Red light theory

Discussion in 'Lighting' started by williet, 13 Aug 2012.

  1. williet

    williet Look at the shiny LEDs!!!

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    Hi Guys

    Hi @RiaanP et all. This is the information I have read. Haven't had time to write a nice article on the matter (Which is what I intended) but here goes.

    What it states is that Red light color spectrum is not found as it gets deeper on the reef (The water Column attenuates the red light wavelengths). Therefore your most predominant light is blue under the sea and corals have the pigmentation to deal and benefit from that. Most corals do not have the pigmentation to deal with the Red color spectrum properly.

    In a nutshell the Red Light spectrum does the following

    It slows growth in Corals by slowing the development and growth of Zooxanthellae. What happens is that this then in turns affects the photosynthesis process and subsequently slows this process down to almost a grinding halt and bleaching then happens.

    Have a read at the articles, you will see the test results and why it does what is does!

    Reference links are

    http://www.advancedaquarist.com/2008/12/aafeature1#section-6

    http://advancedaquarist.com/issues/june2004/feature.htm

    http://www.advancedaquarist.com/2004/6/aafeature
    The Red Light Theory Revisited

    In order for a hypothesis to advance to a theory, there must be some sort of evidence from experiments in support of the idea. The following presents the evidence in support of the 'red light theory.'
    Hawaiian researchers, in the 1980's, found that exposure to broad bandwidth red light resulted in low growth rates in corals (Kinzie et al., 1984). Further experiments (Kinzie and Hunter, 1987) found that corals exposed for more than 60 days to light composed of mostly the red portion of the spectrum resulted in corals that "…were almost entirely free of algae and appeared white, but retained complete coverage of living animal tissue. We have not been able to obtain this degree of bleaching with any other method, including prolonged shading."
    Results from further experiments would suggest that red light generated by light-emitting diodes (LEDs) can induce coral bleaching. Experiments conducted in early 2002 (see http://advancedaquarist.com/issues/june2004/feature.htm) demonstrated that narrow bandwidth red light produced by an LED in underwater housings caused bleaching in the stony coral Pocillopora meandrina. I conducted later experiments in 2004 that resulted in bleaching of an expanded selection of corals (including stony corals Porites, Pavona, Pocillopora and unidentified zoanthids - see Figures 6 and 7).
    [​IMG]
    Figure 6. The LED/coral experiment to determine effects of various narrow bandwidth light on corals.​

    [​IMG]
    Figure 7. Effects on a Porites coral of light skewed towards the red portion of the spectrum as determined under the circumstances shown in Figure 6. Red light intensity was low at 160 µmol·m²·sec.​
    In light of the evidence, should we really be surprised that red light can possibly be detrimental to at least some corals' zooxanthellae? Just a quick look at Figure 8 confirms that many corals are found in environments deficient in red light. 'Strong' red light is unnatural and seems to be a factor in regulating zooxanthellae density and/or pigment content.
     
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  3. RiaanP

    RiaanP Moderator

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    Yip interesting article, problem is, that running corals under only RED LED will give you different results, especially if you only look at deeper water corals.

    Agree.

    But Radion do no only have red LEDs. The red and green are only a few in between. And you are not running purely RED.

    Saying red should not be in marine lights, why do Giesemann sell Midday?

    D-D Giesemann Powerchrome Midday T5 High Output Fluorescent Lamp

    These Giesemann Midday tubes got almost the same amount of red and green as the blue part?
    So both companies got it wrong? Nope

    and Plasma lights with their full colour spectrum? Then they are also not correct either?

    Doing tests on only one narrow band of light will show problems in the corals.

    Another thing to ponder. SPS is shallow corals. Sunlight reach SPS before all the reds and greens get filtered out. But LPS that are deeper reef corals will do better with less red and green. Softies depends on type. Pincushions and Sinularia cannot handle big wave actions, and that is another indication that they are deeper water species. For them less red and green. But Zoa and button polyps that we find in tidal pools can handle waves crashing down on them. So more red and green for them.

    So yes, a lot of "informative" knowledge are out there. and depending on how its interpreted, can be used to proof or discredit anything.
     
    Last edited: 13 Aug 2012
  4. williet

    williet Thread Starter Look at the shiny LEDs!!!

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    Hi Riaan

    To answer all your questions from my reading, Take in consideration what most guys who own metal halides have SPS/LPS or both.

    Discussing Giesemann Lets look at their Spectral graph
    [​IMG]
    They are hitting the right target colors...

    Lots of Blue a bit of green and some orange... look at the W/nm. You will never have the accuracy of LEDs where you can almost be specific of the nm's you will hit.
    Lets look at the seashine
    [​IMG]

    The Seashine spectral graph the red is only slightly more than on the Giesemann middays. Not really much difference between the two 0.1w/nm (if I read the graph correctly)

    Interestingly note how quickly the red attenuates after 1m !

    I am sure you find most of the Acro's and Montis below 1m? Also with regards to softies, this document was directed at SPS/LPS mostly. Zoas are far more capable of producing the pigmentation required to ensure survival ? @brentch ?


    I hope this answers ? Please note this is my research on the matter, any comments are more than welcome!:thumbup:
     
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  5. williet

    williet Thread Starter Look at the shiny LEDs!!!

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    @butcherman

    What I mean with bad is that Red Light actually regulates the growth of Zooxanthlellae. (in this case slows(or stops) it down by disrupting the photosynthetic process.). Us as reefers don't want this... We want them beasties to grow !

    With regards to your algae question, I have read somewhere just can't remember so I cannot state the validity that green actually stimulates algal growth !

    A bit lazy to go and reference that info, but if you read the links above it will answer that.
     
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  6. brentch

    brentch

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    Sorry just saw my mention here, I feel so famous right now:biggrin:

    I'm more on the genetic and ecology side of things and biochem and physiology isn't really my thing... What I do know is this....

    Red light penetrates to ~ 0m-10m (depending on water clarity, light angle etc.) so corals within the red range will be exposed to it (on low tide some are exposed to air).

    Photosystem 1 and 2 are the working bits that convert photons of light to chemical energy, where the bonds between H2O are broken, and electrons are liberated for use in driving protons across the thylakoid membrane, converting NADP to NADPH and ADP to ATP.

    If too much light hits the photosystem molecules, they "bounce" off and if they really come in too fast/too many, photosystem can be damaged. Another problem is that each photosystem molecule operates by absorbing photons at different wavelengths (chl a and b). If a wavelength is too short or long, the cell is effectively losing out on energy it could possibly use. Accessory pigments help solve these problems. They bounce excited photons (mostly in the intermediate visible light wavelengths, green) off themselves, or change the energy of the photon and allow for a greater range of wavelegth to be absorbed.

    If these pigments are overwhelmed, they can fail (they denature), leading to damage to the photosystem molecules, and then bleaching occurs. This can happen when a coral has not been acclimated, to raise its photopigments to be able to protect its photosystem molecules, or if there is just too much light.

    Now that is what I know (which should be 93% factually correct), and below is my opinion (which is 100% correct, because I said so... :) )

    I don't think the output of MH's or LED, or any other artificial light source at the moment could bleach a coral if it has gradually been acclimated to its environment... Natural light is so much stronger that I think it isn't really possible to slow growth. As long as the primary wavelengths (about 440nm and 680nm) are covered, any other wavelengths (within a reasonable certain range) can be used by zoox as an added extra bit of energy...

    The wavelengths in algae are the same as zoox in coral (they are all actually protists...). They clearly reflect green light; that is why algae is green.... So having green light surely cannot help grow algae, as they don't use it, and rather "bounce" it off the thylakoid... I know that yellow light does help grow algae cause they have accessory pigments to help absorb that side of the spectrum...
     
  7. irie ivan

    irie ivan MASA Contributor

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    OR........ as a deterrant...... Also highly doubt that the lamps we use will damage corals if acclimatised to them slowly.......

    Have always been intrigued by this........ Red light, slows down zoox activity, less zoox present, less brown colour..... pretty much what we want in sps????? Add some UV to it and you have an even greater production of the colourful sunscreen sps produce...... Hmm..... bring on the infa red and uv lamps......
    Seriously though.... its all about balancing the wavelengths.....and a few more things...
     
  8. RiaanP

    RiaanP Moderator

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    I believe that running purely blue or actinic LEDs is not correct. Their wavelength bands are very narrow. Where T5, even if 20000K tube still give some other wavelengths, but not much. That is the reason why we always mixed up T5 tubes and why multiple fixtures, 6 or more bulbs, are better (they allow more mixing).

    Looking at Giesemann T5 tubes, the best T5 tubes for coral growth (apparently) is the Midday tube. But that one gives the yellow look to the water. We offset it with Aquablue to get the look we like. And also its better to run the Midday during the day when you are not home, so you do not see it.

    That is why LED units with multiple colour optics should be better than only 1 or 2 colours. But the trick is the spread of the wavelength and the intensity of each wave. Good to have some red, but it should not take the unit over. Be that Radion units or DIY.
     
  9. CW

    CW

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    Interesting read hear.
    Ill be watching this carefully.

    Thanx to all
     
  10. cclarity

    cclarity

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    Whew, I was getting worried for a bit there, as I have ordered the red and UV pads for my Vertex.
    So my noobi theory was correct then.
     
  11. 459b

    459b Moderator MASA Contributor

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    This is true, however not all the corals in our tanks come from the deeper reefs. We tend to buy what we think is pretty and end up with a mix of corals from all over the world living in different conditions. Hence the need to have some variation with regards to lighting to try and make all corals as happy as possible.
     
  12. Jamie@Vertex

    Jamie@Vertex

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    I know I will regret joining in on this, as I do not have enough time to explain all the processes involved, but.....

    The understanding of spectrum and coral photosynthesis has grown rapidly in the last few years. After the first experiement by Dana Riddle about 10-12 years ago, it was clear that red spectrum had little use for photosynthesis.

    We have since become aware of what is know as the Emerson Effect, whereby light between 660nm and about 720nm creates an effective photosynthesis when present TOGETHER. This has not been proven in corals, however! The research was done on certain alga in a lab. This form of photosynthesis requires both wavelengths to function and these wavelengths will only be found together in air exposed corals, therefore tidal. This would make Emerson photosynthesis close to useless for all corals and this for two reasons. First, the time frame for such a photosynthesis is very short and the conditions at this time would be quite hostile for the coral. Without water flushing through the system of the coral, it would quickly come into photoinhibition, and would not be able to remove waste products from its system. Secondly, coral pigments would tend to prevent this kind of photosynthesis. Remember, the colour of a coral is related to the light it reflects away. Reddish corals are common on the reef flat.

    As we know, there is literally no red light left at 5 m below the water surface and over 90% is filtered in the first 1 meter! Clearly, the very nature of water makes red-light photosynthesis inappropriate. Blue is where it's at. Still, we have a small amount of this light available in shallow waters, which is, also where many red corals are collected (not all, however). The red pigments would seem to be a reaction to this fluxuating red light. The first thought would be that the red light is responsible for the pigment production, but we know that large amounts of red bleach corals. It appears that the UV-Violet spectrum is closely associated to red pigment production, indeed, it is responsible for the kaede reds. Other pigments may be dependant on wavelengths up to 510nm for their production/ripening. We are still in the blue range to turqouise-green. We have no evidence that coral pigment are dependant on wavelengths above this range, but we shouldn't say it doesn't happen. We are still learning about their production. Keep in mind, fluorescent response has nothing to do with pigment production.

    Most of the corals we keep come from below the 5m mark and typically around 10m. Red radiation plays no real role in their metabolism. For our eyes, it remains an interesting part of the spectrum.

    Also, for the record, I have damaged corals (bleached them) with 630nm red LEDs, and this is possible. Mind you, I was really pushing the levels to find the extreme. Using only red may well kill a coral, not so much from the red itself, but the missing energy for the required photosynthesis, which cannot take place under red radiation. This appears to be a genetic component of corals. They have adapted themselves to a variety of extremes and based their basic metabolism on blue radiation, which is available up to 100m below the surface in sufficient quantity to run photosynthesis. This alone makes it clear that being even partly dependant on red radiation would be a fatal evoutionary mistake.

    More on this later.

    Jamie
     
  13. cclarity

    cclarity

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    Thanks for the info. It is now asa cleaer asa mud
     
  14. williet

    williet Thread Starter Look at the shiny LEDs!!!

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    @Jamie@Vertex

    Thanks for clearing this up. Have been very busy myself so I have not had a minute availble till now to respond. I cannot agree anymore ! From what I have read is that the light actually affects the whole photosynthetic process and shuts it down by affecting PS1 (Photosynthetic system 1). For me as a SPS reefer yes, you want colours but, my tank is covered in frags
    and I would like them to grow and with the prolonged exposure to Red Light spectrum I can only think it is even less beneficial in the long run.

    Red LED's and Green Led's are used by manufacturers only to make it look "Pretty" to the eye imho.

    Please see the additional extract about it I got from the articles above

    "Replicate experiments by Kinzie and Hunter (1987) corrected some errors advanced in the earlier work of 1984. Interestingly, the 1987 paper advanced a theory that the amount of incident red light is the parameter that regulates zooxanthellae cell density and, hence, pigment content. This hypothesis (confirmed by results of their experiments) states that corals subjected to increasing amounts of red light will reduce the number of zooxanthellae cells until totally bleached. These scientists used natural sunlight and filters to transmit a broad red bandwidth (~600 to 800 nm). (Note: Coral bleaching has also been seen at a narrower red bandwidth produced by an artificial light source - a light-emitting diode (LED) - Riddle, in press). Why might red light induce a reduction of zooxanthellae and/or photopigments? Why does red light seem to be the controlling bandwidth for the content of zooxanthellae photopigments? An answer lies in the remarkable process we know as photosynthesis.
    Photosynthesis, as we know, is the link between the inorganic and organic worlds. Light energy absorbed by photopigments leads to production of oxygen, simple sugars, amino acids and fatty acids. These photochemical processes are dependent upon two distinct photosystems acting in unison, and are called, appropriately enough, Photosystem II (PS II) and Photosystem I (PS I). Very simply, these photosystems are dependent upon each other. There must be a balanced energy distribution between PS II and PS I (since Photosystem II produces an oxidant and PS I a reductant, and makes possible the electron donor/acceptor shuttle between the systems). In photosynthetic corals, this balance is probably achieved through control and/or alteration of photosynthetic pigment content of zooxanthellae (Kinzie et al., 1984). For instance, the accessory pigment peridinin transfers harvested light energy to chlorophyll a (with efficiencies ranging from 88% to >95%, see Damjanovic et al., 2000) and hence to PS II's reaction centers containing Pigment 680. On the other hand, the carotenoid beta-carotene transfers its harvested energy to chlorophyll a and PS I (which contains Pigment 700). Increased absorption of light energy above 680 nm by coral zooxanthellae is associated with aggregated forms of chlorophyll a and PS I's Pigment 700 (Titlyanov et al., 1980). Corals adapted to a certain light field will, when subjected to different light quality, adjust to the new light environment, or, under extreme circumstances, will bleach. It is possible that an imbalance of energy distribution could destroy PS II within a zooxanthella, thereby shutting down photosynthesis."

    I hope this clears things up !

    Willie
     
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  15. cclarity

    cclarity

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    Now this is what the forum is for. Sharing all this valuble info.
     
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