Coral coloration FAQ

[Timfish]

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.

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.

:lolspin:

First of all, I am not questioning the role of the photochemical perdinin in the role of photosynthesis and the research paper you referenced on the discovery of a new form of peridinin in Symbodinium spp. dinoflagellates was fascinating. But as that is the only reference you have posted to support your claim that corals "don't have their own pigmentation" tells me you have a great deal to learn.

For starters the photopigments perdinin, and also beta carotine (diadinoxanthin), have nothing to do with the production of fluorescing and chromo proteins in corals. (1) And probably the most parsimonious hypothesis for the production of these proteins is in fact for photoprotection, to shade the corals symbionts. (2)(3) Additionally, while a bleached coral might appear white to our eyes under white light it may still have fluorescence when stimulated with blue light (3) (see fig. 1 here: http://www.nature.com/srep/2013/130312/srep01421/fig_tab/srep01421_F1.html )


(1) http://www.advancedaquarist.com/2006/9/aafeature Par. 5

(2) http://cel.webofknowledge.com/Inbou...th=Highwire&IsProductCode=Yes&mode=FullRecord

(3) http://www.nature.com/srep/2013/130312/srep01421/full/srep01421.html

 

[Ptyochromis]

:lolspin:

First of all, I am not questioning the role of the photochemical perdinin in the role of photosynthesis and the research paper you referenced on the discovery of a new form of peridinin in Symbodinium spp. dinoflagellates was fascinating. But as that is the only reference you have posted to support your claim that corals "don't have their own pigmentation" tells me you have a great deal to learn.

For starters the photopigments perdinin, and also beta carotine (diadinoxanthin), have nothing to do with the production of fluorescing and chromo proteins in corals. (1) And probably the most parsimonious hypothesis for the production of these proteins is in fact for photoprotection, to shade the corals symbionts. (2)(3) Additionally, while a bleached coral might appear white to our eyes under white light it may still have fluorescence when stimulated with blue light (3) (see fig. 1 here: http://www.nature.com/srep/2013/130312/srep01421/fig_tab/srep01421_F1.html )




(1) http://www.advancedaquarist.com/2006/9/aafeature Par. 5

(2) http://cel.webofknowledge.com/Inbou...th=Highwire&IsProductCode=Yes&mode=FullRecord

(3) http://www.nature.com/srep/2013/130312/srep01421/full/srep01421.html

In the nature.com article: "Green fluorescence was positively correlated with dinoflagellate photobiology". The flourescence shown on the bleached acropora looks strangely like calcium carbonate under UV, hummm I wonder why that could be? http://www.sciencelearn.org.nz/Contexts/A-Fizzy-Rock/Sci-Media/Images/Calcium-carbonate-otoliths.

There's more on the skeleton "Transition metal ions occupy the Ca2+ site of the carbonate and this results in a strong yellow luminescence."
"We have shown that coral skeletons have high absorbance in UVR, emitting a weak yellow fluorescence as a result. This is consistent with observations of previous studies [e.g. 22], [33]. By emitting potentially harmful UVR as safe yellow light, coral skeletons dampen the amplification of the UVR while amplifying and increasing harvesting efficiency of the PAR" They also discuss that the properties of the skeleton will vary depending on what is in the water.
Source: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007995



I'm pretty sure nobody said or implied that "photopigments perdinin, and also beta carotine" have anything to do with the production of pigments in corals.

Caratenoids don't refer to β-carotine specifically, there are a bunch of different carotenoids. Here is a basic article on what carotenoids are

There have been several types of caratenoids found in a few species of acropora originating from the zoxanthelae. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164383/
.
Here is a list of caratenoids found http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164383/figure/f1-marinedrugs-09-01419/

I think these provide pretty good support for photosynthetic corals' pigmentation being attributed to zooxanthellae and not the coral itself.

 

[Timfish]

:lolspin: :lolspin:

In the nature.com article: "Green fluorescence was positively correlated with dinoflagellate photobiology". The flourescence shown on the bleached acropora looks strangely like calcium carbonate under UV, hummm I wonder why that could be? http://www.sciencelearn.org.nz/Contexts/A-Fizzy-Rock/Sci-Media/Images/Calcium-carbonate-otoliths.

I have no idea why you linked to a colored electron micrograph of calcium carbonate crystals from inner ear organs. Corals don't have inner ears.

There's more on the skeleton "Transition metal ions occupy the Ca2+ site of the carbonate and this results in a strong yellow luminescence."
"We have shown that coral skeletons have high absorbance in UVR, emitting a weak yellow fluorescence as a result. This is consistent with observations of previous studies [e.g. 22], [33]. By emitting potentially harmful UVR as safe yellow light, coral skeletons dampen the amplification of the UVR while amplifying and increasing harvesting efficiency of the PAR" They also discuss that the properties of the skeleton will vary depending on what is in the water.
Source: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007995

Again a fascinating research paper. Do you really think the yellow fluorescence of the coral skeleton irradiated by UVB light looks the same as the green fluorescence of the bleached Acropora youngii irradiated with visable blue light (450nm)?! Anyway, I fail to see how this proves your positions that corals don't make their own pigments.

I'm pretty sure nobody said or implied that "photopigments perdinin, and also beta carotine" have anything to do with the production of pigments in corals.

Caratenoids don't refer to β-carotine specifically, there are a bunch of different carotenoids. Here is a basic article on what carotenoids are

There have been several types of caratenoids found in a few species of acropora originating from the zoxanthelae. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164383/
.
Here is a list of caratenoids found http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164383/figure/f1-marinedrugs-09-01419/

I think these provide pretty good support for photosynthetic corals' pigmentation being attributed to zooxanthellae and not the coral itself.

Fascinating articles on carotinoids. Since they are important photopigments used in photosynthesis they will be found all corals with Symbodinium spp dinoflagellates (two carotines I specifically know of are beta-carotine and diadinoxanthin) and in just about anything else, even you if you remember to eat your vegetables.

If you recall in your first post the reference you used to support the position that the zooxanthellae in corals are responsible for the coloration in corals was specifically looking at peridinin. In the introduction to his series of article on the fluorescing and chromo proteins made by corals Dana Riddle wanted to make it clear that besides peridinin carotines are also not responsible for any of the fluorescing and chromo proteins that corals produce. (Understandable as it seems some individuals are quick to assume carotenes like beta-carotine might account for the orange coloration found in corals.)

Any way, on with the show! :debi:

Fluorescent protein candidate genes in the coral Acropora digitifera genome:
http://www.ncbi.nlm.nih.gov/pubmed/22468836

Diversity and Evolution of Coral Fluorescent Proteins
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2481297/?report=classic

Fluorescent proteins from nonbioluminescent Anthozoa species:
http://www.nature.com/nbt/journal/v17/n10/full/nbt1099_969.html

Contributions of host and symbiont pigments to the coloration of reef corals:
http://onlinelibrary.wiley.com/doi/...ionid=03ACD5DF6283540A52711C9B2B04CE66.f02t04

 

[Spyderturbo007]

:lolspin: :lolspin:

I have no idea why you linked to a colored electron micrograph of calcium carbonate crystals from inner ear organs. Corals don't have inner ears.

What?!?!!?!

Is that why I never get a response when I ask my coral if they are hungry or why they don't color up like everyone elses' coral? I've been going about this all wrong. Back to the drawing board. :wavehand:

Sorry, I couldn't help myself after opening that Inner Ear link in a coral pigmentation thread.

 

[Timfish]

What?!?!!?!

Is that why I never get a response when I ask my coral if they are hungry or why they don't color up like everyone elses' coral? I've been going about this all wrong. Back to the drawing board. :wavehand:

Sorry, I couldn't help myself after opening that Inner Ear link in a coral pigmentation thread.

Well, now that I think about it I actually haven't seen a research paper saying corals don't have inner ears. And my cats don't listen to me and I've always thought they had inner ears. And there really isn't any difference between my cats not listening to me or my corals not listening to me. My friends dog listen to me though. After due consideration it seems pretty obvious to me cats are more closely related to corals than they are to dogs. That water thing isn't relevant. :lol: :lol: