[Coral-List] bleaching and acidification

Xinping Hu xhu at uga.edu
Mon Feb 23 10:58:05 EST 2009

Hi Charles,

I think you are right about the factors that control coral calcification. That is pH is only one part of the story. So comparison between an artificial aquarium with natural environments in terms of pH impact seems to me a little stretched even though there were indeed species-specific responses that have been observed in the tank. 
>From a chemist's point of view, as far as the ocean acidification is concerned, pH decrease caused by OA is accompanied by virtually no change in alkalinity in natural seawaters in the short term (which means no extra carbonate is being dissolved or the dissolution effect is not shown on alkalinity inventory yet), therefore OA results in a decrease in carbonate ion concentration, thus saturation index.  

Xinping Hu
Post-Doctoral Associate
Department of Marine Sciences
The University of Georgia
Athens, GA 30602

Message: 2
Date: Sat, 21 Feb 2009 14:06:38 -0800
From: "Delbeek, Charles" <cdelbeek at calacademy.org>
Subject: Re: [Coral-List] bleaching and acidification
To: "David Vaughan" <dvaughan at mote.org>
Cc: coral-list at coral.aoml.noaa.gov
	<D6A836974C189D4AAFB7BBC34FA2BF6CE452F2 at yoshi.calacademy.org>
Content-Type: text/plain;	charset="us-ascii"

The Waikiki Aquarium water successfully grows several dozen species of
Acropora from Palau, Guam, Vanuatu, Solomon Islands, Fiji and Hawaii. About
25 years ago we had a small piece of Acropora palmate that never grew much
and eventually died. It seems that in closed systems as well, Caribbean
Acropora is more delicate than many of the Indo-Pacific species.

The incoming water pH in the tanks is around 7.8 however, photosynthesis by
the algae in the system most likely, results in effluent water having a pH of
8.0-8.2. The water is also high in nitrogen, phosphorous, manganese, iron,
silicate etc etc ... but very low in organics as pointed out by Bill.

Marlin once commented that while WAQ water had a high CO2 content, the
calcium saturation state was quite high and led him to dub it "magic water"
based on how it could grow many soft and hard corals despite the high
nutrient levels. I believe he later showed in work at Biosphere II that high
alkalinity would allow calcification at high nutrient levels, again it has
been published but I don't have the reference handy.


J. Charles Delbeek, M.Sc.
Senior Aquatic Biologist, Steinhart Aquarium
California Academy of Sciences
55 Music Concourse Dr.
San Francisco CA 94118

phone (415) 379-5303
fax (415) 379-5304
cdelbeek at calacademy.org

-----Original Message-----
From: David Vaughan [mailto:dvaughan at mote.org] 
Sent: Friday, February 20, 2009 8:09 AM
To: Delbeek, Charles
Cc: coral-list at coral.aoml.noaa.gov
Subject: Re: [Coral-List] bleaching and acidification

To All,
    The source of saltwater at the Mote Marine Laboratory, Tropical 
Research Lab in the Florida Keys is also an 80 ft. deep saltwater 
well.   This water is also high in Hydrogen Sulfide (H2S), and CO2.  We 
can easily degass  most of the H2S but it takes some additional time to 
degass all of the CO2.  Our water starts off at about pH 7.4 and after a 
short time in our aeration chamber, the pH is increased to about 
7.6-7.8.   It takes longer to reach 8.1 or 8.2, in which we keep all of 
our indoor coral tanks. Our outdoor flow-through raceways have been run 
at the 7.6-7.8 pH levels in outdoor sunlight with hard corals for many 
years.  However,  the results seem to be species specific.   The 
Acropora species (/A. palmata, A. cervicornis)/ do not grow well or 
survive long.   The /Montastraea ( M. cavernosa, M. annularis) s/eem to 
survive fair, but grows slower than the inside tanks.  But the  /Oculina 
/species (/O. diffusa, O. robusta/) seem to do very well, and grow 
fast.  This may be an indication  of why we are loosing our /Acropora 
/in the wild and what to expect of other species in the near future. 
    The good news is that we have a very nice experimental design 
potential, with having large scale flow-through raceways that could be 
controlled at different pH levels for long term ocean acidification 
experiments.  We could selectively control individual tanks using a pH 
monitor to control the amount of time water is degassed of CO2 before 
entering the raceway and therefor have one tank at7.4, one at  7.6 one 
at 7.8,  8.0, etc.   This would allow for some larger-scaled studies for 
longer periods of time and under natural sunlight conditions.  Anyone 
interested in setting up experiments at our Laboratory, can contact me 
for space or information about coral projects and experiments.  For 
information about the lab capabilities see the following link:  

Dave Vaughan,
Executive Director, Mote Tropical Research Lab
Center for Coral Reef Research, Summerland Key, Florida, USA 33042
(305) 745-2729 ext 202.
DVaughan at Mote.org

Delbeek, Charles wrote:

> > The source of saltwater at the Waikiki Aquarium is an 80ft deep saltwater
> > well. This water is high in dissolved nitrogen and CO2 so is heavily

> > in an adjacent aeration chamber before it is used. The pH is around 7.8 on
> > exit from the aeration well, and is used in all their live coral exhibits

> > the corals grow extremely well. Dr. Marlin Atkinson at U of Hawaii has
> > published a few papers on this system in the 1990s and Dr. Bruce Carlson

> > published a paper in the late 90's on the growth rate of the coral in this
> > water. Perhaps they can chime in with the references which I do not have
> > handy at the moment. 
> >
> > I have always found it puzzling why more researchers have not investigated
> > the corals and giant clams that have been grown in this water at this
> > facility for over 30 years, since it seems to present the possible future
> > situation of our ocean water.
> >
> > Cheers!
> >
> > J. Charles Delbeek, M.Sc.
> > Senior Aquatic Biologist, Steinhart Aquarium
> > California Academy of Sciences
> > 55 Music Concourse Dr.
> > San Francisco CA 94118
> >
> > phone (415) 379-5303
> > fax (415) 379-5304
> > cdelbeek at calacademy.org
> > www.calacademy.org


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