Calcification rate in the Day vs Night

[SPSEMPIRE]

After reducing my light schedule from being on 11 hours a day to 8 hours a day, I have noticed more better growth in my stony corals than before. Also, I am noticing daily progression corals when the lights come on after being turned off for 16 hours. I am not sure if this is because the calcification rate is higher when the lights are off or if it is just because I have not seen the coral in 16+ hours.

A while ago I heard a presentation from a graduate student from UNCW that mentioned something about the calcification rate increasing when the lights are off vs on. Does anybody have any thoughts on this topic?

 

[plantastic]

SPSEMPIRE-

You are very observant...and Yes, there are biological processes that happen in the dark, that are associated with calcification. Basically there is a "light" period of calcification, and a "dark" period. Which makes sense, as there has a been a "day and night" forever. And, if you think about how the sun moves, then even the most intense sunliight is penetrating the water at certain angles...not "blasting" for 12 hours and then "off". And...maybe the corals that recieve the maximum of their tolerances in the natural setting, also have reduced growth rates realtive to their counterparts that recieve less than "tolerable limitations". Nilsen's and Fossa's series of books explain it much more inteligently than I can, and I highly reccomend their series when you start to have questions that require "real" answers.

I would speculate, that the metabolic resources that the corals had allocated to photo-inhibition, are now being re-allocated to growth...given that nothing else has changed. (hard to quantify...)

hope this helps some...

 

[dzhuo]

I am not sure if this is because the calcification rate is higher when the lights are off or if it is just because I have not seen the coral in 16+ hours.

I think it's the later. Calcification is roughly estimated to be 14 times faster when there are sufficient light. In the dark, calcification drops more than 90%. In fact, that's why calcification is normally referred to as light-enhanced calcification while with darkness, it's called dark decalcification.

I saw an interesting article a while back from advancedaquarist.com (or another source as I couldn't find it now) which explain how stony corals grow. I have always been under the impression that if longer lighting period equals faster calcification then why do so many people report better and faster grow when they reduce light period? It was explained in the article that calcification is not the only factor when it comes to grow. For example, calcification is only responsible for the underlaying carbonate skeleton but not the tissue. Although calcification is faster when there is light, the tissue grows faster in the dark. This leads me to believe majority of our tanks are nutrient depleted and a longer darkness "helps" the corals to grow the tissue faster which gives the apparent of faster grow. In a sense, grow rate is limited by nutrient other than light in our tanks.

Here is the article that explains the calcification process:

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification

 

[jc-reef]

I think it's the later. Calcification is roughly estimated to be 14 times faster when there are sufficient light. In the dark, calcification drops more than 90%. In fact, that's why calcification is normally referred to as light-enhanced calcification while with darkness, it's called dark decalcification.

I saw an interesting article a while back from advancedaquarist.com (or another source as I couldn't find it now) which explain how stony corals grow. I have always been under the impression that if longer lighting period equals faster calcification then why do so many people report better and faster grow when they reduce light period? It was explained in the article that calcification is not the only factor when it comes to grow. For example, calcification is only responsible for the underlaying carbonate skeleton but not the tissue. Although calcification is faster when there is light, the tissue grows faster in the dark. This leads me to believe majority of our tanks are nutrient depleted and a longer darkness "helps" the corals to grow the tissue faster which gives the apparent of faster grow. In a sense, grow rate is limited by nutrient other than light in our tanks.

Here is the article that explains the calcification process:

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification

This would seem to make scense since most stony corals, especially SPS, tend to 'catch' their prey during dark hours which would promote tissue repair/growth as most prey are lacking calcium but are high in protein & fatty acids. It seems the key is to provide the correct balance. I also have thought the same thing as to why reefers report increased growth with a decrease in lighting...which could elude to 'starved' tanks in comparison to the 'food dense' ocean as the additional time needed is to make the tissue repairs/growth.

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[M007]

Just to add, since switching from MH on/off to T5 dimmed from 0 to 100% and back down again the overall quality of my reef has improved 10 fold. Ihave tried to mimic sun rise to sunset as best as I can.

 

[batt600]

Sounds like you guys are also talking about photoinhibition

 

[Dog boy Dave]

My reactor runs hard 24/7. During the day light cycle the alk drops about .5 on the scale. IE morning read is 9.0 and by evening when the lights go off its closer to 8.5 . By morning it will have risen back to 9 or even 9.5. As the day progreses it tends to drop again. Assuming the reactor puts out the same amount during light and dark cycles the tank must use more during the light cycle for the Alk to drop during the day the way it does. Total tank volume is about 425 US Gallons so the difference is substantial.

 

[dzhuo]

Sounds like you guys are also talking about photoinhibition

No. We are not. Photoinhibition and light-enhanced calcification are different thing. In fact, it's completely opposite as far as grow is concern. Photoinhibition basically means (in a few words) the intensity of the light excess the coral's ability to photosynthesis. The coral spends almost all its energy repair tissue damaged by light and it's a condition you don't want your corals to be under (it's a huge stress to the corals). Light-enhanced calcification is how corals builds carbonate skeleton. You want as much calcification as possible.

Here is photoinhibition is you are interested:

Feature Article: Too Much Light!

 

[jc-reef]

Just to add, since switching from MH on/off to T5 dimmed from 0 to 100% and back down again the overall quality of my reef has improved 10 fold. Ihave tried to mimic sun rise to sunset as best as I can.

M007 - How do you get your T5's to dim?? I thought that the ballast needs a certain amount of current to work or it will not light the bulbs.

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[Mindflux]

M007 - How do you get your T5's to dim?? I thought that the ballast needs a certain amount of current to work or it will not light the bulbs.

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Controllable/dimmable ballasts.

 

[dzhuo]

IE morning read is 9.0 and by evening when the lights go off its closer to 8.5 . By morning it will have risen back to 9 or even 9.5.

Did you intentionally let alk swing .5 unit every day? Or have you consider turn up the Rx reactor to compensate for the alk lost? It seems like your Rx reactor is having problem catching up on consumption? I wouldn't be surprise with .5 unit swing given your tank size and the huge colonies of acros you have.

 

[Dog boy Dave]

I am very happy to have it maintain the stable alk over a weeks time. If the reactor kept up during the day then the decreased demand at night would cause the alk to rise over a week. This way now i seldom need to add sodium bicarb to push it back or turn off the reactor to allow the alk to drop. With no reactor running and no suppliment the tank will drop 3 to 4 units on the alk scale in 24 hours. 4 heaping table spoons of sodium bicarb and four tablespoons of ca are needed to maintain a 24 hours period if reactor goes off line. My reactor now is three stages with over three gallons of media and has a 120 per minute bubble count and effluent is a almost a steady stream. Reactor is wide open now.

 

[M007]

Controllable/dimmable ballasts.

Exactly, together with Profilux dim control modules.

 

[batt600]

No. We are not. Photoinhibition and light-enhanced calcification are different thing. In fact, it's completely opposite as far as grow is concern. Photoinhibition basically means (in a few words) the intensity of the light excess the coral's ability to photosynthesis. The coral spends almost all its energy repair tissue damaged by light and it's a condition you don't want your corals to be under (it's a huge stress to the corals). Light-enhanced calcification is how corals builds carbonate skeleton. You want as much calcification as possible.

Here is photoinhibition is you are interested:

Feature Article: Too Much Light!

I just brought that up because he said lowering the light cycle. But this is a really good post learning alot. More please......

 

[ousnakebyte]

Here is a paper that might be of interest. I just skimmed it, however.

Study of calcification during a daily cycle of the coral Stylophora pistillata: implications for ‘light-enhanced calcification’


Cheers
Mike

 

[SPSEMPIRE]

SPSEMPIRE- You are very observant...

Can I get that it writing on a piece of paper so I can present that to my manager?

Nilsen's and Fossa's series of books explain it much more inteligently...

Are you talking about Reef Secrets?

http://www.amazon.com/Reef-Secrets-Selecting-Invertebrates-Techniques/dp/189008767X

Here is the article that explains the calcification process:

Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification

Great Article! Thanks for the link.

Here is a paper that might be of interest. I just skimmed it, however.

Study of calcification during a daily cycle of the coral Stylophora pistillata: implications for ‘light-enhanced calcification’


Cheers
Mike

Very nice Mike! Well done sir. Awesome find on the write up.