What is Green Hair Algae really?

[taricha]

Ok. Can we maybe try to say what this GHA is? At least down to a genus? Or at least be clear about what it is not?
*crowd protests* But there are hundreds of species of GHA, and they all look the same - it's pointless!
Maybe. But maybe not.
Whenever I've seen description or pics of GHA that nothing wants to eat, it looks like this...

I've gotten samples from other people's tanks, and this is what theirs looks like too.
Important features:
Filamentous, branched, no visible cell divisions or segmentation within filament (siphonous), no segmentation at branch points, chloroplasts visible and arranged around the walls, branching not symmetric, branching not fern-like, growth tip is clear half-dome free of chloroplasts, no spore structures visible.






Other filamentous algaes that it's definitely not (and why):
Lyngbya, Calothrix, Spirulina, or any other cyanobacteria (they have cell segments)
Spirogyra (different internal structure)
Cladophora, Cladophoropsis "turf" algae (cell segments)
Enteromorpha another "turf" algae (cell structure/arrangement within filament is very different)
These 3 are very close, but wrong in some way
Derbesia (these form spores - see adv aquarist article)
Vaucheria (weird curvy spore structure)
Bryopsis (large scale growth structure is fern-like with segmentation at the branches)

Any ideas?
Bonus: here's a video sped up 6x where you can see chloroplasts moving within the filament.

 

[sfin52]

Very interesting

 

[Clownfishy]

Following

 

[taricha]

After talking to an expert and looking again, I was wrong. It is in fact common derbesia. Spore formation all over the place that makes it match derbesia perfectly. (See pic) I guess I was originally growing samples under conditions that discouraged spore formation.

So "what is GHA?" Well, there doesn't seem to be any mystery "GHA" that is distinct from the ones we know (and which are listed in first post) Green filamentous stuff with no cell divisions seems to always be bryopsis if it has fern-like/ feather-like structure, and derbesia if it doesn't.
But bugging an algae researcher to look at my common derbesia (lol) wasn't a total waste.
He sent a paper that is basically a catalog of all the algae types that appear in the saltwater aquarium trade.

View attachment 2018_Vranken_BiolInvasions.pdf

 

[mcarroll]

Where's the paper? Or title?

Seems like all the good-sounding articles on algae I've come across are only pertaining to freshwater!

 

[taricha]

Where's the paper? Or title?

Seems like all the good-sounding articles on algae I've come across are only pertaining to freshwater!

I tried to attach the paper, but maybe it only shows up for me.
"A risk assessment of aquarium trade introductions of seaweed in European waters"
https://www.researchgate.net/public...e_introductions_of_seaweed_in_European_waters

 

[mcarroll]

Thanks!

(It looks like a blank image placeholder where the doc was supposed to be. Un-clickable.)

 

[mcarroll]

(Research Gate doesn't have it either.....check Google Scholar for the "vliz.be" server in Belgium that has it)

 

[mcarroll]

That's not something that's very skimmable – 8 chapters, each longer than a "typical" journal article. LOL Will have to dedicate some time to go through this.

Looks great though!

 

[taricha]

That's not something that's very skimmable – 8 chapters, each longer than a "typical" journal article. LOL Will have to dedicate some time to go through this.

Looks great though!

that's a cool find too. But it's not the article that I was referring to.
Lemme see if this attachment attempt worked.

edit: oh, actually the paper I was referring to is included in your find. It's listed as "chapter 6"
In that big .pdf on pages 130-132 is the list of all the algae they ID'd from saltwater aquariums.

 

[mcarroll]

I'll begin with #6 then!