What would all the bacteria look like?

I was thinking about bacteria and they are too small to be seen by the naked eye. Then I wondered what it would be like if you got all the bacteria in the world and put them together in one big pile! Tried a few google searches but no luck. Then I thought you guys are likely to have a good shot at answering this.

How big would the pile be? The size of a tv, a large room. an olympic sized swimming pool?

And what would it look like? A big pool of brown goop? Extremely fine green dust?

I seem to remember in biology class that we grew something in a petri dish. It was white (I think), is that mostly bacteria or would it have been spores??

Solid human feces is about 50% bacteria. Just extrapolate from that.

bacteria when grown as colony often tend towards the whitish colour you remember from biology, but I’ve also seen green, yellow, brown and, red, I’ve no idea what colour the resultant pile would be if you mixed them all up together.

I can’t think of any easy way to try and figure the total mass of all those bugs without doing some actual work, but I think you’re likely thinking a bit too small scale, bacteria have to represent a significant chunk of the worlds biomass and I suspect they’d take up a LOT of space if you got them all in one place.


That sounds crazy, doc. I’m going to have to ask for a cite…

I don’t have a cite for you but I remember being told in school that more than half of the weight of dried stool is bacteria. I can also tell you that looking at poop under the microscope it looks to be mostly bacteria.

Most (I’d say >80%) of the bacteria that we are able to culture in a clinical laboratory are whiteish-greyish-yellowish goop. I’d imagine that if you gathered up all the bacteria an put it in one place you’d have a giant, off-white goopy blob. I also wouldn’t be surprised if there was enough to cover Minnesota in a layer 2 feet thick, but that’s just WAG.

The color of feces if from bilirubin, not from bacteria.

Physiological Reviews, July 2001 v81 i3 p1031 Short-Chain Fatty Acids and Human Colonic Function: Roles of Resistant Starch and Nonstarch Polysaccharides. DAVID L. TOPPING; PETER M. CLIFTON.

Also see
The control and consequences of bacterial fermentation in the human colon.
J AppI Bacteriol 79:443-459, 1991 for more data.

You’d think someone from SE Wisconsin would know this stuff! What with Crypto, the deep tunnel spilling raw sewage out when it rains, the odors from the tannery down in the viaduct by the Menominee valley, and the dairy air in general.

Bacteria do form colonies, masses, aggregates, filaments and mats that can be seen with the naked eye; try googling ‘bacterial mats’ for some pictres.

Bacteria collectively look like slime, ooze or leathery muck, assorted colours.

It’d be dusty if you’ve dried them out, goopy if you hadn’t. Color depends on the species and the nutrients they’ve been growing in.

In fact, I think that’s the Wisconsin Motto: Come smell our dairy air.

xo, C.

Don’t forget 5 Star Yeast.
Thanks for the info. I had Crypto too, not the least bit pleasant and I can tell you that most of my feces was colored water.

PS, Is that 40-55 percent of the dried fecal weight or the fresh stuff. Have to know.

Isn’t there anyone who can express this in units of Roman Colosseums?

Wow! Thanks guys!

The info was surprising and a little bit gross. May curiosity has been sated.

A little hi jack on bacterial colony color. Serratia is bright red.
Cultured bacteria can be almost any color.

Bacterial culture is an extremely plastic trait. Most bacterial colonies are white in labsbecause they are mostly grown on nutrient agar or HPDA. The exact same bacteria grown on other agar would be totally different colours. You can make most bacterial species change colour simply by selecting different growth media.

Bacteria are everywhere - in the soil, on and within living organisms, in freshwater, the oceans, and in rock layers deep underground. Their total mass is enormous - some estimates indicate that it is as high as 60-100% of the total global biomass of plants.

I haven’t been able to find a good figure for total global plant biomass, but this site says the the total global biomass contains 5.6 x 10[sup]12[/sup] tons of carbon. This means total global biomass itself is much greater, since carbon makes up only part of its mass. A substantial part of global biomass is made up of plants, and we can assume bacteria make up a similar order of magnitude they do.

Therefore we can say that all the bacteria in the world taken together weigh something like 1,000,000,000,000 tons, give or take an order of magnitude or so. I will leave it for someone else to calculate the volume required, but it probably would be enough to cover a continent or two.

Huh. From my hours of screening fecal smears for yeast, I would have guessed 67 - 75% of fecal matter was bacteria. Now, the cite mentions CFUs, but it doesn’t mention dead CFUs. Those would be non-viable bacteria that would add mass and perhaps throw off the calculations if they were based on CFUs.