[Coral-List] Coral ecology questions

Barbara Gratzer barbaragratzer at gmail.com
Mon Jul 29 12:50:28 EDT 2013

Dear all,

Lately I came across some open questions within coral ecology and hope for
some answers here:

1. I thought corals possessing colours have many GFP like proteins.  Now I
have discovered several acroporid finger-corals with purple colour that are
not fluorescent. Do you know why? Does GFP like protein not necessarily
mean they are fluorescent or does the colour derive from other proteins?
And why do some colours not possess colouration but are highly fluorescent
in contrast to others?
2. What's exactly the purpose of being fluorescent. I know the pigments
causing fluorescence are thought to act either as protection from
stress/sunlight or as enhancer for symbiodinium to increase photosynthesis,
but is it just a coincidence that they are fluorescent at the same time? I
dont understand the correlation.
3. Whats the purpose of different fluorescent light levels? Most of the
corals emmit green and yellow light and very few emmit red light. Is it
caused by the proteins or does it have something to do with different
photosynthetic active pigments?
4. Within our coral nursery I have come across several Acropora species
(especially purple coloured) that lost their original colour after being
transplanted and only had a bright brown colour after 6 month. Is that a
process caused by stress? Whats the purpose?
5. How old can one single polyp within a colony grow? And whats the oldest
still growing coral colony found so fare?
6. Is there any intracellular structural change of polyps within a table
coral colony (some corals sit on the trunk and their shape is completely
different from polyps on the top)?
7. What causes the biorhythm of corals regarding when to extend their
tentacles and when not? Sometimes I see Fungia with extended polyps during
the night, sometimes during the day, some corals with Zooxanthellae extend
their polyps during daytime only, although it seems to be more efficient
during night to catch plankton... etc.
8. After the event of bleaching: how long does a polyp survive without
9. Are there any studies being made about what effect touching/skin has on
corals? I have only been reading so many times to avoid contact with skin
because of additional stress for corals but are there actual numbers to
that statement?

I am looking forward to getting some answers and thank you in advance,


~~~ Σ^^°> ~~~
Barbara Gratzer  MSc
Resident Marine Biologist
Huvafen Fushi Resort per PerAquum
Republic of Maldives
marine.biologist at huvafenfushi.com


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