Why Xenia pulse

Very cool article on Advanced Aquarist today about how a team of scientists discovered the answer to one of the longest standing questions in our hobby... why do Xenia pulse?

Why do soft corals like Xenia pulse? — Advanced Aquarist | Aquarist Magazine and Blog

I particularly liked how they found the pulsing motion decreased photorespiration.

 

nice

 

thx 4 sharing

 

Finally!!!

 

very cool!

 

Wow! I just thought they were "Trying to catch food particles"...

 

So are they basically saying that Xenia pulses in oxygen rich water, trying to circulate water to get less oxygenated water? I am very curious, since I have some of the same colony of xenia in 2 tanks. In one, it does not pulse at all. In another, it pulses constantly. The one it does not pulse in, I would expect it to have a higher DO level due to the sump, larger skimmer, higher flow, etc, so basically the opposite of what they are saying...

 

It's flow dependant too I believe I've seen many times where they stop pulsing in high flow tanks

 

Flow is basically the same in either tank, so I don't think that is it. At least not in my case.

 

Actually no, it's ridding it's body of O2.

The Zooxanthellae algae produces O2 for it's host coral as well as food. If the temp or lighting is increased, it increases the Zooxanthellae's metabolism, which of course causes it to work faster and produce more O2. With other photosynthetic corals, if the O2 in their cells nears toxic levels, they must bleach- expel their Zooxanthellae to survive; they can always recover Zooxanthellae when the temp/lighting returns to normal. The Xenia, OTOH, pulses to shed the excess O2.

And yes, they may stop pulsing in higher flow as it won't be necessary.