From the Biofilm

[DonSchaeffer]

I have water samples in small prescription bottles. Biofilms have been developing, floating on top. They appear to be made mostly of the spores of algae fused with a bunch of skeletons and fibers. I found many diatoms in it--many of them look like just the silicon shells are left. I made some pictures of my journey through this strange place.

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[Hobbyst46]

Very nice catch ! how did the biofilm form ? a closed prescription bottle is not (AFAIK) an ideal growth environment for plants. Thanks in advance for details.

[DonSchaeffer]

It was in a closed bottle--but I received the original water sample from my son who has a salt water aquarium. It's been in the small bottle for a two months or so. At first it was overrun with algae harboring long worms. Then the algae produced multitudes of spores. The spores seems to have formed the basis for the biofilm.

PS., Does anybody know what those round things in the first photo are. I keep seeing them along with long X shaped crystalline formations.

[charlie g]

Hello Don, happy Earth Day to all of us! I am curious, what is the source of your water samples which you placed in those Rx-bottle containers? I often thought of patiently collecting: 'naturally cleared diatom frustules'...to on some rainy day..set about mounting as fixed/'permanent' slides. Often in enjoyment of collected water samples from outdoor waters...there one is...one huge pennate diatom frustule ( large as a cough drop I will say!) pristinely naturally cleared!

It actually provoked me to seeing if I could setup a variety of diatom rich water containers..and leave outdoors with a variety of specific contents...to then time to time see if diatom frustules were in process of: 'naturally biogenically being cleared'. Of course this yet another microscopy back-burner pursuit. To paraphrase a con-US wine commercial...'no naturally cleared frustule will be mounted before it's time.' .

Indeed you aptly call your small bottle cultures 'unique habitats', compared to marine waters habitats..the spectrum of freshwater habitats is a blizzard of specific niches, many freshwater niches have been cycling season after season..for deep geologic time scales. I enjoy your attention to these nicrohabitats you here share with us. Again...what was the source of your Rx-vials water samples? all enjoy Spring '20 and this sobering Earth Day. charlie guevara, finger lakes, US

[Hobbyst46]

I often thought of patiently collecting: 'naturally cleared diatom frustules'...to on some rainy day..set about mounting as fixed/'permanent' slides. Often in enjoyment of collected water samples from outdoor waters...there one is...one huge pennate diatom frustule ( large as a cough drop I will say!) pristinely naturally cleared!

Forum member Charles once hinted that such diatoms could be found at the estuary of a river (he referred to a river mouth in the Chesapeake bay). Sort of benthic diatoms.

...It actually provoked me to seeing if I could setup a variety of diatom rich water containers..and leave outdoors with a variety of specific contents...to then time to time see if diatom frustules were in process of: 'naturally biogenically being cleared'. Of course this yet another microscopy back-burner pursuit..

Same ambition here.
Growing diatoms requires a specific solution of chemicals. But I thought of another idea: A transparent shallow glass container, with a layer of clean calcium-free beach sand (as source of silicon) on the bottom; fill it with a dilute solution of mineral plant fertilizer like 20/20/20, inject some water from a natural source, cover loosely and leave in daylight. Will it work ? Hope to try.

[DonSchaeffer]

I got a sample from my son's salt water aquarium. The water was in there for about a month. The diatoms didn't appear for me until the biofilm built up.