Diversity and seasonal dynamics of airborne archaea

• Main Authors: J. Fröhlich-Nowoisky, C. Ruzene Nespoli, D. A. Pickersgill, P. E. Galand, I. Müller-Germann, T. Nunes, J. Gomes Cardoso, S. M. Almeida, C. Pio, M. O. Andreae, R. Conrad, U. Pöschl, V. R. Després
• Format: Article
• Language: English
• Published: Copernicus Publications 2014-11-01
• Series: Biogeosciences
• Online Access: http://www.biogeosciences.net/11/6067/2014/bg-11-6067-2014.pdf
• ISSN: 1726-4170; 1726-4189

Archaea are widespread and abundant in many terrestrial and aquatic environments, and are thus outside extreme environments, accounting for up to ~10% of the prokaryotes. Compared to bacteria and other microorganisms, however, very little is known about the abundance, diversity, and dispersal of archaea in the atmosphere. By means of DNA analysis and Sanger sequencing targeting the 16S rRNA (435 sequences) and <i>amoA</i> genes in samples of air particulate matter collected over 1 year at a continental sampling site in Germany, we obtained first insights into the seasonal dynamics of airborne archaea. The detected archaea were identified as <i>Thaumarchaeota</i> or <i>Euryarchaeota</i>, with soil <i>Thaumarchaeota</i> (group I.1b) being present in all samples. The normalized species richness of <i>Thaumarchaeota</i> correlated positively with relative humidity and negatively with temperature. This together with an increase in bare agricultural soil surfaces may explain the diversity peaks observed in fall and winter. The detected <i>Euryarchaeota</i> were mainly predicted methanogens with a low relative frequency of occurrence. A slight increase in their frequency during spring may be linked to fertilization processes in the surrounding agricultural fields. Comparison with samples from the Cape Verde islands (72 sequences) and from other coastal and continental sites indicates that the proportions of <i>Euryarchaeota</i> are enhanced in coastal air, which is consistent with their suggested abundance in marine surface waters. We conclude that air transport may play an important role in the dispersal of archaea, including assumed ammonia-oxidizing <i>Thaumarchaeota</i> and methanogens.