I think there is confusion going on in this whole discussion due in part to Tom referring to a-formosa as a "diatom". Kaye answered one of my questions saying 'a formosa is a DIATOM'! Well yes Tom, but that isn't the whole story especially when it comes to interpreting your photos and understanding the different forms a-formosa may take during its life cycle ...
Maybe the chart attached will help?
Its my understanding that a-formosa starts as a bud, grows into a stalk, and then given enough time and space, individual stalks (each a diatom) may attach to each other at the base of the valve to form a star-shaped "colony" which is the star shaped form of a-formosa often shown. The star-shaped a-formosa often shown is actually a "colony" of individual a-formosa diatoms. I think that needs to be clearly understood.
Tom has shown one photo showing individual stalks (each a diatom) in the process of trying to attach to form a colony ...
Tom's latest photo shows individual stalks (each a diatom) which are presumably wedged in between fragments of bills and Tom draws conclusions from that ...
I just think it is important to explain what is being shown, before people start drawing conclusions about what is being reported. Here is a chart that may be helpful... each star shaped object is a "colony" of individual a-formosa diatoms.
If I am wrong somebody please correct me! *My personal bias is that things needs to be well-explained and sourced, but this is proving difficult with so many people playing or being experts. Its the Cooper curse of competing personalities and agendas. (No, I did not use the word "agendae" for critics who will pounce... on nothing!)