There is a paper on coral growth at different light spectra (blue only, white only, mix) and basically as far as I remember corals grow in any light but were growing slightly better under full spectrum. The difference was quite negligible though so basically they grow anyway at similar rate, its just up to what you like, they will adapt.
Clarifying your posted links. Since you tried to show coral growth depths ect. I mean you might as well have posted coral growth graphs at 800 meters after all theres a lot of nps coral reefs down at that depth, but those are not commonly kept either.
Here is my noon spectra with 3 pcs GHL Mitras LED bars 120 deep actinic and one 120 actinic.
And here is my tank (two days ago) 4K. No manipulation with the video according filters or light regime.
Sincerely Lasse
A tip - test with some simple RGB strips before adding more "white LEDs" RGB will trick your eyes to see a whiter shade of pale and do not change the photosynthetic spectra to much. As you can see in my morning video - is mostly my RGB chips that works
There is way less PAR at deeper depths hence less coral. If you actually read the write-up I linked and the associated studies it shows that the spectrum found near the surface of the water is not optimal. You get increased photosynthesis if you add blue and you get higher par before bleaching if you remove some red.
ocean.si.edu
What you posted has nothing to do with light, it had to do with water temp changes triggering bleaching.
www.aquariumcomputer.com
Repost
Another question – is green light important for the growth rate and photosynthesis? It’s true that there is no type of chlorophyll that peak at these wavelengths we call green and that a green plant is green because the photons is reflected. But its also known that there are co-systems that can pick up different wavelengths and transfer them to usable quanta so green is maybe not the most effective wavelengths but in some way, they are linked to the photosynthesis. Its known – from terrestrial plants that green can penetrate rather deep in the tissue and hence provide some help for the photosynthesis in deeper layer.
There is also some prove for green photons can go trough leaves and hence make some photosynthesis rather low in the canopy. I got an idea – I can test that. I took my headlight (a strong phosphorus coated white LED) and hold it above a rather thick green leave from one of my wife's potted plants. The result you can see in the pictures below. From the upper side – there is reflecting many green photons – because the green colour of the leaf.
But how its look on the backside of the leaf – there is no light or reflected green photons there. If all photons are reflected (green) or absorbed (all others) it should be black on the backside. If the backside has any colour in this experiment – it means that the photons of that special wavelengths (read colour) has travel through the leaf – look self for the result.
I have never, ever before proved a theory so easy as I did in this case. Green photons can travel through plants cells in a way that others do not! It means that leaves further down in a tree can use green wavelengths – the red and blue is already absorbed.
Has this importance’s for stony corals – I think so. If it can travel down in a cell structure – it can work in the deeper layers and be reflected of the white skeleton.
Needs the definition of "shallow" in terms of the ocean.
Depends on the light (and settings) for example.
Then why do the branches of Acropora species grow upwards almost to the point of breaking the waters surface? Wouldn’t it benefit them to grow downwards away from this suboptimal “red zone”?
because they evolved close to the surface. Different corals need different conditions. Deeper corals usually want want more blues and less reds than shallower ones.
Who's arguing against green?
"Morphology" effects are tricky but one thing is pretty standard.. If you grow a cylinder straight up you have less surface area during peak irradiation then if you are growing horizontal.
