Color azoox
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CuttleKid
New member
Im not sure i fully understand. Our you asking if having no zooxanthallae gives nps corals their vivid coloration? If that is the question then i believe the answer is no. Look at anemones for example, The huge bright pink bases of certain H. magnifica, and the electric blues, greens, and reds of S. haddonni. I think that the color is predetermined in their DNA and being azoox doesnt necessarily mean that they are going to be vividly colored (although that seems the case). I did read that certain amino acids in the corals diet can enhance the colors, but this may be false information. Remember that color is lost very quickly underwater and the corals that are in the deep reefs that seem brilliantly colored are actually dull when looked at under the normal lighting.
Hopefully this is information is accurate and if it is then i hope i answered your question.
Hopefully this is information is accurate and if it is then i hope i answered your question.
coltrref
New member
for example in the photosynthetic corals:
Reef-building corals occur as a range of colour morphs because of varying types and concentrations of pigments within the host tissues, but little is known about their physiological or ecological significance. Here, we examined whether specific host pigments act as an alternative mechanism for photoacclimation in the coral holobiont. We used the coral Montipora monasteriata (ForskÃ¥l 1775) as a case study because it occurs in multiple colour morphs (tan, blue, brown, green and red) within varying light-habitat distributions. We demonstrated that two of the non-fluorescent host pigments are responsive to changes in external irradiance, with some host pigments up-regulating in response to elevated irradiance. This appeared to facilitate the retention of antennal chlorophyll by endosymbionts and hence, photosynthetic capacity. Specifically, net Pmax Chl a−1 correlated strongly with the concentration of an orange-absorbing non-fluorescent pigment (CP-580). This had major implications for the energetics of bleached blue-pigmented (CP-580) colonies that maintained net Pmax cm−2 by increasing Pmax Chl a−1. The data suggested that blue morphs can bleach, decreasing their symbiont populations by an order of magnitude without compromising symbiont or coral health.
Reef-building corals contain host pigments, termed pocilloporins, that function to regulate the light environment of their resident microalgae by acting as a photoprotectant in excessive sunlight. We have determined the crystal structure of an intensely blue, nonfluorescent pocilloporin to 2.2 Ã… resolution and a genetically engineered fluorescent variant to 2.4 Ã… resolution. The pocilloporin chromophore structure adopts a markedly different conformation in comparison with the DsRed chromophore, despite the chromophore sequences (Gln-Tyr-Gly) being identical; the tyrosine ring of the pocilloporin chromophore is noncoplanar and in the trans configuration. Furthermore, the fluorescent variant adopted a noncoplanar chromophore conformation. The data presented here demonstrates that the conformation of the chromophore is highly dependent on its immediate environment.
but in azoox?
Reef-building corals occur as a range of colour morphs because of varying types and concentrations of pigments within the host tissues, but little is known about their physiological or ecological significance. Here, we examined whether specific host pigments act as an alternative mechanism for photoacclimation in the coral holobiont. We used the coral Montipora monasteriata (ForskÃ¥l 1775) as a case study because it occurs in multiple colour morphs (tan, blue, brown, green and red) within varying light-habitat distributions. We demonstrated that two of the non-fluorescent host pigments are responsive to changes in external irradiance, with some host pigments up-regulating in response to elevated irradiance. This appeared to facilitate the retention of antennal chlorophyll by endosymbionts and hence, photosynthetic capacity. Specifically, net Pmax Chl a−1 correlated strongly with the concentration of an orange-absorbing non-fluorescent pigment (CP-580). This had major implications for the energetics of bleached blue-pigmented (CP-580) colonies that maintained net Pmax cm−2 by increasing Pmax Chl a−1. The data suggested that blue morphs can bleach, decreasing their symbiont populations by an order of magnitude without compromising symbiont or coral health.
Reef-building corals contain host pigments, termed pocilloporins, that function to regulate the light environment of their resident microalgae by acting as a photoprotectant in excessive sunlight. We have determined the crystal structure of an intensely blue, nonfluorescent pocilloporin to 2.2 Ã… resolution and a genetically engineered fluorescent variant to 2.4 Ã… resolution. The pocilloporin chromophore structure adopts a markedly different conformation in comparison with the DsRed chromophore, despite the chromophore sequences (Gln-Tyr-Gly) being identical; the tyrosine ring of the pocilloporin chromophore is noncoplanar and in the trans configuration. Furthermore, the fluorescent variant adopted a noncoplanar chromophore conformation. The data presented here demonstrates that the conformation of the chromophore is highly dependent on its immediate environment.
but in azoox?
CuttleKid
New member
zooxanthellae does not provide color. it is just the internal symbiotic algae that helps to utilize sunlight and convert it to feed both itself and the coral. when a coral bleaches it's internal algae dies and the coral is weakened and that causes it to bleach. im pretty confident in saying that zooxnthellae has little to no determination of coral color.
ousnakebyte
New member
The overwhelming color of corals on a natural reef is brown. Yes, there are pinks, purples, greens, etc. that show up - and those are the ones that make it to our tanks b/c that's what we like - but, the majority color on a natural reef is brown. This brown comes from the color of the zoox.
A great example in the Caribbean is Siderastrea siderea (Sid sid). Normally, these corals are a dark brown in coloration, but, show up during bleaching season - late September to early October, and you can often find very pretty light pink Sid colonies - b/c they have bleached.
Other factors do come into play to determine coral coloration, but zoox is definitely one of them.
Cheers
Mike
A great example in the Caribbean is Siderastrea siderea (Sid sid). Normally, these corals are a dark brown in coloration, but, show up during bleaching season - late September to early October, and you can often find very pretty light pink Sid colonies - b/c they have bleached.
Other factors do come into play to determine coral coloration, but zoox is definitely one of them.
Cheers
Mike
AquaticFins
Premium Member
I will speculate a little, though I do not know for certain.
Zooxanthellae certainly are responsible for a large percentage of photosynthetic coral colouration. It's right in the name - "xanth" comes from the Greek "xanthos," meaning golden or yellow. They produce a good deal of the golden brown colouration of many corals.
However, NPS corals generally don't have a lot of zooxanthellae...and are usually distinctly not brown.
Reds, oranges and yellows are some of the most common colours in NPS corals. Carotenoids are probably responsible for much of this colouration and definitely commonly found in corals.
Carotenes are one type of carotenoid. Most appear as varying shades of orange to our eyes. They are a photosynthetic pigment - they absorb blue light. Some carotenes are used as light-blockers - they can protect cells from too much near-UV light. I don't believe they are directly synthesized by any coral, but rather derived through diet. I wouldn't be surprised to learn that some zooxanthellae can produce them, though that's not directly germane to our discussion. These are also what give carrots and sweet potatoes their colour.
Another type of carotenoid is xanthophyll - basically a carotene that's been oxidized. These are generally yellow pigments...the yolk of an egg is coloured by xanthophylls. Also not synthesized, but very common in diatoms (and thus phytoplankton). They are also light-modulators.
Some xanthophylls and carotenes can be converted to retinol or retinal (Vitamin A), but I do not know if corals can create the enzyme required to do so. They are also great antioxidants.
Astaxanthin is another related pigment. Common in micro-algae, but not directly synthesized by corals, it can give pink, yellow, white and red colourations. It's the main component in giving farm raised salmon and shrimp their pink hue.
Melanins, porphyrins, pterines, flavonoids are also commonly found in coral. Melanins are certainly familiar to anyone who's been sunburnt - they do a good job protecting from overexposure to light and can impart browns and blacks.
Porphyrins and pterines are commonly purple and green. Flavonoids are yellow, as the name would suggest.
The last few I'm not particularly familiar with - we need a biochemist to wander over here and tell us more about them (and probably correct some of my mistakes with the carotenoids)!
Hope that helps!
David
EDIT: Beyond the dietarily-derived pigments, there is perhaps a genetic component to colouration. While corals that brood their offspring likely "seed" them with their own pigments before release, the broadcast spawners often produce offspring with very similar colouration to the parent corals. It's hard to rule out the environmental factors (again, diet) since we don't have a whole lot of data points with broadcast spawning corals, but if any of the pigments can be synthesized by the coral it seems likely a genetic component would come into play.
Also, do remember that many of these corals can be found right next to Acropora species, in full sun and shallow water. Just because they do not have zooxanthellae does not mean they are restricted to low-light zones - UV blocking pigments can be critical for zooxanthellate and azooxanthellate corals alike.
It also may be helpful to add that the term "pigments," which I used without explanation, refers to a chemical compound that reflects and absorbs certain portions of the light spectrum (which makes them coloured to our eyes). The portion of light they reflect is what we see them as - if a compound reflects only blue light, it will appear blue to us.
One final thought as well, on the short growing bushy Scleronephthya spp. - I have found that certain colour forms seem a good deal easier to keep than others. I've had specimens come in off the same shipment, same size, same growth form...but the yellow-orange ones seem to regularly fair far better in captivity (at least initially, I've never kept them truly long-term) than the purple or red individuals. If this is a common observation, it seems logical that the pigmentation is playing a much more important role than previously thought.
Carotenes certainly contribute to photosynthesis in terrestrial plants, though as energy transfer agents...not as principal conversion agents. It seems worth exploring if their role is somehow altered in coral. It would certainly explain why yellow-orange bushy Scleros fair better initially if they can gain even a small percentage of their energy needs from photosynthesis rather than strictly relying on what they can catch.
Zooxanthellae certainly are responsible for a large percentage of photosynthetic coral colouration. It's right in the name - "xanth" comes from the Greek "xanthos," meaning golden or yellow. They produce a good deal of the golden brown colouration of many corals.
However, NPS corals generally don't have a lot of zooxanthellae...and are usually distinctly not brown.
Reds, oranges and yellows are some of the most common colours in NPS corals. Carotenoids are probably responsible for much of this colouration and definitely commonly found in corals.
Carotenes are one type of carotenoid. Most appear as varying shades of orange to our eyes. They are a photosynthetic pigment - they absorb blue light. Some carotenes are used as light-blockers - they can protect cells from too much near-UV light. I don't believe they are directly synthesized by any coral, but rather derived through diet. I wouldn't be surprised to learn that some zooxanthellae can produce them, though that's not directly germane to our discussion. These are also what give carrots and sweet potatoes their colour.
Another type of carotenoid is xanthophyll - basically a carotene that's been oxidized. These are generally yellow pigments...the yolk of an egg is coloured by xanthophylls. Also not synthesized, but very common in diatoms (and thus phytoplankton). They are also light-modulators.
Some xanthophylls and carotenes can be converted to retinol or retinal (Vitamin A), but I do not know if corals can create the enzyme required to do so. They are also great antioxidants.
Astaxanthin is another related pigment. Common in micro-algae, but not directly synthesized by corals, it can give pink, yellow, white and red colourations. It's the main component in giving farm raised salmon and shrimp their pink hue.
Melanins, porphyrins, pterines, flavonoids are also commonly found in coral. Melanins are certainly familiar to anyone who's been sunburnt - they do a good job protecting from overexposure to light and can impart browns and blacks.
Porphyrins and pterines are commonly purple and green. Flavonoids are yellow, as the name would suggest.
The last few I'm not particularly familiar with - we need a biochemist to wander over here and tell us more about them (and probably correct some of my mistakes with the carotenoids)!
Hope that helps!
David
EDIT: Beyond the dietarily-derived pigments, there is perhaps a genetic component to colouration. While corals that brood their offspring likely "seed" them with their own pigments before release, the broadcast spawners often produce offspring with very similar colouration to the parent corals. It's hard to rule out the environmental factors (again, diet) since we don't have a whole lot of data points with broadcast spawning corals, but if any of the pigments can be synthesized by the coral it seems likely a genetic component would come into play.
Also, do remember that many of these corals can be found right next to Acropora species, in full sun and shallow water. Just because they do not have zooxanthellae does not mean they are restricted to low-light zones - UV blocking pigments can be critical for zooxanthellate and azooxanthellate corals alike.
It also may be helpful to add that the term "pigments," which I used without explanation, refers to a chemical compound that reflects and absorbs certain portions of the light spectrum (which makes them coloured to our eyes). The portion of light they reflect is what we see them as - if a compound reflects only blue light, it will appear blue to us.
One final thought as well, on the short growing bushy Scleronephthya spp. - I have found that certain colour forms seem a good deal easier to keep than others. I've had specimens come in off the same shipment, same size, same growth form...but the yellow-orange ones seem to regularly fair far better in captivity (at least initially, I've never kept them truly long-term) than the purple or red individuals. If this is a common observation, it seems logical that the pigmentation is playing a much more important role than previously thought.
Carotenes certainly contribute to photosynthesis in terrestrial plants, though as energy transfer agents...not as principal conversion agents. It seems worth exploring if their role is somehow altered in coral. It would certainly explain why yellow-orange bushy Scleros fair better initially if they can gain even a small percentage of their energy needs from photosynthesis rather than strictly relying on what they can catch.
Last edited:
coltrref
New member
Extracted from:Aquarium Corals. Selection, Husbandry, and Natural History,
Eric Borneman, T.F.H. Publications, Inc., 2001
he coral animal itself produces some interesting stuff ... in different places. And since zooxanthellae are intimately connected with the development of tissues and skeletal structure, so too is PAR related as well.
Some non-zooxanthellae pigments from the soft tissues of corals:
astaxanthines & related compounds (pink-orange)
ketones, carotenoids & xanthophylls (orange-red)
phoenicoxanthin (pink)
astaxanthines, carotenoids & xanthophylls (deep orange)
carotenes (yellow-orange)
melanin, purines, astaxanthin, ommochromes (brown)
astaxanthines (white)
porphyrins & bilines (green)
carotenoids, flavines, astaxanthines, metridene,
xanthophylls & ommochromes (red)
Some skeletal pigments of Stony Corals, Hydrocorals, and Gorgonians:
carotenoids (yellow-orange)
astaxanthines (pink-orange)
astaxanthines (pink)
astaxanthines (purple)
astacene & xanthophylls (orange)
Eric Borneman, T.F.H. Publications, Inc., 2001
he coral animal itself produces some interesting stuff ... in different places. And since zooxanthellae are intimately connected with the development of tissues and skeletal structure, so too is PAR related as well.
Some non-zooxanthellae pigments from the soft tissues of corals:
astaxanthines & related compounds (pink-orange)
ketones, carotenoids & xanthophylls (orange-red)
phoenicoxanthin (pink)
astaxanthines, carotenoids & xanthophylls (deep orange)
carotenes (yellow-orange)
melanin, purines, astaxanthin, ommochromes (brown)
astaxanthines (white)
porphyrins & bilines (green)
carotenoids, flavines, astaxanthines, metridene,
xanthophylls & ommochromes (red)
Some skeletal pigments of Stony Corals, Hydrocorals, and Gorgonians:
carotenoids (yellow-orange)
astaxanthines (pink-orange)
astaxanthines (pink)
astaxanthines (purple)
astacene & xanthophylls (orange)
