Light Spectrum for Corals

[Lucent]

Read this today thought it was intresting. Makes me wonder why you cant just rack up any high intensity lighting no matter what the k value and be good to go. Intresting reading if you have the time.

"This article presented a comparison of natural underwater light (based on specific data from natural waters) to the light over our aquariums. While there are variations to be expected in natural waters, the general shape of the spectral distribution underwater will be quite similar. Clearly there is a wide discrepancy between the spectral irradiance provided by MH and the natural under water light field. We know from experience that we can grow coral under all the 3 major classes of metal halide lamps 6500K, 10000K and 20000K, so the corals must either adapt to the spectrum or ignore the spectral quality. Unfortunately I do not have any definitive answers to this, hopefully further research will be able to provide more definitive answers."
http://www.advancedaquarist.com/2005/8/aafeature

 

[MikeS]

Well, notice that he is only referring to MH's....and made a note of spectral shape distribution...

MikeS

 

[Scooterman]

We look at the lower K lamps because of the ability to punch through depths of water more so than the spectrum.

 

[Lucent]

so intensity is more valuable than color spectrum in theory. Though I find several postings and theories that go in the exact opposite direction.

 

[Scooterman]

no not necessary, the punch is to meet a certain amount needed at different depths but also spectrum also plays a part, I'll have to look it up but it is within a range that corals do use most & that would depend on several things like the type of coral we're talking about etc. Tomorrow I'll look up some of this information, if you don't beat me to it IT is always good to brush up & learn on subjects like these.

 

[Lucent]

Scooterman,

I did some more digging and found a good article on the effects of light intensity and spectrum effects on photosythesis in coral. Most of all another point in the direction that light intensity is more important than full spectrum lighting. This pushes me more towards the idea that any form of high intensity light may be more beneficial than spectral quality.

This experiment's results suggest information potentially valuable for hobbyists - that rates of photosynthesis were essentially the same under these two distinctly different light sources. Other than aesthetic value, there appears to be no advantage, photosynthetically speaking, in using high Kelvin lamps.
The implication of these results should be of interest to hobbyists; it suggests that lamp selection (with due regard to lamp intensity) may be based on appeal, whether that is price or the "look" it gives to a tank, without fear of hindering photosynthesis. Economy-minded hobbyists and coral farmers may find this especially useful. It appears that light intensity and relatively simple light measurements alone adequately judge lamp efficiencies within the context of zooxanthellae photosynthesis. This should not be construed to mean that all light sources are adequate for reef aquaria use.

http://www.advancedaquarist.com/2002/2/aafeature/view

 

[liveforphysics]

Good articles, but as the articles themselves indicate, this goes a lot deeper than we understand.

Not directly related perhaps, but I had some killer intensity on my chaeto with 6500k lamps, and the chaeto withered and died. After changeing to 2700k with the same intensity, it doubles more than weekly and stays dark green.

My nano that I setup uses 3 of the same 2700k lamps I use to grow chaeto (just because I had them laying around). The tank looks a really boreing and dull yellow. However, the 20+ species of zoo's, pumping xenia, many leathers, mushrooms, and other easy to keep corals are all growing and thriving in there. Everything looks very healthy, and the tank hasnt had any nusicance algae occur yet, which I was concerned about.

It hasnt even been up for a month yet though, so I will need to give it more time before knowing if it really works well as a long term option, but so far it would seem changeing the color temp from actincs and 10ks down to 2700k has no negitive effects on the above mentioned soft corals.

 

[Scooterman]

Myth 5: The "K" rating of aquarium lamps plays an important role in the coloration of corals.

Myth 6: Corals are colorful because of their symbiotic zooxanthellae.

Zooxanthellae are golden brown to deep brown in color, depending on their pigment content and the light/temperature environment in which they are found. The bright colors in corals arise from either animal-based or skeleton-based pigments. Many gorgonians, soft corals, and a few stony corals incorporate pigments into skeletal elements. Others have animal based pigments that are either biosynthesized or acquired through diet. Many zooxanthellate corals have their bright colors because of a family of multi-hued fluorescing proteins. These pigments seem to be produced in response to a given light environment. The primary control on their production appears to be total irradiance level, and little evidence exists to suggest that the "k" rating of bulbs will influence their production. There is also a strong genetic component, although the specific aspects of fluorescing proteins and their respective genes have not yet been worked out. The color temperature of light bulbs most likely influences the perceived color of corals in a tank, with ultraviolet components enhancing highly fluorescent pigments. Certain bulb temperatures may have enough of their spectrum skewed in relative distribution that total irradiance with a given wattage may be affected, and thus total irradiance influencing the relative production of fluorescing proteins.
It is notable that some pigments appear to be formed as a result of low light, while others appear to be formed in environments with high irradiance levels. For more information, see the article and references located here.
Potential: varied. If a brightly colored coral is producing fluorescing proteins in response to low light, placement in high light environments may result in bleaching. Other aspects of fluorescing protein production may be related to bleaching resistance in high light environments. Otherwise, coloration is largely aesthetic for reef aquariums.
Distribution: widespread. It is becoming more widely recognized in aquarium circles that coral coloration does not arise from the colors of zooxanthellae. However, many articles in the lay press still wrongfully propose this notion. The belief that the k-rating of bulbs is important to coral coloration is widespread among the hobby populace, and appears to be a common misconception in all countries.

http://www.reefkeeping.com/issues/2003-11/eb/index.php

 

[Scooterman]

http://www.reeffrontiers.com/forums/showthread.php?t=14453&page=4

We were covering some good information at this point of this thread.

 

[Scooterman]

Ok these a few more.


http://www.reefs.org/library/article/c_bingman3.html

http://www.reefs.org/library/talklog/s_tyree_060202.html

http://www.reeffrontiers.com/forums/showthread.php?t=2654

 

[mojoreef]

Yea it can get pretty deep. Basically the pigments with in the zoox need a certain spectrum of light, so for that it is critical. Now in saying that the pigment outside the zoox do play a large role in both coverting spectrums and flouresing. Intencity is required in order to give the zoox enough energy to start a photosynthetic cycle


Mike