How many bacteria can the world support?

  • Thread starter dipungal
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The title says all I'm asking. Thank you.
 

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  • #2
jim mcnamara
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The short answer is: nobody knows, and it is very unlikely that anything really reliable, unlike the exercise below, will be available any time soon.


See:
'A Natural History of Subterranean Life' by David W. Wolfe

A large percentage of the total Earth's biomass is found beneath the surface, mostly as
bacteria-like organisms [per Wolfe]. Biomass estimates for above ground biomass vary a lot, however, for fun and a way to make a wild guess let's use 56 billion metric tons of fixed carbon. For above ground biomass.

Since this is just a fun exercise, not real Science, let's also assume that 20% of the biomass above ground is 'bacterial' however that gets defined.... In the same vein, we can use 56 billion tons as the amount of fixed carbon in subterranean life.

So we have 56 * .20 = 11.2 billion tons (above ground) + 56 billion tons (subterranean) , so our total is 67.2 billion tons.

So you can get a grip on what we're doing: your body has about one trillion cells in it,
and let's pretend you weigh 150 pounds. That means we can guess that 1 pound of you is: 1 trillion / 150. This comes out close to 660,000,000,000 cells. (that's 660 billion, the US billion)

So, let's pretend that our cells and bacterial cells are similar in size and mass (which is not a great assumption). Therefore, to get an really rough idea of the number of bacteria and their relatives on Earth now, multiply 660,000,000,000 * 672,000,000,000.

I should also mention that some of your biomass is bacteria, e.g., about 10% of the volume of your colon is bacteria and other primitive organisms.

Also note that what we are calling bacteria here are really a whole range of living one-celled things from primitive algae to organisms that metabolize metals like manganese, to what you probably think of as germs.
 
  • #3
Ryan_m_b
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I should also mention that some of your biomass is bacteria, e.g., about 10% of the volume of your colon is bacteria and other primitive organisms.
IIRC we carry about 1kg of bacteria. There are far more bacteria than human cells in our body with far more genetic material than our genome;
wikipedia said:
The human body, consisting of about 100 trillion cells, carries about ten times as many microorganisms in the intestines. The metabolic activities performed by these bacteria resemble those of an organ, leading some to liken gut bacteria to a "forgotten" organ. It is estimated that these gut flora have around 100 times as many genes in aggregate as there are in the human genome.
 
  • #4
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The title says all I'm asking. Thank you.
How about we start off with Earth.:smile:
Proc. Natl. Acad. Sci. USA
Vol. 95, pp. 6578–6583, June 1998
Perspective
Prokaryotes: The unseen majority
William B. Whitman*†, David C. Coleman‡, and William J. Wiebe§
Departments of *Microbiology, ‡Ecology, and §Marine Sciences, University of Georgia, Athens GA 30602
http://www.pnas.org/content/95/12/6578.full.pdf+html

ScienceDaily reported the article as well entitled First-Ever Scientific Estimate Of Total Bacteria On Earth Shows Far Greater Numbers Than Ever Known Before:
When people think of bacteria, they likely first consider the nasty ones that cause disease, but the bacteria inside all animals combined -- including humans -- makes up less than one percent of the total amount. By far the greatest numbers are in the subsurface, soil and oceans.
http://www.sciencedaily.com/releases/1998/08/980825080732.htm
 
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Evo
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Off topic posts deleted. Thread closed.
 

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