What are these growth?

[Azedenkae]

So there are some nodular growth on my macroalgae, which I am rather confused about. Just wondering if anyone has any ideas:

And the original for comparison:

I really have no idea what they are. The tank is currently cycling. I found these washed up on the beach, so I tossed them into the tank.
Further details on my tank and tank parameters so far are here. Essentially there's been quite a lot of spikes in nutrients I am sure, as I have been excessively adding pureed seafood to my aquarium as part of the cycle.

 

[Michael Hoaster]

I'm not sure from your photo, but you appear to be pointing to new growth nodes, which is good.

If you are pointing to whitish encrusting 'stuff', I had something similar on some of my red macros. My best guest is an encrusting sponge. Whatever it is, was pretty devastating for the macro. It broke apart into pieces.

 

[Azedenkae]

I'm not sure from your photo, but you appear to be pointing to new growth nodes, which is good.

If you are pointing to whitish encrusting 'stuff', I had something similar on some of my red macros. My best guest is an encrusting sponge. Whatever it is, was pretty devastating for the macro. It broke apart into pieces.

Hi mate, thanks for that. New growth nodes is what I thought of too, though I've been suggested that they are anything from bacterial infections, to air sacs, to symbiotic bacterial colonies, to spore sacs, to well, yeah sponges and stuff.

XD

I guess part of it is because of the picture quality. >_<

But thanks for that. Does help me keep an eye out for the possibilities and what may have to be done in the future.

 

[Michael Hoaster]

My pleasure! One thing to keep in mind also, is these plants can exhibit some (wait for it), xenotypic plasticity. This means they can 'shapeshift' to better adapt to the conditions they find themselves in. So new growth can often look different from old growth.

 

[Phycophila]

It may be new growths, but those actually look like reproductive structures to me! Red algae have crazy life cycles and these carposporangium (or carpogonium) are part of it. It's also common for species to go into reproductive mode when they're stressed.