Do actinics provide any value to corals?

[shaggydoo541]

Let's not forget that efficiancy doesn't mean better, it means competency in performance.

 

Correct but you stated blue light is the most efficient adding to the meaning of the word.

 

I never they only used blue light. I said that blue light is what they most efficiantly process.

 

And I stated it is unknown as to what is most efficiently processed. Your claim here is unsupported. Show me a study that states blue light is more efficiently processed. As you go lower in the ocean it is the only lightsource available so it wins by default. In our aquariums (where the full spectrum is available) blue light could be the least efficient for all we know.

 

... coral growth is slow in the wild, of course it would be slow in a tank sporting only blue light. Yes, their endosymbionts will use more wavelengths of light if you give it to them, but they don't need it.

 

You assume they don't need it. But who is to say that in our aquariums they do not need it? We are not keeping these specimens in the same condition (depth) you keep referring to. Who has a setup that reaches the depths you mention with only high depth specimens? No one. These examples of corals surviving at extreme depths only proves that they are highly adaptable not what our corals need or do not need in a home aquarium. Let me see a successful setup that uses actinics only and I will concede that our livestock needs only the blue spectrum. Can certain corals survive in blue light only? Yes, as you pointed out in nature they do (certain species). In our aquariums (far from nature), I'm not so sure these same rules apply as the species of corals we keep is so diverse and the conditions (water movement, light source, etc) is so far removed from natural conditions.

 

Why would you want to see a study that "that undeniably points to actinic lighting as being the ultimate lighting solution to our home aquariums"? This is not an argument that has been made in this thread...

 

Not the argument made by the op, who had a much simpler question/answer in mind I'm sure. But by stating blue light is the most efficient, you are leading one to the conclusion that blue lighting is the ultimate lighting solution for our reefs. Since ultimately we want to use the most efficient lighting setup. You also stated that the 10k is in fact for aesthetics (vs the usual idea that actinics are for aethestics). So I just took these statements to the next logical level drawing conclusions based on your ideas being correct (which I'm not sure that they are) and based on the idea that we want the most efficient lighting setup as possible.

 

We are definitely in agreement that some stimulation is provided by actinics. We differ in that you are making the statement that actinics have more importance than I feel that they do in home aquariums.

[idog]

Anecdotally, I can report that there is a large difference in my NC24 which ran for 6 months stock, and now for 2 months with an extra 32 watt true actinic. My softies and other deep water corals are doing MUCH better. Now whether that is simply due to creating a dawn/dusk effect, or whether they are actually benefitting form the extra lighting or just a more natural pattern is anybody's guess.

 

What I can report is that in the AM, when the actinics come on, the coarals open up WIDE so they are not dormant when the daylights pop on an hour later.

 

I don't have a PH meter so someone should measure this while just the actinics are on to see if CO2 is being absorbed and PS is happening.

[Mr. Fosi]

Correct but you stated blue light is the most efficient adding to the meaning of the word.

 

I did in fact state that.

 

Show me a study that states blue light is more efficiently processed.

 

Done.

 

Motoaki Kishino, et al. (1986) Light Utilization Efficiency and Quantum Yield of Phytoplankton in a Thermally Stratified Sea. Limnology and Oceanography, Vol. 31. No 3. pp. 557-566

 

This is a little ugly because NR.com doesn't support sub/superscripts. From that paper:

 

"Two primary factors control the photosynthetic efficiency of phytoplankton in aquatic environments. One is the basis of energy transfer efficiency in the ecosystem: the photosynthetic organisms as primary producers are the only ones to capture light energy and convert it to chemical energy with some efficiency.... The quantum yield of photosynthesis (mol C Einst-1) is derived from the photosynthetic rate based on chlorophyll a, P' (mmol C (mg Chl a)-1h-1) divided by the quanta absorbed by the phytoplankton (photosynthetically usable radiation) PUR (mEinst m-3 h-1 (mg Chl a m-3)-1)."

 

"In the present study, light utilization efficiency and quantum yield of phytoplankton were measured under natural conditions. Particular attention was given to determining underwater spectral irradiance with a specially designed optical instrument which give a more precise estimate of the radient energy field."

 

"The differential curve of absorption coefficient for ap and ad was compared to the absorption coefficient curve of phytoplankton (aph). Values of ap increased consistently toward short wavelengths from 0.007 m-1 at 740nm to 0.028 m-1 at 340nm at the 20m...

 

"The curve of aph showed two major peaks at 440 and 680 nm... However kc, which took into account spectral irradiance at each depth as defined in Eq. 4, showed a different vertical pattern. The value of kc increased rapidly with depth from 0.022 at the durface to 0.044 at 30 m and fluctuated between 0.036 and 0.050 m-1 (mg Chl a m-3)-1. The high kc was due to the combined effects of high specific light absorption of phytoplankton at wavelengths <500nm and the increase of the relative proportion of blue light."

 

If you want to read more about specific phytoplankton spectral absorptions coefficients, you can read: Bannister, T.T (1979) Quantitative description of steady state, nutrient-saturated algal growth, including adaptation. Limnology and Oceanography. Vol. 24 pp76-96

 

Who has a setup that reaches the depths you mention with only high depth specimens? No one. These examples of corals surviving at extreme depths only proves that they are highly adaptable not what our corals need or do not need in a home aquarium.

 

Please stop misrepresenting what I say to further your as yet unsupported point of view. I never said that this only applid to "high depth specimens", in fact the very term "high depth" is vague. How deep is deep? 5m, 10m, 20m, 120m?

 

Many of the corals that people keep in home aquaria are found deeper than 20m. Pick virtually any Acropora, Pocillopora, or Madracis species and you can easily find colonies both above and below 20m on natural reefs. If you don't believe me, ask Eric Borneman.

 

Can certain corals survive in blue light only? Yes, as you pointed out in nature they do (certain species). In our aquariums (far from nature), I'm not so sure these same rules apply as the species of corals we keep is so diverse and the conditions (water movement, light source, etc) is so far removed from natural conditions.

 

Skepticism is not evidence. I am afraid that you'll need to provide some evidence that we can't assume that corals and their zooxanthellae don't behave in virtually the same way as they do naturally. We strive to simulate nature and we succeed in keeping corals, is that merely a correlation with no cause/effect value?

 

But by stating blue light is the most efficient, you are leading one to the conclusion that blue lighting is the ultimate lighting solution for our reefs. Since ultimately we want to use the most efficient lighting setup.

 

That is an implication that is completely inside your own perception, even by the definition you just gave.

 

You also stated that the 10k is in fact for aesthetics (vs the usual idea that actinics are for aesthetics).

 

I did not say they were "in fact aesthetics". I said they were for aesthetics as much as actinics are. We use whiter light to see the colors of corals, we use actinics to fluoresce them and simulate deeper water than we have in our aquariums. As I stated, you can argue that both of them are used for aesthetics and that they are both used in photosynthesis.

 

So I just took these statements to the next logical level drawing conclusions based on your ideas being correct (which I'm not sure that they are)...

 

These are not my ideas, they are the ideas of researchers shown to be the case through empirical investigation.

 

I suppose at this point I am not concerned that you don't believe what I said.

 

This whole discussion has been taxing not because it has been challenging, but because it has been rendered meaningless by your lack of supporting evidence. I have ponied up quite a bit of widely accepted, empirical data supporting my position(s) and you have done little but reference "experience" and spout a lot of conjecture. I am not sure that this dialog can continue until I see something solid on your end.

 

If you do nothing but set up straw men and beg questions, your arguments are weak.

 

EDIT: As a bonus, since you apparantly like Advanced Aquarist: http://www.advancedaquarist.com/2005/12/aa...rchterm=actinic. I am not going to bother quoting from this article, it is easy to read and there is plenty of info in there to support the things I have said.

[MrAnderson]

Wassamatter, you guys never heard of a dictionary?

 

actinic: n: radiation having a marked photochemical action.

 

The spectrum of actinics are usually 420 or 460 or both. Oh my, I wonder why that is? Maybe because those are the excitation wavelengths of chlorophyll a and b. And yes, zooxanthellae have chlorophyll.

 

In the context of reefing, if it doesn't stimulate photosythesis, then by definition it is not actinic. Note that this is a qulaitative, not quantitative statement, regardless of intensity or PAR.

[Mr. Fosi]

(MrA to me = )

 

I guess that definition sort of solves the argument at hand.

[calvin]

"chlorophyll? more like borophyll!!"

 

and Fosi - dude, you're still posting like a madman here and you just had your first child!! heed the advice of the elders and sleep whenever possible.

[Mr. Fosi]

I was relieved at the hospital this morning by my mother-in-law.

 

I came home, prepped for the bio labs I have to teach on Tuesday, refuted a bunch of incorrect points on this thread, and I plan to go to bed early (9PM-ish).

 

I have had about 4 hours of unbroken sleep in the last two days and probably about 4 hours of constantly interrupted (or otherwise poor quality) sleep as well.

 

I plan to get at least 8 hours tonite, but I will shoot for 10. Tomorrow, everyone comes home and then the real fun starts.

[junkitu]

Wassamatter, you guys never heard of a dictionary?

 

actinic: n: radiation having a marked photochemical action.

 

The spectrum of actinics are usually 420 or 460 or both. Oh my, I wonder why that is? Maybe because those are the excitation wavelengths of chlorophyll a and b. And yes, zooxanthellae have chlorophyll.

 

In the context of reefing, if it doesn't stimulate photosythesis, then by definition it is not actinic. Note that this is a qulaitative, not quantitative statement, regardless of intensity or PAR.

Outstanding MrAnderson! Thank you.

[civicsit]

I don't mean to hijack this thread or anything, but I had a slightly different question about actinics.

 

I have a MH setup with a 20k bulb. So would it be benifitial for me to add in actinic to my MH. I read somewere that you didn't need actinics with 14k or 20k, so is that really true?

[Mr. Fosi]

If you are using standard aquarium lamps (PC or MH) you don't ever need actinics.

 

If you want to get more overall light or just more blue light (and the fluoreascence that comes with actinics), go ahead and add some.

[Mr. Fosi]

For anyone who read this thread and wants to know more about photopigments and light spectra, I recommend this book:

 

Light & Photosynthesis in Aquatic Ecosystems by John T. O. Kirk. There is more info than you ever wanted to know about photosynthesis as well as specific information regarding absorption, light spectra, and the below-surface light field. I borrowed it from my oceanography prof and it is the bomb-biggity.

[yardboy]

Wow! I'm impressed with all the research and have fortunately read most of the texts cited, as I find the subject fascinating.

To interject a little experience, I started my display with a cycling of the liverock for four months under just 220W of actinic VHO in my garage. There happened to be a nice plate of Turbinaria renniformis on one of the pieces of rock, which survived and grew the entire time under this regimen of 10hr on/day. No metal halides, no natural light, only the actinic.

And as an aside, after I got the tank set up inside the house with the addition of 750W of 10000K metal halides, I noticed no radical increase in growth of the coral.

Actinics have the highest energy wavelength output of any of the lights normally available. Any more energetic and you couldn't see it anyway. It's just the intensity thats kind of low.

Oh, and I tried 20000K with actinics. Too blue for me. But that's just a personal aesthetic reason.

You guys are cool! Keep up the great research and keep those nano's going!

[chuckfullservice]

Wow are you guys sure your not closet marine biologist??

Thats the most scientific data I have read in a month.

What happens to most scientific data that conflicts though is arguments occur! The most important question could be answered by the seasoned hobbist because the bottom line is this , what light does our corals do best under I would take the word of any seasoned aquarist with healthy brilliant corals over the documentation of any Dr. or biologist wouldn't you? Proof is in the pudding!

I think the debate can be answered with pics who has the best looking corals and what lighting do you use and in what order, in my oppinion the one with the best looking corals wins hands down !

Back up your data with your own tanks who runs acintics all the time and who doesn't ? Post your pics and light specs!

Personally I am gonna run both at the same time why not give your coral the opportunity to have several shades of light available all the time, could n't hurt anyways!

[Mr. Fosi]

A problem is that the "pudding" is made up of more than light regime. How about flow amount and direction, salinity, temp, and whatever shifts these (and other) parameters may go through.

[chuckfullservice]

Point taken, but why not ask a few people to due case studies ? People whom have established tanks that are already doing well with their own lighting schemes? Maybe someone would be willing to turn off there whites for a week or two and view the status of there existing corals would they suffer or lose color, and maybe another person could turn off the blues and see what we come up with, include photos and we could compilate our own hypothesis? I think you get my drift who needs scientist when we have well educated people with all the tools we need at hand?

If I was up and running I would partake but I'm an idiot who's still cycling I just love experimenting and diagnoising problems !

What do you think?

[Mr. Fosi]

Case studies would be fine, but I am not sure what they would tell us.

 

Regardless of the results of such a go-round, someone would attack the fact that it didn't control certain factors.

 

I guess there is as much reason to try it as there is not to try it...

[Nyxis]

Link

 

Fosi you might want to take a look at that link. I know it makes more sence that more blue light = better but in that experiment they determined that spectral qualities were unimportant. Apparently if you have enough intensity a wide spectrum bulb of any kind works just as well as one with a higher output in the blue range. The lousy part about it is there is no way to tell how much intensity you need to cross over into any light works just fine land.

[Mr. Fosi]

Read it a while back, very good link for this thread.

 

Blue doesn't = better, it equals effciant absorption by chlorophyll a.

 

Accessory pigments are a wonder.

[The Propagator]

Beat me to it FOSI

 

didnt Sanjay, Borneman, Califo, and other big names in this hobby already do this experiment and come up with a conclusive YES, actinic does increase the health of your coral?

[Mr. Fosi]

LINKSLINKSLINKS!

 

I don't recall. Post a couple links?

[Nyxis]

I need links too. I'm beginning to think sanjay is just someone you made up as a fake scientist to win arguments. Seriously I can find nothing on the web written by this person. Also according to that experiment I linked actinic only provides benifit if you are below a certain intensity threshold so I would be very interested in seeing what intensity they used.

 

edit: Is it Sanjay Joshi?

[shaggydoo541]

Sanjay

 

http://reefkeeping.com/authors/sj.php

[Mr. Fosi]

http://www.personal.psu.edu/faculty/s/b/sbj4/

[Nyxis]

Sanjay

 

http://reefkeeping.com/authors/sj.php

 

What the hell he's not even a biologist he's a professor of Industrial and Manufacturing Engineering. That's about as far from this topic as it gets.

[yardboy]

He never claimed to be anything other than an engineer, but he sure has done a lot of research on metal halide lighting:

http://www.reeflightinginfo.arvixe.com/