Sent: Saturday, 8 September 2001 4:00 AM
> > >To: Jim Hendee
> > >Cc: Coral-List
> > >Subject: Re: coral reefs doomed?
> > >
> > >
> > >Jim, et al.,
> > >
> > >Good questions, good points, -- and like it or not, a pretty good if
> >disturbing
> > >article.
> > >
> > >On your question about range expansion to compensate for temperature
> > increase
> > >and inhospitably hot tropics -- there are unfortunately 3 geographic factors
> > >that work against that.
> > >1. The available shallow water benthic area decreases rather significantly
> >as
> > >you move to higher latitudes (no atolls, narrower shelves, etc.)
> > >2. Light -- see the Kleypas et al analysis -- Kleypas, J.A., McManus, J.W.
> >and
> > >Menez, L.A.B., 1999. Environmental limits to coral reef development:
> > Where do
> >we
> > >draw the line? American Zoologist, 39(1): 146-159. Maximum reef depth
> > shoals
> > >dramatically at higher latitudes, even within the thermal mixed layer. This
> > >presumably reflects light limitations due to sunangle and day lenght
> >variations
> > >-- which aren't going to change.
> > >3. Carbonate saturation state decrease is squeezing from the high latitude
> > >sides -- see the US National Assessment,
> > >http://www.cop.noaa.gov/pubs/coastalclimate.PDF, section 4.4.
> > >
> > >So there is little basis for optimism there.
> > >
> > >With acknowledgment of the terminological problems, some form of
> > >adaptation/acclimatization probably does have real potential to ensure the
> > >survival of corals , but not necessarily "reefs as we know them." The
> > Ware
> >et
> > >al article and its precursor, Buddemeier, R.W. and Fautin, D.G., 1993. Coral
> > >Bleaching as an Adaptive Mechanism: A Testable Hypothesis. BioScience, 43:
> > >320-326, are looking more solid as experimental tests come in (Kinzie et al
> >in
> > >Biol. Bull. earlier this year, Baker in Nature more recently), but for some
> > >reason this concept has been anathema to some reef cology and conservation
> > >types. (see also Buddemeier, R.W., Fautin, D.G. and Ware, J.R., 1997.
> > >Acclimation, Adaptation, and Algal Symbiosis in Reef-Building Scleractinian
> > >Corals. In: J.C. den Hartog (Editor), Proceedings of the 6th International
> > >Conference on Coelenterate Biology (16-21 July 1995, Noordwijkerhout, The
> > >Netherlands). National Museum of Natural History, Leiden, pp. 71-76 for a
> > >related issue). This may be because it is seen as diminishing the
> >seriousness
> > >of the bleaching problem, but in my view your position is the more valid --
> > >without some mechanistic reason to believe that corals CAN survive, there is
> > >very little justification for investing money in research and conservation.
> > >
> > >This also relates to my tired old hobby horse of the non-reef coral
> > habitats
> >--
> > >I don't think we are getting the real picture, or doing ourselves any
> > favors,
> >by
> > >exclusive concentration on reefs; corals have survived many periods of
> > >non-reef-building, and we had better figure out how, why and where.
> > >
> > >Thanks for bringing this up.
> > >
> > >Bob Buddemeier
> > >
> > >
> > >Jim Hendee wrote:
> > >
> > >> Dear Coral Colleagues,
> > >>
> > >> I know I'll get raked over the coals on this (especially because I don't
> > >> have all the literature at my fingertips), but the content and tone of the
> > >> news article below is troublesome to me, even though such a tone helps to
> > >> gain attention, as well as funding, so that we can more thoroughly study
> > >> the problem of coral bleacing and global warming. Of course I respect our
> > >> colleague's right to a viewpoint, but when I see this, I can't help but
> > >> have these thoughts:
> > >>
> > >> Such a projection gives no "credit" to adapatation and natural selection,
> > >> even though such adaptation would have to occur under a relatively short
> > >> time span (50 years). I believe Ware et al (1996), among others, have
> > >> addressed this.
> > >>
> > >> As Dr. Al Strong and I have discussed, and as alluded to but unfortunately
> > >> not expanded upon in the last sentence of the article, if the seas are
> > >> warming, then you might expect the zoogeography of corals to expand
> > >> (relocate?) into the cooler areas, as long as the substrate, circulation,
> > >> light and water quality regimes are conducive. (I would imagine some
> > >> coral researchers have modeled these possibilities, and I apologize for
> > >> not referencing your work.)
> > >>
> > >> Even though high sea temperatures are the primary cause and indicator of
> > >> coral bleaching, that is not the only cause, and no credit is given to the
> > >> evidence in the literature (e.g., Lesser 1996, among others) that high UV
> > >> is also an agent in coral bleaching. Higher UV, especially in the
> > >> tropics, is part of the problem as it relates to the earth's ozone layer.
> > >> There is evidence that high sea temperatures that elicited coral bleaching
> > >> at some localities in the past did not elicit coral bleaching during
> > >> extended cloudy periods (Mumby et al, in press). (Perhaps the cooler areas
> > >> mentioned in the above paragraph might also have lower UV?)
> > >>
> > >> There are other causes of coral bleaching (e.g., see Glynn 1993, 1996) and
> > >> this manifestation of stress is complex and to my mind public statements
> > >> on coral bleaching should emphasize this.
> > >>
> > >> Would an annual update to the ITMEMS statement on coral bleaching
> > >> (http://coral.aoml.noaa.gov/bulls/ITMEMS-bleach.html) be helpful for the
> > >> public in this regard? It is my opinion that it would, that we should
> > >> address the topics above (among others, e.g., coastal effects), and that
> > >> it would behoove us to widely circulate the update among the press as a
> > >> consensus opinion (if that is possible!).
> > >>
> > >> Just my two cents worth...
> > >>
> > >> Cheers,
> > >>
> > >> Jim Hendee
> > >> NOAA/AOML
> > >> Miami, FL
> > >>
> > >> Glynn, P. (1993). Coral reef bleaching: ecological perspectives. Coral
> > >> Reefs 12, 1-17.
> > >>
> > >> Glynn, P. (1996). Coral reef bleaching: facts, hypotheses and
> > >> implications. Global Change Biology 2, 495-509.
> > >>
> > >> Lesser, M.P. (1996). Elevated temperatures and ultraviolet radiation
> > >> cause oxidative stress and inhibit photosynthesis in symbiotic
> > >> dinoflagellates. Limnol Oceanogr. 41(2): 271-283.
> > >>
> > >> Mumby, P.J., Chisholm, J.R.M., Edwards, A.J., Andrefouet, S. & Jaubert, J.
> > >> 2001. Cloudy weather may have saved Society Island reef corals during the
> > >> 1998 ENSO event. Mar Ecol Prog Ser (in press).
> > >>
> > >> Ware, J.R., Fautin, D.G., & Buddemeier, R.W. (1996). Patterns of coral
> > >> bleaching: modeling the adaptive bleaching hypothesis. Ecological
> > >> Modelling 84, 199-214.
> > >>
> > >> -------- Original Message --------
> > >>
> > >> World coral reefs to die by 2050, scientist warns
> > >> By Ed Cropley, Reuters
> > >> Thursday, September 06, 2001
> > >>
> > >> GLASGOW, Scotland — The world's coral reefs will be dead within 50 years
> > >> because of global warming, and there is nothing we can do to save them, a
> > >> scientist warned Wednesday.
> > >>
> > >> "It is hard to avoid the conclusion that most coral in most areas will be
> > >> lost," Rupert Ormond, a marine biologist from Glasgow University, told a
> > >> science conference. "We are looking at a loss which is equivalent to the
> > >> tropical rain forests."
> > >>
> > >> Only the coral reefs in nontropical regions such as Egypt stand any chance
> > >> of lasting beyond 2050, Ormond said, but even the days of the stunning
> > >> marine parks of the Red Sea are numbered as sea temperatures continue to
> > >> creep up.
> > >>
> > >> In the past, reefs have suffered from sediment buildup and the
> > coral-eating
> > >> crown-of-thorns starfish, whose numbers have exploded due to the
> > >> over-fishing of their predators.
> > >>
> > >> Now the main threat to the delicate structures that harbor some of
> > nature's
> > >> most stunning creations comes from warmer seas, which cause coral
> >bleaching.
> > >>
> > >> Microscopic algae that support the coral polyps cannot live in the warmer
> > >> water, and the polyps, the tiny creatures who actually create the reefs,
> >die
> > >> off within weeks.
> > >>
> > >> Scientists agree the world's oceans are now warming at a rate of between
> >one
> > >> and two degrees Celsius every 100 years due to the increased amounts of
> > >> greenhouse gases in the atmosphere which trap the sun's rays.
> > >>
> > >> But even if humans stopped pumping out greenhouse gases such as carbon
> > >> dioxide tomorrow in a bid to halt the process, it would still be too
> > >> late to
> > >> save the reefs, Ormond said. "I don't know what can be done, given that
> > >> there's a 50-year time lag between trying to limit carbon dioxide levels
> >and
> > >> any effect on ocean temperature," he told the conference, held by the
> > >> British Association for the Advancement of Science.
> > >>
> > >> The implications stretch far beyond the death of the colorful coral
> > >> structures themselves. The weird and wonderful eels and fish which inhabit
> > >> the nooks and crannies will become homeless, and many species will die
> > out.
> > >> "We are looking at a gradual running down of the whole system. Over time,
> > >> the diversity of coral fish will die," Ormond said.
> > >>
> > >> Humankind will also suffer directly as the dead reefs are eroded and
> > >> shorelines that have been protected for the last 10,000 years face the
> >wrath
> > >> of the oceans without their natural defenses.
> > >>
> > >> In an age of relatively cheap scuba-diving holidays, this also means many
> > >> developing countries in the tropics, such as Kenya or those in the
> > >> Caribbean, face losing a major source of revenue.
> > >>
> > >> The only cause for optimism was that new coral reefs could start to emerge
> > >> in colder waters such as the north Atlantic Ocean and Mediterranean Sea.
> > >>
> > >> Copyright 2001 — Reuters
> > >>
> > >> ~~~~~~~
> > >> For directions on subscribing and unsubscribing to coral-list or the
> > >> digests, please visit www.coral.noaa.gov, click on Popular on the
> > >> menu bar, then click on Coral-List Listserver.
> > >
> > >--
> > >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 at kgs.ukans.edu
> > >
> > >
> > >~~~~~~~
> > >For directions on subscribing and unsubscribing to coral-list or the
> > >digests, please visit www.coral.noaa.gov, click on Popular on the
> > >menu bar, then click on Coral-List Listserver.
> >
> >Dr. Robert W. Buddemeier
> >Senior Scientist, Geohydrology
> >Kansas Geological Survey
> >University of Kansas
> >1930 Constant Avenue
> >Lawrence, KS 66047
> >USA
> >ph (785) 864-2112; fax (785) 864-5317
> >email: buddrw at kgs.ukans.edu
> >
> >~~~~~~~
> >For directions on subscribing and unsubscribing to coral-list or the
> >digests, please visit www.coral.noaa.gov, click on Popular on the
> >menu bar, then click on Coral-List Listserver.
--
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 at kgs.ukans.edu
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Rick and not-quite captive audience –
<p>I’ll answer your questions/comments in reverse order. As far as
I know there is no published/refereed statement of the putative effects
of Mg-calcite on reef calcification, so it will have to be what I think
about what I think it is.
<p>I. As I understand what I will call the Magnesium Salvation Theory
(MST for a convenient shorthand), it goes something like this:
<br>1. There is a lot of magnesian calcite in the (low-latitude) carbonate
sediments of the world ocean.
<br>2. High-Mg calcite is more soluble than aragonite.
<br>3. As saturation state and pH of the surface ocean drop as a result
of anthropogenic CO2 additions (or for any other reason), high-Mg calcite
will dissolve before aragonite does, buffering the surface ocean carbonate
saturation state.
<br>4. Therefore concerns about the effects of lowered carbonate saturation
state on calcification by corals and coralline algae are not warranted.
<p>Points 1-2 are valid, point 3 is valid in principle but questionable
in practice, and the extension to point 4 isn’t valid. For the MST
to work, two conditions would have to obtain:
<br>a. The saturation state at which the high-Mg calcite buffers the surface
water would have be high enough to avoid negative calcification effects,
and
<br>b. The equilibration (that is, dissolution kinetics) would have to
be rapid on the 50-100 year time scale of anthropogenic CO2 additions.
<br>Neither of these two conditions will be met.
<p>Since Greek letters do not translate to text files, I use OM in place
of Omega, the saturation index (where 1 = solid-solution equilibrium, larger
numbers = supersaturation, and smaller numbers = undersaturation).
OMh= saturation state of high-Mg calcite, OMa= saturation state of aragonite.
OMc= saturation state of calcite.
<p>1. Considering point a above:
<p>Aragonite is more soluble than calcite and the ratio of their saturation
states is well-known: to 2 significant figures, OMc/OMa is 1.5. High-Mg
calcite is a little less precisely definable because it is not a well defined
molecule, but rather a range of solid solutions (0-30 mole % MgCO3 is stable,
<8% has little or no effect on calcite solubility, 11% has approximately
the same solubility as aragonite), we will be close enough to use the value
of OMa/OMh = 1.3-1.5.
<p>Essentially by definition, chemical dissolution does not occur at all
above a value of OM = 1. We can see that when high-Mg calcite would
first start dissolving, OMa would be 1.3-1.5 or less. If we consider
the modeled results of Kleypas, J.A. et al., 1999. Geochemical consequences
of increased atmospheric carbon dioxide on coral reefs. Science, 284(2
April 1999): 118-120 (figure 1C), we see that the most extreme and extended
prediction is for an average tropical surface ocean OMa of >1.5 in the
year 2100. It is this prediction on which the predictions of calcification
decline are based, and all of the projected calcification effects occur
before there could be any large-scale dissolution of high-Mg calcite –
hence, no salvation by magnesium.
<p>2. Relevant to both points a and b:
<p>Equilibrium is defined as the net balance between forward and back reactions
(in this case precipitation and dissolution). Not only the fact that
the surface oceans are strongly supersaturated with respect to calcite
and aragonite, but also a great deal of experimental work testify to the
extremely limited occurrence of inorganic (as opposed to biogenic) precipitation.
Reaction kinetics are strongly hindered and absolute rates are very slow,
almost certainly due to the occlusion of mineral surfaces by organics and/or
less soluble mineral phases. Chemical symmetry raises the question
of why we would expect the surface ocean saturation state to be controlled
by mineral dissolution in the near future when it is not currently controlled
by mineral precipitation
<p>This is probably the point to insert the qualifying comment that organisms
are constrained by environmental chemistry, but not absolutely controlled
at the rates and/or equilibria of inorganic chemistry (that is, they may
be able to get around some aspects of thermodynamics, but they are stuck
with ultimate conservation of mass and energy). The observations
to date indicate that zooxanthellate corals and coralline algae exhibit
high rates of calcification at OMa >4, and that most species show significant
declines at levels that are still supersaturated but well above 1.
<p>3. Relevant to point b:
<p>Apart from the micro-scale inhibition of dissolution and precipitation
at the carbonate surface, there are macro-scale advective issues that reduce
potential reaction rates. The large inventory of Mg-calcite in the
world sediments is mostly buried. Only the top few cm (in high energy
environments) or mm (in low-energy environments) is in any kind of well-exchanged
contact with the overlying water. Below that, pore water residence
times rise exponentially. Interstitial pore water in reef systems
is normally (or at least often) controlled at the saturation state of high-Mg
calcite, with the help of biogenically mediated solution or precipitation,
but the volumetric exchange of this water with the overlying water is extremely
slow compared to both surface layer mixing and the physical and biological
processes acting in the open water and at the air-sea interface to maintain
the (super)saturation state there. Empirical evidence for this is
that the Holocene reef sediments (up to 8000 years in age) are neither
flushed of high-Mg calcite by dissolution, nor totally locked up by diagenetic
cement formation. And, there is no reason to expect a major change
in pore water residence times in the near future.
<p>Another comment or two – the one place in the ocean where you do see
reasonably prompt responses of saturation equilibria is in the lysocline-carbonate
compensation depth region. This is far below the mixed layer, and
is driven by organic/carbonate ratios in the sedimentary rainout – all
of which, in the pelagic world, have much higher specific surface areas
and therefore reaction rates than the big, organic-rich lumps on a reef.
The reason that the surface ocean can maintain its saturation disequilibrium
so well is that the mixed layer is rather strongly compartmentalized in
terms of its dissolved constitutents (as opposed to particulates, which
can fall through the pycnocline). And, since the exchangeable carbon
inventories of the mixed layer and the atmosphere are similar in size,
and air-sea exchange keeps them nearly in equilibrium, surface ocean response
to CO2 input to the atmosphere is prompt and substantial.
<p>Recommended or suggested reading (sorry if this seems egocentric, but
obviously it’s easiest for me to remember and judge relevance of what I’ve
been involved in, so there are a thoroughly disproportionate number of
Buddemeier things):
<br>
<p>Morse, J. W. and Mackenzie, F. T., 1990. Geochemistry of Sedimentary
Carbonates. Elsevier, Amsterdam, 707 pp.
<br>Gattuso, J.P., Allemand, D. and Frankignoulle, M., 1999. Photosynthesis
and calcification at cellular, organismal and community levels in coral
reefs: A review on interactions and control by the carbonate chemistry.
American Zoologist, 39(1): 160-183.
<br>Kleypas, J.A. et al., 1999a. Geochemical consequences of increased
atmospheric carbon dioxide on coral reefs. Science, 284(2 April 1999):
118-120.
<br><b>Kleypas, J.A., Buddemeier, R.W. and Gattuso, J.-P., 2001. Defining
'coral reef' for the age of global change. International Journal of Earth
Sciences, 90: 426-437.</b>
<br>Kleypas, J.A., McManus, J.W. and Menez, L.A.B., 1999b. Environmental
limits to coral reef development: Where do we draw the line? American Zoologist,
39(1): 146-159.
<br>Tribble, G.W., Sansone, F.J., Buddemeier, R.W. and Li, Y.-H., 1992.
Hydraulic Exchange between a Coral Reef and Surface Seawater. Geological
Society of America Bulletin, 104: 1280-1291.
<br>Buddemeier, R.W. and Oberdorfer, J.A., 1986. Internal Hydrology and
Geochemistry of Coral Reefs and Atoll Islands: Key to Diagenetic
Variations. In: J.H.S.a.B.H. Purser (Editor), Reef Diagenesis. Springer-Verlag,
Heidelberg, pp. 91-111.
<br>Buddemeier, R.W. and Oberdorfer, J.A., 1988. Hydrogeology and Hydrodynamics
of Coral Reef Pore Waters. In: J.H. Choate et al. (Editor), Proceedings,
6th Int. Coral Reef Symp., Townsville, Australia, pp. 485-490.
<br>Buddemeier, R.W., 1994. Symbiosis, calcification, and environmental
Interactions. In: F. Doumenge (Editor), Past and Present Biomineralization
Processes. Musée Océanographique, Monaco, pp. 119-137.
<br>Buddemeier, R.W. and Fautin, D.G., 1996a. Global CO2 and evolution
among the Scleractinia. In: D. Allemand and J.-P. Cuif (Editors), Biomineralization
'93, 7th International Symposium on Biomineralization. Bulletin de l'Institut
oceanographique, Monaco, pp. 33-38.
<br>Buddemeier, R.W. and Fautin, D.G., 1996b. Saturation state and the
evolution and biogeography of symbiotic calcification. In: D. Allemand
and J.-P. Cuif (Editors), Biomineralization '93, 7th International Symposium
on Biomineralization. Bulletin de l'Institute oceanographique, Monaco,
Monaco, pp. 23-32.
<br>
<p>II. ABH –
<p>I think, and sincerely hope, that Daphne’s recent response will have
clarified the issues. Most of the so-called debate or criticism has
consisted of other people redefining or misinterpreting our statements
and then claiming that there is something wrong with the concept on the
basis of their revision.
<p>Related to your comments – one of reasons for proposing the existence
of an adaptively flexible multilateral symbiosis was precisely the points
you make – long taxon lifetimes in both corals and algae, in combination
with an obligately variable preferred habitat and no particular evidence
of high extinction rates. The ecospecies concept preserves the benefits
of very rapid adaptation (of the symbiotic combination) in the presence
of the other features.
<p>I thought it might be good to get the idea as close to a one-liner as
possible – a brief synopsis:
<p>The question is: Can the application of stress (any stress or
combination, not just warm water) that results in a diminution of the pre-existing
population of endosymbionts (a.k.a. bleaching) lead to a change (from either
endogenous or exogenous sources) in the balance or nature of the symbiont
types that results in an increase in the fitness of the host-symbiont complex
(ecospecies) with respect to environmental stresses?
<br>We hypothesized (on the basis of very real hard, if indirect evidence)
that the answer is yes, and proposed some tests. We consider both
the indirect and the direct evidence emerging since then to support, but
certainly not to 'prove' the hypothesis.
<p>Bob Buddemeier
<br>
<br>
<br>
<br>
<br>
<p>Richard Grigg wrote:
<blockquote TYPE=CITE>Dear Bob,
<p> Thank you for shedding
some more light on your adaptive bleaching
<br>hypothesis and as you point out, there is almost a complete absence
of hard
<br>evidence either for or against the argument. In this regard,
I don't have
<br>to remind you, that absence of evidence is not evidence of absence
(of
<br>coral's adaptive abilities). Also, in this regard, I think we
can infer
<br>more from the fossil record than most of us seem now willing to accept
even
<br>though the adaptive responses have the benefit of thousand or even
millions
<br>of years. BUT, over the millenia, there must have been some rapid
bursts
<br>of sudden change such as the K-T event itself. Stephen J. Gould's
view of
<br>evolution by punctuated equilibrium is, in fact, based on such bursts
of
<br>change. And yet, we don't see much extinction in corals at least
at the
<br>generic or Family level (Re: Veron's work). Doesn't this imply
high
<br>adaptive ability? Perhaps we need to revisit the fossil record
more often
<br>and pull in the views of John Pandolfi and Charley Veron (where are
you
<br>guys?).
<p> Also, while I am at
it, let me ask you to shed some of your
<br>exceptional knowledge and experience in marine geo-chemistry on the
problem
<br>of decreasing carbonate saturation state in the world's oceans as a
result
<br>of increasing co2 globally. I think there is an equally broad
pool of
<br>misunderstanding about the degree to which existing carbonate sediments
in
<br>the world's oceans, can serve as a buffer to this effect??? I
for one
<br>would appreciate hearing your insights on this question. Hope
this
<br>question does not pose to great a burden but I'm sure the coral reef
<br>community will appreciate your views.
<p>
Rick Grigg
<br>
Dept. of
<br>Oceanography
<br>
University
<br>of Hawaii
<p>At 12:58 AM 9/18/01 -0500, buddrw wrote:
<br>>Coral-listers;
<br>>
<br>>I have received, in addition to this broadcast message from Ove, other
<br>>personal communications that indicate that there is a fairly broad
pool of
<br>>misunderstanding about what the Adaptive Bleaching Hypothesis is and
<br>>isn't. The comments below address primarily things that it isn't,
and I
<br>>have sent messages to Ove and others on an individual basis to try
to get
<br>>this sorted out so that a productive discussion can ensue.
<br>>
<br>>In the meantime, I heartily recommend recourse to the original literature
<br>>as a source of primary information -- I, Daphne Fautin, and John Ware
will
<br>>all be more than happy to answer questions or attempt to clear up
<br>>confusion.
<br>>
<br>>Bob Buddemeier
<br>>
<br>>PS: I stand by my original statements.
<br>>
<br>> >===== Original Message From <oveh at uq.edu.au> =====
<br>> >Dear Bob and others,
<br>> >
<br>> >I was triggered to respond by the inferences in your statement that
some
<br>>"reef
<br>> >ecology and conservation" types have trouble with the Adaptive Bleaching
<br>> >Hypothesis. Any practicing experimental scientist would have
an issue with
<br>>the
<br>> >state of play regarding support for this hypothesis. The basic problem
at
<br>>this
<br>> >point is nothing to do with "culture" - it is more to do with hard
evidence,
<br>> >which is almost completely lacking to support this still very soft
and
<br>> >hypothetical explanation for why coral bleach. While experimental
tests
<br>> have
<br>> >been coming in, they have had serious problems in terms of design
and the
<br>> >conclusions they draw. Us "reef ecology and conservation types"
still wait
<br>>for
<br>> >the definitive data that shows corals will bleach, get rid of one
<br>>dinoflagellate
<br>> >genotype and adopt another WHILE the thermal (or other) stress is
still
<br>> being
<br>> >applied to the coral-dinoflagellate association. This has
never been shown.
<br>> >Showing diversity in rDNA is interesting but irrelevant if diversity
here
<br>>does
<br>> >not relate to relevant physiological differences. The recent
paper by Baker
<br>> >(whom I greatly respect), for example, used light and could not
prove (using
<br>> >RFLPs) that his corals had changed from one dinoflagellate genotype
to
<br>>another
<br>> >(simply up-regulating one strain over another is not sufficient
- that is
<br>> >acclimation and is not surprising). The experimental design
was also
<br>>confounded
<br>> >by the fact that stressed corals were placed in the two contrasting
and
<br>> >confounding (for the experiment) habitats (one, the deeper site,
was at the
<br>> >extreme depth limit of the species concerned while the other was
clearly
<br>> more
<br>> >optimal after photo acclimation). It is therefore not surprising
that the
<br>>corals
<br>> >died more at deeper site - which has nothing to do with the fact
that they
<br>>did
<br>> >not bleach!).
<br>> >
<br>> >Other issues abound and concern us "reef ecology and conservation
types" -
<br>>the
<br>> >idea of range of expansion is limited (as outlined by several people
so
<br>> far)
<br>>by
<br>> >the fact that light may be a more important limiting than temperature.
I
<br>>also
<br>> >want to stress that the issue of the decline of reefs (as you, Bob,
did
<br>>state)
<br>> >has nothing to do with the extinction of corals. As the "geo
types"
<br>>(deliberate
<br>> >use here) tell us worse things have happened to corals and they
have bounced
<br>> >back (but over thousands if not millions of years). The issue,
however, is
<br>>the
<br>> >current human dependency on coral reef ecosystems - reefs disappearing
for
<br>>even
<br>> >a few decades would present serious issues for several hundred million
<br>>people.
<br>> >The idea of finding out how reefs survived major extinction events
is
<br>> >interesting but largely irrelevant to the current discussion.
<br>> >
<br>> >So - out I come on my old hobby horse - we still have no evidence
of unusual
<br>> >adaptive abilities of corals that will match the fast rate of change.
Us
<br>>reef
<br>> >ecology types keep looking. While looking for this evidence - perhaps
we
<br>> also
<br>> >need to focus on how reefs will change and how we can "adapt" as
human
<br>>societies
<br>> >to these changes. This research direction, if the projections
of the
<br>> future
<br>>are
<br>> >correct, will assume a major significance as we enter the next few
decades.
<br>> >
<br>> >Best wishes,
<br>> >
<br>> >Ove
<br>> >
<br>> >Professor Ove Hoegh-Guldberg
<br>> >Director, Centre for Marine Studies
<br>> >University of Queensland
<br>> >St Lucia, 4072, QLD
<br>> >
<br>> >Phone: +61 07 3365 4333
<br>> >Fax: +61 07 3365 4755
<br>> >Email: oveh at uq.edu.au
<br>> ><a href="http://www.marine.uq.edu.au/CMS_pro/www/staff.html">http://www.marine.uq.edu.au/CMS_pro/www/staff.html</a>
<br>> >
<br>> >
<br>> >-----Original Message-----
<br>> >From: owner-coral-list at coral.aoml.noaa.gov
<br>> >[<a href="mailto:owner-coral-list at coral.aoml.noaa.gov">mailto:owner-coral-list at coral.aoml.noaa.gov</a>]On
Behalf Of Bob Buddemeier
<br>> >Sent: Saturday, 8 September 2001 4:00 AM
<br>> >To: Jim Hendee
<br>> >Cc: Coral-List
<br>> >Subject: Re: coral reefs doomed?
<br>> >
<br>> >
<br>> >Jim, et al.,
<br>> >
<br>> >Good questions, good points, -- and like it or not, a pretty good
if
<br>>disturbing
<br>> >article.
<br>> >
<br>> >On your question about range expansion to compensate for temperature
<br>> increase
<br>> >and inhospitably hot tropics -- there are unfortunately 3 geographic
factors
<br>> >that work against that.
<br>> >1. The available shallow water benthic area decreases rather
significantly
<br>>as
<br>> >you move to higher latitudes (no atolls, narrower shelves, etc.)
<br>> >2. Light -- see the Kleypas et al analysis -- Kleypas, J.A.,
McManus, J.W.
<br>>and
<br>> >Menez, L.A.B., 1999. Environmental limits to coral reef development:
<br>> Where do
<br>>we
<br>> >draw the line? American Zoologist, 39(1): 146-159. Maximum
reef depth
<br>> shoals
<br>> >dramatically at higher latitudes, even within the thermal mixed
layer. This
<br>> >presumably reflects light limitations due to sunangle and day lenght
<br>>variations
<br>> >-- which aren't going to change.
<br>> >3. Carbonate saturation state decrease is squeezing from the
high latitude
<br>> >sides -- see the US National Assessment,
<br>> ><a href="http://www.cop.noaa.gov/pubs/coastalclimate.PDF">http://www.cop.noaa.gov/pubs/coastalclimate.PDF</a>,
section 4.4.
<br>> >
<br>> >So there is little basis for optimism there.
<br>> >
<br>> >With acknowledgment of the terminological problems, some form of
<br>> >adaptation/acclimatization probably does have real potential to
ensure the
<br>> >survival of corals , but not necessarily "reefs as we know them."
The
<br>> Ware
<br>>et
<br>> >al article and its precursor, Buddemeier, R.W. and Fautin, D.G.,
1993. Coral
<br>> >Bleaching as an Adaptive Mechanism: A Testable Hypothesis. BioScience,
43:
<br>> >320-326, are looking more solid as experimental tests come in (Kinzie
et al
<br>>in
<br>> >Biol. Bull. earlier this year, Baker in Nature more recently), but
for some
<br>> >reason this concept has been anathema to some reef cology and conservation
<br>> >types. (see also Buddemeier, R.W., Fautin, D.G. and Ware,
J.R., 1997.
<br>> >Acclimation, Adaptation, and Algal Symbiosis in Reef-Building Scleractinian
<br>> >Corals. In: J.C. den Hartog (Editor), Proceedings of the 6th International
<br>> >Conference on Coelenterate Biology (16-21 July 1995, Noordwijkerhout,
The
<br>> >Netherlands). National Museum of Natural History, Leiden, pp. 71-76
for a
<br>> >related issue). This may be because it is seen as diminishing
the
<br>>seriousness
<br>> >of the bleaching problem, but in my view your position is the more
valid --
<br>> >without some mechanistic reason to believe that corals CAN survive,
there is
<br>> >very little justification for investing money in research and conservation.
<br>> >
<br>> >This also relates to my tired old hobby horse of the non-reef coral
<br>> habitats
<br>>--
<br>> >I don't think we are getting the real picture, or doing ourselves
any
<br>> favors,
<br>>by
<br>> >exclusive concentration on reefs; corals have survived many periods
of
<br>> >non-reef-building, and we had better figure out how, why and where.
<br>> >
<br>> >Thanks for bringing this up.
<br>> >
<br>> >Bob Buddemeier
<br>> >
<br>> >
<br>> >Jim Hendee wrote:
<br>> >
<br>> >> Dear Coral Colleagues,
<br>> >>
<br>> >> I know I'll get raked over the coals on this (especially because
I don't
<br>> >> have all the literature at my fingertips), but the content and
tone of the
<br>> >> news article below is troublesome to me, even though such a tone
helps to
<br>> >> gain attention, as well as funding, so that we can more thoroughly
study
<br>> >> the problem of coral bleacing and global warming. Of course
I respect our
<br>> >> colleague's right to a viewpoint, but when I see this, I can't
help but
<br>> >> have these thoughts:
<br>> >>
<br>> >> Such a projection gives no "credit" to adapatation and natural
selection,
<br>> >> even though such adaptation would have to occur under a relatively
short
<br>> >> time span (50 years). I believe Ware et al (1996), among
others, have
<br>> >> addressed this.
<br>> >>
<br>> >> As Dr. Al Strong and I have discussed, and as alluded to but unfortunately
<br>> >> not expanded upon in the last sentence of the article, if the
seas are
<br>> >> warming, then you might expect the zoogeography of corals to expand
<br>> >> (relocate?) into the cooler areas, as long as the substrate, circulation,
<br>> >> light and water quality regimes are conducive. (I would
imagine some
<br>> >> coral researchers have modeled these possibilities, and I apologize
for
<br>> >> not referencing your work.)
<br>> >>
<br>> >> Even though high sea temperatures are the primary cause and indicator
of
<br>> >> coral bleaching, that is not the only cause, and no credit is
given to the
<br>> >> evidence in the literature (e.g., Lesser 1996, among others) that
high UV
<br>> >> is also an agent in coral bleaching. Higher UV, especially
in the
<br>> >> tropics, is part of the problem as it relates to the earth's ozone
layer.
<br>> >> There is evidence that high sea temperatures that elicited coral
bleaching
<br>> >> at some localities in the past did not elicit coral bleaching
during
<br>> >> extended cloudy periods (Mumby et al, in press). (Perhaps the
cooler areas
<br>> >> mentioned in the above paragraph might also have lower UV?)
<br>> >>
<br>> >> There are other causes of coral bleaching (e.g., see Glynn 1993,
1996) and
<br>> >> this manifestation of stress is complex and to my mind public
statements
<br>> >> on coral bleaching should emphasize this.
<br>> >>
<br>> >> Would an annual update to the ITMEMS statement on coral bleaching
<br>> >> (<a href="http://coral.aoml.noaa.gov/bulls/ITMEMS-bleach.html">http://coral.aoml.noaa.gov/bulls/ITMEMS-bleach.html</a>)
be helpful for the
<br>> >> public in this regard? It is my opinion that it would, that
we should
<br>> >> address the topics above (among others, e.g., coastal effects),
and that
<br>> >> it would behoove us to widely circulate the update among the press
as a
<br>> >> consensus opinion (if that is possible!).
<br>> >>
<br>> >> Just my two cents worth...
<br>> >>
<br>> >> Cheers,
<br>> >>
<br>> >> Jim Hendee
<br>> >> NOAA/AOML
<br>> >> Miami, FL
<br>> >>
<br>> >> Glynn, P. (1993). Coral reef bleaching: ecological perspectives.
Coral
<br>> >> Reefs 12, 1-17.
<br>> >>
<br>> >> Glynn, P. (1996). Coral reef bleaching: facts, hypotheses and
<br>> >> implications. Global Change Biology 2, 495-509.
<br>> >>
<br>> >> Lesser, M.P. (1996). Elevated temperatures and ultraviolet
radiation
<br>> >> cause oxidative stress and inhibit photosynthesis in symbiotic
<br>> >> dinoflagellates. Limnol Oceanogr. 41(2): 271-283.
<br>> >>
<br>> >> Mumby, P.J., Chisholm, J.R.M., Edwards, A.J., Andrefouet, S. &
Jaubert, J.
<br>> >> 2001. Cloudy weather may have saved Society Island reef corals
during the
<br>> >> 1998 ENSO event. Mar Ecol Prog Ser (in press).
<br>> >>
<br>> >> Ware, J.R., Fautin, D.G., & Buddemeier, R.W. (1996). Patterns
of coral
<br>> >> bleaching: modeling the adaptive bleaching hypothesis. Ecological
<br>> >> Modelling 84, 199-214.
<br>> >>
<br>> >> -------- Original Message --------
<br>> >>
<br>> >> World coral reefs to die by 2050, scientist warns
<br>> >> By Ed Cropley, Reuters
<br>> >> Thursday, September 06, 2001
<br>> >>
<br>> >> GLASGOW, Scotland — The world's coral reefs will be dead within
50 years
<br>> >> because of global warming, and there is nothing we can do to save
them, a
<br>> >> scientist warned Wednesday.
<br>> >>
<br>> >> "It is hard to avoid the conclusion that most coral in most areas
will be
<br>> >> lost," Rupert Ormond, a marine biologist from Glasgow University,
told a
<br>> >> science conference. "We are looking at a loss which is equivalent
to the
<br>> >> tropical rain forests."
<br>> >>
<br>> >> Only the coral reefs in nontropical regions such as Egypt stand
any chance
<br>> >> of lasting beyond 2050, Ormond said, but even the days of the
stunning
<br>> >> marine parks of the Red Sea are numbered as sea temperatures continue
to
<br>> >> creep up.
<br>> >>
<br>> >> In the past, reefs have suffered from sediment buildup and the
<br>> coral-eating
<br>> >> crown-of-thorns starfish, whose numbers have exploded due to the
<br>> >> over-fishing of their predators.
<br>> >>
<br>> >> Now the main threat to the delicate structures that harbor some
of
<br>> nature's
<br>> >> most stunning creations comes from warmer seas, which cause coral
<br>>bleaching.
<br>> >>
<br>> >> Microscopic algae that support the coral polyps cannot live in
the warmer
<br>> >> water, and the polyps, the tiny creatures who actually create
the reefs,
<br>>die
<br>> >> off within weeks.
<br>> >>
<br>> >> Scientists agree the world's oceans are now warming at a rate
of between
<br>>one
<br>> >> and two degrees Celsius every 100 years due to the increased amounts
of
<br>> >> greenhouse gases in the atmosphere which trap the sun's rays.
<br>> >>
<br>> >> But even if humans stopped pumping out greenhouse gases such as
carbon
<br>> >> dioxide tomorrow in a bid to halt the process, it would still
be too
<br>> >> late to
<br>> >> save the reefs, Ormond said. "I don't know what can be done, given
that
<br>> >> there's a 50-year time lag between trying to limit carbon dioxide
levels
<br>>and
<br>> >> any effect on ocean temperature," he told the conference, held
by the
<br>> >> British Association for the Advancement of Science.
<br>> >>
<br>> >> The implications stretch far beyond the death of the colorful
coral
<br>> >> structures themselves. The weird and wonderful eels and fish which
inhabit
<br>> >> the nooks and crannies will become homeless, and many species
will die
<br>> out.
<br>> >> "We are looking at a gradual running down of the whole system.
Over time,
<br>> >> the diversity of coral fish will die," Ormond said.
<br>> >>
<br>> >> Humankind will also suffer directly as the dead reefs are eroded
and
<br>> >> shorelines that have been protected for the last 10,000 years
face the
<br>>wrath
<br>> >> of the oceans without their natural defenses.
<br>> >>
<br>> >> In an age of relatively cheap scuba-diving holidays, this also
means many
<br>> >> developing countries in the tropics, such as Kenya or those in
the
<br>> >> Caribbean, face losing a major source of revenue.
<br>> >>
<br>> >> The only cause for optimism was that new coral reefs could start
to emerge
<br>> >> in colder waters such as the north Atlantic Ocean and Mediterranean
Sea.
<br>> >>
<br>> >> Copyright 2001 — Reuters
<br>> >>
<br>> >> ~~~~~~~
<br>> >> For directions on subscribing and unsubscribing to coral-list
or the
<br>> >> digests, please visit www.coral.noaa.gov, click on Popular on
the
<br>> >> menu bar, then click on Coral-List Listserver.
<br>> >
<br>> >--
<br>> >Dr. Robert W. Buddemeier
<br>> >Kansas Geological Survey
<br>> >University of Kansas
<br>> >1930 Constant Avenue
<br>> >Lawrence, KS 66047 USA
<br>> >Ph (1) (785) 864-2112
<br>> >Fax (1) (785) 864-5317
<br>> >e-mail: buddrw at kgs.ukans.edu
<br>> >
<br>> >
<br>> >~~~~~~~
<br>> >For directions on subscribing and unsubscribing to coral-list or
the
<br>> >digests, please visit www.coral.noaa.gov, click on Popular on the
<br>> >menu bar, then click on Coral-List Listserver.
<br>>
<br>>Dr. Robert W. Buddemeier
<br>>Senior Scientist, Geohydrology
<br>>Kansas Geological Survey
<br>>University of Kansas
<br>>1930 Constant Avenue
<br>>Lawrence, KS 66047
<br>>USA
<br>>ph (785) 864-2112; fax (785) 864-5317
<br>>email: buddrw at kgs.ukans.edu
<br>>
<br>>~~~~~~~
<br>>For directions on subscribing and unsubscribing to coral-list or the
<br>>digests, please visit www.coral.noaa.gov, click on Popular on the
<br>>menu bar, then click on Coral-List Listserver.</blockquote>
<p>--
<br>Dr. Robert W. Buddemeier
<br>Kansas Geological Survey
<br>University of Kansas
<br>1930 Constant Avenue
<br>Lawrence, KS 66047 USA
<br>Ph (1) (785) 864-2112
<br>Fax (1) (785) 864-5317
<br>e-mail: buddrw at kgs.ukans.edu
<br> </html>
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