Just for Fun - The Perfect Spectrum

[taricha]

A question and a provocation:

...I arrived at these numbers while working on a project. It includes UV-A as well as the normally considered violet-red wavelengths. Again, just for giggles, but its fairly close.

Question on interpreting this correctly. Since they are described as light absorption expressed in percents that add up to 100%... I assume that means when hit with full spectrum light - zooxanthellae photopigments absorb a certain amount of that light, and this is a breakdown of how much of each part of the spectrum is represented in the absorbed light. In other words "29% of the light absorbed by zoox photopigments is in the 431-480 range."

And just to be provocative - these bands vary greatly in size (green-blue is 9nm and red is 99nm), what if we scaled the percent by the size of the assigned color band...

UV (350-399) 13.6%
Violet (400-430) 22.3%
Blue (431-480) 29.0%
Green-Blue (481-490) 4.6%
Blue-Green (491-510) 4.4%
Green (511-530) 7.5%
Yellow-Green (531-570) 5.0%
Yellow (571-580) 1.0%
Orange (581-600) 1.7%
Red (601-700) 10.8%

...Percent per 10 nm, just to compare how much is absorbed in a given 10nm window within each color band...
UV (350-399) 2.78% per 10nm
Violet (400-430) 7.4% per 10nm
Blue (431-480) 5.9% per 10nm
Green-Blue (481-490) 5.1% per 10nm
Blue-Green (491-510) 2.3% per 10nm
Green (511-530) 3.9% per 10nm
Yellow-Green (531-570) 1.3% per 10nm
Yellow (571-580) 1.1% per 10nm
Orange (581-600) 0.89% per 10nm
Red (601-700) 1.1% per 10nm

viewed this way, green looks even more surprising (we already knew B-V was a powerhouse) and ROY look pretty puny - though every bit matters.

 

[becks]

I struggle so much with lighting, what ratio between channel one and two do you think would match your findings as close as possible.

I think my peak settings: channel A: 35%
Channel B: 55% maybe 65%

 

[Lasse]

Algae spore germination has been shown to be encouraged by free Ammonia/Ammonium.
Locally or overall..

Anything that encourages its production will encourage germination.

Once growth begins than nutrient excesses play a part..

Little to do w/ spectrum except for its effects on growth/death/ammonia changes due to..........

At least as I currently understand it..

Same w/ freshwater.. High nutrients/high light fast plant growth and fast decay.. higher ammonia levels.. more algae (blooms).

+100

Sincerely Lasse

 

[tigé21v]

A question and a provocation:

Question on interpreting this correctly. Since they are described as light absorption expressed in percents that add up to 100%... I assume that means when hit with full spectrum light - zooxanthellae photopigments absorb a certain amount of that light, and this is a breakdown of how much of each part of the spectrum is represented in the absorbed light. In other words "29% of the light absorbed by zoox photopigments is in the 431-480 range."

And just to be provocative - these bands vary greatly in size (green-blue is 9nm and red is 99nm), what if we scaled the percent by the size of the assigned color band...


...Percent per 10 nm, just to compare how much is absorbed in a given 10nm window within each color band...
UV (350-399) 2.78% per 10nm
Violet (400-430) 7.4% per 10nm
Blue (431-480) 5.9% per 10nm
Green-Blue (481-490) 5.1% per 10nm
Blue-Green (491-510) 2.3% per 10nm
Green (511-530) 3.9% per 10nm
Yellow-Green (531-570) 1.3% per 10nm
Yellow (571-580) 1.1% per 10nm
Orange (581-600) 0.89% per 10nm
Red (601-700) 1.1% per 10nm

viewed this way, green looks even more surprising (we already knew B-V was a powerhouse) and ROY look pretty puny - though every bit matters.

This is an awesome thread.
Taricha, thanks for taking the time to break it down to give everyone a different perspective.

In a T5 fixture, it seems that a 1:1, or maybe a 2:1 mix of Actinic/6500k would come pretty close to matching Dana's chart? You may need a SuperBlue thrown into the mix?
(Although, it may not be the prettiest to look at.)

 

[alton]

I was amazed at the amount of UV shown? Something LEDS where missing for years

 

[7hogwarts]

Following!

 

[Daniel@R2R]

Very interesting... *going to check Radion configuration*

 

[BradB]

You say this is just for fun, but lots of us take this very seriously.

Interesting, but perfect can mean different things. It seems this is an attempt to optimize for efficiency - this is the spectrum that is best absorbed. But "perfect" could be whatever spectrum gives the best coral colors, shows off the coral colors best, or is the most natural. And I'd expect all of these to be different for corals at different depths.

 

[jda]

Why no IR? If "perfect" included the best growth, then why would Emerson Effect not be considered?

 

[lbacha]

Here is an interesting article I pulled out the section on color penetration in water

https://manoa.hawaii.edu/exploringourfluidearth/physical/ocean-depths/light-ocean

Colors in the Photic Zone
When sunlight strikes the ocean, some of it reflects off the surface back into the atmosphere. The amount of energy that penetrates the surface of the water depends on the angle at which the sunlight strikes the ocean. Near the equator, the sun’s rays strike the ocean almost perpendicular to the ocean’s surface. Near the poles, the sun’s rays strike the ocean at an angle, rather than directly. The direct angle of the sun’s rays to the surface of the water at the equator means that more energy penetrates the surface of the water at the equator than at the poles. Water absorbs almost all of the infrared energy from sunlight within 10 centimeters of the surface. In this very shallow layer light energy is converted to heat, which can raise the water temperature and cause some the water to evaporate. When winds and waves stir the surface of the ocean, heat mixes in to cooler water layers below.

For a review of how sunlight affects sea surface temperature, see Ocean Temperature Profiles.

<p><strong>Fig. 9.7.</strong> Visible colors of light penetrate differently into the ocean depths, as seen in this image depicting light penetration in Lake Superior. Longer wavelengths such as red are absorbed at a shallower depth than shorter wavelengths such as blue, which penetrates to a deeper depth.</p><br />
Fig. 9.7. Visible colors of light penetrate differently into the ocean depths, as seen in this image depicting light penetration in Lake Superior. Longer wavelengths such as red are absorbed at a shallower depth than shorter wavelengths such as blue, which penetrates to a deeper depth.
Image courtesy of The University of Minnesota Sea Grant Program
Visible red light has slightly more energy than invisible infrared radiation and is more readily absorbed by water than other visible wavelengths (Fig. 9.7). This is why red fish appear nearly black at 20 m. Light with longer wavelengths is absorbed more quickly than that with shorter wavelengths. Because of this, the higher energy light with short wavelengths, such as blue, is able to penetrate more deeply. At 40 m, saltwater has absorbed nearly all the red visible light, yet blue light is still able to penetrate beyond these depths. At this depth, a scuba diver without a flashlight sees all underwater features only in shades of blue (Fig. 9.8 A). To see a full spectrum of colors, a diver must shine a white light directly on an object (Fig. 9.8 B).
<p><strong>Fig. 9.8.</strong> (<strong>A</strong>) A view of a mussel bed near New Zealand at 100 m depth, lit only by sunlight. Note the blue color tones.</p><br />
Fig. 9.8. (A) A view of a mussel bed near New Zealand at 100 m depth, lit only by sunlight. Note the blue color tones.
Image courtesy of New Zealand-American Submarine Ring of Fire 2005 Exploration, National Oceanic and Atmospheric Administration (NOAA) Vents Program
<p><strong>Fig. 9.8.</strong> (<strong>B</strong>) A submarine spotlight illuminates a fish and colorful rocks off the coast of New Zealand.</p><br />
Fig. 9.8. (B) A submarine spotlight illuminates a fish and colorful rocks off the coast of New Zealand.
Image courtesy of New Zealand-American Submarine Ring of Fire 2005 Exploration, National Oceanic and Atmospheric Administration (NOAA) Vents Program

<p><strong>Fig. 9.9.</strong> The intensity of sunlight decreases rapidly with depth.</p><br />
Fig. 9.9. The intensity of sunlight decreases rapidly with depth.
Image by Byron Inouye
The depth of the water not only affects the colors of light that are noticeable underwater, it also affects the intensity, or amount of light. Within the first 10 m, water absorbs more than 50 percent of the visible light energy (Fig. 9.9). Even in clear tropical water only about 1 percent of visible light—mostly in the blue range—penetrates to 100 m. Light attenuation is the gradual decrease in light intensity as it travels through matter.

 

[jda]

There are better charts out there. That one only covers the visible spectrum and is incomplete. IR up to 800 penetrates down to 10m and 850 to 7 or 8, IIRC. Dana posted a spectrum from when he was in Hawaii... it is around here somewhere. UV also fades off quickly, but 350+ penetrates decently well, but I do not think down to 50m.

 

[lbacha]

Why no IR? If "perfect" included the best growth, then why would Emerson Effect not be considered?

So the article I posted above states that IR light doesn't make it past the first 10cm of water. I find that pretty interesting as it means that only on the shallowest of reefs does IR have any effect on coral growth. I've snorkled on some reefs in panama and Thailand where the coral was only a few inches under the water and minimal tides meant it was that way most of the time. I wonder how these corals have adapted to the IR light they must be getting

 

[jda]

I do not think that is right where our corals come from... maybe in Lake Superior or up north. Some IR, maybe... like at 1000nm, but not the lower parts of IR that are part of the Emerson Effect. There is some nuance here that is being left out. There are more complete charts out there. IR will hit the bottom of our usually-less-than-1-meter-deep tanks.

 

[lbacha]

I do not think that is right where our corals come from... maybe in Lake Superior or up north. Some IR, maybe... like at 1000nm, but not the lower parts of IR that are part of the Emerson Effect. There is some nuance here that is being left out. There are more complete charts out there. IR will hit the bottom of our usually-less-than-1-meter-deep tanks.

I think the issue with the Emerson effect is the research was all on terrestrial plants. I looked and Orphek states that their 850nm IR led will penetrate 60cm which is still pretty shallow by reef standards.

While the Emerson effect may benefit corals in nature it would seem that very few actually receive substantial amounts even if it does penetrate 60cm vs terrestrial plants that would receive it in direct sunlight.

 

[lbacha]

I looked again and Emerson discussed anything above 680nm which is far Red (IR starts at 700nm) so dana's spectrum does support the Emerson effect as it has 10% in that range

This is a fun and thought invoking conversation thanks for starting it Dana

 

[jda]

There was a thread on Emerson Effect... it should not be too far back. You need way more than 680nm. 720 to 850 play a role - it is no coincidence that Orphek choose this diode. If their low wattage diode can penetrate 60cm, then imagine what more power can do.

It is observed by every person who has MH over their tank that contain good amounts of IR - if you have ever used one competently, it is hard to deny. The Orphek IR LED is a grain of salt next to the IR in a MH bulb. 10m is about all that have access to IR in nature from account in the equator, but that is nearly everything that we keep... when we were in the Coral Sea, corals were collected with mask with guys holding their breath... they do not have scuba equipment (the fish collectors do). Sure, there are deeper, but lots of it was also waist high. I have no idea what they do in Tahati, Red Sea, etc. since I was never there... they could be deeper or just as shallow. This is where what I mostly keep comes from:

 

[lbacha]

Is that the Great Barrier Reef? Pictures like that are what got me into reefkeeping way back when. It was actually what I was thinking of when I mentioned shallow reefs receiving IR.

I actually just purchased a Atlantik V4 primarily because it's spectrum looked a lot closer to a shallow reef vs some of the other led's out there that are way more blue.

So far the colors are amazing but it's too soon to say what my coral will think about it

 

[Nicholas Dushynsky]

What colour/wavelength is the other 0.1% you haven't allowed for?

 

[jda]

Here is that chart that Dana posted with his equipment at 1 meter of depth in Hawaii. 10cm just did not seem right. The 8-10 meter range is probably still more accurate... so nearly everything in our tanks is grown and collected at those depths and most are much shallower.

https://www.reef2reef.com/threads/advanced-topic-thoughts-on-emerson-effect.369404/#post-4556123

 

[lbacha]

Here is that chart that Dana posted with his equipment at 1 meter of depth in Hawaii. 10cm just did not seem right. The 8-10 meter range is probably still more accurate... so nearly everything in our tanks is grown and collected at those depths and most are much shallower.

https://www.reef2reef.com/threads/advanced-topic-thoughts-on-emerson-effect.369404/#post-4556123

Thanks for posting that it was a good read. I think the penetration numbers make sense for Red and far red. Still not sure how far IR will penetrate in nature other than Orphek stating they measured it down to 60cm with their fixture which only has two 850nm led's in it so I would think it's definitely more in nature but 8-10m is probably not the case for IR