how do bleached corals come back?

[Riona]

Say someone buys a coral and bleaches it on accident. Then they figure out what a bonehead they were, and somehow get it to recover. Does it look more or less the same as before? If so How?

 

Correct me if I'm wrong here, but isn't bleaching when a coral looses its zooanthelae(NO idea how to spell that!)? Which is what gives it the colour that we see. So how does it recover? Do they not lose all of the zooanth, or do they lose it all and just have something coded in their genes that allow them to produce the same colour as they had before?

[bigredreefer]

Colors will never be the same.. and its going to be tough bringing them back.

 

What type of coral did "someone" accidentally bleach?

And what type of lighting?

 

RED

[Riona]

It didn't happen to/near me. I just was wondering about it. I'll take pics of my cruddy looking tank if it helps me

[ldballoon4]

IME when it bleaches in the tank , .....its toast.

[LoBo]

a coral will bleach if the tempature is too high, too low, too much light, not enough light, stuff like that.

to bring it back, you must do the keep everything stable, if the temp is too high, then you must lower it a little.

for LPS and SPS, i heard usual feeding really helps, stuff like shrimp or cyclopeeze.

[keith1569]

ya i have heard it is not a easy road to recovery when that happens

[Chebon]

I bleached a couple of blue/green yumas that are coming back red.

[chew*]

Colors will never be the same.. and its going to be tough bringing them back.

 

What type of coral did "someone" accidentally bleach?

And what type of lighting?

 

RED

 

I beg to differ, I have brought back bleached corals and they're colors were right on the money.

 

Stable water conditions are a must, start in low light and work your way brighter a week at a time, the coral will eventually brown out over likely a months time, then may go dormant for some time and or start reverting to its true color, It can take anywhere from a month once browned to ??????. I recently have a coral frag from a store, the colony was preety much wiped ( tabling acro ) and on my frag rack now I have literally a snow white coral frag with polyps extended, if there were no polyps you would swear it was dead, the base in a week has started to brown. I will be glad to take pics once it makes a full recovery. I have no clue however what color it is as it was brown in the store before it bleached.

 

Rotifers and reef chili are geared more towards sps than cyclopeeze, and contain higher nutrition.

 

Chances of bringing back a coral in your own tank that bleached in your tank due to reasons other than to much light are slim to none however, especially if the bleaching was caused by an alk spike. Alk is more important than calcium and magnesium combined.

[Riona]

I wasn't wanting to know how to bring them back(had a brain I got for less than 1/2 price at one point because the idiots at the store had bleached it out most of the way, got it nearly 100% again before my tank crashed ) I was just wondering how they get their zoanth. and their colour back. Do they regenerate it, like a person regenerates skin after a cut, or is it somehow attracted to the coral from the water(though that'd make NO sense in an aquarium since it'd have to have stayed in the tank for however long) And if it will regain mostly the same colouring or if it'd be different. That sort of thing.

[chew*]

I wasn't wanting to know how to bring them back(had a brain I got for less than 1/2 price at one point because the idiots at the store had bleached it out most of the way, got it nearly 100% again before my tank crashed ) I was just wondering how they get their zoanth. and their colour back. Do they regenerate it, like a person regenerates skin after a cut, or is it somehow attracted to the coral from the water(though that'd make NO sense in an aquarium since it'd have to have stayed in the tank for however long) And if it will regain mostly the same colouring or if it'd be different. That sort of thing.

 

They can reproduce it over time in a healthy tank.

[neanderthalman]

the colors aren't from zooxanthellae. The colors are pigments produced by the coral to knock high energy photons down into the energy levels where they can be used by the zooxanthellae.

 

Brown is from zooxanthellae, which is why SPS browns in high nitrate water - the zooxanthellae grow out of control. A bleached coral doesn't release ALL of it's zooxanthellae. Just nearly all. It only takes one survivor within the coral to repopulate.

[Hoobahans]

Yeah, the pigments are there to protect the zooxanthellae from intense light and light of wavelengths that the zooxanthellae cannot use, hence shallow coral have less pigment than deep water coral. They coral adjusts what colors they produce to fit the amount of light that is hitting it. So they will produce similar colors when they color-up if the lighting condition is similar, but if it is different than the pigments concentrations will change.

 

I have a couple frags that are coloring back up now after falling unnoticed into the rock work for a couple months. They have the same colors, although their lighting condition is pretty similar. It was a blasto and it went from zero pigmentation to full color in three weeks.

[andykee]

Yeah, the pigments are there to protect the zooxanthellae from intense light and light of wavelengths that the zooxanthellae cannot use, hence shallow coral have less pigment than deep water coral.

i think you have this backwards

[Sharpie129]

Think of it this way... for LPS (the easiest example to describe, the zooxanthellae forms a coating on the skeletal surface... The coral tissue covers that part of the skeleton and can inflate to bring water with nutrients past it's algae... Zooxanthellae is typically brown or pinkish in color (think of the typical soft coral peach for example). That color difference depends on the species of zooxanthellae that the coral has adapted to care for...

 

The coral want to keep its zooxanthellae happy and in most cases that means that it has to shield it from the light... Coral pigment is like sunblock that the polyps make to keep the zooxanthellae from burning. Photoshock happens when the coral is placed in an environment where the light is able to overpower the pigments... You wouldn't wear SPF 8 if you were going to be out in the sun all day... So the zooxanthellae fries and the coral expells it before it decomposes in there... The pigments typically are lost at the same time too (of which I wouldnt be surprised if thats evolutionarily advantageous for reasons I'll explain)... The browning of SPS is actually a reaction of the zooxanthellae trying to defend itself. They start producing large amounts of carotenoid pigments which give you your brown color...

 

After the initial stress is removed, you'll be left with and empty/mostly empty coral... one of two things can happen then... 1. the last remnants manage to recolonize the skeletal surface.... or 2. Free floating single cells of zooxanthellae are pulled in and manage to settle on the surface and begin to grow... This doesn't particularly happen in our tanks but I'd think that's the only way that the corals primary pigment would change... I don't have anything to back that up tho but it seems likely that the color variations of a species of coral is dependent on which species of zooxanthellae they're protecting...

[dzhuo]

The coral want to keep its zooxanthellae happy and in most cases that means that it has to shield it from the light... Coral pigment is like sunblock that the polyps make to keep the zooxanthellae from burning.

 

where did you get this from?

 

for what i understand, this is completely the opposite. the layer of the color pigment is actually below the zooxanthellae, not above it as `sunblock'. this is why sps over run by zooxanthellae appear to be brown as the color pigment below the zoox are all covered up.

 

my understand could be completely wrong so it would be great if you could point me to the source of your statement so i can read up.

 

thx!

[Hoobahans]

i think you have this backwards

 

Damn. I had the idea right but wrote the wrong words. Funny thing, I reread the post twice to make sure i didn't screw it up. Apparently not.

[Reef Gator]

First, for the original poster, you are correct. Bleaching occurs when a coral looses zooanthellae. Zooanthellae are single-celled algae that have co-evolved with coral. They are two separate organisms, but they have gotten so used to living together that most coral cannot live without their zooanthellae. The zooanthellae (like all algae) are photosynthetic. They absorb photons of light and use the energy to turn nutrients into sugars. The zooanthellae make more sugar than they need to survive, so they allow the coral to use some of it. In return, the coral provides physical protection and access to light for the zooanthellae (it keeps them out of the water column where they would risk being eaten by filter feeders, buried in the substrate, sunk into the depths, etc.)

 

As was said above, the process of recovery or "coloring up" is simply the few remaining zooanthellae growing within the tissue of the coral. If the zooanthellae population can recover before the coral uses up it's stored sugars, then it will live and recover. If not, it will die.

 

There are quite a few mistakes in the rest of this thread. The worst are about the actual pigments and their source and physiological location. All of the colorful pigments are produced by and reside within the zooanthellae and NOT the coral itself. The only "colorful" compounds that the corals make themselves are fluorescent proteins. These produce the glow you see under actinic light. If anyone has any references that state otherwise I would like to know about them. Here is a long review paper about pigments in simple biological systems. It goes way beyond the scope of this discussion, but there is a clearly defined section about corals and coral bleaching.

http://www.blackwell-synergy.com/doi/pdf/1...6.x?cookieSet=1

I hope this is a publicly available paper. I'm typing this from a university computer. If not, you'll have to go look it up at a science library.

 

Dawson, T L. "Light-harvesting and light-protecting

pigments in simple life forms" Color. Technol., 123, 129–142

[reefdan]

so if that's all how it works with light shock, will they come back in they were just subjected to the elements (temp swings, salinity swings, pH, nutrient, etc.)?

[Reef Gator]

reefdan,

 

I don't think it really matters what causes the bleaching, only how severe. All of the things you mentioned (including light shock) kill off the zooanthellae. Assuming that the tank conditions are corrected, it just becomes a race to see if the remaining zooanthellae can grow fast enough to provide enough sugar to keep the coral from starving to death.

[dsim]

how to rescue bleached coral in our tank? does it need to be placed in a shaded area regardless of species?

[metrokat]

Eric Borneman.

[Spirofucci]

SPS corals can and do survive bleaching in our tanks.......but there is a difference between bleachg and dead and not always easy to tell the difference at first. If you are not sure just leave it in the tank.

 

Example, I have a Walindi which I dipped and it bleached and look very dead the next day. I left it in the tank and after 2-3 months it started to grow. It evan had all kinds of algae growing on it.

[jcarman81]

SPS corals can and do survive bleaching in our tanks.......but there is a difference between bleachg and dead and not always easy to tell the difference at first. If you are not sure just leave it in the tank.

 

Example, I have a Walindi which I dipped and it bleached and look very dead the next day. I left it in the tank and after 2-3 months it started to grow. It evan had all kinds of algae growing on it.

The same thing happened to some montipora I bought a few weeks ago and the coral is rebounding remarkably well.

[Mr. Microscope]

It's possible to bring it back to it's original glory, but it takes a very long time and a lot of care (six months to a year in some cases). Stable water parameters are the key. Also, bleached corals benefit from feedings. Finally, Vitamin C supposedly helps to prevent corals from expelling their zooxanthellae and might help in a recovery.

[NanoDiver]

I bleached an acan from having to little nutrients in the tank, mainly no phosphates. It lost almost all of its color except some red, it's been about 3 months since I fixed the problem and the color hasn't really came back but it's growing new heads and looks healthy besides the color loss. Hopefully it will get it back!