Lighting spectra, Photosynthesis, and You (new plots!)

[kgoldy]

Bumping so it gets more eyes on.

[jedimasterben]

[BradVincent]

UV is right - very little penetrates the water. At 15", nearly all UVB is gone, and most of UVA, which is still detrimental to coral health

http://www.aquarium-design.com/reef/uvlighting.html

 

I believe much more UV penetrates water.

 

Riddle's article above does show that 15" in an aquarium UV falls off rapidly, but this could be do to distance from the light, or things in aquarium water not in the ocean.

 

This article shows 84% of 300nm light (almost the center of UVB) at 1 meter in clearest ocean water.

http://www.britannica.com/EBchecked/topic/...ical-properties

 

This means UVB falls off faster than yellow (580nm) but not as fast as orange (640nm). The response is a curve, so UVA penetrates deeper. If you have any NW, WW, OCW or Red Leds in your build, you have wavelengths that would be filtered out at shallower depths than UVB. If you have practically anything other than UV, TV, RB, or Cool Blue, you have wavelengths that would be filtered out at shallower depths than UVA.

 

Riddle's article seems mainly to argue against including more UV than what is found in nature. I don't see anything in it to support that natural levels of UV are harmful.

[jedimasterben]

Edited the OP a bit.

[reddogf5]

Hi, I'm new here, but find this very interesting.

I'll add what I know to the conversation.

One, regardless of the utilization of zooxanthellae, coral in nature doesn't receive much red light.

Two, they are augmented by auxaxillary pigments, which can absorb available light and transfer the freed electron to the primary photosynthesis structures.

Three, natural light makes coral look about as blah as can be. I built a light to be as close to natural light at 10m as I could calculate at the time, and it looks like crap. I've already shifted it toward the blue end of the spectrum.

Four, is maximum growth what everyone is actually looking for, or is it a combination of coral health and appearance?

[Nano sapiens]

Hi, I'm new here, but find this very interesting.

I'll add what I know to the conversation.

One, regardless of the utilization of zooxanthellae, coral in nature doesn't receive much red light.

Two, they are augmented by auxaxillary pigments, which can absorb available light and transfer the freed electron to the primary photosynthesis structures.

Three, natural light makes coral look about as blah as can be. I built a light to be as close to natural light at 10m as I could calculate at the time, and it looks like crap. I've already shifted it toward the blue end of the spectrum.

Four, is maximum growth what everyone is actually looking for, or is it a combination of coral health and appearance?

 

#1: How much 'red' a coral receives would depend on its depth location. Very shallow corals would receive a fair amount, but for anything deeper red wavelengths diminish quickly.

 

#4: Depends on the reefer. Some judge the success of their corals on growth, some on coloration. I'd say most are looking for a combination. Personally, as a small Nano reef keeper I'm more concerned about health and coloration vs growth (I'd rather not have to scrape and prune all the time).

[jedimasterben]

Updated the spectral plots in the OP with ones I made.

[Tripwyr]

Out of curiosity Ben, do you know what the approximate ratios of the Carotenoids and Primary Pigments are? For example, you said there is approximately 10:1 Chl.a: Chl.c, but how much Peridinin and Neo-Peridinin is there compared to Chl.a or Chl,c?

[Polarcollision]

Ben, great post! What are the Y-axis values on the spectral plots and is the max value the same on each plot?

 

Also curious about the proportions of pigments above

[jedimasterben]

I'll have to do more research on that. In the meantime, I realized that my graph for peridinin was not actually peridinin, but PCP. I will make a true peridinin graph today.

Ben, great post! What are the Y-axis values on the spectral plots and is the max value the same on each plot?

 

Also curious about the proportions of pigments above

Y-axis is simply relative absorbency of that spectra, with no reference value.

[Tripwyr]

I'll have to do more research on that.

 

It would be interesting to know.

 

I realized that my graph for peridinin was not actually peridinin, but PCP.

 

How does PCP end up with this spectrum graph? Does Peridinin have a fairly high peak in the green wavelengths? As it stands, Chl. a has almost no response in the green range, and Peridinin and Neo-Peridinin's spikes are both in the Royal-Cool Blue area. Does Peridinin have some additional significant reponse in the green range?

[Polarcollision]

I'll have to do more research on that. In the meantime, I realized that my graph for peridinin was not actually peridinin, but PCP. I will make a true peridinin graph today.

 

Y-axis is simply relative absorbency of that spectra, with no reference value.

I wanted to overlay each of the plots to get an idea of total combined absorbancy and wasn't sure how much vertical scale each plot had relative to one another. Any way to find this out? (I'm assuming that if multiple pigments absorb the same wavelength I'd want to add more LEDs of that wavelength for more light output, right?)

 

Edit: This series of articles makes my head hurt, but I'm still trying to make sense of it in hopes of getting better coral colors. So far, I assume these pigments are not part of the chlorophyll complex and serve different functions?

Links: http://www.advancedaquarist.com/2012/12/corals

http://www.advancedaquarist.com/2006/11/aafeature2

http://www.advancedaquarist.com/2009/2/aafeature1

http://www.advancedaquarist.com/2007/11/aafeature

etc...

[kratos1028]

I am trying to redo my led layout for my tank and am having a hard time with it. I have a zoa dominant tank. I read about neutral whites and cool whites but what about whites in the 14k-20k area? Are they any good for corals? I like a bluer look to my tank, around 18k.

 

Here is my new layout I just made. What do you think? Any help and suggestions would be greatly appreciated. The blues are all RB.

 

http://s589.photobucket.com/user/fahad09_2009/media/new2080_zpse3b43418.jpg.html'>

[jedimasterben]

Not the thread for that, this is just about photosynthetic needs of corals and how we can use LEDs to fill them more precisely.

[kratos1028]

Not the thread for that, this is just about photosynthetic needs of corals and how we can use LEDs to fill them more precisely.

 

Sorry about that.

[jedimasterben]

No worries - I just don't want this thread to become cluttered like the Full spectrum picture thread turned into a recommendation thread with only a few pictures

[kevin_E]

Question:

 

It's widely believed that 6,500 K is the best temperature for photo syntheses. Neutral white has a temperature between 3,700-5,000 K and Cool White has a color temperature between 5,000-8,300 K. When then do we use neutral white?

 

Thank you.

[bdevillier19]

 

Question:

 

It's widely believed that 6,500 K is the best temperature for photo syntheses. Neutral white has a temperature between 3,700-5,000 K and Cool White has a color temperature between 5,000-8,300 K. When then do we use neutral white?

 

Thank you.

Actually a 4000k 80 CRI white is the common practice in most builds these days. Some even add a few in the warmer white spectrum.

[kevin_E]

Thank you.

 

Is there a scientific reason for this? Seems contrary to practical thought (i.e. 6,500 K for photosynthesis).

[blasterman]

Zombie thread alert.

 

It's widely believed that 6,500 K is the best temperature for photo syntheses.

 

No. Blue / red are the optimum colors for photosynthesis, which means the more blue/red your light emits the higher percent of it's energy is available for photosynthesis. Kelvin is a measurement of all color weights of which many are of little benefit to photosynthesis.

 

6500k sunlight has no practical reference to artifical light at 6500k.

 

A Cool white LED is mostly 450nm blue with a bit of green and just a tiny bit of red/yellow. A Neutral has much less blue and a far higher component of green/yellow/red. The cool white per watt is going to promote more photo synthesis than the neutral, but it's a moot point given the neutral will likely have a higher percentage of blue LEDs to balance it out.

 

We otherwise use Neutral because they deliver better color than cool whites. You have more color to work with other than just blue and green with a cool white based light.

 

With most LED reef lights being over-kill in terms of PAR and having to be turned down 50% the issue of raw PPFD per watt is delegated to engineers worrying about long term space flights with solar power.

[jedimasterben]

6500K means nothing to photosynthesis. Photosynthesis wants photons of any wavelength that it can absorb - the plots you see are the absorption efficiency. Blue LEDs have no kelvin temperature, but promote the most photosynthesis. See where I'm going?

 

Blaster beat me to it.

[kevin_E]

Thanks for the insight!

 

I am thinking this for my 20 tall:

 

8 Royal Blue

4 Neutral White

4 Violet

3 Cyan

3 Cool Blue

2 Deep Red

 

 

 

I have an image, but no idea how to post it. I have 4 lusters of 6 LEDs on my heat sink.

[jedimasterben]

If you wouldn't mind, please make another thread for that - I'd like to keep only the discussions in this one.