Diversity and seasonal dynamics of airborne archaea

[摘要] Archaea are widespread and abundant in many terrestrial and aquaticenvironments, and are thus outside extreme environments, accounting for up to~10% of the prokaryotes. Compared to bacteria and othermicroorganisms, however, very little is known about the abundance, diversity,and dispersal of archaea in the atmosphere. By means of DNA analysis and Sangersequencing targeting the 16S rRNA (435 sequences) and amoA genes insamples of air particulate matter collected over 1 year at a continentalsampling site in Germany, we obtained first insights into the seasonaldynamics of airborne archaea. The detected archaea were identified asThaumarchaeota or Euryarchaeota, with soilThaumarchaeota (group I.1b) being present in all samples.The normalized species richness of Thaumarchaeota correlatedpositively with relative humidity and negatively with temperature. Thistogether with an increase in bare agricultural soil surfaces may explain thediversity peaks observed in fall and winter. The detectedEuryarchaeota were mainly predicted methanogens with a low relativefrequency of occurrence. A slight increase in their frequency during springmay be linked to fertilization processes in the surrounding agriculturalfields. Comparison with samples from the Cape Verde islands (72 sequences)and from other coastal and continental sites indicates that the proportionsof Euryarchaeota are enhanced in coastal air, which is consistentwith their suggested abundance in marine surface waters. We conclude that airtransport may play an important role in the dispersal of archaea, includingassumed ammonia-oxidizing Thaumarchaeota and methanogens.

[学科分类] 地球化学与岩石