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I restarted my experiment after having learned lots of approaches that don't work -- specifically I've learned lots of ways to corrode metal, which is not what I want.

Anyway, I restarted a couple days ago. The negative electrode has developed a cloudy haze around it, which the positive electrode doesn't have. So what's in that haze? Bacteria! Check out this incredible picture. It's so perfect it looks like it came from a textbook!

I'm using 1V DC in a jar of fresh water with 304 stainless steel mesh electrodes, a small pinch of salt, and a small pinch of yeast extract. No aeration.
in reply to Kim

Can you remind me again what you're trying to accomplish? Is it CO2 fixation using microbes and electricity?
in reply to Kim

Nice. Very interesting! If you ever want a larger lab space to try things out you'd probably be a good member at BwoB. And/Or if you want to talk to folks about your project it would be great to chat IRL, run a journal club, or throw a talk.
in reply to Kim

Oh my God. The entire jar turned cloudy over night.
in reply to Kim

This is why you should never drink cloudy water!

This video shows the bacteria in only about 0.001 ml of water from my jar. At the beginning the focus is on the upper plane, and then I slowly move the focus down into the seething mass. This is terrifying. #horror #science #bacteria #OhMyGodWhatHaveIDone
in reply to Kim

There's lots of different kinds of bacteria in there. Yesterday almost all the cells were long and slender, but today they're mostly small and stubby. And they really seem to like swarming (yes that is apparently the technical term for it)
#bacteria #science #IttyBittyBees
in reply to Kim

I started a new jar, in parallel with the old jar. The only difference is that the new one uses distilled water instead of tap water, and about half as much yeast extract. I inoculated the new jar with about 8oz from the old one. #ScienceExperiment #microbiology
in reply to Danny (he/they)

@danwchan if anything at all manages to keep growing after reducing the amount of food to zero, then I think of that as success. It means the microbes had to get carbon from somewhere, and I think that's likely to be from co2.

Eventually I'll have to be much more controlled, eg sealed lids to prevent dust from falling in. But I'm not yet at the point where that matters, because so far I haven't gotten anything to grow without carbohydrates or light.

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