Characterization of free amino acids, bacteria and fungi in size-segregated atmospheric aerosols in boreal forest: seasonal patterns, abundances and size distributions

摘要

Primary biological aerosol particles (PBAPs) are ubiquitous in theatmosphere and constitute ∼ 30 % of atmospheric aerosolparticle mass in sizes   1 µm.PBAP components, such as bacteria, fungi and pollen, mayaffect the climate by acting as cloud-active particles, thus havingan effect on cloud and precipitation formation processes. In thisstudy, size-segregated aerosol samples ( 1.0, 1–2.5, 2.5–10 and   10 µm) were collected in boreal forest(Hyytiälä, Finland) during a 9-month period covering allseasons and analysed for free amino acids (FAAs), DNA concentrationand microorganism (bacteria, andfungi). Measurements were performed using tandem mass spectrometry,spectrophotometry and qPCR, respectively. Meteorological parametersand statistical analysis were used to study their atmosphericimplication for results. Distinct annual patterns of PBAP componentswere observed, late spring and autumn being seasons of dominantoccurrence. Elevated abundances of FAAs and bacteria were observedduring the local pollen season, whereas fungi were observed at thehighest level during autumn. Meteorological parameters such as airand soil temperature, radiation and rainfall were observed topossess a close relationship with PBAP abundances on an annual scale.