Effect of Red and Green Light on Coral

[Brymac1]

Hey all, this is a subject that I have been very interested in. I would like to get @Dana Riddle 's opinion on this as well as everyone else.

Fairly recent studies suggest that green light has a greater impact on photosynthesis in terrestrial plants than previously thought. Because it is not quickly absorbed at the surface of the leaf (like red and blue light), the green light can penetrate deeper into the leaf, driving photosynthesis in deeper layers of the leaf.

There is also the fact that green light penetrates fairly deep in the ocean, along with blue light.

I was wondering if increasing the amount of green light output from our light fixtures could lead to more photosynthesis deeper in the coral tissue, leading to a faster growing and healthier coral?

As for red light. I know that there are multiple studies that suggest that red light can cause photoinhibition in coral. Although in these studies, the red light that was used, was provided at the same intensity as the blue light provided. In many LED fixtures, the maximum red light output is nowhere near the strength of the blue light output.

So my question about red light is: is there an "optimal" ratio of red to blue light that could increase photosynthesis without causing photoinhibition?

The reason I am wondering this is because of the Emerson effect. I know that this applies to terrestrial plants, but could it, to some extent, apply to coral? Could a small amount of red and far red light increase photosynthesis in coral?

 

[vetteguy53081]

Red mainly will encourage algae and its growth
Keep it at less than 4%

 

[Brymac1]

Red mainly will encourage algae and its growth
Keep it at less than 4%

What made you arrive at 4%? Assuming you are able to keep low nutrient levels and have a healthy herbivore population, couldn’t more red light go to the corals and not the algae?

 

[LiveFreeAndReef]

What made you arrive at 4%? Assuming you are able to keep low nutrient levels and have a healthy herbivore population, couldn’t more red light go to the corals and not the algae?

Its not that the algae is blocking the red light from the corals, corals have evolved to use light on the blue side of the spectrum because that's what is readily available underwater

 

[Brymac1]

Its not that the algae is blocking the red light from the corals, corals have evolved to use light on the blue side of the spectrum because that's what is readily available underwater

I’m not saying that the algae is blocking the red light. I am wondering if you can get past the promotion of algae growth and find an optimal blue/red balance to increase photosynthesis.

 

[Brymac1]

Its not that the algae is blocking the red light from the corals, corals have evolved to use light on the blue side of the spectrum because that's what is readily available underwater

Considering many people have been very successful using metal halide bulbs with considerably more green and red light than LEDs.

 

[Dana Riddle]

Here's a short article I wrote some years back. I investigated effects of UV, blue, blue/white, and red LEDs on coral photosynthesis. Note, in particular, that the Xanthophyll Cycle was never activated by red light. Since Photosystem II has a pigment called P-680 and PS I has P-700, there is little doubt the Emerson Effect could be present. It is also possible that 'spill-over' energy from PS II to PS I could keep electron flow balanced. I did not test green light but have since acquired a 'green' LED strip light and could look at the effects. Bear in mind that the accessory pigment peridinin can absorb green light up to about 550nm.

Photosynthetic Efficiencies of LEDs: Results of Short Term Exposure to LED Lights

Dana Riddle studies zooxanthallae exposed to varying intensities and colors of LEDs between 365nm (UV-A) and 657nm (red). The collected data sheds light on how different spectra affect photosynthesis and the Xanthophyll Cycle, helping us to better understand how corals use and respond to light.

reefs.com

 

[LiveFreeAndReef]

Considering many people have been very successful using metal halide bulbs with considerably more green and red light than LEDs.

Because LED's can be tailored to only provide the spectrum you're looking for and MH produces a whiter light that covers a wide spectrum

 

[Brymac1]

Here's a short article I wrote some years back. I investigated effects of UV, blue, blue/white, and red LEDs on coral photosynthesis. Note, in particular, that the Xanthophyll Cycle was never activated by red light. Since Photosystem II has a pigment called P-680 and PS I has P-700, there is little doubt the Emerson Effect could be present. It is also possible that 'spill-over' energy from PS II to PS I could keep electron flow balanced. I did not test green light but have since acquired a 'green' LED strip light and could look at the effects. Bear in mind that the accessory pigment peridinin can absorb green light up to about 550nm.

Photosynthetic Efficiencies of LEDs: Results of Short Term Exposure to LED Lights

Dana Riddle studies zooxanthallae exposed to varying intensities and colors of LEDs between 365nm (UV-A) and 657nm (red). The collected data sheds light on how different spectra affect photosynthesis and the Xanthophyll Cycle, helping us to better understand how corals use and respond to light.

reefs.com

Very interesting findings. Thank you for sharing!

 

[Haacheew]

well, way too much 'technical', nomenclatures for me to understand. Is there any simpler, even it's very broad and general, straight answer to OP's question which I am deeply interested to learn about.
... "So my question about red light is: is there an "optimal" ratio of red to blue light that could increase photosynthesis without causing photoinhibition?"

 

[Dana Riddle]

well, way too much 'technical', nomenclatures for me to understand. Is there any simpler, even it's very broad and general, straight answer to OP's question which I am deeply interested to learn about.
... "So my question about red light is: is there an "optimal" ratio of red to blue light that could increase photosynthesis without causing photoinhibition?"

When your red/orange clownfish don't appear black anymore, you have enough red light. As far as hard data, I've thought about an experimental protocol for years. I hope I have enough years left to get the details worked out.

 

[chadfish]

Here's a short article I wrote some years back. I investigated effects of UV, blue, blue/white, and red LEDs on coral photosynthesis. Note, in particular, that the Xanthophyll Cycle was never activated by red light. Since Photosystem II has a pigment called P-680 and PS I has P-700, there is little doubt the Emerson Effect could be present. It is also possible that 'spill-over' energy from PS II to PS I could keep electron flow balanced. I did not test green light but have since acquired a 'green' LED strip light and could look at the effects. Bear in mind that the accessory pigment peridinin can absorb green light up to about 550nm.

Photosynthetic Efficiencies of LEDs: Results of Short Term Exposure to LED Lights

Dana Riddle studies zooxanthallae exposed to varying intensities and colors of LEDs between 365nm (UV-A) and 657nm (red). The collected data sheds light on how different spectra affect photosynthesis and the Xanthophyll Cycle, helping us to better understand how corals use and respond to light.

reefs.com

This is incredible. Great article, great experiment. Thank you

 

[Dana Riddle]

This is incredible. Great article, great experiment. Thank you

Thank you! That experiment was a lot of work. I hope to get back into fluorometer work soon. BRS is thinking about getting a Walz fluorometer and, if they do, I'll probably do some work in conjunction with them.

 

[chadfish]

Thank you! That experiment was a lot of work. I hope to get back into fluorometer work soon. BRS is thinking about getting a Walz fluorometer and, if they do, I'll probably do some work in conjunction with them.

That was actually one of my questions: who funded this? The applicability seems to be mostly hobbyists. Are there university grants for research like this?

 

[Dana Riddle]

That was actually one of my questions: who funded this? The applicability seems to be mostly hobbyists. Are there university grants for research like this?

I funded the fluorometer research out of my pocket, although there was spotty research done by universities, where insitu reports are common. To my knowledge, there are only one other reports of ETRs in aquarium corals.

 

[jda]

Lasse has posted for years about green penetrating tissue and even around/into the lower depths of a colony where other light does not physically get. Red helps drive pigments like blue and purple and also helps move energy between the photo-systems, like has been posted already. There are a lot of proteins that also have photosynthesis driven at these wavelengths too, even if not ideal.

People who think that too much red drives algae and not coral, should take a look at my MH and 6500k T5 driven tanks. As it turns out, these creatures have indeed evolved to use probably every bit of spectrum from 350-850nm and only the hubris of man thinks that they can outsmart it by cutting spectrum down to a narrower band. Remember that working is not the same as thriving... humans can live on just McDonalds, but a better diet does more things.

Please, please, please, please don't pay attention to ocean depths with light and our corals. If you have never been to the coral sea or elsewhere, the vast majority of what we have in our tanks is collected on one breath with a mask, bag and some tool to cut or break. Not everything, but almost all. Take a look at the expense, training and risk to get to depths where only blue and green penetrate - 20 meters is the common limit for all but the most experienced with 40 meters needing some James Cameron type equipment and stuff. Then, see how much collectors get for corals (pennies) versus rare deepwater fish (hundreds of dollars) and you will know what gets collected when a trained, semi-rich collector goes deep.... it is not coral. If you ever go to the islands in the south pacific, some places will let you go with them and collect your own things and you can do most of it in waist deep water and without even going under. The water here is crystal clear and the light penetrates well over 100 meters. I am sorry that some dumb LED company put in a paper made to look like it was from a real lab that corals are collected where only blue light penetrates... and that hobbyists believed it, but it is mostly a complete lie.

 

[jda]

Sorry for 2 posts, but there is little doubt that corals can do better under wider range light sources like T5, MH and even LED with all channels up way high and the main supposition is from more red, more green and more UV. Red for the Emerson Effect and for blue and violet development. Green for more photosynthesis. UV for high powered energy and also to great pigments in coral that don't develop without it - I know that this post is not about UV, but it is in this trio that is misunderstood.

If anybody is in doubt about what can be accomplished with LEDs with large amounts of the whole spectrum, find photos of Dr. Joshi's tank or find thermans build or for-sale thread around here... wonderful looking corals and no algae. If your corals don't look like theirs and you have nice things (some corals just never look good), then think about adding in more of the entire spectrum. It helps.

I post this a lot, but while dry and hard to watch, force yourself to sit through Tullio's Facts of Light from MACNA a few years back and he goes into a lot of just the facts about what is important. Most of it is not what you think if you have just gotten your knowledge from a message board, retailer (even BRS) or manufacturer which are less than accurate most of the time. If you are well read on more fact-based stuff, like the article above, then you might know a lot, but can still learn something from this video. This is a good one-hour in video form to supplement the good articles that have been written and posted over the decades that most people just don't want to read.

Look at a spectrum chart of sunlight if you want to see natural ratios. These things absolutely thrive in the sunlight in this state and are under about a 6500k spectrum when the tide rolls back in... yet people struggle with them in their tanks using spectrums from a manufacturer or vendor. I know that there is more to it that light, but light is the most important, IMO, since it brings the energy and I would rather have my MH spectrum and just OK water and stability than just an OK light and perfect water and stability. I did not take this photo, but stuff gets collected no far from here. Don't tell me that red and green are an issue for these things:

 

[Nonya]

Th

Don't tell me that red and green are an issue for these things:

Those look like candidates for photoinhibition, regardless.