Red Light - Good or Bad for Corals?

[Sallstrom]

I am definitely not trying to be sarcastic with this statement, but obviously the red light isn’t that bad then right?? Or is the Radion red a better or different type of red or something?

No red is not bad as long as it's not too much(or just red). We have had a couple of corals(Seriatopora) that has survived under just 660nm(red) for a couple of month now(for an experiment). But they doesn't look like corals you want in your tank, they are almost white :)
How much red is too much? I don't know.

/ David

 

[Straight.Reefin]

No red is not bad as long as it's not too much(or just red). We have had a couple of corals(Seriatopora) that has survived under just 660nm(red) for a couple of month now(for an experiment). But they doesn't look like corals you want in your tank, they are almost white :)
How much red is too much? I don't know.

/ David

Haha gotcha!!!! Yeah I always see this red argument and never really got a real answer and I see some Radion schedules running low reds like the coral AB plus schedule and be successful and then some like Sanjay joshi and run red at 100%!

 

[Lasse]

No red is not bad as long as it's not too much(or just red). We have had a couple of corals(Seriatopora) that has survived under just 660nm(red) for a couple of month now(for an experiment). But they doesn't look like corals you want in your tank, they are almost white :)
How much red is too much? I don't know.

/ David

But in the combine red and blue - it looks better :)

Sincerely Lasse

 

[Dana Riddle]

Here's the reason red light should be used sparingly - look at the orange line at the bottom, it is the xanthophyll cycle that offers photoprotection. There is none. The y-axis is the rETR (relative electron transport rate between Photosystem II and Photosystem I.) Red light in these experiments generated the highest rate of photosynthesis, yet the xanthophyll cycle never occurs. Hence, loss of zooxanthellate density/chlorophyll content will occur at lower light levels. The human eye has difficulty perceiving this loss. Yes, the corals will grow and appear fine, but too much red light is not good for corals/zooxanthellate.

 

[Straight.Reefin]

Here's the reason red light should be used sparingly - look at the orange line at the bottom, it is the xanthophyll cycle that offers photoprotection. There is none. The y-axis is the rETR (relative electron transport rate between Photosystem II and Photosystem I.) Red light in these experiments generated the highest rate of photosynthesis, yet the xanthophyll cycle never occurs. Hence, loss of zooxanthellate density/chlorophyll content will occur at lower light levels. The human eye has difficulty perceiving this loss. Yes, the corals will grow and appear fine, but too much red light is not good for corals/zooxanthellate.

So is the Radion red LED at 100% considered TOO MUCH red?

 

[Dana Riddle]

So is the Radion red LED at 100% considered TOO MUCH red?

I don't own a Radion, so I'm not qualified to make a judgment.

 

[Brew12]

I don't own a Radion, so I'm not qualified to make a judgment.

Am I understanding correctly that corals will grow, but the color would be pale under too much red? And that this effect wouldn't be canceled by adding more blue light?

 

[Dana Riddle]

Am I understanding correctly that corals will grow, but the color would be pale under too much red? And that this effect wouldn't be canceled by adding more blue light?

It's my opinion that the effects of red light will not be negated by addition of blue light. Red light will still be absorbed and the xanthophyll cycle will offer protection against blue light only. We often hear arguments that corals can be exposed to air during periods of low tide and they are exposed to full strength ultraviolet, blue, red, etc. and they survive. Agreed. But I think there is a big difference between surviving and thriving - a good portion of energy reserves have to be dedicated to repair of damage corals/zoox experience in such harsh environments. A table Acropora subjected to such stressors might be a foot or so across, while those in deeper waters might be yards across.
I'll fall back to this paper (Red Light Represses the Photophysiology...):
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0092781

 

[Dana Riddle]

And this reference:
https://www.advancedaquarist.com/20...ider&utm_medium=slider&utm_campaign=clickthru
Work I did 15 years ago with LEDs is referenced in this peer-reviewed paper, which is unusual in that an article in hobbyist literature is generally ignored by researchers.

 

[Lasse]

Just a thought - Dr Tim Wirjgerde see the reduction of zooxanthella under red light as a sign of degeneration in spite of the fact that the growth rate for blue and red light was nearly the same.

Can´t you not see this in another way? 40 % less zooxanthella produce the same amount of energy as the amount of zooxanthella under blue light. Hence - the photosynthesis under red light was more effective/ zooxanthella and if you lower the PAR level with 40 % (or something like that) for the red test compared with the blue test - could you have the same amount zooxantheller as for blue then?

By the way - 300 PAR in only red light is a very high value


Sincerely Lasse

 

[oreo54]

128 and 256 is "PAR" levels
Should have ran a 256 "PAR" white control...

 

[oreo54]

 

[mcarroll]

Just a thought - Dr Tim Wirjgerde see the reduction of zooxanthella under red light as a sign of degeneration in spite of the fact that the growth rate for blue and red light was nearly the same.

I still need to read the whole article, but at least in the Abstract they clain that red light resulted in slow growth or less growth...hopefully that means "statistically significant".

But I still think you're onto something.

IMO, the high-zooxanthalae density under blue lights carries risks (not tested in this study), and I'm sure the low-zooxanthellae density state asserted under red light also carries some risk (tested in this study).

I believe the chart...red 256 and red+blue 256 both had problems first....if they had an explanation for the white 128 and red 128, then that consolidates the results regarding red IMO.

It would be interesting to see if Symbiodinium follow the same trends sans host.

It would also be interesting to fold nutrient variables into the mix for high, low and replete to see how that alters things.

I suspect we'd see the downside of blue light at least a little bit.

 

[Lasse]

Interesting - link to that study

Sincerely Lasse

 

[Brew12]

I'm curious as to why there was degradation on the last sample of the white control.

I've decided to try and specifically check for change in the growth pattern of my monti caps even though it may not be best overall for my aquarium. I've decided to keep all of my lights at 100% during the peak period but the red. I will run these at 40%. I'm curious to see if they will start growing up instead of down.

 

[oreo54]

I'm curious as to why there was degradation on the last sample of the white control.

I've decided to try and specifically check for change in the growth pattern of my monti caps even though it may not be best overall for my aquarium. I've decided to keep all of my lights at 100% during the peak period but the red. I will run these at 40%. I'm curious to see if they will start growing up instead of down.

Actually apparently all "degraded" over the course of the experiment..

During the experimental period, all corals exhibited a decreasing trend in MQY. Although this may be indicative of stress, e.g. photoinhibition of photosystem II [31] or elevated zinc levels in the experimental system (see above), corals maintained under blue and white light showed a less pronounced negative trend in MQY. In addition, corals cultured under blue light had a significantly higher MQY at the lower irradiance applied, which suggests that higher energy associated with blue light causes (more) damage to photosystem II, possibly through D1 protein degradation [31]. At the end of the experiment, corals exposed to red 256 exhibited a MQY of 0.3 and were starting to bleach, which may have resulted in the necrosis that ensued.

Similarly to MQY, all corals showed a decreasing trend in NDVI

 

[taricha]

that's very cool - i don't remember seeing anything before proposing a mechanism for red light to reduce coral health.
To be clear, is this a mechanism that is harmful to the individual symbionts? Or one that creates unhealthy conditions in the coral tissues (like bleaching typically).

 

[mcarroll]

According to the plos article cited...

100% healthy
Blue 128
Blue 256
Blue+red 128 column.

At least some die-back
All other combo's that included red, including white.

Mortality
Red 256
Blue+red 256

Certainly interesting results....especially in light of Dana's comments about what enables the tolerance of blue light.

I guess certain corals can only stand so much red light, and it's for a good reason....probably lots of good reasons. ;)

My guess is that their red-light mechanism is tuned for deep water where (strange as it may seem) far-red light becomes more and more prominent (really as blue fades out more and more), but intensity is low. I bet corals that are adapted for tide-level light have a tough time down deep.

Deep red is the final emission of "waste light" from photosynthesis so the deep sea apparently glows "red".

(Or something like that... :D I've linked the reference on this before, but it's lost in the threads for now....don't recall the source for sure. Maybe C. Mobley? Think this deep red and far red actually get used together to power photosynthesis with "useless red photons" via the Emerson effect.)

 

[Dana Riddle]

Just a thought - Dr Tim Wirjgerde see the reduction of zooxanthella under red light as a sign of degeneration in spite of the fact that the growth rate for blue and red light was nearly the same.

Can´t you not see this in another way? 40 % less zooxanthella produce the same amount of energy as the amount of zooxanthella under blue light. Hence - the photosynthesis under red light was more effective/ zooxanthella and if you lower the PAR level with 40 % (or something like that) for the red test compared with the blue test - could you have the same amount zooxantheller as for blue then?

By the way - 300 PAR in only red light is a very high value


Sincerely Lasse

I think it is the absence of photoprotection in red light that concerns me most. As your experiments have shown, high levels of red light will bleach corals. What we need to define (and perhaps this has been done and I'm unaware of it) is how much red light is 'good' or 'bad.'

 

[leepink23]

I don't own a Radion, so I'm not qualified to make a judgment.

So is the Radion red LED at 100% considered TOO MUCH red?

I run red at 14 on the radions, but 24 would be my max. That’s based on sps ab+ schedule by Ecotech