What is the actual evidence for marine algae growth vs lighting spectrum?

[Randy Holmes-Farley]

I read all the time about comments relating algae growth to red light and not to blue light.

What is the evidence supporting that?

Assuming it is real, what is the hypothesized reason for it?

 

[SomeHappyFish]

Actually, I'm interested in this. While snorkelling and scuba diving, I have observed the same quantity of algae at 5–10 feet and 30–60 feet.

 

[Nor'easter Reefer]

Green algae is directly opposite to red light in the color wheel!

I'm joking as I have genuinely no clue but would be interested in more info on this topic

 

[Miami Reef]

Assuming it is real, what is the hypothesized reason for it?

I think the hypothesis is algae takes red light better, so having more would make light less limiting.

 

[Reefering1]

My take...
Blue lights Make it hard to see green algea. So if having algea problems, people tell others to "turn down the white light"- and the algea magically "disappears". Meaning the white light caused the algea problem.

--Spoiler-- 90% of the bluecrew's tank are green when lit properly. 90% of decent "full spectrum tanks" look amazing regardless what you do with the lights.

 

[Garf]

I saw no difference when using a 50watt Blurple LED UFO, or 2 x 23 white compact flouescents until the CFLs started to dim after several months.

howdy from the uk - day one - Page 14

thought i would chip in and let you comment on my effort so far. Backgroung of display- 5 x 2 x 2 with 240 ltr sump containing skimmer (massively inefficient), DSB in display (silica play sand), approx 100 kgs live rock. Most corals are 7 years old and all fish but 2 of the tangs, are of...

algaescrubber.net

 

[sixty_reefer]

I read all the time about comments relating algae growth to red light and not to blue light.

What is the evidence supporting that?

Assuming it is real, what is the hypothesized reason for it?

Maybe for the same reason it is a fairly common colour used for hydroponics.

 

[tripdad]

All of my plant grow lights are red/pink diodes. They do grow orchids and such very well. Anectdotal?(sp)

 

[Poseidon03]

I read all the time about comments relating algae growth to red light and not to blue light.

What is the evidence supporting that?

Assuming it is real, what is the hypothesized reason for it?

My hypothesis is chlorophyll a is the main contributor to photosynthesis in marine algae, and it absorbs red minutely better than blue. This can lead to more slippery slope assumptions.

 

[Poseidon03]

My hypothesis is chlorophyll a is the main contributor to photosynthesis in marine algae, and it absorbs red minutely better than blue. This can lead to more slippery slope assumptions.

Blue LEDs are also more expensive and complex to make

 

[klc]

In my FOWLR, previously an SPS dominant with Reefi lighting, I have the blue spectrum on from 7am til about 5, then normal spectrum for 2 hours, then back to blue until 10:30 then lights off.

The long blue photoperiod was put in place primarily to limit algae growth. I have not really noticed any decline in algae growth for the 2 months I’ve had blue on most of the day.

I tell my reefing buddies those that say blue light grows no algae has never done any testing with it, because blue light grows algae just as well as full spectrum does in my tanks. You can argue with me all day long and I’m going to stick with what I see in person on my own tank. I don’t think it matters, and if it does it’s an insignificant amount.

 

[Randy Holmes-Farley]

Maybe for the same reason it is a fairly common colour used for hydroponics.

In looking at freshwater planted lights, the better ones look like this for the Fluval 3.0:

 

[klc]

Blue LEDs are also more expensive and complex to make

Perhaps, but blue LEDs are still as cheap as dirt. I bought a 25 pack of 3w 420nm diodes for less than $10 on Amazon. Maybe 620nm reds are $5

 

[sixty_reefer]

In looking at freshwater planted lights, the better ones look like this for the Fluval 3.0:

I mean more like this

The Ideal LED Grow Light Spectrum for Plants

What is the ideal grow light spectrum for plants? Do different plants need different LED lights? What about for cannabis growth? Learn more from BIOS!

bioslighting.com

 

[Reefering1]

Maybe for the same reason it is a fairly common colour used for hydroponics.

"I believe" the bluer light will stimulate flowering cycle, but the plant needs to grow 1st...

 

[taricha]

The closest to evidence I think I've seen comes from the Algae Turf Scrubber threads. Most everyone who makes or uses ATS seems to think that 660nm Red light is what they want when trying to grow green dominated stuff on the screen, they throw in a little pinch of blue if they have lots of reds.
Attempting to use blue dominated-lights for ATS they say grew everything, brown slimes, etc. Not the attractive, easily harvested turfs dominated of green.

So maybe the more precise story is that red light excludes growth other than green.

sidenote: Absorption spectrums for photosynthetic pigments can be misleading. There's a million different ones with the peaks in different places, so you can probably find one to prove any point you want to make. The peaks also change depending on the solvent used for extraction, and the location of the absorption peaks in the actual photosynthetic tissue is not going to be in the same places as it is when extracted in solvent.

This is my favorite set of absorption spectra: it's specifically the absorption spectrum in-vivo for algae/phyto. It matches well the spectrum you get if you measure live algae, cyano, etc without solvents.
https://www.oceanopticsbook.info/view/optical-constituents-of-the-ocean/phytoplankton

We could note from the chart that the ATS preferred red LED of 660nm tickles the ChlA and B, but not Chl C ( C is in diatoms, dinos, and a bunch of other brown slimey's)

 

[Randy Holmes-Farley]

Dana poses much the same question here 8 years ago.

Just for Fun - The Perfect Spectrum

There is no such thing as a *perfect* spectrum for corals, but 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. UV (350-399) 13.6% Violet (400-430) 22.3% Blue...

www.reef2reef.com

 

[exnisstech]

My take...
Blue lights Make it hard to see green algea. So if having algea problems, people tell others to "turn down the white light"- and the algea magically "disappears". Meaning the white light caused the algea problem.

--Spoiler-- 90% of the bluecrew's tank are green when lit properly. 90% of decent "full spectrum tanks" look amazing regardless what you do with the lights.

I agree with this I'm in the 90 percentile

 

[Poseidon03]

I mean more like this

The Ideal LED Grow Light Spectrum for Plants

What is the ideal grow light spectrum for plants? Do different plants need different LED lights? What about for cannabis growth? Learn more from BIOS!

bioslighting.com

"Ideal" takes in a ton of assumptions. This is also for cannabis, which is not aquatic.

In looking at freshwater planted lights, the better ones look like this for the Fluval 3.0:

What is "better"? Freshwater planted lights take in the account of how plants will look to the eye, which we all know doesn't always correlate with best for the organism.

 

[Reefering1]

I agree with this I'm in the 90 percentile

Imo, once cuc is optimized and that coraline/ coral continues to spread- problem solved(green goes away).