Frogspawn Zooanthallae

[flaunt]

Just a curious question here.

I recently aquired a frogspawn frag from a local reefer, and I noticed something. In his aquarium, when the frogspawn was viewed from the side of the tank, there was no noticeable green color. When viewed from above, however, lots of green was visible. I didn't think a whole lot of it at that time other than to think it was interesting. I got home, stuck it in my aquarium, and thought it was strange that I was able to see the green color from the side of my tank. I wrote it off as having something to do with the lighting since he used hallides and I used a combination of PC and VHO. Well, over the course of the several weeks I've had the frag, the green color slowly disappeared when viewed from the side of the tank, but it is visible from the top, just like in the tank of the guy from whom I got it.

This is what I think is going on; hopefully someone can confirm it or give a different explanation. It's pretty simply I guess: The zooanthallae in the body of the frogspawn are simply aligning themselves such that they gets maximum exposure to the light source. Does that sound reasonable? The only problem with that explanation is why would the zooanthallae only grow in those areas exposed to the most light? The sides of the tentacles should still get enough indirect light to allow them to survive? Strange creatures, corals are.

[saltshop]

FWIW, zooxanthellae have basically one color and that is golden brown. The green color is from a pigment produced by the coral. It is entirely possible/likely that the coral is producing the pigment in one area and not a more shaded one. Pigmentation can be used to help reflect back some light as a photoprotective response(showing you the color as it reflects back), or can be used to enhance photosynthesis by bouncing light back up into the zooxanthellae, and some of it is just plain genetics. As far as zooxanthellae alignment is concerned, they are most likely throughout the tissue anywhere it receives light with a density of approx. one cell layer thick.

Another possibility could just be the placement/configuration of the coral causing most of the light to be reflected straight up and not towards the glass. For instance, most clams look like they have much better coloration when viewed from above simply because that is the direction the reflected light goes. The pigments are there regardless of which viewing angle you take, but how the clam actually looks will vary depending on your vantage point.

[ReefDiver]

Yes, I agree that the zoox will orient towards maximum lighting for photosynthesis. I also think that the reason you are seeing more density of color is due to depth of the tissues that you are looking through. Take a typical polyp which contains zoox, now look at it from the side and it will appear lighter than if you look at it from the top. In other words, the zoox appear more numerous when you look down the tube vs. looking sideways across the tube.

[flaunt]

ah makes sense... thanks for the help!