Aerosol bacteria over the Southern Ocean during ACE-1

Pósfai, Mihály and Li, Jia and Anderson, James R. and Buseck, Peter R. (2003) Aerosol bacteria over the Southern Ocean during ACE-1. Atmospheric Research, 66 (4). pp. 231-240. ISSN 0169-8095

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Abstract

Individual bacterial cells occur in many samples that were collected at Cape Grim, Tasmania and during the Lagrangian "B" experiment of the Aerosol Characterization Experiment 1 (ACE-1) campaign that was conducted above the Southern Ocean. They are present in samples from altitudes as high as 5.4 kin. Morphologically, almost all bacteria are rod-shaped, about 1 mum long or smaller, have one polar flagellum, and contain inclusions that are rich in P and K. Their morphological features suggest that these bacteria are motile, marine species. It seems likely that the cells became airborne by the same bubble-bursting mechanism that ejects sea-salt aerosol particles into the atmosphere;, however, the bacteria and sea-salt particles are typically not aggregated with one another. The estimated number ratio of bacteria and the dominant aerosol species, sea salt, varies in the samples and averages about 1%. The aerosol bacteria seem to represent an important atmospheric reservoir of P and organic compounds; on the other hand, since they are externally mixed with sea salt, they are unlikely to be effective as cloud condensation nuclei.

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