Lighting and photosynthesis

[cheeks69]

http://reefcentral.com/forums/showth...pagenu mber=1

Just wondering what you guys think about what Eric Bourneman says in this thread.

[cheeks69]

specifically this quote :

Thus, any potential deficit in carbon and all deficit in nitrogen must be met by heterotrophy (feeeding). All corals studied can potentially meet all of their carbon and their nitrogen requirements by feeding alone. Thus, arguably, feeding is more important to coral's maintenance, growth, and reprodution than light. Its just that light is a plentiful resource in clear shallow tropical waters, and in practice, most corals get most of their carbon from light (practically energetically free to obtain) than by feeding (energetically costly to obtain).

[cheeks69]

I'm just curious as to why I would have some success with some corals and anemones when my lighting isn't what would be considered Ideal, having just over 3 watts per gallon. Although most of what was said in the thread was greek to me, but I just found the explanation Eric gave to be very interesting and somewhat applicable to my situation. What do you guys think ?

[cheeks69]

bump^^

[Curtswearing]

Here is some basic knowledge on Zooxanthellae

I believe in feeding corals food in addition to light as I don't ever want a coral so hungry it eats its zooxanthellae. I have 2 dogs. I could probably keep both dogs alive with 25% less food than they are currently getting. In fact, I could probably do so for quite a while. Both Cheyenne and Cherokee are now fully grown. Would there be an impact if I did this during their growth phase. I don't know for sure----it's just a question. I have my suspicions though. For them to be healthy, they need proteins, lipids, carbohydrates, etc. What if I fed them the same amount of calories but decided they should have 25% less protein. Again, they would likely do fine for quite some time but it might not be optimal.

Don't even ask me what I think of the whole watts per gallon recommendations I see on the internet. Think about it. You have a corner tank that is 30" tall and has 5 watts per gallon. Your best friend has an 18" tall tank with 3 watts per gallon----in other words, the watts per gallon in this example are the same. You put a frag of the same mother colony on the floor of both tanks. All else being equal, which one grows fastest? Again, I don't know---it's just a question.

As a general rule, I hate general rules.

It is possible you are giving them enough "carbohydrates" to offset the "protein" shortage in my example. It's also possible you have great lighting for your tank and the fact that you feed also is making for some happy corals.

[ReefLady]

Not sure what I make of it. I'm certainly not qualified to argue with Mr. Borneman.

One thing that I do believe is that we could never provide enough food in our tanks for corals to survive off of (without light), without totally polluting our tanks. This is the main reason it is almost impossilbe for hobbyists to keep many non-photosynthetic corals, like the dendroneptheas, etc.

Again, not to argue with the coral expert, but if this were *truly* the case, why not find more of an abundance of sps in deep/dark/food-abundant waters? Why are they mostly found in the shallow, heavily-lit, nutrient-free waters?

I'm just curious as to why I would have some success with some corals and anemones when my lighting isn't what would be considered Ideal, having just over 3 watts per gallon

Personally, I often think that the recommended amount of light is not always necessary. For sps/clams, yes, you need extremely bright light, and I always suggest MH's. For LPS & softies, however, you don't need your own personal power station. Many of these corals will thrive under a *minumum* of light - much less than is usually recommended. Sure, they will sometimes do better in more light, but that doesn't need they *need* it.

Interestingly enough, I also fully believe that softies and LPS do not fare as well in nutrient-free, super-skimmed, ultra clean enviroments. Our old 75g softy/LPS tank had incredible growth rates -- the tank *always* had darn high nitrate levels, a CC substrate, a cruddy skimmer, and just VHO lighting. Granted, 440w of VHO, but still. We put the same corals under the MH's in the 180g, with a DSB, 0.00 readings on nitrates, phosphates, etc., and a lot of the growth (Xenia is a prime example) - came to a grinding halt.

I also believe that ppl tend to over-light LPS. I think too-bright tanks are the cause of many problems with Torch, Anchor, Hammer, Brains, even the elusive Elegance coral.

I apologize for the length of this. One last point. Our refugium holds most of the *remains* of our 75g softy tank. Red & blue mushrooms, green & brown star polyps, button polyps, zo's, Colt coral, Finger leather, etc. The refugium is lit by a single NO Home Depot shop light which sits quite high off of the water. All of these critters are thriving, and have been for quite some time.

Just my long-winded 2 cents....

[Pro_builder]

I have always done better with the brains under a lower light conditions. When I went to MH (2-175 watters) they seemed to slow down. Not sure if this is because of the light or my imagination. But, it does make ya think.

[cheeks69]

Originally posted by ReefLady
Interestingly enough, I also fully believe that softies and LPS do not fare as well in nutrient-free, super-skimmed, ultra clean enviroments. Our old 75g softy/LPS tank had incredible growth rates -- the tank *always* had darn high nitrate levels, a CC substrate, a cruddy skimmer, and just VHO lighting.
I also believe that ppl tend to over-light LPS. I think too-bright tanks are the cause of many problems with Torch, Anchor, Hammer, Brains, even the elusive Elegance coral.

My experience is very similar Teri. I have been fighting a nitarate problem which is always around 20-30ppm even with weekly 15-25% waterchanges. I'm sure having 6 fish in a 42 gal doen't help, although their small but my point is my hammer, xenia and elegance are growing at an alarming rate and I had a Sebae anemone that had tripled in size before wrapping itself around my heater and perishing all this with a minimal amount of light , relatively speaking and when I read that thread it started to make sense.

[mojoreef]

Hehe I think Eric stuck his foot in his mouth and got slapped around abit, lol
Again as Teri said it is all depending on the corals you are keeping, every coral has its needs. Here is a little trick you can use to figure out wich coral needs what. Corals get the vast majority of thier food from zoox, but they also need some nitrogen for the growth of tissue. Nitrogen comes from feeding and from absorbtion.
So if a coral has very little tissue (ie: a SPS) then it doesnt need much Nitrogen, but if you have a coral with alot of tissue (say a Torch coral) then it would need more.

Not to be overly critical, but neither Dana, nor Steve, nor Richard Harker who has also done this kind of work, are biologists, physicists, nor even scientists...so honestly critiquing anything they have "experimentally done" is sort of like debating air

I just love that and what exactly is Eric?????/


MIke

[Travis]

I'm pretty sure Eric has a ph.D. in Marine Biology.

[ScottT1980]

I think Eric is correct in that heterotrphy can certainly provide our corals enough carbon and nitrogen by-products. The problem is, I do not feel like this is practical in such small aquatic systems as our tanks. Sure, you can always feed and feed corals and eventually they will get everything they need but this would really compromise our systems. So, this might work in the wild but in the aquarium, VHOs/halides/PCs are needed in order to compensate for our aquarium's inability to "flush out" wastes...

Just my 2 pesos

Take er easy
Scott T.

[mojoreef]

Good post Scott!!!

I'm pretty sure Eric has a ph.D. in Marine Biology.

Hobbist Mr T.

[sharks]

LOL Great thread
Now my head hurts and I need a drink

[Travis]

He's definitely a hobbyist, but he's also a marine biologist. I spoke with him when he was in Dallas about it. He graduated from the University of Houston.

T

[mojoreef]

Hmm I knew he was studing to be a marine biologist but I thought he still had a few years to go. I will shoot him a email.

Mike