Is this macroalgae reproduction?

[Brad]

Look at the attached photo of my Halmedia (sp?). This happened overnight and has affected about 1/2 of the population of the algae. Is this reproduction?

This is supposed to be bad because it suddenly releases the nutrients, right?

This could have been prevented by more active pruning?

You can see some healthy algae in the background...upper right. for comparison. The algae disappears down to it's calcium skeleton and looks like it has broken down into individual green cells.

 

[reefrunner69]

t could be going sexual, although it is not unheard of...it is rare for this to happen to halemida. I personally would remove any that is going white like that, the marbling is what is bothering me, the ends that have bleached aren't a big deal but the marbling suggests (to me anyway) that it might be on it's way.

 

[Brad]

macroalgae

I had a small one do this about 1 week ago, near the same spot in the tank. This time, there are 3 "plants", all are much larger, doing it.

The entire algae changes at the same rate, over the entire surface of the entire algae. It's gone from perfectly healthy looking to this in less than 12 hours. In 12 more hours, it will be a completely white skeleton. Meanwhile, other Halemida in the tank are unchanged.

I'm going to take a look at some of it under the microscope and I'll let you know if I see anything. I'm sure it will be interesting, but I will have no idea of what I'm looking at!

 

[Brad]

Found online...

Halimeda spp. reproduce sexually from time-to-time and when it does gametophites (or game-
tangia depending on the species) grow on the outside segments. This process kills the original
plant since it takes nutrients from it to do so. Although sexual reproduction of this algae in our
tanks is pretty rare, but if it happens one can expect most of the plants to turn white and
crumble away as they die.

This is very descriptive of what has occurred in my tank.