what is the real color of a clam?

[basser1]

Hello All, I have an ORA crocea maxima that I bought recently form my LFS. How can you tell what the real color is? I've noticed mine looks different depending on how you look at it. Straight on it looks purpleish, while overhead it looks more turquoise blue. Thanks

[skinz78]

real color is from the top down

[a4twenty]

actually the beautiful color we see from above is the reaction of the zooxanthellae to the light. the true color of the zoox is actually brown. that is why when you look from the side where the mantle is not getting direct light the colors look duller and closer to a brown rather than the colors we see from above.

[mscarpena]

Top looking down on it.

[reefkoi]

<a href=showthread.php?s=&postid=11234132#post11234132 target=_blank>Originally posted</a> by a4twenty
actually the beautiful color we see from above is the reaction of the zooxanthellae to the light. the true color of the zoox is actually brown. that is why when you look from the side where the mantle is not getting direct light the colors look duller and closer to a brown rather than the colors we see from above.

huh never heard that theory before, care to expand on the zoox reaction to light?
I had heard the colors we see is from reflective pigments, I remember that Dana Riddle gave a lengthy talk on how they have identified hundreds if not thousands of reflective pigment colors, they actually have a chart and records of each of these pigments identified, such as "green 560" e.t.c. I agree that zoox is brown and brown only.

I think when viewed from the top it looks different because you are getting the "reflection" of the pigments direct from the bulb and not any other light source.

Maybe there is another theory I haven't heard of?

[a4twenty]

<a href=showthread.php?s=&postid=11235209#post11235209 target=_blank>Originally posted</a> by reefkoi
huh never heard that theory before, care to expand on the zoox reaction to light?

Maybe there is another theory I haven't heard of?


no its the same theory, the clam and the zoox both produce pigments. the pigments produced by the clam are used mostly to act as a sun screen and protect the clam while the pigments produced by the zoox are used for photosynthesis.

as you said the pigments are as individual as 'green 560' ( or as individual as the zoox ) and each pigment utilizes a different part of the spectrum for photosynthesis, reflecting what it can't use. the reflected light may even be able to be utilized by a neighboring pigment, reflecting an even narrower part of the spectrum giving off a completely different color. this is why you hear people say their clam looks different than from in the store. different light source = different spectrum = different looking clam


the color we see from above is a mixture of the reflected light from the photosynthetic pigments. the less light, the more brown the clam will appear because there is nothing to reflect. just like in bassers case the color goes from turquoise to a purplish color going from top down to from the side.

[reefkoi]

Thanks for the info, I wonder why a crocea will sometimes look blue from the side yet green from the top? Do you suppose it is the light from the room we are in reflecting sideways? or the tank light reflecting off the glass somehow?
C

[a4twenty]

<a href=showthread.php?s=&postid=11238414#post11238414 target=_blank>Originally posted</a> by reefkoi
Thanks for the info, I wonder why a crocea will sometimes look blue from the side yet green from the top? Do you suppose it is the light from the room we are in reflecting sideways? or the tank light reflecting off the glass somehow?
C
from both, the combination of the room light and the weakened and reflected spectrum of the tank lighting will make the clam look different. the 'pop' we get when looking down on the clam is from reflective iridophores that are produced by the mantle. they act as light intensifiers for the clams eyes and work as a sunscreen on the rest of the mantle to protect the clam from the strong light.

[s ruppa]

unless you have starphire glass, regular aquarium glass has a green tint to it.

steve

[reefkoi]

James Fatheree told me that all clams lose the iridiphores once they are in our tanks. Thats why they lose that initial "sheen" they have after being freshly plucked out of the ocean.
C

[a4twenty]

<a href=showthread.php?s=&postid=11242906#post11242906 target=_blank>Originally posted</a> by reefkoi
James Fatheree told me that all clams lose the iridiphores once they are in our tanks. Thats why they lose that initial "sheen" they have after being freshly plucked out of the ocean.
C

i'm not to sure about that. here is a close up pic of a gigas mantle.


http://reefcentral.com/gallery/data/500/109536gigasiridophores.jpg

it is my understanding that the beautiful green surrounding the eyes on this gigas is a result of the iridophores. James sometimes comes through here, maybe he can give us the answer?

[RiddleLabs]

Aloha all,

Interesting topic - here's the scoop. Tridacna's mantles are layer and these have different refractive indices. That's why they appear most colrful from the top, but appear to lose their color as the viewing angle changes. As the clam grows, the mantle become thicker, and it is possible for the coloration patterns to change. American Scientist did a short article on this subject about 10 years ago. So, in a nutshell, Tridacna coloration is completely different phenomenon than any known 'coral' coloration.

Dana

[reefkoi]

That's awesome thanks for chiming in Dana! Your answer makes perfect sense to me.
Thanks
Chris

[a4twenty]

very interesting, the only thing i don't get is why even when the mantle is folded over the edge of the clam so the viewing angle ( our eyes perpendicular to the mantle ) is the same, the color is still different.

oh well, i'm off in search of this article ( any idea's where to look ), i love reading this stuff :spin3:

[basser1]

Been out of town for a few days and read the responses tonight. Very good info everyone! I enjoyed reading them.

[NanoReefWanabe]

though the "green' of standard annealed glass plays a slight role in the colour of the clam...i have to agree it has to do with reflective/refractive properties of light on the mantle...my clam is quite brownish purple from the front...and very turquoise and blue from the top...however at night when i am critter hunting, and i hit my clam with the flashlight(just white light, as i see better with it)...he lights up nice and blue and turquoise...

i break out the red light if i see something i really dont like..critter wise.

[LockeOak]

Another interesting aspect is that in corals the zooxanthellae are actually intracellular, that is, they exist within the coral host cells. In tridacnids they exist intercellularly, between the host clam cells. Just one of those random facts :)

[rckrzy1]

<a href=showthread.php?s=&postid=11262081#post11262081 target=_blank>Originally posted</a> by NanoReefWanabe
though the "green' of standard annealed glass plays a slight role in the colour of the clam..

SLIGHT ? Not when viewing a green crocea , mine looks totally purplish and blue through the nasty green glass but from above is dazzling green. I'm ordering a starphire tank with my xmas money.