The truth about lighting

[Scooterman]

Yea Scott, you fired up everyone...Great Job!
Ok now back to work!

[mojoreef]

Oh, I wasn't "hmm-ing" as in "in your face" Hmmm... I am really "hmm...?" for things that I'm trying to understand here.

RC I was just joking around with ya, trying to keep it light. I think we know each other well enough my friend.

think it was David Cripe of Monterey who said that growth structure had little to do with "reaching" towards light, and has much more to do with flow.

Wow that another new one on me, lol. If you have a link I would like to see it, if possible. Corals compete in different ways, we all know about softies and chemical warfare, lps and the stinging sweepers, SPS type corals compete for the main thing they need and that is light. Branching acro's such as stags and so on go for the high ground trying to shade out competitors by over growing them and starving them for light. Massive and plating corals go for the low ground trying to take up as much real estate as possible. As per flow and structure, what I imagine he is refering to is that water flow will change the structure of the coral. example wouold be a stag lets say. if it has direct flow is hitting it, the braches will grow thicker, if in low flow or no flow the braches will grow a bit thinner. Thats just how the coral adapts to its particular enviroment. Not why they grow up.

Wait a sec... So if they can't effectively catch food then why extend at night at all?

I thought I listed that before, could be a number of different reasons, or even combination of reasons. it could be just a stimulated responce.

but am wondering why many biologists are saying to feed your corals if you're saying that they hardly eat.

What marine biologist??? the ones doing coral research or the ones making money off of the hobby?????

I think finicky acros growing as well as staying well colored under a 175mh is evidence that food is an important part of the formula

I am not sure what ou mean??? I grow all my frags under those type of lights, Did I say somewhere that it wouldnt work.

RC and folks you really have to qualify the coral. they all have different requirements in regards to both lighting ammounts and supplimental food. I think that is where these statements are getting confused.

Mike

[Craig Manoukian]

Is it safe to say that in general LPS and Soft corals are more dependant on food than SPS? This might be what Anthony Calfo was meaning. He spoke about a lot of things that night.

I know that by not traget feeding my Trachophyllia I slowly and unitentionally starved it to death. It had plenty of light, but after a year it just shriveled away. I believe that with less light and more food the Trachophyllia would have lasted longer, and with the correct combination of food, light, and water would still be alive and growing today.

On the subject of anenomes. I know from my own observation, that my photosynthetic BTA grows substantially more when I target feed a couple of times per week when compared to the same lighting, but letting the Clown Fish to feed it.

Are my experiences close to what the studies say?

[Scooterman]

And in this corner we have..........

[mojoreef]

Craig your dead on. on both cases. the trick I use is the flesh trick..hmmm that sounds kinda creepie. You will find that in most all cases when it comes to corals that the ammount of tissue it has is directly related to the ammount of supplimental feeding it needs. Example would be. An sps coral only has a very very thin veneer of tissue, thus its requirements for outside source are less. a Open brain on the other hand has alot more tissue and thus its feeding should reflect that. P and N, wiether thier from outside feeding or through absorbtion through thier tissue are mainly used for the growth of tissue, so it kinda relates.

Mike

[mps9506]

One biologist that comes to mind that is an advocate of feeding would be Eric Borneman (I doubt he makes much money off the hobby compared to what he gets paid at the university). When I took a coral reef ecology class here with Dr.Schmanzt we were taught that hermatypic coral polyps were filter feeding structures designed to capture zooplankton.
In addtion I have actually seen photos of acropora sp. polyps engulfing food particles. No doubt in my mind what these sturctures are for. The reason they come out at night, most likely because that is when food is abundant on the reef. I have read but not observed that many corals will begin to extend polyps during the day if that is when the aquarium is feed on a constant schedule. No doubt this has been seen in LPS corals like Trachyphilla. Most Brain corals I get in only extend there tenticles when the lights are off, which makes it a PITA to feed at the store...
LaBarbera (1984) describes the methods of particule or prey capture that occurs in major corals.
The citation for that is :
Labarbera,M. 1984. Feeding currents and particle capture mechanisms in suspension feeding animals. Amer. Zool. 24:71-84

Some reading that should be available at any local university library.

There is actually a TON of papers out there regarding the function of tenticles, and the whole debate about how much light actually contributes to the corals energy budgets.
If anyone wants a list of some let me know. There is a lot more on this subject than Scott's questions about light intensity.
Just glad I kept my book and notes from my coral reef ecology class...
Mike

[Craig Manoukian]

Thanks Boomer, Mike O, and Mike!

[mojoreef]

MPS I have also seen and studied coral polyps, and I am not trying to say they dont feed. What I am saying is that it all depends on the coral. No dought if a zooplankton smacks a sps polyp in the mouth it going to eat it. As per active capture throught the use of nemacysts, it is not set up properly for that as I have stated prior. Thier perfered method (best method of capture using less energy) is throught the use of a mucus slime that nets its prey, be it bacteria or zooplankton. the net is drawn throught the polyp via the cilca (sp), and the coral injests it thier. As per energ budjets for hermatypic corals I have also read alot including sorkin and most of the other Boomer mentioned above. But I have never seen any study that should a SPS had a supplimental food supply requirement above 10%????
Now moving away from the SPS type of coral it becomes a completely different story. where the pendulm swings away from light requirements and more towards the the supplimental feedings, but we must be clear of the types of corals we are refering to, as water quality can become a huge factor if all these natural feedings are taking place.

Also I was not trying to take a dig at Eric, as he is a friend, so is Anthony. So my above statement was a bit to broad, so I recant, hehe. But in the same breathe I dont agree.

Mike

[Maxx]

I just finished reading the interview with Dana Riddle. He states that Actinics don't actually do anything for the aquarium other than asthetics. I thought they helped the corals fluoresce.

EK,
If you are running actinics in combination w/ more poerful lights of 10K or higher than this is true. Blue spectrum, (higher K) light penetrates deeper than red spectrum (lower K), as Michelle(Cougra) posted. What does this mean to us? Pretty much that anything living deeper than about 45 feet in the ocean is gonna be living off primarily blue spectrum light. Not to say it cant adapt to the higher intensity of red spectrum (lower K lighting)....
As stated before, white lighting has all color spectrums in it. But in a 65k bulb (which has all the color spectrums in it) our eyes pick up predominantly yellows and oranges in the wavelengths.
The actinics will help your corals flouresce, but thats really just an aesthetic thing to you. The corals will use the light, (so the bulbs arent useless) but the corals dont care what color/flouresecent pigment they are...they just want the light.
hope this makes sense.
Nick

[mojoreef]

In regards to a corals design showing it dependance on light and/or prey here is a little about it

Among-species morphological heterogeneity in skeletal morphology and polyp size suggests a spectrum of dependence on zooxanthellae as a food source (Porter, 1976). Polyp diameter P is positively correlated with tentacle length and is a good indicator of zooplankton-capturing ability. The surface area of the coral skeleton covered by live tissue, S, divided by the volume of the skeleton plus tissue, V, is a good index of light-capturing ability. As S/V increases in branching and platy forms, more light can be intercepted because not all incident radiation will be captured by a single intercepting plane. A multilayered morphology, as in the branching Caribbean coral Acropora palmata, allows S to be three times the surface area of bottom substrate that they cover (Dahl, 1973). Light can then be intercepted by more surface area of live coral tissue. Zooplankton capture favors a single continuous surface of tissue because feeding structures cannot be saturated with light, as can the photosynthetic zooxanthellae. Branches increase the number of feeding mouths, but a single plane of feeding polyps would effectively remove all the zooplankton.
S/V and polyp diameter are hyperbolically inversely correlated . Thus corals with a shape well adapted to zooplankton capture have large polyps similarly adapted to this function (Porter, 1976). Although this factor suggests a range of depend-ency of hermatypes on zooxanthellae as food, even species with low values of (S/V)/P show a strong apparent need for such a food source. The large-polyped Montastrea cavernosa can only obtain 10 to 20% of its daily energy requirement during the two most successful hours of its 12-hour night feeding period (Porter, 1974a, 1976).\\

Mike

[Maxx]

I ahd to read it carefully, but its good info Mike.
Nick

[Craig Manoukian]

I have a headache! can Mike O, or Nick translate into laymens terms? I'm assuming it supports the notion that SPs are more light and less food dependant than LPS and soft corals.

TIA

[Maxx]

Craig,
basically the shape of a coral, (acros for example...branching and random shapes) allows it to get light from many different angles...up to 3 times more than it would if it were flat.
To feed on Zooplankton moer efficiently, corals would be more flat and a continuous feeding plane. But this would eat all of the zoo plankton , not leaving ebnough for all polyps....branches allow the coral to eat from different parts of the water column.
Corals that are better suited to eating zooplankton have large polyps designed for this.
thats basically it...
Nick

[Boomer]

So I go to work and come back and find a bazillion posts.


Mike;

Of course, lets not try to exaggerate, when we say K has no effect on growth. I believe I said as long as it is a reasonable K.

That came out wrong, I was agreeing with you. I was saying that others maybe exaggerating that K make 0 dif at all. So UPS will not be at your door

First Mike nice piece from Porter, now I don't have to type all of that from Sorokin Same for the other post before it it





In general, photosynthetic corals receive about 60-70 % of their daily need from light. Some need more others need less. When one speaks of P:R values they need to be careful. There are a number of ways of doing this. A straight P:R value for corals does not take such things into consideration such as mucous production, while others do and is the reason behind some of the labels, i.e, P :R, Pt/Mt, CZAR, etc. A straight P :R for some corals may be 1.2 ( = 120%) of their daily needs by light alone but when you throw in mucous, mobility energy it drops to a "corrected" P :R,which may now be only P :R .8 ( 80%). Here is just one example from Sorokin

"The ratio Pt/Mt, calculated per day, decreases much faster with depth and the decrease in light than these ratios, calculated per hour, mostly because of the shortening of the light period of day at depth. For example, in the coral Stylophora pistillata the Pt/Mt per day at a depth of 2m was 2.0 and at depth of 45m it was 0.4. Thus, at the depth of 45m this coral may compensate its energy expenditures only by about 25-30 % (counting expenditures additional to respiration).The rest the coral should compensate for by heterotrophic feeding."


Sorokin is a wealth of info, more than one would ever want to know. Ex ; SED's of corals, table after table of P:R, rhythm of diurnal activity, polyp size relationship, fed rates and how much of plankton, Artemi, bacterial feeding, DOM, POM feeding, ciliate feeding, elements of food balance rates of feeding ( on many corals), and on and on and on........

I have always said corals need to be fed, they can not survive without supplemental feeding of some kind. And those capture tentacles are there for a reason, not just looks. And those capture tentacles do not need nematocysts to fed with. There is a 30 page chapter in Sorokin just on feeding and everything that is involved. And another 30 more so on "light" feeding and everything that is involved

This is not a simple or easy subject it is very, very complex, with many other variables that can shift things i.e, salinity temperature, currents. location, depth, etc..

Other stuff;


Many corals come out at night to feed for a big reasons, that is when the plankton count is the highest.

Actinic lights were not introduced into this hobby to make the tank look nice, that is a myth. The were brought in for the reason that they produced blue light, based on the fact that most of the light is absorbed in the first meter of water, leaving mostly blue behind. This however, is more on the order of the deep ocean where the water is blue. Ever seen a blue reef, they are usually some shade of green or blue-green. The biggest peaks are in the blue 380-450 nm, then the red 650-700nm with a low peak in the green 550-600nm, in ***general***. Ex, Favia on one species was peaks at 440, 540 and 670 nm

Craig

On the subject of anenomes. I know from my own observation, that my photosynthetic BTA grows substantially more when I target feed a couple of times per week when compared to the same lighting, but letting the Clown Fish to feed it.

Are my experiences close to what the studies say?

Yes, they need to be fed also. However, clownfish don't feed their anemones, that is a myth, people just THINK they are. I have watched them feed dead barnacles. They are just moving **their food to a safe place, which really isn't so safe as the anemone just eats it. This so called feeding by clowns is nonexistent in the wild.



I'm sure I forgot something but time for bed

[Scooterman]

So the shape, texture & design of a coral is determined by the needs of the coral to Eat, right? Layman's terms 101!
Really good information, I have to reread it again but One thing I didn't know before is the design of the coral is of purpose. I have noticed my Candy Cane, reach out at night, with tine tentacles on each edge of the faces, it is weird, then at times during the day different tentacles reach out., these are way longer & thicker, I'm not sure where these come from, other than it is from within the coral.
Some of the P's & q's loose me but I'm getting a better idea of how they eat & what, so this is a big help. P's & Q's = SUV's?