Atmospheric transport of soil microorganisms and higher plant waxes in East Asia significantly influences the aerosol composition over the North Pacific. This study investigates the year-round atmospheric abundances of hydroxy fatty acids (FAs), tracers of soil microorganisms (β-isomers), and plant waxes (α- and ω-isomers), in total suspended particles collected at Gosan, Jeju Island, during April 2001 to March 2002. These hydroxy FAs showed a pronounced seasonality, higher concentrations in winter/spring and lower concentrations in summer/autumn, which are consistent with other tracers of soil microbes (trehalose), resuspended dust (nss-Ca2+), and stable carbon isotopic composition (δ13C) of total carbon. The molecular distributions of β-hydroxy FAs (predominance of C12 and C16 in winter/spring and summer/autumn, respectively) are consistent with those from a remote island (Chichijima) in the North Pacific and Asian dust standards (CJ-1 and CJ-2). This observation together with back trajectories over Gosan reveal that desert sources in China during winter and arid regions of Mongolia and Russian Far East during spring are the major contributors of soil microbes over the North Pacific. Predominance of ωisomers (83%) over β-hydroxy FAs (16%) revealed a major contribution of terrestrial lipids from higher plant waxes over soil microbes in the East Asian outflow.
Bibliographical noteFunding Information:
The authors thank the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) for financially supporting this study through grant-in-aid 14204055 and 24221001. This research is a contribution to the International Global Atmospheric Chemistry (IGAC) Core Project of the International Geosphere Biosphere Program (IGBP) and a part of the IGAC Aerosol Characterization Experiments (ACE). P.T. appreciates MEXT (Monbukagakusho) for the PhD scholarship. We acknowledge Phil Meyers of Michigan University for his English corrections. The data used are listed in the references, tables, figures, and supporting information.
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ASJC Scopus subject areas
- Aquatic Science
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Space and Planetary Science
- Earth and Planetary Sciences (miscellaneous)