Characterization of atmospheric bioaerosols along the transport pathway of Asian dust during the Dust-Bioaerosol 2016 Campaign
Previous studies have shown that bioaerosols are injected into the atmosphere during dust events. These bioaerosols may affect leeward ecosystems, human health, and agricultural productivity and may even induce climate change. However, bioaerosol dynamics have rarely been investigated along the...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/7131/2018/acp-18-7131-2018.pdf |
| Summary: | Previous studies have shown that bioaerosols are injected into the atmosphere
during dust events. These bioaerosols may affect leeward ecosystems, human
health, and agricultural productivity and may even induce climate change.
However, bioaerosol dynamics have rarely been investigated along the
transport pathway of Asian dust, especially in China where dust events affect
huge areas and massive numbers of people. Given this situation, the
Dust-Bioaerosol (DuBi) Campaign was carried out over northern China, and the
effects of dust events on the amount and diversity of bioaerosols were
investigated. The results indicate that the number of bacteria showed
remarkable increases during the dust events, and the diversity of the
bacterial communities also increased significantly, as determined by means of
microscopic observations with 4,6-diamidino-2-phenylindole (DAPI) staining
and MiSeq sequencing analysis. These results indicate that dust clouds can
carry many bacteria of various types into downwind regions and may have
potentially important impacts on ecological environments and climate change.
The abundances of DAPI-stained bacteria in the dust samples were 1 to 2
orders of magnitude greater than those in the non-dust samples and reached
10<sup>5</sup>–10<sup>6</sup> particles m<sup>−3</sup>. Moreover, the concentration ratios of
DAPI-stained bacteria to yellow fluorescent particles increased from
5.1 % ± 6.3 % (non-dust samples) to 9.8 % ± 6.3 %
(dust samples). A beta diversity analysis of the bacterial communities
demonstrated the distinct clustering of separate prokaryotic communities in
the dust and non-dust samples. Actinobacteria, Bacteroidetes, and
Proteobacteria remained the dominant phyla in all samples. As for Erenhot,
the relative abundances of Acidobacteria and Chloroflexi had a remarkable
rise in dust events. In contrast, the relative abundances of Acidobacteria
and Chloroflexi in non-dust samples of R-DzToUb were greater than those in
dust samples. Alphaproteobacteria made the major contribution to the
increasing relative abundance of the phylum Proteobacteria in all dust
samples. The relative abundance of Firmicutes did not exceed 5 % in all
the air samples, even though it is the predominant phylum in the surface sand
samples from the Gobi Desert. These results illustrate that the bacterial
community contained in dust aerosol samples has a different pattern compared
with non-dust aerosol samples, and the relative abundances of airborne
bacteria are different from those in the surface sand or soil and differ by
location and transmitting vector. |
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| ISSN: | 1680-7316 1680-7324 |