Do corals actually change color under actinic lighting?

Mr. Brooks

MASVC Member
Or do they just look different.

I installed some VHO actinics in my canopy. Some of the corals fluoresce and stand out a bit more. Problem is, these VHO's are HOT. The water temperature is shooting up way quicker then normal. I'm wondering if it's worth while to leave the VHO's in. Will my coral change color? Get brighter? If not, the color difference isn't enough to justify the extra heat.
 

LockeOak

New member
In the short term, no, the fluorescent proteins simply fluoresce more brightly. In photobiology an "actinic" light means one that stimulates a photochemical reaction. Over time the increased irradiance may stimulate the production of more fluorescent proteins as a protective response, but that is photoacclimation and takes place on the order of weeks to months ("coloring up" in the hobby).
 

Mr. Brooks

MASVC Member
So if I leave the actinics in.. My corals will "color up" eventually? Might be worth while to leave them in. I'm running 400 watt coralvue 20k bulbs at the moment. I wonder how much they'll change in the course of a couple months.
 

Peter Eichler

New member
Actually, no. The whole "color up" thing in this hobby is based on little to no scientific evidence. Coral color in relation to lighting seems heavily based on total irradiance and has little to do with the kelvin rating or spectrum of a bulb. If something gets more colorful under heavy blue or actinic lighting it more likely a response to lower light levels rather than the color of the light. Typically though it's just perceived color or someone seeing what they want to see, which happens a lot in this hobby.
 

spleify

Premium Member
<a href=showthread.php?s=&postid=14826193#post14826193 target=_blank>Originally posted</a> by LockeOak
In the short term, no, the fluorescent proteins simply fluoresce more brightly. In photobiology an "actinic" light means one that stimulates a photochemical reaction. Over time the increased irradiance may stimulate the production of more fluorescent proteins as a protective response, but that is photoacclimation and takes place on the order of weeks to months ("coloring up" in the hobby).

This is interesting, I went back and read your response again, and it makes me wonder. I have asked this question a couple of times in the past and never really got a direct answer. I would really like to see some substantiated evidence of this theory. I would like to see some tests that support or negate these claims.


Thanks for your response LockeOak!
 

greenbean36191

Premium Member
The whole "color up" thing in this hobby is based on little to no scientific evidence. Coral color in relation to lighting seems heavily based on total irradiance and has little to do with the kelvin rating or spectrum of a bulb.
A year ago this may have been an accurate reflection of our knowledge. Now it isn't. There have been recent papers that do indeed show that under constant irradiance, bluer light is effective in inducing production of most fluorescent pigments.
 

john rochon

New member
I've seen corals change color wether brighter/duller/highlights etc
from not only K ratings but from brands of lamps!
If the color looks different then the color IS different. its what you perceive that counts because thats what you see.

and to add, I believe over a short period of time corals do actually change there shade to a certain extent when you change lamps add/subtract.
 

Peter Eichler

New member
<a href=showthread.php?s=&postid=14829464#post14829464 target=_blank>Originally posted</a> by greenbean36191
A year ago this may have been an accurate reflection of our knowledge. Now it isn't. There have been recent papers that do indeed show that under constant irradiance, bluer light is effective in inducing production of most fluorescent pigments.

Looks like I'm behind the times, it happens when you get old :p Are any of the papers viewable on the web?
 

ludnix

New member
Is the forced production of fluorescence significant enough to be noticed by the hobbyist? I noticed my MH are flooding out the effect the of my actinics visually and I can't tell the difference between having my actinics on or off while my MH are on. Because of this I'm considering replacing the actinics with more daylight bulbs to help increase light intensity, but if it's at the cost of overall fluorescence it might not be worth it.
 

LobsterOfJustice

Recovering Detritophobe
<a href=showthread.php?s=&postid=14829547#post14829547 target=_blank>Originally posted</a> by john rochon
If the color looks different then the color IS different. its what you perceive that counts because thats what you see.

Not quite. For example, turn on a blue flashlight in a dark room, everything looks shades of blue (or black). Turn on a red flashlight, everything (the same objects) looks shades of red or black. The objects didnt change - the light changed. This is obviously not the same as shining a white light in a room full of red objects, then a room full of blue objects.

I guess what I'm saying is there are different ways to make an object appear any color - you can change the object itself, or change the light with which you are looking at it.
 
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