Orange Montastrea cavernosa recruits?

Charles Mazel mazel at
Tue Jul 25 13:49:27 EDT 2000

Mikhail, Iain and others,

Mikhail Matz has kindly pointed to the list of references on the NightSea web stite that I maintain as an adjunct to my research in coral fluorescence (NightSea supplies equipment for observing and photographing fluorescence in situ).  A while back I created a framework for on-line discussion of all aspects of underwater fluorescence - biology, ecology, photography, etc. - but have so far not announced its existence.  I would like to offer that now as a place where people interested in the topic can share infoirmation.  The discussion board is at .  It is admittedly crude, and suggestions for topics/format are quite welcome.

The orange fluorescence in Montastraea cavernosa is not at all uncommon, and is often brighter around the edges, as noted by Iain Macdonald.  In some cases an entire colony is orange, while in still others I have seen orange isolated at just a few polyps in an otherwise green colony.  The same orange fluorescence can be found in a number of other species, although it is usually not as striking as it appears in M cavernosa.  An exception to that is Scolymia sp., which can also occur in intensely orange varieties.  In the cases of both M cavernosa and Scolymia it is common to find orange specimens in close proximity to non-orange specimens, with no obvious difference in the environmental conditions the colonies experience.


Charles Mazel

Charles Mazel
Principal Research Scientist
Physical Sciences Inc.
20 New England Business Center
Andover, MA 01810
(978) 689-0003
(978) 689-3232 (fax)

>>> Mikhail Matz <matz at> 07/25/00 12:33PM >>>
Hi Iain,
we know a little bit what is the substance causing the fluorescence in
and observations, measurements and photos were made about this
(see for the list of related
papers and websites)
Moreover, in particular M.cavernosa fluorescence was measured (in situ)
by Charles Mazel
and is studied by me (in vitro) right now.

However, so far we have absolutely no clue as to the function of this
fluorescence in
nature (if we forget for a moment about older hypotheses all of which
seem wrong by now),
and the subject is my primary interest. Your observation is, as far as I
know, the first
information which might help to link fluorescence to some aspect of coral
ecology. I would be
extremely grateful if you could provide some more details on your
* I would like to ask all coral listers as well - perhaps you saw
something like Iain? Anything
which could give a hint about the function of fluorescence? Or perhaps I
simply missed something
in literature?
*** best wishes,

Mike Matz

Iain Macdonald wrote:

> During a recent field trip i noted the following along my transects.
> M. cavernosa recruits (i use the plural as this was seen three
> different times), of only one polyp was noted at approx. 15-20m depth
> to appear to the unaided eye as fluorescent orange. Close by (ie
> 10cm away) 5 polyps were the typical olive green colour with this
> "day glow" orange colour around its edges. Again a few cms away
> larger colonies 20-25 polyps were only olive green. Is this typical
> for recruits (i think not) or maybe as a result of some stress
> (sediment) stimulus? I was startled to see such colour from this type
> of coral and would like to konw of any other observations.
> Cheers
> Iain Macd.
> Room E402 John Dalton Extension Building,
> Department of Environmental and Geographical Science,
> Manchester Metropolitian University,
> Chester Street,
> Manchester,
> M1 5GD
> Tel: 0161 247 6234
> Fax: 0161 247 6318

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