prolong effect of actinic lights

[Dana Riddle]

LOL. Is it correct for me to assume that lights (the whole bunch of details about lighting) is the culprit for color mismatch?. My sps corals is a mixed of wild sticks, from tidal line (2 - 3 feet of water at lowest tide) to several meters deep (roughly 10 - 20 meters) so the light changes are quite dramatic as compared to 18" deep tank.

The Japanese researcher Kawaguti published two papers on coral coloration back in the 1940s. He speculated (correctly) that light was a major factor, but also reported that temperature, hydrogen peroxide, and (if memory serves) pH affected color. Very interesting works but the devices available then simply do not compare to what we have today. It is my intent to repeat his experiments in much more detail.

 

[Dana Riddle]

Another question lingering in my head is for every meter of sea depth, how much PAR dropped?. Any scientific data on this?. In our tank, the losses is quite significant and we are talking about inches depth here.

I have published PAR values taken in the clear, oceanic waters off the coast of Kona, Hawaii. Then used that to apply Jerlov's attenuation factors to arrive at PAR values at depth in oceanic and coastal types waters. This is buried in the research I did over the last 18 years while in Hawaii. I'll report back when I find it.

 

[Donovan Joannes]

Great!. Can't wait and I believe a lot of reefers would love to dig more on these as well. Appreciate your input here Dana.

 

[mcarroll]

Instead, we used vertically-mounted Iwasaki 400 watt 6500K lamps in high-bay fixtures that could deliver up to around 900 PAR. In fact, we grew the 'Purple Monster' Acropora in this amount of light, although growth was slow (but coloration was superb.)

Now growth was slow for the Purple Monster because of the high PAR of 900 or because of the nature of the acropora itself to grow slowly.

It's interesting to me that slower growth seems correlated with healthier (or at least more resilient) corals.

Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata

 

[mcarroll]

I have published PAR values taken in the clear, oceanic waters off the coast of Kona, Hawaii. Then used that to apply Jerlov's attenuation factors to arrive at PAR values at depth in oceanic and coastal types waters. This is buried in the research I did over the last 18 years while in Hawaii. I'll report back when I find it.

Because there are so many influencing variables I thought attenuation values pretty much always depended on local conditions?

Isn't there an old-school rule of thumb that light attenuates 1:4 in water and 1:2 in air? Something like that? (I've never been able to find an online hobby source for it, but it's one I heard a long time ago.)

Is the Jerlov info you're referring to (from Marine Optics?) available to the public anywhere you know of, BTW? I think last time I tried to find a source, a friend pointed me to Ocean Optics by Curtis Mobley (which is free) instead, but honestly I couldn't find/use the info there – what wasn't over my head didn't seem to apply very directly to our limited uses. (That Google Books like for Jerlov is new to me, but it's heavily edited for the free online presentation.)

 

[Dana Riddle]

Because there are so many influencing variables I thought attenuation values pretty much always depended on local conditions?

Isn't there an old-school rule of thumb that light attenuates 1:4 in water and 1:2 in air? Something like that? (I've never been able to find an online hobby source for it, but it's one I heard a long time ago.)

Is the Jerlov info you're referring to (from Marine Optics?) available to the public anywhere you know of, BTW? I think last time I tried to find a source, a friend pointed me to Ocean Optics by Curtis Mobley (which is free) instead, but honestly I couldn't find/use the info there – what wasn't over my head didn't seem to apply very directly to our limited uses. (That Google Books like for Jerlov is new to me, but it's heavily edited for the free online presentation.)

Yes, Marine Optics. I think I've got those factors in an Excel sheet. If so, I can send privately if you wish.

 

[Abhishek]

So test out the theory of extended monochromatic actinic supplement for long hours causing fluroscent colors like acros turning green, i have reduced the photo period of reefbrite leds to half and now its completely switched off
. Will see how it impacts colors.

Regards,
Abhishek

 

[BCSreef]

So test out the theory of extended monochromatic actinic supplement for long hours causing fluroscent colors like acros turning green, i have reduced the photo period of reefbrite leds to half and now its completely switched off
. Will see how it impacts colors.

Regards,
Abhishek

Following! I also have an OG Purple Monster frag (Feb. 2017). Purple has faded a bit and I also see a slight green fluorescence on the base. PAR ~500.

Bob

 

[Alitoo.81]

Hi, so how it is going? Did you manage to solve the greening efect? Regards

 

[Dana Riddle]

See here:
http://www.advancedaquarist.com/2012/12/corals
I'll get back to you as soon as I can!

 

[Rakie]

In my experience greening of acros means one of 3 things.

1. Too much light, I've seen this with deep water acros.
2. Low light, depends on the acro. (More common, red planet for example)
3. Maricultured that turns green no matter what you do because maricultured almost always change colors the first 6 weeks out of the ocean.

Interesting on #1 and #2 -- I always hear people swear only one is true, not the other.

 

[Dana Riddle]

Hi, so how it is going? Did you manage to solve the greening efect? Regards

I now have reason to believe greening is related to spectral quality. I've got some experiments going.

 

[jda]

I am totally down with #2 and #3 from Boom. My deep waters get greener when the P raises even slightly... they just slow down growth under too much light. I took my fuge offline and my P went from .01 to about .05 for a few weeks and my deep waters got green stalks instead of white... light stayed the same... overall tank grows slowed and coralline stopped making new spots (although I am sure that the plating stuff keeps going). Once fuge was back online, then all was good again after a few more weeks.

Dana - I love the mic drop without even a hit about what lights have bad quality and what have good... although most should probably know already, I suppose.

 

[Dana Riddle]

I am totally down with #2 and #3 from Boom. My deep waters get greener when the P raises even slightly... they just slow down growth under too much light. I took my fuge offline and my P went from .01 to about .05 for a few weeks and my deep waters got green stalks instead of white... light stayed the same... overall tank grows slowed and coralline stopped making new spots (although I am sure that the plating stuff keeps going). Once fuge was back online, then all was good again after a few more weeks.

Dana - I love the mic drop without even a hit about what lights have bad quality and what have good... although most should probably know already, I suppose.

I'm hesitant to discuss the topic much further at the moment, as I want to see if results are repeatable. The experiments are for the MACNA presentation, and I've signed a document to allow a video to be made of it. The time allowed for the presentation is about 35-40 minutes, and I'm pretty sure there will a lot more info to present than the slot allows. I'll write up the results and publish on-line in due time.

 

[Dana Riddle]

Here's info on activators for coral color conversion. Many questions remain:
Host Protein Activator Direction Shift
Acropora millepora amilFP513 UV-A Reversible 2-fold Increase in fluorescence
Acropora millepora amilFP594 Blue light @ 488nm Red to Green
Aequorea victoria GFP Anoxic/anaerobic Conditions/Blue light Green to Red
Anemonia sculata "Kindling" Protein Green Light (540-560nm) Reversible/Irreversible None to Red
Dendronephthya sp. Dendra Blue Light @ 488nm Green to Red
Dendronephthya sp. DendFP UV-A at 366nm Irreversible Green to Red
Discosoma DsRed Exposure to light at ~ 488nm Green-blue to Orange
Discosoma DsRed Exposure to light at ~570nm Red to Super Red
Favia favus Kikume UV & Violet (350-420nm) Green to Red
Lobophyllia hemprichii Eos UV @ 390nm/Violet Light ~400nm Green to Red
Montastraea annularis UV/Violet Light Green to Red
Montastraea cavernosa mcavRFP UV Violet Light Irreversible Green to Red
"Pectiniidae" Dronpa ~490nm to bleach Reversible Green to None
Ricordea florida rfloRFP UV/Violet Light Green to Red
Trachyphyllia geoffroyi Kaede/tgeoRFP UV - Violet Light (350-410nm) Irreversible Green to Red

 

[mcarroll]

Dendronephthya sp. Dendra Blue Light @ 488nm Green to Red
Dendronephthya sp. DendFP UV-A at 366nm Irreversible Green to Red

So "non-photosynthetic" does not imply "non-photoreactive" – interesting!

 

[Dana Riddle]

So "non-photosynthetic" does not imply "non-photoreactive" – interesting!

There are a few Dendronephthya species that contain zooxanthellae, although most do not. It is unfortunate that these researchers didn't determine if these Dendros contained symbionts. We do see fluorescence in some animals that are not photosynthetic (such as some large creepy scorpions I recently saw displayed under a black light in a local shop) - but is the fluorescent protein acting as a UV sunscreen? Nature loves to confound us!

 

[mcarroll]

There are a few Dendronephthya species that contain zooxanthellae, although most do not.

I did not know that!

 

[ikolbaba06]

Not sure this has anything related to the original topic but....I have some Mariculture colonies that I have under ap700. Originally I had low nutrients but let them increase significantly light intensity went up as well. I noticed a very prominent green fluorescence on pretty much all my acro pieces. It has just about went away and I think it is related to only two things that I have changed. The light intensity went up even more and I lowered nutrients at the same time. I also changed the setting on the ap700 but that was only recently and the green sheen changed prior. Nutrient related vs light intensity I’m not sure.

 

[Dana Riddle]

Not sure this has anything related to the original topic but....I have some Mariculture colonies that I have under ap700. Originally I had low nutrients but let them increase significantly light intensity went up as well. I noticed a very prominent green fluorescence on pretty much all my acro pieces. It has just about went away and I think it is related to only two things that I have changed. The light intensity went up even more and I lowered nutrients at the same time. I also changed the setting on the ap700 but that was only recently and the green sheen changed prior. Nutrient related vs light intensity I’m not sure.

Likely light related, and more specifically due to increase of UV through blue wavelengths. It would be great if you could share more details.