Read something interesting

[Udest]

So I was browsing the web today and I found a few articles about corals bleaching and it brought up some interesting questions.

1 neon bleaching pretty much the result of corals being stressed out and trying to screen themselves from the sun , also possibly being starved as well and 2 the term I've heard called browning out which seems to be more or less many colas in their normal state when they are fed and don't have too much light.

So question is what do you guys think of this?

 

[Udest]

Here's the article https://www.google.com/amp/s/www.sc...gae-neon-colors-bleaching-recovery-oceans/amp

 

[C. Eymann]

This is my understanding-
high temperatures cause corals expel their zooxanthelle as a form of self preservation, as temperature rises the rate of photosynthesis speeds up as well as other biological processes, at optimal rates corals can oxidize free radical byproducts of photosynthesis, if the rate exceeds their ability to neutralize these byproducts they expell their zooxanxthelle which is generally golden brown in color, this leaves the only pigmentation of their tissues chromoproteins behind giving them this neon bleachy coloration.


Im sure someone like @Dana Riddle has a better, more indepth explanation

 

[Udest]

I knew of the heat stress bleaching when I read this I was thinking of some situations in our tanks when corals do crash badly for no apparent reason , but I also do know corals do exist in areas in nature where the light can be very intense which generally equals heat as well.

Also the neon color makes sense as well since it's pretty much like taking a channel out of your r g b c in a photo

I think some people that have reported massive tank crashes perhaps had left out some key detail its hard to say though .

Right now I'm trying to figure out what is the most common reason for these things to happen in aquaria.

 

[Lasse]

Here is the article and it is very interesting and put a new light on what "colouring up" really means - stressed corals

Sincerely Lasse

 

[Udest]

Yep that's what I gathered too from some other articles too , so in essence I guess some methods stress corals to a point and if any parameters go off I guess that could lead to a crash , it's all a fine balancing act

 

[blasterman]

Bleaching means the coral is tossing it's zooxanthellae. It's either stressed, or in the case of some corals replacing the zooxanthellae with another type of zooxanthellae (clade) that's more tolerant of the current conditions.

Nutrient shock is not something corals are really adapted for because there isn't much change in this respect in the ocean, and when it does occur, usually by pollution it's bad. Temperature shock however is something that corals do have to tools to adapt to. Too many zooxanthellae caused by warm water or nutrient levels starve the corals tissues of nutrients.

I had an example a couple months ago I posted here when a penny fell in one of my SPS tanks and the zinc caused several rapidly growing colonies of digipora to turn stark white over night as the zinc poisoned the zooxanthellae in the coral. Took about 3 weeks to recover.

Also, bio warfare can cause the same issue. Some species of wild palythoas if they get angry can and will poison SPS in this fashion.

 

[Udest]

That's what I was looking for some of the other possibilities for it to happen , another example I've seen is when the water is also depleted of oxygen or swings in salinity my lfs has a story about their ato breaking doing just that.