Tracing atmospheric transport of soil microorganisms and higher plant waxes in the East Asian outflow to the North Pacific Rim by using hydroxy fatty acids: Year‐round observations at Gosan, Jeju Island

Abstract

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 ω‐isomers (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.

Decadal Variations in Hydroxy Fatty Acids Over Chichijima Island in the North Pacific: Long‐Term Seasonal Variability in Plant and Microbial Markers

“…Likewise, similar distributions of β-hydroxy FAs from Chichijima with CJ-1 (i.e., high concentration of C 12 or C 10 or C 8 ) further emphasizes a likely contribution from Chinese loess deposit with the East Asian outflow. This source-specific feature characterized by the predominance of short-chain homologs of β-hydroxy FAs has been observed for the dust outbreak samples from Gosan super-site in Jeju Island in South Korea (Tyagi et al, 2017). The distributions of ω-hydroxy FAs in CJ-1 and CJ-2 showed the predominance of C 22 followed by C 24 and then C 16 , which are in sharp contrast to those of spring and winter aerosols from Chichijima (i.e., seasons with the pronounced impact of the East Asian outflow).…”

“…Hydroxy FAs were measured in several environmental settings, including oceanic particulate/dissolved organic matter (Volkman et al., 1998; Wakeham et al., 2003), deep‐sea and lake sediments (Cardoso & Eglinton, 1983; Eglinton et al., 1968; Kawamura & Ishiwatari, 1981, 1984a; Yang et al., 2020), snow/snow pits (Tyagi, Kawamura, Bikkina, et al., 2016; Tyagi, Yamamoto, & Kawamura, 2015), lake waters (Kawamura et al., 1987), and ambient aerosols (Bikkina et al., 2019; Kawamura, 1995; Tyagi et al., 2017; Tyagi, Ishimura, & Kawamura, 2015; Tyagi, Kawamura, Fu, et al., 2016). All these studies have attributed their origin either from soil microbes or plant waxes.…”

“…waxes (Kawamura et al, 2003;Tyagi et al, 2017;Wakeham et al, 2003). These compounds undergo less (or no) chemical modifications during the atmospheric transport, providing crucial information about their source regions and aeolian transport pathways (Molina et al, 2006;Pollard et al, 2008;Wilkinson, 1988).…”

Regional heterogeneities in the emission of airborne primary sugar compounds and biogenic secondary organic aerosols in the East Asian outflow: evidence for coal combustion as a source of levoglucosan

“…2a and S2;Zhu et al, 2015a;. The KCOG is under the influence of a large-scale advection of mineral dust from East Asia to the WNP during these three seasons (Tyagi et al, 2017;Huebert et al, 2003). The mineral dust transport from East Asia to the WNP can be traced by the high concentrations of non-sea-salt (nss) Ca 2+ in the TSP samples from Gosan (Arimoto et al, 1996).…”

Regional heterogeneities in the emission of airborne primary sugar compounds and biogenic secondary organic aerosols in the East Asian outflow: Evidence for coal combustion as a source of levoglucosan

“…Besides, the temporal variability of trehalose closely resembled that of fungal spore tracers (arabitol, mannitol, and erythritol), showing high concentrations in spring, summer, and fall seasons (Figure 2a) (Zhu et al, 2015a;Fu et al, 2012a). KCOG is influenced by the large scale of advection of mineral dust from East Asia to the WNP during these three seasons (Tyagi et al, 2017;Huebert et al, 2003). The impact of mineral dust in the East Asian outflow can be traced by the high concentrations of non-sea-salt Ca 2+ in the TSP samples from Gosan (Arimoto et al, 1996).…”