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zacharY
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Discussion Starter · #1 ·
Which colors of light found in the PAR spectrum best support zooxanthellae? In what ratios?

The purpose of this thread is to host a discussion in which we will share knowledge about zooxanthellae and the conditions best for its growth and development (with an emphasis on PUR). For a distinction between PAR and PUR, this link explains the difference in a brief, thorough way. As I understand it, PAR is just the light with wavelengths of ~400 nm - ~700 nm. So a measurement of PAR emitted from a light source may tell you the amount of light emitted in this frequency range, however PAR does not tell you how much of that emitted light is actually useful to zooxanthellae. After all, it is a well known fact that green light (~520 nm - ~560 nm) is within the spectrum of PAR, but it does not contribute much at all to photosynthesis. That's where PUR comes in. PUR tells you how much light of a certain frequency actually helps photosynthesis occur (within the wavelengths of ~400 nm - ~700 nm). Blue and red light should have a higher PUR than green or yellow light, but all those colors are included in the definition of PAR. As I understand it, this is a main reason why a metal halide fixture can have higher PAR than an LED fixture, but the LED fixture will have more growth under it - the LEDs target a more specific spectrum with greater PUR than the metal halides (which often have more light in the green-yellow frequencies which are more crisp to the human eye, but not better for zooxanthellae).

With that said, I can now move on to my main questions/points of discussion. As you may know, there are several different pigments/types of chlorophyll. From my research, it appears that chlorophyll a and chlorophyll b are the two pigments that are found in zooxanthellae chloroplasts, but I may be wrong (there may be others, please correct me if so). These two pigments of chlorophyll require different frequencies of light to work. How much more important is chlorophyll a than chlorophyll b? Perhaps someone knows a ratio of how much more chlorophyll a is used than chlorophyll b in zooxanthellae, allowing a new spectral graph to be made showing the frequencies of light best for growing specifically zooxanthellae? Obviously there's going to be some variation in the ideal PUR of species in the symbiodinium (zoax) genus, but perhaps someone has an estimate.
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/chlorophyll3.jpg" alt="Chlorophyll3" />

That's a large post that covers several topics, so any information shared (even a small amount) would be very appreciated. There isn't a lot of literature on this subject on the internet, but perhaps we can pull our collective knowledge together and form a consensus. With a better understanding of the PUR best for zooxanthellae growth, we will be better able to select appropriate lighting for our aquariums and generally further our knowledge in yet another irrelevant, obscure area of science (something I'm sure we'd all appreciate).

BTW, I'm only in high school, so please excuse any fundamental flaws I may have made in my reasoning or any clarifications you feel I must provide.
 

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High school? Really? Dude....great post and I'm along for this ride. In researching led's I learned a little of this but still very much uneducated. I agree that online resources on par vs pur are pretty limited. I'm not sure our individual experiences will amount to more than anecdotal evidence one way or another, but my nem decline makes this topic very interesting to me. Basic understanding of visible light supports green / yellow ( similar wavelengths) are reflected when those colors are seen and thus not absorbed for photosynthesis. Is that still the case with rose tipped nems? I might submit that different organisms of different colors will use different wavelengths to support the photosynthesis within their cells. As such all spectrum of light is necessary to support our reef inhabitants. When dealing with Oceanic species...a dive light reveals colors that we did not detect before adding supplemental light. Those colors are not absorbed by the creature we are viewing....thus reflected back. I can't wait to see if this thread runs because I sure would like to know how to set up my tank lights to make two things possible....1...to provide the best spectrum of light I can to make my critters happy and healthy. 2....help me decide what new inhabitants I might buy that would like living in my artificially created living reef system. Sorry so wordy.
 

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zacharY
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Discussion Starter · #3 ·
...but my nem decline makes this topic very interesting to me. Basic understanding of visible light supports green / yellow ( similar wavelengths) are reflected when those colors are seen and thus not absorbed for photosynthesis. Is that still the case with rose tipped nems? I might submit that different organisms of different colors will use different wavelengths to support the photosynthesis within their cells. As such all spectrum of light is necessary to support our reef inhabitants.
Let me see if I understand what you're saying. You're saying that since different species of corals contain different species of zooxanthellae, different corals' zooxanthellae will absorb different amounts of spectra of light. Simply put, different corals require different colors of light in different amounts. I agree; exploring this topic is the point of this thread. BTW, thanks for your contribution to the thread. How's the nem doing? Sorry I haven't gotten back sooner; I was in Costa Rica for a couple weeks. Some nice wild coral over there, but that's another story. :)

Now that I'm back in town and it's been more than 6 months since I've last replaced my bulbs, I'm looking to replace my old T5-HO bulbs with new ones. When I bought the bulbs I currently have, I knew very little/next to nothing about PUR, so I just followed the advice of others and went with 2 white bulbs and 2 blue bulbs (all bulbs are ATI). I have an Aquablue Special, a Coral+, a Blue+, and a True Actinic. I've seen great growth in most corals with these bulbs, but I know that more blue bulbs will definitely help me see more growth and color/florescence in my corals.

So how exactly is the previous paragraph relevant to this thread? As we already know, different wavelengths/frequencies (colors) of light on the PAR spectrum are more/less important than others for photosynthesis (that's where PUR comes in). To better learn how exactly how important different colors of light are to zooxanthellae (and coral) growth, I've been doing a lot of research the last several hours and have come across a few articles that could be very helpful, but unfortunately 2 of them aren't accessible to me because you need to pay or be an educator to access them. Perhaps someone here (with a little time, interest, and proof of professorship if that's a word) will be so kind as to read these two articles: this and this. Those two articles would clear up my, well, absolute lack of knowledge about chlorophyll c in dinoflagellates. In the meantime, I'll continue reading this extremely helpful and relevant article. In the coming days I may have enough information to come to a conclusion as to what colors of light are most important to zooxanthellae (a question more complex than I first thought) and perhaps how important each relevant pigment of chlorophyll is. Maybe then I can make form an informed decision as to which bulbs would best grow corals in my tank (or anyone's tank really). From my thus far limited research, it appears that chlorophyll a is by far the most important pigment of chlorophyll for all plants and algae (including taxologically anomalous protists, such as zooxanthellae), and as such, the colors of light that best serve chlorophyll a are probably the colors of light that best serve zooxanthellae. Of course, I'll see if my research (and perhaps yours, reader) will confirm or deny this.
 

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Nem didn't make it......pretty bummed about that one and will not try another. I dont want to have to evict my shrimp to keep one....they wouldnt stop raiding the food. Anyway, I will check out the articles you found.....
 

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zacharY
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Discussion Starter · #5 ·
Nem didn't make it......pretty bummed about that one and will not try another. I dont want to have to evict my shrimp to keep one....they wouldnt stop raiding the food. Anyway, I will check out the articles you found.....
Sorry to hear that. :(. When I feed my corals I try to keep the shrimp busy with food placed far away specifically for the shrimp; you may want to try doing that.

I've found a few more articles to read. However, family is coming over today and I may or may not have time to read them later, so I'll just leave them here. This article has several parts, I've linked one of them, but they're all possibly helpful. This article and this article will likely be helpful too. This one too. And here's a thread on RC that's similar to this thread; it points out some good information that I'll probably quote later.
 

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From my experience - Pacific Sun has done a lot of research regarding PUR. Give this thread (from RC) a read: http://www.reefcentral.com/forums/showthread.php?t=2315500

Remember too - the studies you read are usually broken into two camps of thought: Maximize Growth or Maximize Color. The lights and intensities we use for maximizing growth do not tend to light to coral in a way that makes it aesthetically pleasing or colorful.

Finally - Advanced Aquarist has some excellent articles on this very subject. Most written by Dana Riddle.

http://www.advancedaquarist.com/201...ider&utm_medium=slider&utm_campaign=clickthru
 

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zacharY
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Discussion Starter · #7 · (Edited)
From my experience - Pacific Sun has done a lot of research regarding PUR. Give this thread (from RC) a read: http://www.reefcentral.com/forums/showthread.php?t=2315500

Remember too - the studies you read are usually broken into two camps of thought: Maximize Growth or Maximize Color. The lights and intensities we use for maximizing growth do not tend to light to coral in a way that makes it aesthetically pleasing or colorful.

Finally - Advanced Aquarist has some excellent articles on this very subject. Most written by Dana Riddle.

http://www.advancedaquarist.com/201...ider&utm_medium=slider&utm_campaign=clickthru
Thanks for the RC thread (I'm reading it now) and the advancedaquarist link too. I'm trying my best to find articles that are impartial to the hobby; rather, that don't have any bias towards the growth nor coloration of corals (scientific articles published in journals are best). However, it seems that the ramblings of hobbyists like us and the at least partial truths put out by those involved in selling the hobby are helping me put together a general consensus.

Zooxanthellae is a dinoflagellate, a weird protist that is a relic from the times when proto-animals and algae weren't all that different. Despite the fact that dinoflagellates probably deserve their place in a kingdom of other misfits (Chromalveolata), most continue calling them algae (which is fine by me; up to now I've always though of zooxanthellae as an algae). As such, zooxanthellae (and other misfit photosynthetic protists) are pretty different from true plants and green algae. True plants use Chl a and Chl b (and possibly others) to photosynthesize. Zooxanthellae use Chl a (which is instrumental in all photosynthetic organisms) and Chl c. Unfortunately, Chl c is a less studied pigment, so it's difficult to find out out as much information about it. Additionally, the ratio of Chl a : Chl c used in zooxanthellae is an elusive factoid; a factoid that could be instrumental to our hobby and knowledge of corals in general. The reason that this could be so important is that if we knew this ratio, we could put lights over our tanks that emit wavelengths in amounts that are actually useful to zooxanthellae rather than the likely useless wavelengths that constitute a large portion of the light we currently use over our tanks. For example, many LED fixtures use a lot of cool and neutral white LEDs which, although partially hitting the useful wavelengths, mostly put out useless wavelengths (colors green, yellow, and orange; wavelengths roughly 500 nm - 650 nm). Additionally, Chl a seems to be much more important to zooxanthellae photosynthesis than Chl c, but I still haven't read any stats on this. For future reference, I've included a spectral graph for several chlorophyll pigments and related pigments (which I haven't even attempted to understand the relevance of yet).
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/chl_c.png" alt="Chl C" />
Another interesting thing is that, at least according to this graph and a few others, Chl c absorbs much more light than Chl a, but of course if Chl a is found in much higher ratios than Chl c this doesn't really matter much. You can see why we should find this magic ratio. Right now I'm coming across more reading material than I can read in a reasonable amount of time, so I may have to sort through everything again (perhaps I skipped over it).

*I plan on quoting my sources/references later: right now I'm just waiting to see where this thread is going.


:beer: Take a swing whenever I say "zooxanthellae" in my posts! :beer:
 

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zacharY
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Discussion Starter · #8 ·
Another thing I've read in a few places through my researching (thanks for another source of info on this Ted_C) is that there are limitations to LED lighting as it currently stands. This is not the purpose of this thread, but I do feel that it's relevant enough for me to post on it here.

There are plenty of people on reefkeeping forums who ignorantly go about saying how LEDs are "untested" and "new" technology not capable of sustaining corals. These statements are flat out incorrect. However, there is some merit to the conclusion: LEDs are not optimal for reefkeeping in their current form.
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/leds_spectral_graph.jpg" alt="Leds Spectral Graph" />
In this spectral graph, popular Cree LEDs (XP-G white, blue, and royal blue) are the colored lines and the actual photosynthetic needs of zooxanthellae (at least according to this article) is in grey. The LEDs only cover a small portion of the colors useful to zooxanthellae and often overuse colors that both aren't useful to photosynthesis and (at least IMO) don't improve the tank's aesthetics either. Why is this the case? Why is it that the even the brand that provides us with our most recommended LEDs still isn't giving us light that best helps coral grow? The answer is simple: money. There's little economic incentive for Cree or any other LED manufacturer start making LEDs that better suit our hobby because reefkeepers are a very small fraction of a percent of the LED manufacturers' consumer population, and as such, it is only marginally profitable (or not profitable at all) for these manufacturers to start making LEDs designed for coral growth. The result? People today are growing corals under LEDs that don't live up to their full potential, resulting in less growth than possible under specifically coral-orientated LEDs. Sure the corals are growing, but half the LEDs in most fixtures are white (actually a shade of yellow likely designed for illumination of homes or headlights in cars; not growing corals). Not only are these white/yellow LEDs not helpful (many hobbyists dim them if possible), but they take away spaces on fixtures that could be filled by actually useful LEDs: LEDs that are designed to grow corals. Even the LEDs that actually provide most of the light needed for photosynthesis over LED-lit tanks (royal blues and similar LEDs) have extremely narrow spectra that don't allow the LED technology to be used to its fullest.

Metal halide bulbs certainly weren't invented to grow corals. Someone decades ago with knowledge of photosynthesis of zooxanthellae adjusted metal halides (and T5-HOs and PCs for that matter) to emit light useful for coral growth. Hopefully someday soon someone will reinvent LEDs in this manner.
 

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Whites and yellows are not only unused - but may be harmful to corals - triggering a Zooxanthellae expulsion. Red - while used in the chlorophyll cycles - can also trigger this expulsion event if present in too high of an intensity.

None of this is really quantified though - Dana is getting close (on Advanced Aquarist) with quantifiable values.

I'm really impressed with your research - especially being in High School. This material your presenting is well beyond collegiate undergraduate and well into doctor territory. I certainly hope you are enrolled in AP science classes and can present this (and hope you have some good science teachers in your school that recognize the wonderful job your doing) and may help in getting your research published.
 

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zacharY
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Discussion Starter · #10 · (Edited)
Whites and yellows are not only unused - but may be harmful to corals - triggering a Zooxanthellae expulsion. Red - while used in the chlorophyll cycles - can also trigger this expulsion event if present in too high of an intensity.

None of this is really quantified though - Dana is getting close (on Advanced Aquarist) with quantifiable values.

I'm really impressed with your research - especially being in High School. This material your presenting is well beyond collegiate undergraduate and well into doctor territory. I certainly hope you are enrolled in AP science classes and can present this (and hope you have some good science teachers in your school that recognize the wonderful job your doing) and may help in getting your research published.
Thanks for the compliment. I haven't taken any AP science classes yet, but I do plan on taking AP Biology senior year. I plan on being a medical doctor, so this research I'm doing may actually be helpful for my higher education in biology (in addition to it being learning for learning's sake, of course). Do you mind providing a link to where the detrimental value of yellow and (certain) white light is discussed? Similarly, it's highly rumored on reefkeeping forums that red light is bad for coral growth, but apart from this single source, I've yet to find any scientific proof. That said, I haven't really looked into it that much. Another thing, I found out that zooxanthellae use Chl a and Chl c2 (not Chl c1). For future reference, I've included a new spectral graph for Chl c2 (obviously, please ignore the data pertaining to Chl c1 as it is not relevant). I think that the rightmost graph that I posted in post #7 displays the same information as this graph (in regards to Chl c2, although it appears to be mislabeled as both Chl c1 and Chl c2(?)).
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/chl_c2.gif" alt="Chl C2" />


I really like how this thread is branching out a bit from where I originally intended it to go; I think that this thread will produce some very useful results. Some more interesting (and at least mostly relevant) articles that I've been finding useful: this, this, this, this, this, and this. That last article went way over my head, but I think that it could be extremely helpful, so if anyone understands it, please interpret it to the rest of us. :read:. Forgive me if I've already shared any of those links; I have a lot of tabs open. :lol:
 

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Here's a nice table to look at:



Pacific Sun (even though a vendor trying to sell their ideas) has done alot of research into optimizing what the coral needs versus what we need to observe the coral comfortably.

They used to make their LEDs with Cool white and Warm White (what they call pre-smt technology). They discontinued this in their SMT panels.

They also speak of proteins instead of Chlorophyl - as this controls the pigments and coloration of the coral.

This and alot more is in that RC thread I linked.

This study: http://www.advancedaquarist.com/2014/5/aafeature experimented on corals with different wavelenths of light and arrived at some interesting conclusions.

This study: http://www.advancedaquarist.com/blog/red-light-negatively-affects-health-of-stony-coral arrives at some very interesting conclusions - where the conclusions disagree with the title of the article.
 

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zacharY
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Discussion Starter · #13 ·
I think I've found a ratio of Chl a : Chl c in zooxanthellae, but I have a hard time deciphering the information. I've already posted a link to it, but the information can be found in this article. I've posted the relevant charts, but not the actual meat of the article, which I recommend you take a look at (roughly pages 185-187). I think that Table 5 and perhaps Table 3 are of particular significance.
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/chart_3.jpg" alt="Chart 3" />
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/table_4.jpg" alt="Table 4" />
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/table_5.jpg" alt="Table 5" />
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/fig_2.jpg" alt="Fig 2" />
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/table_7.jpg" alt="Table 7" />
 

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zacharY
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Discussion Starter · #14 ·
Another thing that has been brought to my attention is the role of carotenoids, particularly Peridinin. I'm still confused by the role of photopigments other than chlorophylls in zooxanthellae. If anyone has any links or perhaps a brief introduction to these pigments (carotenoids like Peridinin), please do share. Also, it'd be swell if someone knew what the above charts mean for this discussion. :lol:. Perhaps I'll see if I can get an explanation on some science focused forum if no one has any explanation here. I'll report back if I do so.
 

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zacharY
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Discussion Starter · #15 ·
Found the Ratio!

I was looking through this article (page 161) and was pleasantly surprised to find the ratio of Clh c2:Chl a! :cool: :thumbup:

<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/table_5_revised.jpg" alt="Table 5 Revised" />
<img src="http://www.thereeftank.com/gallery/files/5/9/7/8/6/chl_c,_a.jpg" alt="Chl C, A" />

According to the above two sources (I already shared the first one), the ratio of Chl c2:Chl a in corals ranges from ~.05-~.25. I'll discuss the importance of this tomorrow (it's getting late). I was about to say happy Independence Day, but I just looked and saw it's after midnight. :rotflmao:
 

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zacharY
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Discussion Starter · #16 ·
I've found some more examples of ratios of chl c2:chl a. I've found that these studies often show different ratios. In every case but one, there has been more chl a found in zooxanthellae than chl c. It appears that there is a correlation between the ratio of chl c2:chl a and the depth the studied coral is found in, but further research is needed. Some studies found more chl c2 in deeper corals; some found less.

Apart from the article I found earlier, I've found no scientific studies that make concrete claims on the subject and even the previously linked article has its drawbacks. Basically, red light probably stunts the growth of most deep water corals, but has little/no effect upon (extremely) shallow corals. This is due to the fact that red light doesn't penetrate the 10 meter mark in saltwater, so any deep water coral that is exposed to a lot of red light (whether in captivity or the wild) will think that it's in shallow water it's not adapted to live in, and will potentially stop growing or even die. However, red light shouldn't have much of an effect upon shallow corals held in captivity because they are used to getting red light in the wild. In a perfect world, us reefers would know exactly what depth our corals came from and could make an informed decision as to whether or not we should expose our corals to red light. Unfortunately, this is not the case: we usually don't know what depth our corals came from. As such, we can't make that informed decision and must make a choice: should I risk the growth (and potentially life) of my corals for the off chance that they might be from shallow water and will benefit from red light? IMO, it's pretty risky to use red light at all, unless you know for a fact that your corals are from the shallow near-surface part of the reef. This was brought up earlier in the thread, so I guess I'll just post that I've found no evidence whatsoever that green, yellow, or orange light cause issues with coral growth. In fact, I didn't find any articles or even any threads referring to this (excluding the RC thread given by Ted_C earlier).

So what spectra of light do I see as optimal? From my research, it appears that chl a is much more important than chl c2 and the carotenoids (especially peridinin, which is by far the most important carotenoid in zooxanthellae). Some studies even showed that chl c2 and peridinin may make up as little as 1% of the photopigments of zooxanthellae, with chl a making up nearly all of the rest of the mix. This is why I'll be consulting the spectral graph of chl a whenever I buy new lights in the future. Thankfully, both chl c2 and peridinin have absorption spectra very similar to that of chl a, so if you provide zooxanthellae with light of the colors absorbed the most by chl a, you should also be providing light of the colors absorbed most by peridinin and chl c2 as well. Regardless of the ratios of chl c2:chl a and peridinin:chl a, our corals can benefit from all these photopigments if you provide the corals with the light that chl a absorbs the most.

Chl a absorbs the most light at wavelengths of 380-440 nm and 640-675 nm, with peaks at around 410, 430, and 660 nm. However, the red side of this absorption spectra, as I said earlier, may be detrimental to coral health, so I'll be avoiding light of the red spectrum in the future. Although less important, I'll also say that chl c2 absorbs most light at wavelengths of about 370-480 nm, with a huge peak at about 450 nm. Peridinin absorbs most light at wavelengths of about 350-575 nm, with a peak at about 475 nm. As you can see, most of the above ranges and peaks overlap, making it possible to attend to one pigment and still cover the wavelengths required by all. Blue and violet are obviously the colors represented by these ranges and peaks, so these colors are obviously essential to the growth and homeostasis of zooxanthellae and their host corals. However, as I believe I posted in the very beginning of this thread, the human eye evolved to best see green and yellow, and to a lesser extent, orange and red light to see best in the plains and forests of a prehistoric Africa. So even though blue and violet light should best grow our corals, it is still important for us to have at least a little green, yellow, orange, and even red light over our tanks so that our eyes can see the little details that blue and violet light don't allow our eyes to see. That is why I ordered the following T5 HO bulbs for my new bulb combination: 1 ATI Blue Plus (a blue bulb), 1 KZ Super Blue (another blue bulb), 1 ATI True Actinic (an actinic/violet bulb), and 1 ATI Purple Plus (a purple/white bulb). I believe that all of these bulbs will provide light in the right spectrum for coral growth (as well as better color), and the Purple Plus will provide the small amount of white (yellow, green, orange, and red) light that is needed by the human eye to avoid a washed-out looking tank.

Anyhow, I've included some new articles I've found that discuss the importance of different photopigments in zooxanthellae. All of them also discuss the ratio of chl c2:chl a. Unfortunately, as I said earlier, some of these studies have wildly different results, and more research is obviously needed. A few articles even discussed the fact that different studies seem to have different results when studying zooxanthellae's photopigment concentrations and suggest that as technology grows more apt to this field of research, more concrete answers will be given.

This, this, this, this, this, and this.
 

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Will the "blue" setting on a reef light help a Bleached Nem?

this sounds like yes ...
or no....?
Which colors of light found in the PAR spectrum best support zooxanthellae? In what ratios?

The purpose of this thread is to host a discussion in which we will share knowledge about zooxanthellae and the conditions best for its growth and development (with an emphasis on PUR). For a distinction between PAR and PUR, link explains the difference in a brief, thorough way. As I understand it, PAR is just the light with wavelengths of ~400 nm - ~700 nm. So a measurement of PAR emitted from a light source may tell you the amount of light emitted in this frequency range, however PAR does not tell you how much of that emitted light is actually useful to zooxanthellae. After all, it is a well known fact that green light (~520 nm - ~560 nm) is within the spectrum of PAR, but it does not contribute much at all to photosynthesis. That's where PUR comes in. PUR tells you how much light of a certain frequency actually helps photosynthesis occur (within the wavelengths of ~400 nm - ~700 nm). Blue and red light should have a higher PUR than green or yellow light, but all those colors are included in the definition of PAR. As I understand it, this is a main reason why a metal halide fixture can have higher PAR than an LED fixture, but the LED fixture will have more growth under it - the LEDs target a more specific spectrum with greater PUR than the metal halides (which often have more light in the green-yellow frequencies which are more crisp to the human eye, but not better for zooxanthellae).

With that said, I can now move on to my main questions/points of discussion. As you may know, there are several different pigments/types of chlorophyll. From my research, it appears that chlorophyll a and chlorophyll b are the two pigments that are found in zooxanthellae chloroplasts, but I may be wrong (there may be others, please correct me if so). These two pigments of chlorophyll require different frequencies of light to work. How much more important is chlorophyll a than chlorophyll b? Perhaps someone knows a ratio of how much more chlorophyll a is used than chlorophyll b in zooxanthellae, allowing a new spectral graph to be made showing the frequencies of light best for growing specifically zooxanthellae? Obviously there's going to be some variation in the ideal PUR of species in the symbiodinium (zoax) genus, but perhaps someone has an estimate.

That's a large post that covers several topics, so any information shared (even a small amount) would be very appreciated. There isn't a lot of literature on this subject on the internet, but perhaps we can pull our collective knowledge together and form a consensus. With a better understanding of the PUR best for zooxanthellae growth, we will be better able to select appropriate lighting for our aquariums and generally further our knowledge in yet another irrelevant, obscure area of science (something I'm sure we'd all appreciate).

BTW, I'm only in high school, so please excuse any fundamental flaws I may have made in my reasoning or any clarifications you feel I must provide.
 
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