Are we driving our corals past their light saturation capability?

[Gregcoyote]

An interesting and complex read;

Feature Article: How Much Light?! Analyses of Selected Shallow Water Invertebrates' Light Requirements — Advanced Aquarist | Aquarist Magazine and Blog

It makes a point about how little PAR SPS corals actually need. This jives with my personal observations doing underwater photography of these organisms. I have always thought my home reef was lite far brighter than where I actually found these corals growing.

There can be a debate that aquarium companies have responded to the thought that you can't have too much light. That may be a very wrong conclusion.

 

[PB_Smith]

There can be a debate that aquarium companies have responded to the thought that you can't have too much light. That may be a very wrong conclusion.

Well if they have a choice of offering a $50 T8 setup that works or a $1250 LED set-up, which do you think is going to be promoted, advertised and said is the absolute necessity.
The prices of some of this equipment is extortionate to say the least, especially when soooo much of it is so darn simple a fifth grader with a set of tools and a little brains can build 95% of it.

so yeah, I wouldn't be a bit surprised if there wasn't monetary incentives to push big elaborate lighting systems.

As someone who has re-entered the hobby after about 15 years away, I'm kinda surprised at a few of the concepts floating around and the "walk-on-eggshells" attitude so many seem to have concerning keeping aquaria.

 

[dingusplease]

I think this is a great discussion, both for experienced aquarists who would like to learn something new and for the newbies who are building their understanding of this hobby and it's growing base of enthusiasts (I myself am included in the latter category.)

IMO, one of the best ways we can help resolve the issue of businesses demanding higher prices in a relatively small (but growing) market is to emphasize the DIY aspect of the hobby. One thing I liked about the aquarium hobby when I started reefing was the huge opportunity for DIY solutions.

 

[Gregcoyote]

As said, you can build 100% of the equipment needed if technically capable. If you're a klutz, you can still build 90% of it.

But my theme was, do we really need all this light and are we overdoing it?

 

[Sniperhank]

Really old article you pulled up there Greg. It'd be nice to see the same article written now. I'm sure there is more info out there as to why...something I'm sure is a result in the believe of PUR being more important than PAR if I'm remembering what is important at this point.

 

[dingusplease]

Yes, sorry to get a bit off-topic. One question to consider: can "extra" lighting, either in PAR or PUR, be a good thing. The corals that clearly sustain themselves on less light than is present in home aqauria also live in a relatively unchanging environment, and also happen to reside in an indescribably large ecosystem, the ocean, and have lived there for millions of years.

Our captive coral reefs live in relatively minute sized systems, and in some ways it could be said that the extra light, in whatever form, is a benefactor to the success of our aqauria. The natural benefits of a stable ocean environment are, no matter how much we try, are not close to the level one would find in the ocean. For creatures that depend on light as their source of sustenance, a little or a lot extra than needed could be a good thing when you factor in the fact that they do not have many other benefits they would have in the ocean.

And then, of course, is the question of whether the extra light could be in any way harming our photosynthetically sustained friends, even if the damage is not immediate in the form of bleaching or otherwise cooking.

 

[PB_Smith]

Yes, sorry to get a bit off-topic. One question to consider: can "extra" lighting, either in PAR or PUR, be a good thing. The corals that clearly sustain themselves on less light than is present in home aqauria also live in a relatively unchanging environment, and also happen to reside in an indescribably large ecosystem, the ocean, and have lived there for millions of years.

Our captive coral reefs live in relatively minute sized systems, and in some ways it could be said that the extra light, in whatever form, is a benefactor to the success of our aqauria. The natural benefits of a stable ocean environment are, no matter how much we try, are not close to the level one would find in the ocean. For creatures that depend on light as their source of sustenance, a little or a lot extra than needed could be a good thing when you factor in the fact that they do not have many other benefits they would have in the ocean.

And then, of course, is the question of whether the extra light could be in any way harming our photosynthetically sustained friends, even if the damage is not immediate in the form of bleaching or otherwise cooking.

That really isn't very sound logic. You seem to be implying that extra light could make up for deficits in other areas, such as trace elements or micro-organisms, but the two do not directly correlate in the manner that you suggest.
Regardless of how stable or ancient the oceans are, the amount of light reaching the various flora and fauna is a measurable quantity, and the article is pointing out that not only do the levels of light we are told are required to keep corals not correlate to what occurs normally and regularly naturally, but over a certain threshold is it not only wasted, it can be detrimental.

Now if you are able to maintain a flourishing and relatively consistent population of myriad types of micro algae, plankton, macro-algae, etc., then you would be entering the area where light is a major component beyond photons, but I fear reaching the sheer numbers and concentrations of such organism's freely available in the ocean would quickly turn any home aquaria dead.
That is how light effects coral life in the ocean other than the actual photons reaching it, it's the photons reaching all the other little buggers floating around that is the key.

 

[dingusplease]

That really isn't very sound logic. You seem to be implying that extra light could make up for deficits in other areas, such as trace elements or micro-organisms, but the two do not directly correlate in the manner that you suggest.
Regardless of how stable or ancient the oceans are, the amount of light reaching the various flora and fauna is a measurable quantity, and the article is pointing out that not only do the levels of light we are told are required to keep corals not correlate to what occurs normally and regularly naturally, but over a certain threshold is it not only wasted, it can be detrimental.

Now if you are able to maintain a flourishing and relatively consistent population of myriad types of micro algae, plankton, macro-algae, etc., then you would be entering the area where light is a major component beyond photons, but I fear reaching the sheer numbers and concentrations of such organism's freely available in the ocean would quickly turn any home aquaria dead.
That is how light effects coral life in the ocean other than the actual photons reaching it, it's the photons reaching all the other little buggers floating around that is the key.

Thank you for pointing out this logical error, I am doing my best to express a point of view, but please understand everything I say can be taken as the point of view of someone who is learning about this hobby and the organisms mentioned. This discussion is very helpful to me, and to others I am sure.

On a side note, I have been working a lot :whistles: and missed a silly mistake in my above post. What I said about how we cannot, for the most part, achieve the level of diversity in terms of micro fauna found in the oceans is what I meant to talk about, and that is what I believe you are referring to when you talk about the unrealistic goal of maintaining the high levels of micro fauna naturally found in the ocean. I agree that light only becomes a more key and overarching factor when a higher level of light dependant microorganisms is reached, something not realistically accomplished in home aquaria.

I also completely agree that light cannot replace or provide for any deficit of trace elements or supportive microorganisms, I was simply looking at how light levels above those found in the ocean could be of any possible benefit, and a better way to phrase my above post would have been to state the question of whether extra light can make up for any lack of stability in an aquarium.

I guess what my post was aimed to be is an alternative look at the discussion - I thought about how this topic could be looked at in a different way and supported that alternative as best I could, and am glad to learn something new!

 

[Gregcoyote]

Great discussion.

The lighting corals get is not all that stable, turbidity, angle, reflection, clouds for weeks at a time, all these things they have adapted to. It seems to me they might depend more on the water column to feed, than their algae in the wild. Having the steady food source for the coral might be more important than the sugars made by the algae.

 

[nelix10]

Interesting read, but I disagree that a coral will not adapt to higher intensity lighting!
Do coral in our home made reefs not do better with higher then needed light intensities? Grow faster and become more vibrant.
I understand nutrients were not the topic of this article, but in our nutrient depleted reefs we must make up for the lack of nutrients!

If we all could live long enough and be patient enough we could provide less light and when our reefs are a hundred years old we may be able to enjoy massive colonies with mediocre colours!
Just a thought!

 

[Macscale]

Great discussion.

The lighting corals get is not all that stable, turbidity, angle, reflection, clouds for weeks at a time, all these things they have adapted to. It seems to me they might depend more on the water column to feed, than their algae in the wild. Having the steady food source for the coral might be more important than the sugars made by the algae.

I agree with this completely.


Corals have no control over the weather while in the ocean. Meaning the wild corals we get, may be having a hard time handling all the light we give them.

Maybe though since, Aquacultured corals were born under a higher intensity light, over time wouldn't they adapt to a higher intensity? They've never had to experience the quick changing weather In the wild...

 

[PB_Smith]

Great discussion.

The lighting corals get is not all that stable, turbidity, angle, reflection, clouds for weeks at a time, all these things they have adapted to. It seems to me they might depend more on the water column to feed, than their algae in the wild. Having the steady food source for the coral might be more important than the sugars made by the algae.

So that would definitely call into question the concept that a lot of corals don't need to be specifically fed, just give 'em more light.

I understand nutrients were not the topic of this article, but in our nutrient depleted reefs we must make up for the lack of nutrients!

But you are making the erroneous assumption that the nutrition supplied solely by the symbiotic algae will suffice.
Plus there is an entire market segment dedicated to accounting for the lack of nutrients in keeping corals. If all their needs were supplied by more light, why buy all the other stuff?

As far as I can tell from reading the aforementioned article as well as other sources, the color and vibrancy of corals is directly related to the health of the symbiotic algae, especially those that fluoresce, but are the corals themselves getting all they need?

I'm not disputing the idea that consistent lighting can be more beneficial than natures inconsistency, but all living organisms have saturation points concerning the nutrients they can digest, including photosynthetic ones. Terrestrial plants have saturation points beyond which more light is actually detrimental, why shouldn't the same apply to marine plant/photosynthetic life?

I do believe that was the central point of the research article.

 

[Gregcoyote]

I'm not certain. The algae just produces sugars that sustain the coral, but I'm pretty sure maximum growth happens when they catch some food from the water column as well. Kind of a plan A and B approach.

 

[Macscale]

The points in which it is stated that corals use both the light and the plethora of nutrients in our water to grow are both true. However, we are looking more at if the light we give is too much for our corals to sustain.

 

[Gregcoyote]

It's obviously a balancing act to a degree. It does seem the lights we are using have the potential to bleach cora. As I said before, l wish I had a underwater housing for my PAR meter because I bet at any reasonable depth the readings might be surprisingly low. Tidal pools are a different story.

 

[Macscale]

As Sniper mentioned, from my understanding PUR is more a more useful reading when regarding the algae on the corals..? I may look into buying both a PAR and PUR meter and measuring throughout time in the tank..

 

[Sniperhank]

PUR meters are extremely expensive. This is why you don't see much in terms of PUR readings.
Then, in terms of coral needing both food from the water column and light, well of course they do! It just comes down to what you are looking for in your corals. High nutrient systems will give more dull or browned corals. Still healthy, just not that appealing to the eye.

 

[Macscale]

PUR meters are extremely expensive. This is why you don't see much in terms of PUR readings.

Thus being the reason for, "May look into". Unfortunately the money to purchase such a meter is not in my wallet the moment, or at most moments. It would sure be interesting to see the differences in your specific tank with Pur.

 

[Sniperhank]

Powerful Radions helping growth, distilled water from walmart giving algae with dulled and browned colors in SPS and LPS.

 

[Gregcoyote]

I've read studies that show browned SPS corals with excess algae actually grow faster than the same more colorful coral in higher lighting. Of course browning can also come from nutrients. Wonder if the browning effects the coral the same from either cause?