Every­body Is Al­ways Talk­ing About The Weather… Re­vis­ited

by Elio

A re­cent pa­per in Sci­ence adds ev­i­dence to the no­tion that ice nu­clei, the par­ti­cles that lead to the for­ma­tion of rain and snow, are mainly of bi­o­log­i­cal ori­gin. In fact, lots of the ice nu­clei con­tain bac­te­ria that have wafted aloft. The re­searchers found that fresh snow in var­i­ous parts of the world, in­clud­ing Antarc­tica, con­tains DNA in par­ti­cles that are sen­si­tive to both lysozyme and heat. We ex­pect that metage­nomics of such sam­ples will fol­low.

Lentic­u­lar clouds above the Big Is­land. Credit: astroday.net

Where do these bac­te­ria that fly through the air with the great­est of ease come from?

The best guess is that they are lifted from the leaves of plants. They may well in­clude Pseudomo­nas sy­ringae, the or­gan­ism with the rep­u­ta­tion for caus­ing ice for­ma­tion on plants at rel­a­tively high tem­per­a­tures. This new work is part of a small but tena­cious lit­er­a­ture on the sub­ject of bac­te­r­ial par­tic­i­pa­tion in at­mos­pheric phe­nom­ena. For an evo­lu­tion­ary view­point, see John Den­nehy's blog; for a de­scrip­tion of the chal­lenges of liv­ing in the clouds, com­plete with per­ti­nent ref­er­ences, see a blog spon­sored by The New York Times. (Not that we suf­fer from com­ment-envy, but we couldn't help but no­tice that the lat­ter got 129 com­ments!)

We have long known that bac­te­ria con­tribute to the cli­mate of this planet (that is, to long range at­mos­pheric changes). There have been good rea­sons to think that bac­te­ria might also in­flu­ence the weather (i.e., what the fore­cast­ers tell you about to­day and the rest of the week). With these re­cent data, such claims be­come even more cred­i­ble.