25 October 2012

The ocean of the air

femur of an elephant bird, skeleton of a hummingbird

The November/December edition of New Humanist includes an article by me about some of the largest and smallest animals ever to have flown, and how life has shaped the atmosphere.

Here is something to think about:
  • In every cubic meter of [normal] air there are between 1.6 million and 40 million viruses.
  • In every cubic meter of [normal] air there are between 860,000 and 11 million bacteria.
Half of the viruses trapped by the scientists who made these observations didn’t match any known virus species. But most belong to groups that infect plants or mammals. Given that we breathe roughly 0.01 cubic meters of air each minute, a simple calculation based on these results suggests we breathe in a few hundred thousand viruses every minute.

Hummingbirds, by the way, fly forwards and backwards with equal ease.

P.S. 13 Nov: The piece is now online here.

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