Emission of primary bioaerosol particles from Baltic seawater

Abstract

Bioaerosols are particles of biological origin with important atmospheric impacts, for example within cloud formation where bioaerosols can act as cloud condensation or ice nuclei. Their sources and properties, however,...

Quantification and Characterization of Microbial Emissions over the Northeastern Atlantic Using Mesocosm Experiments

“…The MBS determined a concentration of 19.4 ± 11.1 PBAP per liter of air in the headspace of the SSC. These PBAPs accounted for approximately 0.5 ± 0.26% of all fluorescent particles and 0.04 ± 0.03% of all coarse particles, which is very close to the PBAP-to-coarse ratio of 0.05% reported by Freitas et al…”

“…The beta diversity of the nascent aerosol samples showed a wider spread and consistently formed distinct clusters compared to the seawater samples, aligning with the findings determined by Freitas et al 32 Furthermore, the seawater samples taken after 48 h in the chamber exhibited closer clustering with the nascent aerosol samples (see Figure 3c). We believe this is a chance effect due to the lower alpha diversity in the aged samples.…”

“…The MBS determined a concentration of 19.4 ± 11.1 PBAP per liter of air in the headspace of the SSC. These PBAPs accounted for approximately 0.5 ± 0.26% of all fluorescent particles and 0.04 ± 0.03% of all coarse particles, which is very close to the PBAP-to-coarse ratio of 0.05% reported by Freitas et al 32 The MBS estimate of PBAPs is lower compared to the cell counts from fluorescence microscopy, particularly for particle sizes smaller than 0.8 μm (see Figure 2). The cell size distributions obtained from the fluorescence microscopy analysis of the seawater and the chamber aerosols exhibited fairly similar shapes, and approximately 84% of the cells were smaller than 0.8 μm, which agrees well with the findings from Sieracki and Viles, 67 who reported that 80% of marine bacteria in North Atlantic seawater are smaller than 0.7 μm.…”

“…Those exceeding only the 3σ threshold are labeled "others". This threshold has been used in previous studies by Savage et al 57 and Freitas et al 32 According to Freitas et al, 32 who performed similar controlled sea spray simulation experiments using Baltic seawater, if the maximum fluorescent signal is observed in the B channel, the particles are consistent with PBAP and are hereafter referred to as PBAP.…”

“…Therefore, caution should be exercised when interpreting the results from such studies. To mitigate the selective growth of certain taxa, we recommend an approach similar to the one used by Freitas et al 32 when possible, where fresh seawater is continuously introduced into the chamber, replacing the existing seawater. Furthermore, we recommend that future studies should use primers to also include archaea.…”