Zooxanthellae only comes in one color.

[Kalkbreath]

To illustrate just how silly many of the die hard urban rumors in reef tank keeping are ..........
I would be interested in many of your responses regarding the silly notion that corals and clams are brightly colored due to the zooxanthellae inside their tissues.
Kalk bashing is encouraged...........

 

[Anonymous]

First, you should make a statement regarding why this rumor is incorrect.

Louey

 

[mkirda]

Kalk bashing is encouraged...........

Why bash you for stating something inherently factual?
There is talk that different clades have different shades, but the colors come from pigments in the corals, not the zooxanthellae. In Acropora, the most brightly colored parts are typically the tips. These areas are typically as yet uncolonized by zooxanthellae.

Regards.
Mike Kirda

 

[Kalkbreath]

how bout giant clams or a red brain coral?

 

[mkirda]

how bout giant clams or a red brain coral?

Are you offering to give me one of each, or are you asking me if the color of zooxanthellae change depending on the host species?

If the first, don't want them, donate them to a local club for a raffle.
If the second, I already answered. There might be slight variations based on clades- this was being debated a bit based on reading the papers a couple of years back, however, unless something major has come up in the past couple of years on zooxanthellae, they are all basically some shade of golden brown. The colors seen on corals or clam mantels are pigments inside the tissue of the coral or clam.

Regards.
Mike Kirda

 

[mkirda]

Seems like Marine Biology 101 material...

Mike

 

[Kalkbreath]

Seems like you have done your home work.
But do you even realize that ninty percent of the hobby including store owners, wholesalers and even collectors dont know this basic simple truth ?

 

[mkirda]

Seems like you have done your home work.
But do you even realize that ninty percent of the hobby including store owners, wholesalers and even collectors dont know this basic simple truth ?

I don't know where you got the 90% figure.
I'll give you that a lot of people confuse pigments, and think that they come from the Zooxanthellae rather than the host animal. For all practical purposes, it really doesn't matter much if you don't understand that the pigments for coloration exist within the host's tissue or the zooxanthellae themselves.

One probably reason for the misunderstanding is that they understand "bleaching" (unrelated to thread on Clorox) involves the expulsion of zooxanthellae, and they know the coral turns "white", so assume the color is in the zooxanthellae themselves. Bleaching doesn't typically involve 100% zooxanthellae expulsion anyway... Some always remains. But pigments are also expelled, for reasons that remain somewhat unclear. That part isn't covered in the journals as much, and pigments have not really been studied in depth, especially when compared to zooxanthellae.
Bleached corals retain some of the original coloration, but usually in a much lighter shade.

A thorough discussion of this would probably start in a 400 level course.

Regards.
Mike Kirda

 

[Kalkbreath]

There is even good evidence that the Dinoflagellates (Zoox)are not expelled, but that they actually leave on there own will!
That is they literally take flight and leave the host coral or clam.
Support for this notion is found in the existance of regrown flagellum tails on the "expelled"zooxanthelae . The tiny algae regain the ablity to swim prior to leaving the host by regrowing flagellum and becoming motile. 8O