Reef Bleaching

[Fishteacher73]

I though I would bring out an issue that does not seem to have much attention shown upon it. The bleaching of coral reefs. Bleaching is when corals expell their zooantelae (the photosynthetic organisms that live in corals) turning the coral pretty much white. The coral the dies becaus it has lost its food source. There are a few theories concerning why this occurs. (It will occur across a reef across species and genera at the same time). One theory is water temp increases. This can be shown in a lab to cause isolated bleaching, but it usually does not affect all the test organisms. Another is polution (predominately organo-phosphates). This too can cause isolated bleaching, but not systemic bleaching.

 

There are trees that produce warning pheromones when they are swarmed by insects that casue the other trees (of the same species) do something (I can not seem to remember and can not find a source.. ;) ) that makes them less appetizing to the swarming insects. Could this be a possiblity, a pheromonal responce to the stress?

 

Any oner ideas?

[Tormod]

Is the heating of the water (if this is the cause) related to global warming?

 

As for the second part (about the trees) I don't quite get it. Is it a different topic?

[Fishteacher73]

Increasing water temps are belived to be linked to global warming, subltle shifts in currents, etc.

 

Ther tree idea was put forth as a correlary example to extrapolate that possibly that the bleaching effect could possibly be induced by the corals themselves by realsing pheremones (possibly, just an idea) that induce the bleaching sequence.

 

Also lunar paterns and photoperiods are used to induce mass release of gametes for sexual reproduction. (Many different genera actually will actuall all spawn on the same night). The point here is that many different species on the reef are intertwined and use each other's processes for their own advanteges. (The mass psawning reuces predation of the gametes by a dilution effect).