Water-Soluble Organic Nitrogen in High Mountain Snow Samples from Central Japan

Abstract

We measured water-soluble organic nitrogen (WSON) in snow pit samples, which were collected at the Murodo-Daira snowfield near the summit of Mt. Tateyama, central Japan in 2008. The concentrations of WSON ranged from 12.8 to 96.7 ng g -1 , which were significantly lower than those reported in continental wet deposition samples from the Asian continent. WSON may be largely diluted in the snow samples during snowing processes over the high mountains. We found that WSON significantly correlated with nss-Ca 2+ and water-soluble organic carbon (WSOC). Concentrations of WSON are likely controlled by the intensity of Asian dust events. Contributions of WSON to water soluble total nitrogen (WSTN) in snow pit sequence was found to be 15 ± 10%, which is lower than those (63-91%) of reference dust materials collected in China. Mass concentration ratio of WSOC/WSON was on average 23.7, which is significantly higher than the C/N weight ratio (5.6) calculated from the Redfield ratio. This result suggests that WSOC is largely produced by secondary photochemical oxidation of anthropogenic volatile organic compounds during the transport from East Asia to the high mountain areas in Japan. On the other hand, WSON may be contributed from Asian dusts from arid areas in China whereas water-soluble inorganic nitrogen may be derived from pollution sources.

Hydroxy fatty acids in snow pit samples from Mount Tateyama in central Japan: Implications for atmospheric transport of microorganisms and plant waxes associated with Asian dust

“…Asian dust is a significant source of atmospheric water‐soluble organic nitrogen (WSON) [ Shi et al ., ; Mochizuki et al ., ]. In a previous study, we observed a moderately significant linear correlation between WSON and nss‐Ca 2+ in the snowpack samples from Mount Tateyama in spring 2009 and 2011 [ Mochizuki et al ., ], suggesting their probable source from Asian dust.…”

“…On 18 April 2009 and 17 April 2011, two snow pit holes were dug to the depth of 6.0 and 6.5 m, respectively, and snowpack samples were collected using a precleaned shovel to avoid possible contamination. We found dust‐containing snow layers in the snow pits; they showed a light yellow‐brown color and were later characterized by high Ca 2+ concentrations, suggesting long‐range transport of Asian dust to the sampling site [ Mochizuki et al ., ]. Previous studies [ Kawamura et al ., ; Maki et al ., ; Osada et al ., ; Tanaka et al ., ] also suggested that snow samples collected from the same site are influenced by Asian dust.…”

“…Because tourism‐related activities are scarce from winter to early spring, this site is ideal for the study of long‐range atmospheric transport of microorganisms without local emissions. The snowpack over Mount Tateyama is a receptor surface and a storage compartment for the deposition of Asian dust [ Kawamura et al ., ; Mochizuki et al ., ]. The snow cover over Mount Tateyama contains deposited and scavenged Asian dust particles [ Osada et al ., ].…”

Long-range atmospheric transport of volatile monocarboxylic acids with Asian dust over a high mountain snow site, central Japan

“…The details on the snow collection and sample storage methods were described in Kawamura et al (2012) and Mochizuki et al (2016). Snowpack samples were collected at the Murodo-Daira site (36.58 • N, 137.36 • E; elevation 2450 m) near Mt.…”

Overview of the Special Issue “Selected Papers from the 2nd Atmospheric Chemistry and Physics at Mountain Sites Symposium”

“…Their results suggest that bacterial ice nuclei are present in the rainwater but play a minor role in ice nucleation in this region. Mochizuki et al (2016) measured water-soluble organic nitrogen (WSON) and carbon in snow from a high elevation site in Japan. They find that WSON is closely connected to dust and pollution transported from the Asian continent.…”