[Coral-List] bleaching vs. not bleaching
Georgina Bustamante
gbustamante at bellsouth.net
Mon Sep 26 15:02:56 EDT 2005
As I understand, the bleaching vs. not bleaching potential for some coral
spots that some sinctists think can be used for MPA desing has to do with
very local physical conditions (shading, cooling waters, etc.), rather than
to larger scale (or regional) conditions.
However, you are right that this question is still unclear, particularly if
the bleaching resilience (or coral reef areas with milder T conditions) is
strong or long lasting enough to be considered special sources of propagules
and so regarded as refuge areas.
Scientists working on this research question in Australia, Florida and other
areas might be able to answer this question better than me.
Georgina Bustamante, Ph.D.
Marine Science and Policy Consultant
3800 N Hills Dr. #216
Hollywood, Florida 33021
U.S.A.
tel/fax(request) 954-963-3626
-----Original Message-----
From: William Skirving [mailto:William.Skirving at noaa.gov]
Sent: Monday, September 26, 2005 1:16 AM
To: Alan E Strong
Cc: gbustamante at bellsouth.net; Charles Birkeland;
coral-list at coral.aoml.noaa.gov; Scott Heron; Jim Hendee
Subject: Re: [Coral-List] Re: Coral-List Digest, Vol 27, Issue 20
Hi Georgina,
Yes, this is obviously a good question, and it is a good question because it
helps people to recognise that the opposite of a phenomenon we are studying
is just as important as the phenomenon itself. One example of this in
action is that there have been many bleaching reports over the past handful
of years, but very very few "non-bleached" reports in warm water to balance
them with.
The quick answer to your question is that we really don't know enough about
the coral physiology and hence their adaptation/acclimation characteristics
to decide if one region is more or less protected from bleaching in a
changing environment than another. For that matter, even if we were to
assume that we know that the change will be towards a warmer environment,
that doesn't mean that we know enough about a particular region to predict
that the waters in that region will warm up uniformly.
Clearly this type of research is very very important, and your way of
thinking is useful to remind people of the fact that there is another side
to this story, but we are far from knowing enough to know which regions
should and should not be protected based on an understanding of the current
and past local marine climate.
Cheers
William
Alan E Strong wrote:
Hi Georgina,
Great question!!!
You need to get a copy of the latest report we have just submitted to TNC
for a project in Palau to do just what you talk about. We are developing
hydrodynamic models for use in these coastal areas after finding several
years ago with our work on the Great Barrier Reef with some Australian
colleagues that these tools may prove the most useful in identifying areas
withing reef ecosystems that might have more resistance and/or resilience to
bleaching.
Papers are in various stages of progress...
I am coying this to Drs. William Skirving and Scott Heron, our Australian
contractors who helped us develop these models, and am hopeful that they can
give you further guidance...if necessary.
Cheers
Al
Charles Birkeland wrote:
Jim,
That is the focus of much research in American samoa. The reefs there
are so remarkably resilient to multiple disturbances and stresses, we
are trying to determine the mechanisms. Are they acclimatization,
adaptation, small-scale environmental factors or particular
combinations? Abstract (first draft) for the USCRTF meeting reads as
follows:
Long-Term Research in American Samoa on Adjustments of Corals to
Climate Changes
Coral reefs have always been dynamic systems, constantly in a state of
recovery from disparate disturbances that have been a perpetual part
of the environment. In the past three decades, however, a large number
of reefs around the world have lost the ability to recover and have
continued to decline, even after the disturbance has gone. There is a
crucial need for coral-reef management to determine the factors that
promote resilience, the ability to recover, in coral reefs. The coral
reefs of American Samoa (AS) have continued to be remarkably resilient
to large scale disturbances, recovering within about 15 years after a
crown-of-thorns starfish outbreak (1977) and also after two hurricanes
(1990 and 1991), and even more rapidly after widespread bleaching
associated with warm seawater (1994, 2002, and 2003). The corals in AS
have also shown special resistance to local stress in particular
sites. In the shallow backreef moat in the National Park on Ofu
Island, at least 80 species of scleractinian corals withstand brief
but severe fluctuations in water temperature (up to 6.5º C within a
day, reaching 35.5º C), fluctuations in dissolved O2 (15 to 220
percent saturation), and strong UV radiation. The determination of
the mechanisms of resilience of Samoan reefs will provide important
guidance for reef management and for selection of sites for MPAs. In
order to tease out the roles of acclimatization (physiological and
biochemical changes in the corals, and shifts in types of
zooxanthellae), adaptations (genetic changes), and extrinsic factors
(e.g., patterns of water motion), transplant experiments were
undertaken by Lance Smith and Dan Barshis. Smith and Barshis performed
754 reciprocal and controlled transplantations of corals between
stressful and benign habitats. Lance found that both acclimatization
and water motion have significant roles in the resilience of corals in
the Ofu backreef moat. Dan is performing biochemical analyses of the
coral tissues to assess changes in levels of heat-shock proteins,
antioxidants and other chemicals that indicate disruption of
photosynthetic and metabolic processes in time sequences following
transplantation. He is aided by Ruth Gates and Rob Toonen (Hawaii
Institute of Marine Biology) and Jonathan Stillman (San Francisco
State Univ.). Greg Piniak (NOAA) took over 600 determinations of
fluorescence yield of zooxanthellae to estimate how well the
photosynthetic system is working in the symbiotic relation with the
coral community. Changes in phylotypes of zooxanthellae are being
assessed by Andrew Baker (WCS and Columbia University). Virginia
Garrison and Christina Kellogg (USGS) are determining changes in
associated microbial communities on the corals. Adaptation will be
tested by comparing the thermal tolerance of juvenile corals from
planulae originating from adults transplanted from the forereef over a
year before parthenogenic planulation, with thermal tolerance of
juvenile corals from planulae from adults transplanted from the
backreef. Genetic differences from forereef and backreef populations
are also being examined. These experimental studies are within a
backdrop of long-term studies. The first permanent transect in AS that
has been quantitatively monitored to this day was started in 1917.
Some large colonies of Porites have recorded climatic changes in their
skeletons for hundreds of years. The goals of these studies are to
provide an understanding of the sensitivity and adaptability of coral
reef systems to environmental changes so that we can predict the
effects of climate changes, and to provide insight into which coral
reef sites are most important to protect from disruptive human
activities so as to provide broodstock of corals for reef recovery.
----- Original Message -----
From: coral-list-request at coral.aoml.noaa.gov
Date: Friday, September 23, 2005 6:00 am
Subject: Coral-List Digest, Vol 27, Issue 20
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1. Re: no-bleaching data (Jim Hendee)
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Message: 1
Date: Fri, 23 Sep 2005 10:24:03 -0400
From: "Jim Hendee" <Jim.Hendee at noaa.gov>
Subject: Re: [Coral-List] no-bleaching data
To: coral-list at coral.aoml.noaa.gov
Message-ID: <43341003.5090101 at noaa.gov>
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Georgina,
Great thought! Instead of focusing quite so much on where and why
"the sky is falling" on our coral reefs, focus on where and why
(under
apparently similar conditions) the sky is not falling, and protect
thoseareas so they can recruit still larger areas. It will be
interesting to
learn if it is the conditions, or the physiology, or both (most
likely),for areas of non-bleaching where high sea temperature/high
irradiance/whatever models predict bleaching. It sounds like a great
line of research.
Cheers,
Jim
Georgina Bustamante wrote:
I hope observers can also detect (and eventually identify) specific
conditions under which some coral reefs located in areas with
high risk
(high temeperature, etc.) are not bleaching at all. That may
provide useful
information for MPA design and planning.
Georgina Bustamante, Ph.D.
Marine Science and Policy Consultant
3800 N Hills Dr. #216
Hollywood, Florida 33021
U.S.A.
tel/fax(request) 954-963-3626
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Alan E. Strong
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NOAA/NESDIS/ORA/SOCD -- E/RA3 {formerly NOAA/NESDIS/ORA/ORAD}
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