SPS coloration, what have you learned?

[Minotaur15]

Hello folks,

A while back when I was actively seeking out info on the net, I read one of Eric B's old Aquarium.net articles dealing with the coloration of acroporas. I believe the focus of that article was in certain pigments and UV levels and the like.

IME, I've found that light and water conditions seem to be equally important when it comes to bringing out bright colors. Also, I have seen dramatic differences in needs of certain species. I have two circumstances that are interesting to share. They are interesting not because of what happened, but that they seem to be exact opposites.

First Case: With a coral that I believe may be a specimen of Acropora tenuis, only after changing from a 175 10k to a 400w 6500, did it turn from brown to bright blue in less than 3" of water with the bulb suspended 12" from the water's surface. When the coral was moved to a new tank, and the distance from the bulb increase dramtically (~8-11" under water, ~10" air distance) the coral lost all blue coloration. I have since, moved the coral higher in the tank once again.

Second Case: A coral I believe may be A. loripes, the opposite seems to be true. In shallow water under the 175 and 400, it stayed brown. In the new tank, after being moved to a lower light area, it has begun to show blue tips! The new tank's water parameters seem to be far superior because coral growth here is astounding.

Interesting to see the different responses although it is far from quantifiable.

Just a few thoughts...

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Dan - minotaur15@hotmail.com http://www.tcnj.edu/~maughme2/

[This message has been edited by Minotaur15 (edited 02-03-2000).]

[smpolyp]

Was this coral always brown?How long was it in captivity before you received it?How old was the 175 w 10k?How old was the 6500?Anyway to put it in a nut before AOL kicks me off.You increased your intensity closer to UV ranges.That of 420 nannometers.UV is just under that.I think the corals produce a pigment(a type of Zooanthallea)to shield them form UV lighting.With the increase it makes new zoo to shield it.Thus resulting in color pigments.

[Minotaur15]

Which coral?

[ATLANTIS]

Excellent Topic Dan,
I have several corals whose pigment change depending on the positioning in my tanks. I run my halides very close to the water and this gives me some "bright" spots. I find that certains strains of Montipora Digitata and many strains of acropora love the "bright" spot. Their growth and coloration are fantastic.
I have an acropora sp, that when I bought the mother colony ages ago, was quite brown with purple tips. When frags are put in the bright spot, they quickly turn a nice purple throughout. I have "colored up" many coral heads & frags this way.
I have a "tri-color" acro, that under less light has a brown stalk, purple tips and green polyps. In the bright spot, the entire stalk becomes bright purple.. Oh NO, no more tri-color ;)
Have you read Dana Riddle and Andy Amussen article about coloration? check it out at http://www.aquarium.net/1298/1298_2.shtml



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brian

atlantisaquatic.com (http://atlantisaquatic.com)

[Mr Hanky-Tanky]

FAMA also ran an article by Riddle and Amussen (two parts: Dec1999 and Jan2000).
It is roughly the same thing as the article on aquarium.net but the conclusion is a bit more detailed:

Light: same as in the net article

Alkalinity: They noted that some coral pigments fade with decresing alkalinity levels. When alk was brought back up with a buffer, the corals pigmentation intensified within days (overnight in the case of Acropora millepora (?)). They recommend to keep the alk at around 10dKH (3.6 meq/l).

Another interesting thing. Feeding won't affect coloration but seems to affect the growth shape. Under the same conditions (lighting, water velocity and water parameters) an unfed acropora grew wide and the fed one grew tall.

[Minotaur15]

Hey Brian,

Actually I did read that just recently. Overall, they were heading in the right direction, but I think they really could have taken the experiment much further, and there were no real controls (every group had different variables). I also dont understand this part: "Two 110watt VHO
fluorescent lamps will deliver a sufficient amount of radiation to a depth of 18 inches." - when their experiment just showed that the coral did not retain its color. (A concession to the drygoods industry perhaps?) I wish they had not half-a**ed it.


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Dan - minotaur15@hotmail.com
http://www.tcnj.edu/~maughme2/

[Minotaur15]

Mr. HT,

Thanks for the additional info! :) The feeding results are very interesting indeed. Did the article make mention of what and how they were feeding the corals?

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Dan - minotaur15@hotmail.com
http://www.tcnj.edu/~maughme2/

[Mr Hanky-Tanky]

They isolated the coral they wanted to feed by enclosing it in an acrylic cylinder for one hour for each feeding. The cylinder was used to ensure that the adjacent coral head, to which it was to be compared, would not be fed.

The food consisted of HUFAs enriched rotifers, spirulina and other (unspecified) ingredients including trace elements. Sorry no more info than that.

[horge]

HankyTanky:
There was an apparently identical study under Ed Gomez' MSI here on table Acroporids that were fed/unfed. The simplistic interpretation is that the colony adapts to maximize exploitation of available nutrition. A tabletop shape maximizes zooxanthellar nutrition. A 'tall' colony maximizes water flow through the colony for predatory nutrition.

Regarding coloration, smpolyp, I believe it's natively-generated piqmentation and not a color-specific strain of zooxanthellae. I'm intrigued with Dan's observations: The relocation downward of the second colony and its subsequent reproduction of presumably-UV-shielding pigmentation may be difficult to correlate due to the relocation to a totally different tank --presumably with totally different lighting. Stating color temp figures --especially for MH lighting can be misleading --given the color shift as the lamps age. More detailed descrips of the params, Dan? :)

Maybe Fang was onto just the tail of the tiger when investigating the color differentiation at the growing edge/tip of corals. Maybe the color (or lack of it) is incidental to that which bears the color (or lack of it). The hypothesized mechanism for nutrient transport to the growing edge/tip could involve "color or the lack of it" only as a side-consequence. Hence the confusing results in coloring under different lighting situations.


[This message has been edited by horge (edited 02-14-2000).]

[Minotaur15]

Heya horge,

Ok, here we go...

Under a 175 10k with less than 4 months burn time, the coral in question (maybe A. loripes) remained brown. This color remained when I upgraded to 400w Iwasaki. The coral was under about 2-3" of water with both lamps 12" above the water. DKH on the old tank was prolly in the neighborhood of 9.

After moving to the new tank, the coral was eventually moved down. Same lighting (<3Month old Iwasaki) on the new tank. DKH runs 11-11.5 on the new tank.

I think it would be pretty safe to assume the slightly higher DKH plays a part, but it was definitely after the move down that the coral has begun to color up (It was in brighter spots at first).

Pretty cool to see the diffs. :D

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Dan - minotaur15@hotmail.com
http://www.tcnj.edu/~maughme2/

[smpolyp]

Could the coloration increase with the DKH ore meg/l be due to a healthier coral?If you feel better you are more active maybe the same.I have been thinking about mounting a uv bulb above a few corals to see if they gain any color.Starting out with a used one ofcourse and moving up.Maybe getting up to the suns uv on low tide for that same amount of time.

[horge]

Dan, your dKH experience ties in with observations by Riddle et Amussen. Mind if I shoot off (in the wild-assed manner that has endeared me to dozens of repressed flamers the web over :))?

I like to think there are any number of levels to this display of pigmentation, and that the many combinations of stimuli governing those levels are what make the prediction of color display confusing.

There is the display of pigments as evolved on the specific level, and on the general level of corals as a whole. While I can accept that the pigments are perhaps for UV protection (the general, coral Genera-wide level), different species of coral may have fine-tuned that ability in the context of different native depths. Thus the light levels (not just UV) that trigger the deployment of pigment can theoretically fall within a narrow range for certain species. Anything outside that range might (again theoretically) produce a lack of --or gibberish-- response. In the same way, some aquarium test kits have been developed to cover only a narrow range of values, and that anything outside that can produce gibberish. Granted, this doesn't quite address the opposing reactions of your two Acroporids :) -- but then the dKH may be a limiting/enabling factor in the deployment of pigments in any case.

To digress, what I said about the misleading nature of color temperature values holds, even if you set aside color shift over time. The whole concept of basing light quality on a linear blackbody-radiating scale seems one dimension short. Several wavelengths are emitted simultaneously by any given lamp, and one wants to measure based on perceived singular wavelength?

I wondered earlier if the pigmentation has been opportunistically utilized to aid metabolic processes. I did that only because nature seems very good at exploitation. I do not know of any data to support that wild-*** wondering :)

BTW, Dan, do you know the chemical composition of the violet/blue pigment employed --at least for a few corals? I haven't read Eric B.'s text yet.

[This message has been edited by horge (edited 02-15-2000).]

[Minotaur15]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I like to think there are any number of levels to this display of pigmentation, and that the many combinations of stimuli governing those levels are what make the prediction of color display confusing.<HR></BLOCKQUOTE>

Most certainly.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>There is the display of pigments as evolved on the specific level, and on the general level of corals as a whole. While I can accept that the pigments are perhaps for UV protection (the general, coral Genera-wide level), different species of coral may have fine-tuned that ability in the context of different native depths.<HR></BLOCKQUOTE>

After re-reading the article, I found that Eric's suggestions were well off the case that UV causes bright colors. He was more concerned with feeding being a large factor in the color maintainence, not UV. Although we certainly cant rule that out. :D

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Thus the light levels (not just UV) that trigger the deployment of pigment can theoretically fall within a narrow range for certain species.<HR></BLOCKQUOTE>

Thats what I've been thinking.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> :) -- but then the dKH may be a limiting/enabling factor in the deployment of pigments in any case.<HR></BLOCKQUOTE>

The reason I think the DKH is less of a causal factor here is that the coral was placed in a higher light area for the first several weeks in the new tank and did not do nearly as well. Only after I moved it down did it get some color and have better polyp extension. Therefore, yours and my thought on the range for certain sp. might have something to do with it.


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>To digress, what I said about the misleading nature of color temperature values holds, even if you set aside color shift over time. The whole concept of basing light quality on a linear blackbody-radiating scale seems one dimension short.<HR></BLOCKQUOTE>

I wasnt ever trying to make an implication on the color temperature of the lamps, just that that was the case :D

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>BTW, Dan, do you know the chemical composition of the violet/blue pigment employed --at least for a few corals? I haven't read Eric B.'s text yet.<HR></BLOCKQUOTE>

Quote the article: "Generally, red, orange and yellow are genuine pigments while green, blue and violet are formed by other factors and combinations." He doesn mention what.

I dunno, it's quite a mess on the whole I think. A whole lot of theory and not enough experiment. :D

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Dan - minotaur15@hotmail.com
http://www.tcnj.edu/~maughme2/

[horge]

On a sidenote,
it will probably get a lot messier:
Some clowns in HungKong are playing around with DYEING coral heads. --to make them prettier and more saleable.

I guess if they could dye fish, then why not?
My head is spinning.

[Minotaur15]

<groans>

Now I've heard everything :P

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Dan - minotaur15@hotmail.com
http://www.tcnj.edu/~maughme2/

[billsreef]

What the heck, they allready dye anemones :( Of course the dyied anemones die even quicker than regular, but if you don't know enough to run away when you see one of these your probably trying to keep anemones in a FO with one NO Flour. tube anyway. The painted glass fish (FW) has a high disease and mortality rate also, while the unadulterated glass fish is very hardy. It disgusts me what some people do in the name of business. On a brighter note, many customers that I educate to these types of practices end up giving up thier quest for these abominations :)
All right time to get off the soap box :rolleyes:
BTW my observations of corals tend to agree with much of what Horge and Dan have said.


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Bill

If damsels grew as big as sharks, the sharks would run in fear!
My dive photos (http://hometown.aol.com/billsreef/)
ICQ 56222784


[This message has been edited by billsreef (edited 02-17-2000).]

[Martyn]

this post that was of mine is out of date and incorrect.

[Minotaur15]

Martyn,

I'm starting a new topic in this forum on SPS care (my response to your article). This will probably be tomorrow however, I'm off to a rugby game now. :)

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Dan - minotaur15@hotmail.com http://www.einsweb.com/minotaur15/

[This message has been edited by Minotaur15 (edited 04-01-2000).]

[Martyn]

Hi thank you very much indeed
I look forward to you post
And again thak you
Martyn

[Martyn]

Hi <Dan>?
I will be changing my 150w metal Halides this week to 250w they are in a hood so i can not raise an lower the unit.
The tank is full so i can not lower the corals.
I have thought that the best way would be to place cover glasses over the tank let them get salted up for a bit then change the units over.
leave them salted up a bit for a week and then clean the glass leave clean for a few days and then remove the glasses for a couple of hours and then put back.
and gradualy increase the time they are left of untill fully left off (over a 3 week or so time period?).
and hope that the sps corals have adapted.
also I have coralline algae from the top rocks to the bottom rock will they adapt to the change over.
Best Regards
Martyn
Update I changed to 400w 10k BLV