Roles of marine biota in the formation of atmospheric bioaerosols, cloud condensation nuclei, and ice-nucleating particles over the North Pacific Ocean, Bering Sea, and Arctic Ocean
<p>We investigated the association of marine biological indicators (polysaccharides, protein-like gel particles, and chl <span class="inline-formula"><i>a</i></span>) with the formation of fluorescent aerosol particles, cloud condensation nuclei (CCNs), and ic...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2024-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/24/1777/2024/acp-24-1777-2024.pdf |
| Summary: | <p>We investigated the association of marine biological indicators (polysaccharides, protein-like gel particles, and chl <span class="inline-formula"><i>a</i></span>) with the formation of fluorescent aerosol particles, cloud condensation nuclei (CCNs), and ice-nucleating particles (INPs) over the North Pacific Ocean, Bering Sea, and Arctic Ocean during September–November 2019. The abundance of bioindicators was high in the North Pacific Ocean and the Bering Sea (e.g., up to 1.3 <span class="inline-formula">mg m<sup>−3</sup></span> of chl <span class="inline-formula"><i>a</i></span>), suggesting high biological activity due to a phytoplankton bloom. In the North Pacific Ocean, particles were characterized by high mass fractions of organics and sulfate with a predominance of terrestrial air masses. Conversely, in the Bering Sea and the Arctic Ocean, particles were characterized by high mass fractions of sea salt and sulfate with a predominance of maritime air masses. The averaged range/value of the CCN concentration at 0.4 % supersaturation were 99–151, 43–139, and 36 <span class="inline-formula">cm<sup>−3</sup></span> over the North Pacific Ocean with terrestrial influences, over the Bering Sea with marine biogenic influences, and over the Arctic Ocean with marine influences, respectively, and the corresponding range/value of the hygroscopicity parameter <span class="inline-formula"><i>κ</i></span> were 0.17–0.59, 0.42–0.68, and 0.66, respectively. The averaged INP concentration (<span class="inline-formula"><i>N</i><sub>INP</sub></span>) measured at temperatures of <span class="inline-formula">−</span>18 and <span class="inline-formula">−</span>24 <span class="inline-formula"><sup>∘</sup>C</span> with marine sources in the North Pacific and Bering Sea was 0.01–0.09 and 0.1–2.5 <span class="inline-formula">L<sup>−1</sup></span>, respectively, and that over the Arctic Ocean was 0.001–0.016 and 0.012–0.27 <span class="inline-formula">L<sup>−1</sup></span>, respectively. When marine sources were dominant, fluorescent bioaerosols in the fine mode were strongly correlated with all bioindicator types (<span class="inline-formula"><i>R</i></span>: 0.81–0.88) when the effect of wind-induced uplift from the sea surface to the atmosphere was considered. Correlations between <span class="inline-formula"><i>N</i><sub>INP</sub></span> measured at <span class="inline-formula">−</span>18 and <span class="inline-formula">−</span>24 <span class="inline-formula"><sup>∘</sup>C</span> and all bioindicator types (<span class="inline-formula"><i>R</i></span>: 0.58–0.95 and 0.79–0.93, respectively) were positive, even when the extreme outlier point was omitted, as were those between <span class="inline-formula"><i>N</i><sub>INP</sub></span> and fluorescent bioaerosols (<span class="inline-formula"><i>R</i></span>: 0.50 and 0.60, respectively), suggesting that marine bioindicators contributed substantially as sources of bioaerosols and to cloud formation.</p> |
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| ISSN: | 1680-7316 1680-7324 |