Colours of corals

[Lasse]

In the thread https://www.reef2reef.com/threads/h...understanding-of-par-this-whole-time.1035018/ all from PAR to coral colourations is discussed.

Among other things - coral colouration during different wavelengths was discussed. I decide to start an own thread according this and I have also done some experiments in order to show what I mean.

The colours of our corals are either from reflection or fluorescence. Reflection colours is just the protons that bounces back to the eye - fluorescence colours is that the coral catch the proton and bounce back another photon of normally longer wavelength (read lower energy quanta) The coral works like a light source. This light is very weak and your eyes will not catch it if there is a lot of reflecting colours in the lumen window. The lumen window is there the eyes works best - in the graph - the yellow line

Look at this

If a coral bounce back green photons (530 nm) you will see them even if they are week . Now we take 6500 K to the same level in watt. There is no chance that you should even notice the weak fluorescence sources

Even if you fill up with blue wavelengths - 6500 K eillcompete out the fluorescence in most cases but not all as we will see later.

First experiment Red Seriatopora hystrix

My normal full light

Close down 6500 K - not much happens

6500 and 8000 K zero - still red

Close down 6500K, 8000K, and red 622 nm - where did the red colour go?

6500K, 8000K, red 622 nm and green 530 nm = 0

6500K, 8000K, red 622 nm, green 530 nm and blue 470 = 0

6500K, 8000K, red 622 nm, green 530 nm, blue 470 and blue 455 = 0 - here some very weak reddish fluorescence
take over

6500K, 8000K, red 622 nm, green 530 nm, blue 470, blue 455 and blue 450 = 0. Only 425 nm and a little bit more fluorescence of reddish brown

Test with RGB - very red

Test with 7750 K white - more yellowish

This experiment shows that Red Seriatopora hystrix¨s colour is mostly a reflecting colour - red LED will help to give a good red colour of it

I will come back tomorrow with more examples - green montipora.

Sincerely Lasse

 

[A. grandis]

Yes, all true, but where does the health of the coral should lay on? The differences in reflection and fluorescence do exist under different exposures, but not all those lights will contribute for optimal health, if they are not in balance. I think it's important to state that, specilly so newbies don't think they can just choose what "spectrum" they like the most. That sems like to be the tendency in this hobby using LEDs. I'm interested to see your contribution and experiences in that matter. Great thread!

 

[BeanAnimal]

Even using “leds” one can provide plenty of healthy spectrum and push the desired color cast to what pleases their eyes.

In fact, it is easy to overpower the blue or neutral white cast with red, yellow or green.

 

[Dom]

In the thread https://www.reef2reef.com/threads/h...understanding-of-par-this-whole-time.1035018/ all from PAR to coral colourations is discussed.

Among other things - coral colouration during different wavelengths was discussed. I decide to start an own thread according this and I have also done some experiments in order to show what I mean.

The colours of our corals are either from reflection or fluorescence. Reflection colours is just the protons that bounces back to the eye - fluorescence colours is that the coral catch the proton and bounce back another photon of normally longer wavelength (read lower energy quanta) The coral works like a light source. This light is very weak and your eyes will not catch it if there is a lot of reflecting colours in the lumen window. The lumen window is there the eyes works best - in the graph - the yellow line

Hello Lasse!

I'd like to know what light you are using in this experiment. Did I miss it?

Dom

 

[Lasse]

I use GHL Mitras bar 2.

Sincerely Lasse

 

[BeanAnimal]

Hello Lasse!

I'd like to know what light you are using in this experiment. Did I miss it?

Dom

GHL Mitras LX72xx and light bars have that control.

 

[JoshO]

In the thread https://www.reef2reef.com/threads/h...understanding-of-par-this-whole-time.1035018/ all from PAR to coral colourations is discussed.

Among other things - coral colouration during different wavelengths was discussed. I decide to start an own thread according this and I have also done some experiments in order to show what I mean.

The colours of our corals are either from reflection or fluorescence. Reflection colours is just the protons that bounces back to the eye - fluorescence colours is that the coral catch the proton and bounce back another photon of normally longer wavelength (read lower energy quanta) The coral works like a light source. This light is very weak and your eyes will not catch it if there is a lot of reflecting colours in the lumen window. The lumen window is there the eyes works best - in the graph - the yellow line

Look at this

If a coral bounce back green photons (530 nm) you will see them even if they are week . Now we take 6500 K to the same level in watt. There is no chance that you should even notice the weak fluorescence sources

Even if you fill up with blue wavelengths - 6500 K eillcompete out the fluorescence in most cases but not all as we will see later.

First experiment Red Seriatopora hystrix

My normal full light

Close down 6500 K - not much happens

6500 and 8000 K zero - still red

Close down 6500K, 8000K, and red 622 nm - where did the red colour go?

6500K, 8000K, red 622 nm and green 530 nm = 0

6500K, 8000K, red 622 nm, green 530 nm and blue 470 = 0

6500K, 8000K, red 622 nm, green 530 nm, blue 470 and blue 455 = 0 - here some very weak reddish fluorescence
take over

6500K, 8000K, red 622 nm, green 530 nm, blue 470, blue 455 and blue 450 = 0. Only 425 nm and a little bit more fluorescence of reddish brown

Test with RGB - very red

Test with 7750 K white - more yellowish

This experiment shows that Red Seriatopora hystrix¨s colour is mostly a reflecting colour - red LED will help to give a good red colour of it

I will come back tomorrow with more examples - green montipora.

Sincerely Lasse

This will very quickly be a very good and interesting thread to read and participate in.
With regards what is visually happening. I agree that the varying spectrums will absolutely provide different appearances to the corals.
The question I'd like answering is how would said corals fare if they were kept under spectrum X or Y for a prolonged period. Would we see the same colouration after 6 months or would it alter?
Would a certain spectrum be best for bringing out the best colouration in corals, and then another for actually viewing it? I'm guessing this is very likely the case

 

[BeanAnimal]

how would said corals fare if they were kept under spectrum X or Y for a prolonged period. Would we see the same colouration after 6 months or would it alter?

I think your answer is all around you. "Joe bobs blue super duper blue acorn acro with orange dinglberry droplets and pink lace cotton candy polyps" has 20 other names and colors, depending on where it has been fragged, propagated and grown out 20 times over the last 5 years.

 

[JoshO]

I think your answer is all around you. "Joe bobs blue super duper blue acorn acro with orange dinglberry droplets and pink lace cotton candy polyps" has 20 other names and colors, depending on where it has been fragged, propagated and grown out 20 times over the last 5 years.

Exactly, so which is healthiest? Which grew the fastest? Which has the best colour? (I know the last one is personal preference)
Simply lighting a coral in a certain way for a very short time frame to assess it's colour isn't necessarily the "best" spectrum...but one of the spectrums will be best, so we as growers need to find it!

 

[BeanAnimal]

Exactly, so which is healthiest? Which grew the fastest? Which has the best colour? (I know the last one is personal preference)
Simply lighting a coral in a certain way for a very short time frame to assess it's colour isn't necessarily the "best" spectrum...but one of the spectrums will be best, so we as growers need to find it!

What is "best" ? Fastest vertical growth? Fastest encrusting growth? Prettiest color for you? Closest to color from it's native reef? Polyp density? Polyp extension? Hardiness? Etc.

 

[areefer01]

What is "best" ? Fastest vertical growth? Fastest encrusting growth? Prettiest color for you? Closest to color from it's native reef? Polyp density? Polyp extension? Hardiness? Etc.

I never understood on the hobbyist level why the need to grow corals fast. We are not aquaculture or similar small businesses so have plenty of time to watch them grow. Mother nature has a pace...

@Lasse you ever talk to Luc Vogels / Philips Engineer?

 

[BeanAnimal]

I never understood on the hobbyist level why the need to grow corals fast. We are not aquaculture or similar small businesses so have plenty of time to watch them grow. Mother nature has a pace...

@Lasse you ever talk to Luc Vogels / Philips Engineer?

Yeah - honestly, I would rather coral barely grow at all and just maintain. I would be happy to BUY large expensive colonies and just "plant" them and maintain them. I don't want to keep fragging and trimming and trying to keep encroachment from happening.

 

[Lasse]

This experiment is not to show which spectrums is best - it is done because I want to show that different corals answer to light in different ways according colours. All three corals have been in my aquarium for years and adapted to my normal light. The hystrix show that its main colouration is reflected colour. It means - there need to be red photons in the water so they can be reflected and our eye see it as red. it also show that there is a small band of fluorescence but it could only be seen at 450 nm below. Light with higher wavelength seems to "mask" this

@Lasse you ever talk to Luc Vogels / Philips Engineer?

Only shortly during some exhibitions I have visit


Sincerely Lasse

 

[JoshO]

What is "best" ? Fastest vertical growth? Fastest encrusting growth? Prettiest color for you? Closest to color from it's native reef? Polyp density? Polyp extension? Hardiness? Etc.

The question we all need answering! I would say growth is a very good metric by which to measure best. If I remember rightly, different spectrums and light sources did actually influence polyp density, I just can't remember in which way! Let's be frank, we all want those hairy acros :face-with-tears-of-joy:
I'm going to say a combination of the above would be a good starting point

 

[JoshO]

This experiment is not to show which spectrums is best - it is done because I want to show that different corals answer to light in different ways according colours. All three corals have been in my aquarium for years and adapted to my normal light. The hystrix show that its main colouration is reflected colour. It means - there need to be red photons in the water so they can be reflected and our eye see it as red. it also show that there is a small band of fluorescence but it could only be seen at 450 nm below. Light with higher wavelength seems to "mask" this


Only shortly during some exhibitions I have visit


Sincerely Lasse

Do you think there would be a spectrum that could encompass both fluorescent visibility but also the true colours that the lower wavelengths seem to help display?

 

[A. grandis]

This experiment is not to show which spectrums is best - it is done because I want to show that different corals answer to light in different ways according colours. All three corals have been in my aquarium for years and adapted to my normal light. The hystrix show that its main colouration is reflected colour. It means - there need to be red photons in the water so they can be reflected and our eye see it as red. it also show that there is a small band of fluorescence but it could only be seen at 450 nm below. Light with higher wavelength seems to "mask" this


Only shortly during some exhibitions I have visit


Sincerely Lasse

Thanks Lasse, for showing us with the images.
I think we all know that the reflection of certain wavelengths will differentiate in the way the human eye will capture that reflection on the corals, allowing or not natural pigments to be perceived by our eyes in comparison to the way they do under natural sunlight, in shallow waters found in the tropics. In my point of view, natural sunlight should be the basis for comparison. That's my opinion.
That is going to happen with ANY type of 3 most used technologies, meaning: halides, T5s and LEDs.
In regards to "normal light" it becomes very subjective as we know. Unless everyone knows what you mean. I have no idea what hat would be in your case.

 

[Reefering1]

I just posted this in the other thread, seems relevant here....

From my humble observations, it seems most true corals are brown. People figured out that if you shine blue light at some, they reflect pretty colors, then they try to optimize spectrum to make look best. It seems that even fanciest snazzberry utra dingleflopper is brown if you shine a flashlight on it- or take it outside(in sunlight). Contrasting them are the corals that are so exposed to light that they need to protect themselves. These produce protective pigments that you can actually see regardless of light source(sun, flashlight, mh, led, candle). True colors. To me, this is the draw to mh(along with not having a dark subdued tank that I can't see every inch of). That and the fact that i can't stop starring at it, its so beautiful(Phoenix 14k). If uv and ir are so irrelevant to health/ color/ growth, why do you get tanned,sunburn while scuba diving reefs? Why/ how do people get vitaminD from sunlight? Why are the prettiest pictures of deep space infrared? Any camera can see the ir repeater of a remote control, why can't corals "see" ir? Simple questions from a simple(ish) man looking for a simple solution to a complex subject.

 

[areefer01]

The question we all need answering! I would say growth is a very good metric by which to measure best. If I remember rightly, different spectrums and light sources did actually influence polyp density, I just can't remember in which way! Let's be frank, we all want those hairy acros :face-with-tears-of-joy:
I'm going to say a combination of the above would be a good starting point

I think the challenge in this case is that there is more to growth than just light. Or in the couple of related threads PAR numbers. What happens if one is on the bleeding edge of ph and alk?

The trouble with both of these threads is that all of our systems are more or less different. Bob and Sally may keep the same acropora or soft coral using the same light and settings yet have different water chemistry. Not only that they may have different maintenance, feeding routines and I didn't even bring forth dosing A, B, or C.

So many variables it can make ones head spin. BTW not arguing with anything you, or anyone here, has posted in either thread.

 

[ISpeakForTheSeas]

I just posted this in the other thread, seems relevant here....

I haven't looked into IR yet, but UV (and likely IR too) definitely plays a role in the wild; I think the largely unanswered question at this point is what impact do different levels of these wavelengths have on corals?

For example, we know too much UV is harmful, but are there measurable benefits to having a little bit of it? (I'd assume the impacts would differ between specific wavelengths and corals, so some may be beneficial while others are harmful).

I don't thinks that type of question has been answered yet with corals. There's a lot of speculation about it, but I don't know if we've tested yet with a broad enough sample of corals to really know.

Also, just a fun, related note (Edit: I removed the accidental repeat info):

I would assume white clownfish would be more susceptible to a "sun burn" (damage from UV rays) than their orange counterparts just like white koi are more susceptible than darker koi (or like how people with light skin are more susceptible than those with dark skin). The white color doesn't reflect UV as well as other colors, so it would absorb more UV and sustain more damage as a result - for example, the UV reflectance of the clownfish Amphiprion akindynos:

"White stripes reflect from <400 nm (UV) to beyond 700 nm (far-red, not shown in figure) with a peak around 520 nm, while oranges show a small peak in the UV (360–380 nm) and another larger one at longer wavelengths (500–700 nm)." *
(See the figure and source study linked below - the "c. Spectral Reflectance Graph" is the relevant part of the figure.)

That said, clownfish can also see UV light,** so it may be rather bright in there for the clown too (it may hurt the clown's eyes if it's bright enough). - Fun fact for anyone interested here, the UV reflectance of clownfish is also related to intraspecific aggression and their social hierarchy.***

Also, for anyone doubting that clownfish can "get sun burns" (i.e. be damaged by UV rays), see the last link below that shows they can.****

*Figure with data first, then the source study:

https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41598-019-52297-0/MediaObjects/41598_2019_52297_Fig1_HTML.png?as=webp

A detailed investigation of the visual system and visual ecology of the Barrier Reef anemonefish, Amphiprion akindynos - Scientific Reports

Vision plays a major role in the life of most teleosts, and is assumingly well adapted to each species ecology and behaviour. Using a multidisciplinary approach, we scrutinised several aspects of the visual system and ecology of the Great Barrier Reef anemonefish, Amphiprion akindynos, including...

www.nature.com

**Source:

Molecular Evolution of Ultraviolet Visual Opsins and Spectral Tuning of Photoreceptors in Anemonefishes (Amphiprioninae) - PMC

Many animals including birds, reptiles, insects, and teleost fishes can see ultraviolet (UV) light (shorter than 400 nm), which has functional importance for foraging and communication. For coral reef fishes, shallow reef environments transmit a ...

www.ncbi.nlm.nih.gov

***Source:

Higher ultraviolet skin reflectance signals submissiveness in the anemonefish, Amphiprion akindynos

When signaling submission, it is important to wave the “white flag.” In the Barrier Reef anemonefish, ultraviolet color patterns serve to signal submissive

academic.oup.com

****Source:

Effects of UV Radiation on Oxidative Stress in Yellowtail Clownfish Amphiprion clarkii - Ocean Science Journal

We investigated oxidative stress under UV radiation (380 nm) at two intensities (0.2 and 0.4 W/m2) for 14 days (0, 1, 3, 7 and 14) in the yellowtail clownfish Amphiprion clarkii. We analyzed mRNA expression and the activity of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)]...

link.springer.com

Surprisingly, they didn't have to use unnatural amounts and it actually would be likely within reef limits - at least according to the data I can find.

The study had UV levels of 0.2 and 0.4 W/m2; using a relatively conservative conversion metric to switch from μmole.m2/s to W/m2, UV levels of 0.4 can be found in shallow water (~6 meters or less deep) and 0.2 can be found pretty deep (~18 meters or less).* If you use Apogee's conversion metric, you could find levels of 0.4 to about 10 meters or less and 0.2 to about 22 meters or less.**

*Source (Figure 4 is particularly relevant):

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1989.34.8.1623

**Source:

PPFD to Watts Conversion

www.apogeeinstruments.com

This last link is here because it's relevant to the unit conversion, though not necessarily for UV wavelengths specifically:

https://www.researchgate.net/post/Can-I-convert-PAR-photo-active-radiation-value-of-micro-mole-M2-S-to-Solar-radiation-in-Watt-m2

Yes, white clowns would be more prone to "sun burns" (damage from UV rays) than clowns of different colors. If the UV is strong enough to be causing problems (i.e. if there's enough UV light to give the clown a "sun burn"), then yes, reducing the UV spectrum would help.

 

[Reefering1]

I haven't looked into IR yet, but UV (and likely IR too) definitely plays a role in the wild; I think the largely unanswered question at this point is what impact do different levels of these wavelengths have on corals?

For example, we know too much UV is harmful, but are there measurable benefits to having a little bit of it? (I'd assume the impacts would differ between specific wavelengths and corals, so some may be beneficial while others are harmful).

I don't thinks that type of question has been answered yet with corals. There's a lot of speculation about it, but I don't know if we've tested yet with a broad enough sample of corals to really know.

Also, just a fun, related note:

I am always impressed with your responses... thank you.
Now about the space stuff, what's your take- why do the pics look so impressive? Something about ir, as far as I know; if so, how could ir possibly not be meaningful to life on earth?