Science Geeks Look Here (Photosynthesis)

[NandKBlock]

I found this looking around for info about the best wavelengths of light for corals (PAR). It specifically deals with plant nurseries but much of the info about light can be applied to our application, particularly up through table 3.1.1. I won't attempt to summarize, but if the science behind the hobby interests you I suggest you have a quick read. http://www.rngr.net/Publications/ctnm/Folder.2003-05-16.1922/vol_3_chapter_3.pdf/file

I look at those spectrum graphs of bulbs in a whole new light now. Pun intended. :gay1:

[NandKBlock]

If an admin could correct my spelling of photosynthesis in the title of this post that'd be great.:biggthumpup: Thanks!

[mattb]

Yeah, its of limited value... chlorophyll from plants are different than zoox and the pigments of the corals are also different. Zoox has a peak absorbtion of 420nm (hence why many actinics peak in this and why Tyree posits that PAR isn't everything and why he uses Radiums - huge spike at 420nm more so than the majority of bulbs).... Pigments are little understood, the hobby has long interpreted coral coloration as related to sunscreen against UV, but science has shown that MAAs are colorless. There is more research happening in the pigments area, as well as the corals symbionts, zoox. There has been some work to identify which pigments absorb specific spectra, and/or reflect others (i.e. my purple M digitata 'reflects' or 'fluoresces' red spectra - not sure which it is )

Those spectral graphs are of limited value as well, if you look at the left hand label of these graphs, they typically read "Relative intensity". This helps understanding on a bulb where the peaks are, but one bulb to another, not so much... This is something that I'm interested in and collaborating with some people on with respect to T5s( as people run multiple ones on a tank and that with sps, many users report a paling effect that may be spectrum related not nutrient limitation).

Thanks for posting that though, learned a bit from it :beerchug:

fwiw, there are a lot of things in this hobby that are misunderstood, even our understanding of how a coral calcifies is nothing more than a hypothesis, not a fact. Interestingly enough, science is shooting holes into this hypothesis. But our understanding of marine environments, initially is correlated with land plants (including calcification models), such as the nitrogen cycle, ie, nitrobacter sp. do oxidate NO2 -> NO3, but only in soils, not aquatic environments....

[NandKBlock]

Hmmm, well it's probably not as useful as I thought. Would you be able to point me to some good, reliable sources on this topic? I'm interested to know the hows and whys rather than the whats. :) Thanks Matt.

Nate

[mattb]

Nate, it is useful, look at the stuff around pigments absorbing red and blue light energy, very similar to corals! The whole stuff around compensation, saturation etc are also very useful to our understanding of corals, especially considering where we are at with lighting equipment (I don't think their numbers are very correct though about 400w metal halides producing 20 PAR!!!!). There's a misconception that running huge amount of PAR, say with a lot of 400w halides in really good reflectors such as lumen brights, that in order to provide less stress to the coral, shorten the photo period... this is absolutely false! (I suspect that this can happen with T5s quite easily with good reflectors/bulbs/ballasts)....Why? Because at the constant irradiance levels the coral reaches saturations quickly and once this happens, the coral does not photosynthesize more, actually less, and combined with a smaller photo period, the coral gets less photosynthase (products translocated from zoox to host) to meet its basic energy budget, survival....


I'll try to dig up some stuff...

[wolmutt]

fwiw, there are a lot of things in this hobby that are misunderstood, even our understanding of how a coral calcifies is nothing more than a hypothesis, not a fact. Interestingly enough, science is shooting holes into this hypothesis.....

Hello??? this is the scientific process :biggrin: Had to give you a hard time Matt cause from the way your write I assume you have training on the empirical process.