Color Differences Within Species

[Anya]

Dear Tom

Coral colours are mainly due to tissue pigments - the greens, white, yellow
and red colours are from UV fluorescent pigment proteins; blues, pinks and
some reds are due to related non fluorescent pigments. A good web site on
coral fluorescent pigmentation and relevant references is by Charles Mazel
at http://www.nightsea.com.

I and my collegues recently showed that fluorescent pigmentation in corals
can protect them from excessive sunlight, results described in paper
"Fluorescent pigments in corals are photoprotective" Nature, DEC 14 2000;
408 (6814) : 850-853.

Given that light is important in the way corals are affected by many
stresses, pigmented morphs which can screen themselves and their
photosynthetic symbionts from excessive sunlight are less susceptible to
various stresses eg. during mass coral bleaching we found that fluorescent
corals bleached less than non fluorescent morphs.

My surveys on Australian reefs showed that almost all coral species have
several colour morphs, either visibly or fluorescently pigmented, or both,
but we are only beginning to understand the function and causes of such
high polymorphism on reefs. There is a probably a higher metabolic cost
associated with production of pigments, and these morphs are slower
growing, but pigmentation affords them higher protection during stressful
conditions. their non pigmented conspecifics may be more competitive by
growing faster when conditions are stable but are more susceptible during
stressful events.

Anya Salih




>Greetings-
>        I am a graduate student at Texas A&M at Corpus Christi.  I plan to
>complete an internship for a M.S. degree in Mariculture this summer.  I
>have a question concerning color of corals.  Why do corals within the
>same species have different colors?  For example, variations of Sinularia
>sp. or Sarcophyton sp. are commonly observed to be green, brown, white,
>yellow or many other colors.
>        Any feedback would be greatly appreciated!
>
>Thanks
>Tom Gray
>~~~~~~~
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Anya Salih                      Email:          anya at emu.usyd.edu.au
Electron Microscope Unit        Telephone:      02-93517540
Madsen Building FO9             Facsimile:      02-93517682
The University of Sydney
Sydney, 2006, AUSTRALIA


~~~~~~~
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.