Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 10583-10595, 2017
https://doi.org/10.5194/acp-17-10583-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
08 Sep 2017
Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater
Victoria E. Irish1, Pablo Elizondo1, Jessie Chen1, Cédric Chou1, Joannie Charette2, Martine Lizotte3, Luis A. Ladino4,a, Theodore W. Wilson5, Michel Gosselin2, Benjamin J. Murray5, Elena Polishchuk1, Jonathan P. D. Abbatt4, Lisa A. Miller6, and Allan K. Bertram1 1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
2Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, Québec, QC G5L 3A1, Canada
3Département de biologie, Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada
4Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario, ON M5S 3H6, Canada
5Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
6Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, BC V8L 4B2, Canada
anow at: Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
Abstract. The sea-surface microlayer and bulk seawater can contain ice-nucleating particles (INPs) and these INPs can be emitted into the atmosphere. Our current understanding of the properties, concentrations, and spatial and temporal distributions of INPs in the microlayer and bulk seawater is limited. In this study we investigate the concentrations and properties of INPs in microlayer and bulk seawater samples collected in the Canadian Arctic during the summer of 2014. INPs were ubiquitous in the microlayer and bulk seawater with freezing temperatures in the immersion mode as high as −14 °C. A strong negative correlation (R = −0. 7, p = 0. 02) was observed between salinity and freezing temperatures (after correction for freezing depression by the salts). One possible explanation is that INPs were associated with melting sea ice. Heat and filtration treatments of the samples show that the INPs were likely heat-labile biological materials with sizes between 0.02 and 0.2 µm in diameter, consistent with previous measurements off the coast of North America and near Greenland in the Arctic. The concentrations of INPs in the microlayer and bulk seawater were consistent with previous measurements at several other locations off the coast of North America. However, our average microlayer concentration was lower than previous observations made near Greenland in the Arctic. This difference could not be explained by chlorophyll a concentrations derived from satellite measurements. In addition, previous studies found significant INP enrichment in the microlayer, relative to bulk seawater, which we did not observe in this study. While further studies are needed to understand these differences, we confirm that there is a source of INP in the microlayer and bulk seawater in the Canadian Arctic that may be important for atmospheric INP concentrations.

Citation: Irish, V. E., Elizondo, P., Chen, J., Chou, C., Charette, J., Lizotte, M., Ladino, L. A., Wilson, T. W., Gosselin, M., Murray, B. J., Polishchuk, E., Abbatt, J. P. D., Miller, L. A., and Bertram, A. K.: Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater, Atmos. Chem. Phys., 17, 10583-10595, https://doi.org/10.5194/acp-17-10583-2017, 2017.
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Short summary
The ocean is a possible source of atmospheric ice-nucleating particles (INPs). In this study we found that INPs were ubiquitous in the sea-surface microlayer and bulk seawater in the Canadian Arctic. A strong negative correlation was observed between salinity and freezing temperatures (after correcting for freezing point depression). Heat and filtration treatments of the samples showed that the INPs were likely biological material with sizes between 0.02 μm and 0.2 μm in diameter.
The ocean is a possible source of atmospheric ice-nucleating particles (INPs). In this study we...
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