what gives sps their colour?

[mhucasey]

Great concise reply, you make it real easy to understand. Appreciate it.

This is incorrect, unfortunately. Zooxanthellae are brown. They only influence the overall color in that they block your view of the coral pigments, which are produced in the coral tissue. The tips are lighter partially due to lower density of zooxanthellae, but also because the coral has not produced a higher density of pigments in the newly grown area. This misconception that zooxanthellae are multi colored is pervasive but just wrong.

 

[Dugless]

I agree with the pervasive comment. I gathered my knowledge from a few articles online over the years, not from within forum threads where a lot of misinformation lies. As I have clearly proven myself.

At the same time, much of the available information concerning fluorescing pigments is still poorly understood and is very much speculative, or so many of the articles have stated.

 

[mhucasey]

This is a hobby rife with misinformation, but its not just us who are at fault. The NOAA site even repeats this stuff, you'd think they would distribute better info:

"Another byproduct of the symbiotic relationship with zooxanthellae is color. Several million zooxanthellae live and produce pigments in just one square inch of coral. These pigments are visible through the clear body of the polyp and are what gives many reef-building coral their beautiful color."
:facepalm:
Two other common pieces of misinformation:
1)Zooxanthellae are algae. They are in fact a symbiotic Dinoflagellate.

2)"Coral Bleaching" is commonly misapplied to corals that are losing tissue. Actual "bleaching" occurs when the coral ejects its zooxanthellae in response to stress. This reduces the overall coloration of the coral and removes the coral's food source, putting the coral in grave danger of starvation. The coral simultaneously stops producing fluorescing proteins as these require energy to produce. The coral reabsorbs these proteins and there is very little left color wise between the coral and its white skeleton, hence the "Bleached" look. Bleached corals can recover by reabsorbing Zooxanthellae from the water column if they do not starve before they do so.

Here are some very good articles about corals and their color:
http://www.advancedaquarist.com/2005/12/aafeature2
http://www.advancedaquarist.com/2009/1/aafeature1
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB4QFjAA&url=http%3A%2F%2Fwww.advancedaquarist.com%2F2009%2F2%2Faafeature1&ei=2LHTVKu4KI2yogSckoGQCg&usg=AFQjCNEATdUTsfU40bbX_6Hm2mVqC4USFQ&bvm=bv.85464276,d.cGU
http://www.advancedaquarist.com/2009/4/aafeature1

 

[mhucasey]

Some pictures of Zooxanthellae:

 

[Tweaked]

Great info here. Have read it many time elsewhere here and there, but this was a bit easier to understand. Much thanks :thumbsup: