Advanced Topic: Thoughts on Emerson Effect

[Dana Riddle]

If you're reading this, you probably know that the Emerson Enhancement Effect is an observed non-proportional increase in the rate of photosynthesis when plants are simultaneously exposed to red and far-red light. In other words, if we expose a plant to a given amount of red light and see a rate of photosynthesis of, say, 100, and we then expose the plant to the same amount of far-red light and get a rate of 100, we would reasonably expect to see a rate of 200 when exposed to the same amounts of red and far-red light. But we don't - we see a rate of, say, 300. So, the question is this - red and far-red doesn't penetrate water very well. What if it did? Would coral growth be increased? Or, as is also known, red light regulates (decreases) zoox density/chlorophyll content. Many questions. Few answers. Your thoughts appreciated.
I've been o a road trip for the last 3 days - trying to catch up.

 

[reefwiser]

I find different corals respond to light differently. Just as in nature the spat settles where it will get the light and nutrients that it requires. If it settles where it can not get that it will die. If a coral. Could use the red light at all since it has never been exposed to a red light.

 

[A4goulet]

Following along. I hope there is some experiments in the near future on the subject.

 

[jda]

Far red penetrates the two-foot-or-less deep tanks that we all keep in our homes - very few have tanks deeper than this, but far-red would still be able to penetrate them. Has anybody else been able to figure out why a good light source with red and far-red will grow corals exponentially faster than those without? This is as good of an explanation as any that I have heard.

This is another place where nature and captivity diverge a bunch. In nature, stuff at less than two feet can be exposed to the air at low tide - we have all seen this (mostly acropora) and it can thrive. In captivity, the whole light spectrum from the source is available, but the coral stays submerged. Is this not the ultimate sweet spot for growth and color?

Can you please define this "red and far-red" range in nm for me? I have always assumed something in the range of 640 to 850nm?

 

[jda]

I have read that 850nm is still present at 3m in the ocean. It seems very likely that at 1m, it is strong. If so, then you can change your "What if it did?" question to "It does in captivity, so should we embrace this?"

 

[A4goulet]

Can you please define this "red and far-red" range in nm for me

I believe it's 660nm and 730nm. At least I hope so as I plan on having a diode of each in my next build.

 

[jda]

In nature, this is not a "peak" thing, although this does happen with bulbs... the line is smoother dropping from 500nm to 800ish where charts do not usually go beyond. The output at 800 is more than half that at 500nm. Orphek has invested in 850nm diodes in their builds.

https://www.advancedaquarist.com/2012/10/aafeature

Here are four MH bulbs that excel at growth, but perhaps none as much as the Iwasaki 6500K. The Ushio 10k is another growth monster. They do not really share any peaks, yet they are all effective. I wonder if this is just an accumulation of far-red? I also wonder if "peaks" could be dangerous?

Notice how they all have a gradual drop from the 500s to the 800s.

http://reefs.com/lighting

I would still suggest to reverse the paradigm that we have in reef lighting where the sun and nature is correct until we can prove that spectrum is not needed. Removing spectrum that people are supposing is not needed has not done too well in the hobby... more and more is getting added back as time goes on.

Do I get the "oreo post of the day award?"

 

[Dana Riddle]

Walz (maker of my PAM fluorometers) uses a LED generating radiation at a peak of 745nm to stimulate Photosystem I, and calls this light 'far-red.' Here is a chart of radiation at a depth of 1 meter on a Hawaiian reef flat at 10:30 am. I wanted to gather info all day, but the water became too dangerous to enter. This reef is awash in what I assume is Jerlov Type I Oceanic water - in other words, it's pretty darn clear. Diver's describe the vis in this water as excellent, and can easily exceed 150 feet.

 

[saltyfilmfolks]

Do I get the "oreo post of the day award?"

Darned close.



I personally would like to see more actuall studies on how red and far red actually penetrate.

Beyond that. Dunno. Following along.

I’ve observed way to many flourishing tanks with way more red than would be reccomended in common reefer thought.

 

[Sallstrom]

My colleague Björn has done some small tests in his lab. I haven't seen his results on paper yet, but he told me he saw a Emerson effect on S. hystrix. I think those LEDs have 715 nm as far red.
I will ask him more about his results next week. Maybe @Lasse remeber this better?

Edit Can't remember if far red is 715 or 735 in our LEDs. I'll try to find out soon.

/ David

 

[Sallstrom]

Darned close.



I personally would like to see more actuall studies on how red and far red actually penetrate.

Beyond that. Dunno. Following along.

I’ve observed way to many flourishing tanks with way more red than would be reccomended in common reefer thought.

About red light and corals.
We have some corals at work under 660nm only, just to see if they survive long term. After six weeks all Seriatopora are alive(2x3 pieces of S.hystrix and 3 pieces of S. caliendrium) and all of them have gained weight Some other species has not done so well, like Echinopora sp.
I hope we can write some about this test when we have time. It's not a perfect experiment, mostly for fun, but I think we can get some results to show.

/ David

 

[jda]

Does anybody know that for the Emerson Effect to work, does the red and far red need to be in proportion to the other waves found in nature? For example, if you were building a LED cluster, would you need 70% of the red and far-red diodes that you have at say, 450-550nm? Is using one or two just throwing a rock against a school bus? Natural selection and adaptations would tell us that the organisms have adapted for it to be this way, so is it safe to assume this?

I wonder if this somewhat explains some of the older fixtures that have white diodes (red producers) in higher concentration with the blue had better growth than some of the new gen which forsake it? Folks have had issues with color on these units, but they grew. Perhaps I am over-reaching.

 

[Dana Riddle]

The amount of far-red would depend, I think, on the amount of light-induced stimulation provided to Photosystem II. Photosynthesis is an electron donor/acceptor balancing act between PS II and PS I, so my guess is its a proportional thing. Or am I babbling aimlessly, which I tend to do on occasion.

 

[jda]

Is there such a thing as babbling with aim? It makes sense at the logical level... which is about as much aim as we have in some of this.

 

[Sallstrom]

My colleague Björn has done some small tests in his lab. I haven't seen his results on paper yet, but he told me he saw a Emerson effect on S. hystrix. I think those LEDs have 715 nm as far red.
I will ask him more about his results next week. Maybe @Lasse remeber this better?

Edit Can't remember if far red is 715 or 735 in our LEDs. I'll try to find out soon.

/ David

I think he needs to redo the test, since far red is hard to measure with a Li-Cor PAR meter. But we borrowed a Jaz last week and tested the far red on these lamps, so I think we can do new test(O2 production).
Sorry if I promised data before we had any! To much at the same time in my head

/ David

 

[Lasse]

I figured I wouldn't get any grief asking a question over here.

My colleague Björn has done some small tests in his lab. I haven't seen his results on paper yet, but he told me he saw a Emerson effect on S. hystrix. I think those LEDs have 715 nm as far red.
I will ask him more about his results next week. Maybe @Lasse remeber this better?

Edit Can't remember if far red is 715 or 735 in our LEDs. I'll try to find out soon.

/ David

Peak at 735 nm in the Helio spectra fixtures.

Sincerely Lasse

 

[Lasse]

I have started an experiment in my tank according to Far Red. I had to relay on 740 - 745 nm as peak wavelength. I started march 9.

The experiment is described here

Lasses Dream Build

Experience after one week: I´m not sure - but there is no negative effects - the corals looks rather good. However - the white edges of my montipora and the tips of my hystrix seems to have been larger and whiter the last week. But maybe its my wish that make me see things - I do not know.

Sincerely Lasse

 

[inktomi]

...Or, as is also known, red light regulates (decreases) zoox density/chlorophyll content...

That's really interesting - so the more red light in the spectra then the less zoox in the coral tissues? Are there any papers or studies anyone knows of with more info on this?

 

[Dana Riddle]

That's really interesting - so the more red light in the spectra then the less zoox in the coral tissues? Are there any papers or studies anyone knows of with more info on this?

Yes, Kinzie et al authored a couple of papers on this back in the 80's, and Wijgerde did a follow up a couple years back. I had an article published in Advanced Aquarist Online in 2001 or 2002 where a Pocillopora meandrina bleached when exposed to light from a red LED (and colored up - became pink - when illuminated with a blue LED.) My reference list isn't on this computer - scary stuff - I'll track those references down and post later.

 

[Lasse]

I wonder if this somewhat explains some of the older fixtures that have white diodes (red producers) in higher concentration with the blue had better growth than some of the new gen which forsake it? Folks have had issues with color on these units, but they grew. Perhaps I am over-reaching.

This and the fact that I have seen different growth pattern between same clone of hystrix there you have a lot of far red through MH compared with LED light (in the same water) was the reason why I start to try to figure out if these wavelengths have any impact for corals. I personally have a LED light without any wavelengths above 700 and get a growth pattern that I could not explain.

Sincerely Lasse