UV light and coral colors

[Sushitheshiba]

Hello @Dana Riddle ! I saw your presentation earlier today at MACNA and I didn’t get a chance to ask you in person. So please correct me if I’m wrong:
According to your presentation, UV lights created a shift in color in the coral that you tested (I think it was an LPS coral?). Then also I think you stated that if we didn’t really want a color change, we should try to expose the coral to a more blue spectrum (450nm I think).
So my question is that is there a certain photoperiod/limit where having a coral exposed to UV lights (LED source) would not affect the colors of the corals? Also does this affect SPS corals also (if the tested coral was indeed an LPS)?
Again please correct me if what I understood from the presentation is wrong (ran on 2 hrs of sleep lol). Thanks sir!!

 

[dave57]

Following, I believe each coral has its own excitation and emission spectra.. so if you were to expose a coral to a specific wavelength like he mentioned only a narrow blue wavelength, you won’t have other triggered fluorescent pigments or shifts in green to red? Each coral has its own genetic preprogrammed pigment changes depending on how you excite the coral with different wavelengths.

 

[Dana Riddle]

Hello @Dana Riddle ! I saw your presentation earlier today at MACNA and I didn’t get a chance to ask you in person. So please correct me if I’m wrong:
According to your presentation, UV lights created a shift in color in the coral that you tested (I think it was an LPS coral?). Then also I think you stated that if we didn’t really want a color change, we should try to expose the coral to a more blue spectrum (450nm I think). Thanks for attending
So my question is that is there a certain photoperiod/limit where having a coral exposed to UV lights (LED source) would not affect the colors of the corals? Also does this affect SPS corals also (if the tested coral was indeed an LPS)?
Again please correct me if what I understood from the presentation is wrong (ran on 2 hrs of sleep lol). Thanks sir!!

The example you're referencing is one of the Clade D fluorescent proteins, specifically the Kaede protein originally isolated from the Open Brain Coral (Trachyphyllia) - a protein sharing a 100% identity is also found in a chalice coral. Kaede is Japanese for 'maple leaf', a reference to the leaves' transition from green to red during the Fall. UV/violet light is the environmental factor triggering the green to red transition. Due to color mixing of green and red, there are intermediate colors ranging from yellow-green, yellow and orange. It is known that 470nm light will not trigger the color change, hence color manipulation is possible through use of certain LEDs. I am uncertain about the dosage of UV/violet to induce color changes, but am under the impression that speed of transition is related to wavelength intensity/dosage. There is a tremendous amount of work that needs to be done in this area. I spoke with Jake Adams at MACNA and he is interested in performing tests in his new facility. I'll either ship some of my instruments to him or fly to Denver and assist. Details have to be worked out. More soon - I hope.

 

[Rakie]

I hate to hijack and ask a different question... But @Dana Riddle -- What do you think is the primary cause of Acropora corals going green under LED? I've heard it be everything from too much blue, not enough light, too much light, etc etc etc. What do you personally feel is the most likely culprit(s)?

 

[Dana Riddle]

I hate to hijack and ask a different question... But @Dana Riddle -- What do you think is the primary cause of Acropora corals going green under LED? I've heard it be everything from too much blue, not enough light, too much light, etc etc etc. What do you personally feel is the most likely culprit(s)?

Do you mean being zooxanthellae-brown and turning green, or transitioning from one color (red, pink, etc.) to green. Each case would involve a different environmental trigger. Just trying for us to be on the same page. ;)

 

[Rakie]

Do you mean being zooxanthellae-brown and turning green, or transitioning from one color (red, pink, etc.) to green. Each case would involve a different environmental trigger. Just trying for us to be on the same page. ;)

The latter, transitioning from one color to green. I've helped people with this before, but frankly not knowing if it was caused by X, Y, or Z lighting, it may have been sheer luck that things normalized.

Again, I notice this most in SPS.

 

[Sushitheshiba]

Thank you @Dana Riddle for the response! I also asked if it affect SPS as well because I have a (supposedly) red frag that goes with what @Rakie noticed where it just shifted to a green color. Could it be in “excitation” and will return to its known “natural” red color later on?

 

[Dana Riddle]

Coral Pigment Name Activator Transition Pigment Clade
Dendronephthya sp. Dendra Blue Light @ 488nm Green to Red D
Dendronephthya sp. DendFP UV-A at 366nm Green to Red D
Favia favus Kikume UV & Violet (350-420nm) Green to Red D
Lobophyllia hemprichii Eos UV @ 390nm/Violet Light ~400nm Green to Red D
Montastraea annularis UV/Violet Light Green to Red D
Montastraea cavernosa mcavRFP UV/Violet Light Green to Red D

Trachyphyllia geoffroyi Kaede UV - Violet Light (350-410nm) Green to Red D
Here's the info from my data base. Note all are from Clade D fluorescent proteins. I do not have any information on other color transitions in other corals.