Hi Strange! I too had this in my tank and gained some insight on it from fellow reefer Twilliard (Very knowledgeable guy about all types of algae). The organism is a bacteria. It feeds off of nutrients like N and P if I remember right. If you are looking to get rid of it, Chemi-Clean works great just a one time treatment and you should be good to go.
As for the Google search, it kind of stinks that there isn't info on it. I searched a lot for info about it but it all kept pointing me back to fish food lol
Edit: Here is what Twilliard said when I asked him what causes it and how to prevent it. Hope this helps!
"I only know how to get rid of it.
Like any cyanobacteria it has to be introduced
I have not done a lot of study with spirulina as it is a beneficial bacteria to tank life.
The problem is when they grow out of hand and create anaerobic conditions spiking sulfides.
Proper qt and coral dipping for new additions helps keep this at bay.
You will hear that this is naturally in the water, this is incorrect. They are naturally on what we put into our tanks."