Re: SCI: Break out the disinfectant! (Estimate of Bacteria Population)
Tue, 25 Aug 1998 23:11:16 EDT wrote...

>Researchers produce the first scientific estimate of the number
>of bacteria on Earth. The tally - 5 x 10^30 bacteria. Anyone know
>what the mass is of the average bacterium? That's such a huge number,
>I'm wondering how much biomass bacteria as a whole possess.

The size and shape of bacteria vary widely. But estimating roughly a micron in average diameter, gives 1 e 12 per cubic centimeter. Approxamating their density as that of water, an estimated weight for a bacteria of 1 e -12 gm is obtained. So times 5 e 30 bacteria gives 5e18 gm . Give or take a couple of orders of magnitude. This seems reasonable considering the CRC (60th ed 1979) gives a 1955 estimate of the mass of the living biosphere as 3.6 e 17 gm.