Zooxanthellae and coral color

Discussion in 'Coral Health' started by TinFury, Nov 27, 2008.

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  1. TinFury

    TinFury Fire Shrimp

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    Ok let me tell you what I think so far, correct me if I'm wrong. You get corals that are very colorfull. You put them in your tank. As they acclimate some become browner (less colorfull) right. You put those browner corals closer to the light and they evict some of the zooxanthellae as they don't need as many to produce the amount of food they need. Right? I've read in many places that zooxanthellae are mostly brown in color... This is what I think so far so heres two questions.

    Q1. Why is it that when coral bleach they turn white? If they evict the zooxanthellae shouldn't they show as much true color as they can at this point?

    Q2. My tank crashed a couple months back. The corals didn't have light for a couple months. Most bleached white but are alive. Everything is set back up now better than ever and all my corals are on the road to recovery. The colors they are taking up aren't like the original reds, orange, purples, etc. They are mostly taking up green and brown. Will the original color come back with time?
     
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  3. PharmrJohn

    PharmrJohn The Dude

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  4. 1st time

    1st time Purple Spiny Lobster

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    Good question, sorry I don't know.
     
  5. Dr.Fragenstein

    Dr.Fragenstein Panda Puffer

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    Zooxanthellae is brown or golden brown in color, as you alluded to it is a dinoflaggelate that lives within the coral. Upwards to 955 of the "food" zooanthellae produce "spills" out into the surrounding area-in this case the coral. So the coral essentially gets free "food" for hosting the zooxanthellae.
    In less intense light the zooxanthellae needs to increase their density to produce the same "food" amount hence "browning out". In VERY INTENSE light the brightening of colors has less to do w/ the Zooxanthellae than it does w/ the coral itself. The bright colors act as sunblock, thats why many of the shallow water acros are so colorful.
    This goes hand in hand w/ your bleaching question, when the zooxanthellae is expelled it DOESN'T show color underneath but white or grey just like the color of bone because in all reality thats what corals are made of, CaCO3. The color like I mentioned doesn't have much to do w/ zooxanthellae.
    To answer you second question I would say most likely yes w/ time. I had a few corals lose color when I put them in my big tank, they couldn't handle the intensity of the light and I didn't really gradually introduce them. They are growing and showing polyp entension but still haven't colored up, but I have faith that in time both our corals will color up.

    Good luck and happy reefing
     
  6. inwall75

    inwall75 Giant Squid

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    It's not merely the amount or lack of zooxanthellae that controls coral coloration. As Dr. Fragenstein mention, the coral has it's own pigment that serve a variety of different purposes. These pigments reside within the tissue of the coral itself. These pigments do not have the ability to transfer light energy, but it has been found that in very deep waters they have the ability to alter particular color wave lengths. This is done by absorbing one color and the fluorescing a color the coral can use. SPS or shallow water corals produce large amounts of pigments under high lighting intensity.

    Most pigments in coral tissue are called pocilloporin and are categorized as either Brightly Colored Low Fluorescent Pocilloporins or as Highly Fluorescent Pocilloporins. Highly Fluorescent Pocilloporin pigments have the ability to absorb light with a specific wavelength and then fluoresce or emit this light into a different wavelength. Most of the highly flourescent variety act as UV protectorents. (I.e. Protecting the coral and algae from UV's and too much light). The lower fluorescent types tend to help the Zoox pigments reflect wavelengths they don't want and only absorb the wavelengths they do want. However, just to make things more difficult, there are also non-fluorescent proteins that provide coloration.

    These pigments absorb light basically with in the zone of 400 to 620 nm. violet to blue to some green and some yellow and some red. They absorb those light but fluoresce different colors back out. The colors that fluoresce out are the colors we see in our tanks.

    Further complicating matters is that corals eventually say to themselves, "Hey, I don't think we're in Kansas anymore". I've seen people say to themselves that since this is an SPS, I should put it up high in the tank under 400W MH's. Probably not a good idea if your coral is a deepwater acro. However, if acclimated slow enough, it will probably be fine. Zooxanthellae come in numerous clades and in a reef tank environment following a bleaching event, a coral might be reinfected by a different clade.

    If you really want to understand this, read these;

    Coral Coloration: Fluorescence: Part 1 by Dana Riddle

    Coral Coloration, Part 2: Fluorescence: Pigments 510 - 565 and Notes on Green Fluorescent Proteins by Dana Riddle

    Coral Coloration, Part 3: Pigments Responsible for Yellow and Orange Coloration, With Notes on Photoconversion by Dana Riddle

    Coral Coloration, Part 4: Red Fluorescent Pigments, a Preliminary Report of Effects of Various Environmental Factors and Color Mixing by Dana Riddle

    Coral Coloration, Part Five: Non-fluorescent Chromoproteins (CP-480 to CP-562) Contrary to popular belief, not all coral colors are fluorescent by Dana Riddle

    Coral Coloration, Part 6: Non-fluorescent Chromoproteins (CP-568 – CP-610) And A Newly Discovered Colorant by Dana Riddle

    Coral Coloration - Part 7: Coral Reflectance, Chromoproteins and Environmental Factors Affecting Non-fluorescent Pigmentation by Dana Riddle

    Coral Coloration, Part 8: Blue and Green Coral Fluorescence: Environmental Factors Affecting Fluorescent Pigmentation

    Lighting by Number: "Types" of Zooxanthellae and What They Tell Us by Dana Riddle
     
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  7. TinFury

    TinFury Fire Shrimp

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    Awesome thanks for the GREAT answers. It's pretty amazing that I've never read about coral pigmentation before. Everyone seems to focus on corals browning out because of the Zooxanthellae. Now I know. :)
     
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  9. coral reefer

    coral reefer Giant Squid

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    To add to what Inwall75 and Dr. Frangenstein so nicely conveyed, Bleaching is a result of two distinct different circumstances. A corals bleaching is the end result of a coral in efforts to try to survive the unfavorable environmental conditions that exist. Too much light as Inwall75 pointed out will cause a symbiotic coral zooxanthellae to go into overload to try and keep up with the intense light. A saturation of dissolved oxygen takes place at different levels, but usually at 7mg/L, but once this limit has been achieved by the coral, the excess oxygen provided by a high level of irradience(20-30000lux) means the coral must be handled metabolically. This is done with the release of a corals zooxanthellae.
    The other end of the spectrum happens with a coral not recieving enough light intensity. A coral will often try to generate one or more strains of zooxanthellae that is best able to handle the reduced light and if the coral is unable to satisfy its host zooxanthellae, it will bleach!
     
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  10. ScubaBrett22

    ScubaBrett22 Fire Shrimp

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    Ahhh lets take a mini trip back to summer of 08 at Seacamp!!

    Q1.) Bleaching happens when a coral is very stressed out and the turn white when the expel there "Zooxanthellae" which causes them to lighten or completely turn/ appear white which hence the term "Bleached"

    If you keep moving the coral they will get upset and might die from the stress!!

    "Zooxanthellae is in there Belly!!!"
    Zooxanthellae - It also give the coral coloration

    Causes of bleaching is:


    - Temperature Change
    - Changes in The Ocean/ Tanks Chemistry
    - Infectious Disease



    -Brett
     
  11. ScubaBrett22

    ScubaBrett22 Fire Shrimp

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    Maybe i should reed before i post lmaoo looks like i was a little late and he has enough information hahaha ;D;D;D Well the More information the Better!!