I think the most interesting insight here is that the trimming on non-coding DNA is correlated with the scarcity of raw materials. Is there an existing article on Talkorigins? If not there should be.
Haven't seen one. We had a thread on the Prochlorococcus genome a while back, IIRC, and it was mentioned that the absence of non-coding DNA might be a result of a N/P shortage.
There are some interesting experiments one might run. Give it has a rapid duplication time, one could culture it in a high N/P environment for five or ten years and see if the genome develops 'junk'. Or one could look for strains living in areas of ocean with lots of land-run off and compare them.