[Coral-List] Re: Coral-List Digest, Vol 27, Issue 20

Charles Birkeland charlesb at hawaii.edu
Fri Sep 23 13:00:35 EDT 2005


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 

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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> Today's Topics:
>   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>
> Content-Type: text/plain; charset=windows-1252
> 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 
> 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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