Coral color, kelvin rating, and growth rates

[Echidna09]

Higher Kelvin ratings have been proven to [generally] make a coral's color more vibrant but slow growth. Would a pink or green coral grow faster than a blue coral of the same species with similar placement in the same tank due to using 20k bulbs intestead of 14k or 10k?

My thought was that along the lines of what certain trees will do when they are in an environment that they do not receive sufficient light; start producing red leaves instead of green to be able to better capture green light for photosynthesis.

[I think] the blue coral would be less efficient at utilizing the bluer 20k light (since blue is the color it reflects rather than absorbs) than the green or pink would be, again all being the same species with as identical as possible conditions.

If my thoughts are correct, the green would grow less than the blue or pink would with lower kelvin ratings in the 6700-12000 range. Green would not be as efficient at handling the more yellow light than the other two since green and yellow are close on the spectrum.

Anyone have info on this?

Thanks for your help; hope I was clear enough.

[JaredWaites]

Bump, I think this could be an awesome discussion of experimentation.

[acrylic_300]

Hmmm...let me get out my color wheel. If this is true then bluish bulbs would make Orange and Reds excel. A lot of times Orange and Red equates to some form of brown.

This is odd because I just went to a frag swap and the hosts lights were a little on the yellow side and most of his stoneys were getting purplish tips.


It would be funny if this is true and blue bulbs cause browning.

[MCsaxmaster]

Nnnnnnn...no.

Higher kelvin bulbs make some corals really stand out while others become very muted in appearance. It depends on which pigments the coral is producing.

The colorful pigments a coral is producing aren't related to light capture though. These coral pigments, if anything, simply reduce the amount of light getting to zoox. There's no evidence that corals produce different pigments in response to different spectra of light though, only different intensitites of light (for some pigments). The pigments that have been characterized that might be used by corals to block light are blue, purple and pink/red for the most part. Green pigments (related to GFP) probably don't have anything to do with this and the production of GFP often is not related to PAR.

Bulbs of lower intensity tend to cause corals to calcify (grow) more slowly, regardless of spectrum. There's no reason to think that different spectra actually induce corals to produce more or less of various pigments (at a given intentsity) though some pigments do "pop" more under blueish light. Other pigments, however, become very washed out.

cj

[fishdoc11]

Originally posted by MCsaxmaster
Nnnnnnn...no.

Higher kelvin bulbs make some corals really stand out while others become very muted in appearance. It depends on which pigments the coral is producing.

The colorful pigments a coral is producing aren't related to light capture though. These coral pigments, if anything, simply reduce the amount of light getting to zoox. There's no evidence that corals produce different pigments in response to different spectra of light though, only different intensities of light (for some pigments). The pigments that have been characterized that might be used by corals to block light are blue, purple and pink/red for the most part. Green pigments (related to GFP) probably don't have anything to do with this and the production of GFP often is not related to PAR.

Bulbs of lower intensity tend to cause corals to calcify (grow) more slowly, regardless of spectrum. There's no reason to think that different spectra actually induce corals to produce more or less of various pigments (at a given intentsity) though some pigments do "pop" more under blueish light. Other pigments, however, become very washed out.

cj

I'm curious Chris why the same coral will be a different color in lighting that is the same after being raised under different spectrums. Say if you took a coral raised under Radiums and one raised under AB 10K's and put them in a tank lit by Ushios (Let's say all 250 watt and we won't get into the ballasts and all that for the sake of simplicity) they will many times be different colors. Sometimes the difference will be more subtle but more often than not they will be different. Some will be dramatically different ie. purple in one tank and brown in the other.
You say intensity is the critical factor so is the difference in intensities of individual spectrums(> 420 nm peak in the 10K and > 450 nm peak in the 20K) what makes the color different? I realize the PAR will be greater under the 10K bulbs but I would bet you could match the overall PAR of the 10K 250 bulbs using 400 watt radiums and still get the same result.

thanks, Chris

[acrylic_300]

Kelvin and Nanometers...always mess me up.

What is the difference between an actinic bulb and a bulb that peaks in the 420nm?

I have some 130w actinic PC bulbs that peak in the 460nm and they look just like 20k to me.

I got the box out to see what Kelvin they are....all I learned is that Current USA bulbs are made in China

[fishdoc11]

A true atinic bulb does peak at 420 nm
A typical 10K bulb just has a lot of other spectrums in it so it looks different but it still has a large 420nm spike.
The "bluer" looking "atinic" bulbs you have probably do peak around 450-460nm.
Here is a good article to check out spectral plots of various bulbs.

Chris

[MCsaxmaster]

Actinic means that the bulb causes 'actinism' or fluorescence, especially of GFP and its analogs. Max. absorption of GFP is around 460 nm, but anything from about 430 - 500 nm works pretty well.

The color temperature indicates the temperature at which a black body would be in order to produce a similar looking spectrum. Thus, a black body at 6500 K (temp) produces a spectrum roughly like sunlight. A black body at 10,000 K produces a spectrum that has a color similar to a 10,000 K bulb. Other than that, 20,000K, 15, 12, 14, or whatever else is whatever the manufacturer decides to call the bulb as none of these have spectra anything remotely like what is produced by a black body. Thus, these bulbs do not have a color temp. per se--they are mostly blue light, peaking around 450 nm, and a small amount of other wavelengths.

cj

[TylerMoore]

here is my impression of it from my studies of biology (which is my undergraduate major) and plant metabolisms......

say a coral is blue... this means they reflect blue light and their pigments absorb everything but blue (mainly red). These corals are going to recieve the light they need from lights with more daylight in them, because they arn't absorbing blue.

If a coral is red, it is more likely to be a deeper ocean coral that absorbs blue light (the only light that exists down there). Here actinic bulbs should be all the coral needs to survive.

This is very basic, and most algae (including zooxanthalae, if i remember correctly) contains what are called "accessory pigments". These pigments are kind of back-ups, which can absorb other spectrums of light. A green plant may have an accessory pigment that allows it to absorb yellow-green or blue-green light along with the red light taken in from the pigment Chlorophyl a, which is the main pigment.



Does that make any sense? haha.... It sounds confusing when I reread it, but I don't know how else to explain it. MCsaxmaster explained the relationships between K and nm.

[MCsaxmaster]

Hi Tyler,

That explanation might make sense if these were photosynthetic pigments, but they are not. Zooxanthellae, with their chl a and chl c2 as well as several accessory pigments, absorb light strongly in a broad region from about 400 - 500 nm and then again at aroun 660 - 680 nm with less absorption (which is not NO absorption) outside of these ranges. Zoox. can and do use all visible wavelengths (and far violet), but photosynthetic pigments absorb best in the blue and red. Overall this pattern gives the zoox. a brownish or golden brown coloration.

Any color in a coral besides brown is due to coral pigments which have nothing to do with harvesting light. A blue coral vs. a red coral vs. a yellow coral vs. a green coral is not using any of those pigments to absorb light for photosynthesis. This is done entirely by the zoox. which are brown. These other pigments are produced by the coral for potentially a variety of reasons, many of which have nothing to do with the fact that these proteins interact with light. Interacting with light may just be a harmless side effect of the utility of these proteins. Some of these pigments may indeed be produced to absorb light and thereby shield the zoox. from intense sunlight. In this case, pigments that are red, blue, purple, or whatever color are simply absorbing light to shade the zoox. Think of them as like tinted glasses.

Chris

[TylerMoore]

Originally posted by MCsaxmaster
Hi Tyler,

That explanation might make sense if these were photosynthetic pigments, but they are not. Zooxanthellae, with their chl a and chl c2 as well as several accessory pigments, absorb light strongly in a broad region from about 400 - 500 nm and then again at aroun 660 - 680 nm with less absorption (which is not NO absorption) outside of these ranges. Zoox. can and do use all visible wavelengths (and far violet), but photosynthetic pigments absorb best in the blue and red. Overall this pattern gives the zoox. a brownish or golden brown coloration.

Any color in a coral besides brown is due to coral pigments which have nothing to do with harvesting light. A blue coral vs. a red coral vs. a yellow coral vs. a green coral is not using any of those pigments to absorb light for photosynthesis. This is done entirely by the zoox. which are brown. These other pigments are produced by the coral for potentially a variety of reasons, many of which have nothing to do with the fact that these proteins interact with light. Interacting with light may just be a harmless side effect of the utility of these proteins. Some of these pigments may indeed be produced to absorb light and thereby shield the zoox. from intense sunlight. In this case, pigments that are red, blue, purple, or whatever color are simply absorbing light to shade the zoox. Think of them as like tinted glasses.

Chris

Hey, ya learn something every day. Hah.. I was basing that on a lot of assumptions. They don't have many marine bio classes in Nebraska...most of my professors don't know too much about zooxanthalae... but corn genes... good god. Thanks for that information, thats really interesting! I didn't realize that zoox kept a constant brown color.

Whats marine bio graduate school like? I've been thinking about going that route for in a couple years when I graduate. Its obviously a totally different relm, anything you would recomend to prepare for that in the undergrads?

[cutegecko3]

ive read that the pigments likely reflect blue light or more precisely that particular spectrum to boost the zoox.just like we use polished aluminium reflectors to maximize the light from the bulbs we use.but as far as a higher k bulb making a coral more colorful is doubtful.it only appears that way because the light being mostly blue you only see blue being reflected back.i once had a bulb burn up and didnt have a replacement and the lfs didnt have one.so i had to go to lowes and buy a 250 watt G.E.the spectrum was very yellow as you would expect,but within just a few days the colors and growth rates almost doubled.so i wouldnt think a 20k bulb of any type could come close to that.although you must consider its the par value of a bulb that is effective and not its color temp.

[Echidna09]

Thanks for the answers .

cutegecko- My guess is that the growth and color got better with the yellow bulb from Lowe's because it was a fresh bulb and the one it replaced was old. Bulbs lose both their spectrum and power as they age. Light that is more blue is more ultraviolet which forces corals to react in a [typically] pleasing way, for the aquarist's eyes, at least. They have to produce something to block out the harmful UV rays from their zooanthellae. Usually this is expressed in a bright color, such as blue or green.

[MCsaxmaster]

UV-blocking compounds in corals are primarily mycosporine-like amino acids (MAAs) which interact weakly with visble light. They are, therefore, clear to our eyes--they don't show up as any sort of color at all. Lights that produce blue don't necessarily produce any significant amount of UV. While many metal halides produce UV, most fluorescents and LED lights can produce gobs of blue without much UV. The pretty pigments that corals produce have nothing to do with UV though.

cj

[WarrenG]

The K of a lamp used to refer to it's general hue with 6000k looking a little more blue than a 4500k, but now that the manufacturers invent their own labels like 10000K and 20000K there's little relevance to the kelvin of the lamp.

In the wild you can see SPS corals side by side, each getting exactly the same light, but exhibiting different colors for each (small) variation of SPS.

[fishdoc11]

Originally posted by fishdoc11
I'm curious Chris why the same coral will be a different color in lighting that is the same after being raised under different spectrums. Say if you took a coral raised under Radiums and one raised under AB 10K's and put them in a tank lit by Ushios (Let's say all 250 watt and we won't get into the ballasts and all that for the sake of simplicity) they will many times be different colors. Sometimes the difference will be more subtle but more often than not they will be different. Some will be dramatically different ie. purple in one tank and brown in the other.
You say intensity is the critical factor so is the difference in intensities of individual spectrums(> 420 nm peak in the 10K and > 450 nm peak in the 20K) what makes the color different? I realize the PAR will be greater under the 10K bulbs but I would bet you could match the overall PAR of the 10K 250 bulbs using 400 watt radiums and still get the same result.

thanks, Chris

Still curious as to your opinion on this MCsaxmaster.

Chris

[MCsaxmaster]

Hi Chris,

Without taking at least some basic measurements, we don't have the slightest idea of what the light field is like hitting our corals. Even the same brand of bulb but different individiual bulbs will produce slight differences. At the very least I think we need a spec. and a decent light meter to have any idea of what might be leading do differences due to lighting (so we can characterize spectrum and intensity).

Without just some very basic data, which we don't have, I really couldn't say....

Chris

[cutegecko3]

thats exactly what i beleive to,because alot of people claim great results from a certain bulb but others dont from the exact same bulb.

[fishdoc11]

Originally posted by MCsaxmaster
Hi Chris,

Without taking at least some basic measurements, we don't have the slightest idea of what the light field is like hitting our corals. Even the same brand of bulb but different individiual bulbs will produce slight differences. At the very least I think we need a spec. and a decent light meter to have any idea of what might be leading do differences due to lighting (so we can characterize spectrum and intensity).

Without just some very basic data, which we don't have, I really couldn't say....

Chris

Thanks..... you are saying that different bulbs (ie different spectrum and intensity) can produce different pigments right?

Higher kelvin bulbs make some corals really stand out while others become very muted in appearance. It depends on which pigments the coral is producing.

Chris

[MCsaxmaster]

Originally posted by fishdoc11
Thanks..... you are saying that different bulbs (ie different spectrum and intensity) can produce different pigments right?



Chris

I would say that different conditions can produce different results. Light intensity is probably a very important factor. I see no reason to think that spectrum is important.

Chris

[fishdoc11]

Originally posted by MCsaxmaster
I would say that different conditions can produce different results. Light intensity is probably a very important factor. I see no reason to think that spectrum is important.

Chris

That just doesn't fit with many people's practical experience with different bulbs keeping "SPS" (typically Acropora sp.) though.

[MCsaxmaster]

How do you mean?

[fishdoc11]

Well like I stated above. The same corals under the same conditions ( in the same tank) can have dramatic changes in color when changing bulbs (say from a Ushio 10K to a Aquaconnect 14K) and those changes are pretty predictable. The corals will actually change color, it's not just the appearance of the bulb. Granted without studies to prove this it's not validated scientifically but it's a well known phenomenon with people that predominately keep "SPS".

Chris

[MCsaxmaster]

Sure, I have no doubt that the corals can and will change coloration as a response to differences in lighting, but we don't know exactly in what manner they are changing or what is inducing the change. Intensity likely has a lot to do with it, spectrum most likely doesn't. Intensity of UV could be an important factor, but we largely ignore that...

cj

[hahnmeister]

Every coral will respond differently, and has different priorities as far as which spectrum it will utilize the most. Some shallow water corals, for instance, are red because they want to reflect the red that they dont want or they would be overexposed. Some deepwater corals are red because red cant be seen by fish, and at depths over 15-20m, there is no red light... so red corals look black.

You have to consider that there are two parts to the coral as well w/ regard to light. Some of the light spectrum is important as far as how the coral will grow... used in pure photosynthesis. Other spectrums are important for how the coral's pigments will fill in. A pink poscillipora, for instance, will do very poorly under a radium 20,000K w/ VHO actinics. It needs a little daylight/yellow/red not only to look good, but to be healthy it seems. Having a narrow blue output, while good for many coral's growth, can lead to photoinhibition alot easier. Scientists in Germany (and elsewhere according to Dana Riddle) have found that light sources like T5s and LEDs that are heavily concentrated in the blue spectrum w/ little other spectrums can actually stunt coral growth at much lower PAR levels than if the light was a full spectrum lamp. So there is not one frequency that corals should be raised on. It makes sense, FWIW, since blue light contains more energy than say, red because of the shorter wavelength/higher frequency... why halides lose their output as they get bluer.

UV-A light for instance, while not as harmful as UV-B or deadly like UV-C, has such a higher energy from being a higher frequency that corals can experience photoinhibition under much lower light levels than even blue.

So, the best all around light is still a 'full spectrum' light. Me, I still like my blue... so I combine 10,000Kish halides (ushio 14,000K and G-man 14,500K are my favorites) with blue and actinic T5s. That way, I give my corals every spectrum under the sun, and a heavy dose of daylight.