[Coral-List] when do we decide a coral is bleaching ?
mpoulicek at ulg.ac.be
Tue Mar 20 06:13:49 EDT 2007
Bonjour à tous,
I was asking myself if anybody already put a
limit to what we call "bleaching" ?
Coral regularly expell zooxanthellae that are
found in the mucus sheets close to the "feet" of
the colonies. This probably constitutes a
regulation behaviour correlated to the algae
division rates in order to keep a stable
symbiotic population. From an experimental point
of view, we can measure that the expelling rate
varies according to different not well understood factors (to my knowledge).
When does this behaviour begin to be pathologic ?
The zooxanthellae content of a given colony can
fluctuate in "normal" conditions.
Some situations are obvious, when the coral loose
a great part of its algae content and "bleach
clearly" but some other are much less clear.
Is there a formal "definition", some limits clearly defined ?
What do YOU think about that limit ?
I am waiting your returns.
Have a nice day,
Bonne journée à tous,
PS If there is interest I can put a digest of answer on the list later.
Dr Mathieu POULICEK, Chargé de cours adjoint
Coordinateur départemental ERASMUS Biologie
Tel lab : 32- (0)4 -366.50.67 Tel. prive : 32- (0)4 -355.06.74
Fax : 32- (0)4 -366.51.47
e-mail: mpoulicek at ulg.ac.be
Unite d'Ecologie Marine, Laboratoire
d'Ecologie animale et d'Ecotoxicologie,
Département des Sciences et Gestion de l'Environnement,
Institut de Chimie B6C, Universite de Liege
Allée du 6 août, 15
Sart Tilman, B-4000 Liège (Belgique)
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