Carotenoids and their roll in the aquarium.

Didn't even know which section of the forum to put this in, but invertebrates utilize Carotenoids so here we go.

I wanted to start a discussion on Carotenoids and their roll in the reef as I have been studying them quite a bit lately.

Carotenoids are sometimes referred to as accessory pigments. They absorb energy from the sun, but cannot transfer it directly to corals ( or other invertebrates ) they have to transfer the energy first to Chlorophyll. Carotenoids are usually red, orange, or brown in pigment. They typically have absorption peaks in Amber light ( ~620nm ) and green light ( ~520nm ). They are present in the infamous Carrot! Giving it it's orange color. Guess what else it is heavily present in? Diatoms and brown species of algae. Ever heard that red light grows more algae? Bam, Carotenoids are why. They are much more present in algae species than corals.

HOWEVER. I got to thinking about Acans. Low light corals are often shielded from red and amber spectrum from spectral diffusion through the water ( the lower you go, the more blue it is ).

How many of you have purchased an Acan and had it turn orange or red instead of the brilliant array of colors it used to display? Are Carotenoids the reason behind it? Maybe moving the spectrum away from ambers and reds will resolve the issue? Is there a specific wavelength of red that promotes chlorophyll, yet is unusable for Carotenoids? Would stepping away from lower spectrum white bulbs, and supplementing high kelvin white with a higher wavelength red reduce algae and promote extra coral growth? Anyone have any experience they want to share? I'm knowledge hungry.

THIS is a fun read. We all know blue lights work, but I am more interested in the effects of red light here. Is anyone willing to put together and fund a test tank with me to observe differences in wavelength and Carotenoid reactions?

Edited by Pete Moss - March 09 2015 at 5:01pm

Edited by Pete Moss - March 10 2015 at 12:20pm

I keep the amber and red portion of my wavelength at an extremely low level, I maintain colors well on all my acans. If I turn up my amber spectrum I get worse coloration. The exact opposite effect reported by your other sources. I'll have to post picture of my acans, they've been under my lights for a couple of months now.

I know the narrow band experiment has been conducted multiple times, I'm more interested in the narrow spectrum bands that weren't tested. Amber and UV in particular.

I know for a fact acans get pissed if they don't have near-UV, I can't get them to thrive under blues and whites alone either, but as soon as I added near-UV they took off.

And if a coral is orange or red, isn't it reflecting red light? Couldn't it be assumed that it is receiving an excess of that spectral band if it is casting it aside? A coral looking to absorb more red light wouldn't achieve much by morphing it's colors to red and orange.

I legitimately don't know, which is why I'm asking.



Edited by Pete Moss - March 10 2015 at 2:41pm

Cool, Cool, Cool. Thanks for the info and discussion. It blew me away when, many years ago, Adam Blundell spoke to us about coral that absorb one color and fluoresce another color. I hope he jumps in here to add a few "nuggets" of his own. Lighting for coral is one of the things that the hobby and science really don't yet know enough about.