Coral coloration FAQ

[FunkieReefJunkie]

If you want these questions answered from Eric you'll find him on the Marine Depot forum.

<a href=showthread.php?s=&postid=11593010#post11593010 target=_blank>Originally posted</a> by jlinzmaier
Please tell me more about proper nutrient levels. I'm confused after reading the comments about underskimming and overskimming.

Is it possible to have "excess nutrients" when the nitrate levels are 0 and the phosphate levels are < 0.03? Are there other significant nutrients that contribute to "excessive nutrients"? Are there appropriate/reliable tests for any other nutrients?

How do I know if I'm overskimming?? I'm trying to maximize my filtration/skimming to keep nitrate and phosphate levels at 0. How do I know when I've done too much? How do I know when the filtation has pulled too much of the vital nutrients in an attempt to keep the undesirable nutrients (nitrate and phosphate) at a low level? Once you get to readings of undetectable how do you know when you've gotten to the point of limiting nutrients that corals need.

If I'm able to feed zooplankton daily or every other day while keeping my nitrates and phosphates at 0, am I still providing enough nutrients for my corals? What is the indication that I'm providing enough nutrients for my corals but not creating conditions of "excessive nutrients"? If I have browning specimens how do I know if the problem is 1) excessive nutrinets 2) not enough nutrients or 3) one of the thousand other possiblities like lighting, water flow, trace elements, etc. I guess I'm hoping for some guidance to rule out nutrient problems in general. How do I know if I'm providing enough but not too much?

Jeremy

 

[NyReefNoob]

so after reading though this and several other thing's, beginning to think my skimmer is wayyyyyyy to big for my system, running a euroreef rs 135 on a 50g breeder, i like to keep alot of fish and it's a complete sps tank, light's are over driven t5's on a icecap 660, all par are in check but color's are more pastel, didnt have this when ran t5's before so dont think it is from the light's, think my proteins might be too low, even though i feed a little heavy and have 8 fish, think the skimmer might be the problem ? i do have a remora urchin pro i could try for a little while to see if it makes a difference

 

[NyReefNoob]

so after reading though this and several other thing's, beginning to think my skimmer is wayyyyyyy to big for my system, running a euroreef rs 135 on a 50g breeder, i like to keep alot of fish and it's a complete sps tank, light's are over driven t5's on a icecap 660, all par are in check but color's are more pastel, didnt have this when ran t5's before so dont think it is from the light's, think my proteins might be too low, even though i feed a little heavy and have 8 fish, think the skimmer might be the problem ? i do have a remora urchin pro i could try for a little while to see if it makes a difference

 

[NyReefNoob]

so after reading though this and several other thing's, beginning to think my skimmer is wayyyyyyy to big for my system, running a euroreef rs 135 on a 50g breeder, i like to keep alot of fish and it's a complete sps tank, light's are over driven t5's on a icecap 660, all par are in check but color's are more pastel, didnt have this when ran t5's before so dont think it is from the light's, think my proteins might be too low, even though i feed a little heavy and have 8 fish, think the skimmer might be the problem ? i do have a remora urchin pro i could try for a little while to see if it makes a difference

 

[timwijgerde]

As always,

nice science education Eric!

 

[tasos]

Ã"¡i Eric, and all of you guys!!!!
It is fan to discuss a very difficult matter like this........
I think it a matter of how we aproach nutrients:
there are good and bad ones.....aminoacids or some fresh fish juise is good nutrients,corals are known to suck the up the water columne....a few hours later (in tropical sea waters) they turn to certain amines (ie cadaverin) that are toxic to everybody except some bacteria....these are bad nutrients and we want to get rid of them through skimming or carbon filtration... .
The problem arrises as the abovementioned filtration strips the good nutrients from the water too...so we keep adding them .I saw great improvement in sps coloration when I started to feed aminos in conjuction of with good skimming of course.
Sprung says the a bit of nitrates works well in reef tanks especially the ones with refugium type filtration.I once saw an sps tank that the corals have not lost the colors and kept growing dispite the 50-80 ppm nitrate reading I took!!!
It is a matter of balance between the bad and the good nutrients in the water and not just the nitrate reading that leads to darkening of the corals.I feel that zooxanthelae control is on the host's hand when everything else in its organism feels OK, like every symbiotic relationship in nature.Nevertheless I am not a marine biologist (just a vet) and all the above are just an opinion

 

[syedjilani]

subscribed

 

[Ptyochromis]

No offense, but the first post is loaded with inaccuracies. I have some fixes/clarification.

Corals are a symbiosis between animal polyps and one or several types of many species and strains of single celled protists (dinoflagellates) collectively called zooxanthellae.

Corals are not a symbiosis between animals and zooxanthelle. Corals are cnidarians in the class anthozoa (frequently colonial), they have nematocysts (stinging cells) that are used to capture prey. Many corals maintain a sybiotic relationship with zooxanthellae (genus Symbiodinium). The zooxanthellae provide sugars to the coral in exchange for a safe place to live.

Coral polyps (sans zooxanthellae) have their own set of animal pigments, too. There are non-light related pigments, such as those that form in the skeleton of Tubipora musica, Heliopora coerulea, and Pocilloporids. Also, there are the vividly bright colors of the skeletal sclerites in soft corals like Dendronephthya spp. and Scleronepthya spp. Colored skeletal elements are also formed in gorgonians, often in their axial rods.

Corals that are photosynthetic don't have their own pigmentation, their tissue is clear. If they had pigmentation they would block light from reaching their sybiotes. This is why corals are white when they bleach; they expell their zooxanthellae leaving the skeleton exposed.

In general, low nutrients and high light will likely allow for the production of bright colored high-light fluorescing proteins int hose corals that have the genetic machinery to produce them. Which ones are expressed (blue, green, orange, etc. is probably not possible at this point to predict). Low nutrients and low light will allow for the expression of low-light fluorescing proteins in those corals with the genetic machinery to produce them.

Can you cite your claim that "low nutrients will allow for the production of bright colored "from a non-anecdotal source?

ALSO, with photosynthetic corals the zooxanthellae is the reason the coral exhibits a particular color.
Here is a good paper: http://www.jstor.org/discover/10.2307/76745?uid=3739600&uid=2&uid=4&uid=3739256&sid=21103322918707

 

[Montireef]

I agree with the two first statements, but not sure about the third.
Any thoughts about photocromatic inhibition? why do some SPSs reach the point before others? I hace acros that stop growing up when under strong PAR, but others just can't get enough.

 

[Ptyochromis]

I agree with the two first statements, but not sure about the third.
Any thoughts about photocromatic inhibition? why do some SPSs reach the point before others? I hace acros that stop growing up when under strong PAR, but others just can't get enough.

Unlike clams, it is possible to overlight coral, you generally see bleaching. Feed them more often (under 100 micron) and keep your kh up.

 

[Timfish]

Thank you Ptyochromis for the link to the reasearch looking at three different Symbodinium spp. I haven't stumbled across it. Also good to see another nonskimmer reefer, here's a video of one of my skimmerless tanks:

http://www.youtube.com/watch?v=_Uf5IyXvajg

Curious critiquing a post from 10 years ago as I would think most people would expect science to progress, I am more than happy to throw in my two cents however.

No offense, but the first post is loaded with inaccuracies. I have some fixes/clarification.

Corals are not a symbiosis between animals and zooxanthelle. Corals are cnidarians in the class anthozoa (frequently colonial), they have nematocysts (stinging cells) that are used to capture prey. Many corals maintain a sybiotic relationship with zooxanthellae (genus Symbiodinium). The zooxanthellae provide sugars to the coral in exchange for a safe place to live.

Honestly this first one seems mostly an issue of semantics but you are correct corals are just animals and many do not utilize Symbodinium spp dinoflagellate symbionts (zooxanthellae).

Corals that are photosynthetic don't have their own pigmentation, their tissue is clear. If they had pigmentation they would block light from reaching their sybiotes. This is why corals are white when they bleach; they expell their zooxanthellae leaving the skeleton exposed.

I am sorry but this statement strikes me as incredibly ignorant and uninformed. The Symbodinium spp. symbionts used by corals only impart a golden brown - brown coloration. ONE species (so far) of coral also has fluorescense coloration produced by a cyanobacteria symbiont (1) Research has shown corals, NOT symbodinium spp. dinoflagellates, are producing a vast array of both fluorescing and chromo proteins which imparts the various colors we see. (Please see the research articles by Dana Riddle for starters, he provides excellent bibliographies for further followup.)

Can you cite your claim that "low nutrients will allow for the production of bright colored "from a non-anecdotal source?

ALSO, with photosynthetic corals the zooxanthellae is the reason the coral exhibits a particular color.
Here is a good paper: http://www.jstor.org/discover/10.2307/76745?uid=3739600&uid=2&uid=4&uid=3739256&sid=21103322918707

Here's a quote from Chalres Delbeek, a world renown scientist and researcher "In the 1990s, a widespread bleaching event hit Fiji resulting in hundreds of miles of bleached reefs. Corals collected and exported at the time were described and being "spectacularly" colored pastels of pink, purple, yellow and orange; spectacular because only coral pigments were visible, having lost their layer of golden brown zooxanthellae". He goes on to say this about low nutrient systems "When I see some of the colors of these low nutrient systems I can't help but be reminded of bleached coral reefs" Coral, Nov/Dec 2010 pg 127

(1) http://www.sciencemag.org/content/305/5686/997

 

[billsreef]

Curious critiquing a post from 10 years ago as I would think most people would expect science to progress, I am more than happy to throw in my two cents however.

Indeed there has been new information learned over the past decade that has changed many of the assumptions made back then.

 

[Ptyochromis]

Corals that are photosynthetic don't have their own pigmentation, their tissue is clear. If they had pigmentation they would block light from reaching their sybiotes. This is why corals are white when they bleach; they expell their zooxanthellae leaving the skeleton exposed.

I am sorry but this statement strikes me as incredibly ignorant and uninformed. The Symbodinium spp. symbionts used by corals only impart a golden brown - brown coloration. ONE species (so far) of coral also has fluorescense coloration produced by a cyanobacteria symbiont (1) Research has shown corals, NOT symbodinium spp. dinoflagellates, are producing a vast array of both fluorescing and chromo proteins which imparts the various colors we see. (Please see the research articles by Dana Riddle for starters, he provides excellent bibliographies for further followup.)

I was not refering to Sybodinium spp. specifically, but to sybiotes as a whole. I was arguing that it is not the coral itself that is colorful but the organisms with which it has a sybiotic relationship (i.e. sybiotes) that are the responsible.

 

[billsreef]

I was not refering to Sybodinium spp. specifically, but to sybiotes as a whole. I was arguing that it is not the coral itself that is colorful but the organisms with which it has a sybiotic relationship (i.e. sybiotes) that are the responsible.

What specific symbiotic organisms are you claiming to be responsible for coral coloration?

 

[rwb500]

ptyochromis - i get the sense that you don't understand much of what you are arguing about.

for example, you say corals are not a symbiosis between animals and zooxanthelle, and then you give a detailed description of how corals are a symbiosis between animals and zooxanthelle... do you think cnidarians are not animals?

and your argument about coral coloration coming entirely from zooxanthelle is very wrong and doesn't make sense for a lot of reasons. did you even read the paper you linked to? that's not what it's about, at all. not even close. just because you found a paper about the spectral absorption of some proteins does not mean it proves your argument. do you know how chlorophyll works? or even what it does? why would it make sense for chlorophyll to come in a wide variety of colors? (hint: it wouldn't)

 

[Ptyochromis]

ptyochromis - i get the sense that you don't understand much of what you are arguing about.

for example, you say corals are not a symbiosis between animals and zooxanthelle, and then you give a detailed description of how corals are a symbiosis between animals and zooxanthelle... do you think cnidarians are not animals?

and your argument about coral coloration coming entirely from zooxanthelle is very wrong and doesn't make sense for a lot of reasons. did you even read the paper you linked to? that's not what it's about, at all. not even close. just because you found a paper about the spectral absorption of some proteins does not mean it proves your argument. do you know how chlorophyll works? or even what it does? why would it make sense for chlorophyll to come in a wide variety of colors? (hint: it wouldn't)

Does a coral stop being a coral when it looses its zooxanthelle? Of course not. You need to distinguish between a symbiotic relationship and an individual species.

Of course the coloration from every coral comes from zooxanthelle, but in may corals it does. The article I linked was not intended to discuss coral coloration coming from zooxanthelle but to discuss the coloration from various types of zooxanthelle.
Furthermore, chlorophyll comes in at least 2 types (I know there a more than 2, but I am only familiar with two of them). There is chlorophyll a (and the P680 pair) in photosystem II and chlorophyll b (and the P700 pair) in Photosystem I. These two molecules have different absorption spectrum, meaning it takes different wavelengths for excitation to occur. There are also other pigments, an example being carotenoids, many may work to broaden the spectrum of light that can drive photosynthesis and play some role in photoprotection.
The article I previously linked discusses Chlorophyll c, which has a different absorption spectrum than a or b.
We know that the light that is not absorbed is reflected, and it is the reflected light that you see.

 

[Timfish]

. . . I was arguing that it is not the coral itself that is colorful but the organisms with which it has a sybiotic relationship (i.e. sybiotes) that are the responsible.

I strongly urge you (and anybody else reading this who wants to know more about coral coloration) to read the various articles about the fluorescing and chromo proteins produced by corals (the animals) by Dana Riddle (start with the ones in advanced aquarist). With the exception of one fluorescing protein made by a symbiotic cyanobacteria (currently found in one species of coral [the animal]) ALL the other fluorescing and most of the chromo proteins are made by the coral (the animal0 not by the symbiotic dinoflagellates.

 

[Timfish]

. . .
The article I previously linked discusses Chlorophyll c, which has a different absorption spectrum than a or b.
We know that the light that is not absorbed is reflected, and it is the reflected light that you see.

I don't know if this is a typo but the article you linked earlier is dealing with chlorophyll a not c. It does lend the image you don't understand very well what you are talking about.

Yes, it is true the light not absorbed is reflected but the fluorescing proteins corals (the animal) produces is absorbing different wavelengths, many outside the absortion band for chlorophyll a or b, and reemitting it as light of a longer wavelength.

Again, I strongly urge you to read the various articles by Dana Riddle on the fluorescing and chromo proteins made by corals (the animals)

 

[rwb500]

Does a coral stop being a coral when it looses its zooxanthelle? Of course not. You need to distinguish between a symbiotic relationship and an individual species.

Of course the coloration from every coral comes from zooxanthelle, but in may corals it does. The article I linked was not intended to discuss coral coloration coming from zooxanthelle but to discuss the coloration from various types of zooxanthelle.
Furthermore, chlorophyll comes in at least 2 types (I know there a more than 2, but I am only familiar with two of them). There is chlorophyll a (and the P680 pair) in photosystem II and chlorophyll b (and the P700 pair) in Photosystem I. These two molecules have different absorption spectrum, meaning it takes different wavelengths for excitation to occur. There are also other pigments, an example being carotenoids, many may work to broaden the spectrum of light that can drive photosynthesis and play some role in photoprotection.
The article I previously linked discusses Chlorophyll c, which has a different absorption spectrum than a or b.
We know that the light that is not absorbed is reflected, and it is the reflected light that you see.

ok so you must agree then that the first point is an issue of semantics that is not worth anyone's time discussing.

and thank you for proving your knowledge of photosynthetic pigments, although it is still clear that you don't quite get it. The relatively minor differences in absorption spectrum between different chlorophylls will not produce large differences in appearance, relative to the rainbow of colors we see in corals. linking a functional absorption spectrum to the appearance of a coral is foolish. can you just agree that you are dead wrong about the source of coral coloration? I don't see how we are still arguing here.

 

[Ptyochromis]

I don't know if this is a typo but the article you linked earlier is dealing with chlorophyll a not c. It does lend the image you don't understand very well what you are talking about.

Yes, it is true the light not absorbed is reflected but the fluorescing proteins corals (the animal) produces is absorbing different wavelengths, many outside the absortion band for chlorophyll a or b, and reemitting it as light of a longer wavelength.

Again, I strongly urge you to read the various articles by Dana Riddle on the fluorescing and chromo proteins made by corals (the animals)

Funny, one type-o and your whole argument goes out the window.... You don't have to look very far to verify what I was saying, especially with regards to the types of chlorophyll and various pigmentation.

I am not so interested in what Dana has to say but in the published works she cites. I have access to the Uni's database so ill check out some of those sources and see what else I can find.