Importance of anthropogenic inputs and continental‐derived dust for the distribution and flux of water‐soluble nitrogen and phosphorus species in aerosol within the atmosphere over the East China Sea

Abstract

[1] We analyzed 156 aerosol samples, including 10 dust storm samples, collected from January to December 2005 at a coastal site on the southern East China Sea at Keelung city, Taiwan, for water-soluble major ions, nitrogen, and phosphorus species. In addition, 4-d back trajectories of air masses arriving daily at the sampling site were calculated to determine the potential aerosol source regions. The obtained concentrations of major ions indicate that a continental source was dominant from January to May and from November to December, a local source during July, and an oceanic source from September to October. The measured atmospheric concentrations of nitrogen and phosphorus species show clear seasonal variations and correspond to the different sources and weather conditions. During the dust storm period, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) concentrations showed statistically significant linear relationships with the amount of aerosol particles, suggesting a continental source. The results of a factor analysis of combined major ions and DIN and DIP indicate that crustal sources, marine sources, and combustion sources are the three major controlling factors during the non-dust-storm period. Natural and anthropogenic land sources and marine sources are the most influential factors in terms of the distribution of aerosol during the dust storm period. A strong correlation was also found between DIN and DIP, indicating similar sources and transportation mechanisms. The results of flux calculations indicate that aerosols derived from dust storms and biomass burning provide 12 ± 8% and 46 ± 36% of total DIN and 16 ± 10% and 46 ± 38% of total DIP, respectively. Consequently, the inputs of aerosol derived from biomass burning may be an important source of nitrogen and phosphorus in aerosols over the East China Sea.

Atmospheric P deposition to the subtropical North Atlantic: sources, properties, and relationship to N deposition

“…Although some rain samples had basic pH values up to 8.8, indicating some neutralization of acids, possibly from dust-based CaCO 3 [Nenes et al, 2011], no relationship was observed between pH and SRP or dust. These findings are in contrast to several studies that found good correlations (in aerosols) between SRP and nss-SO 4 2À and -Ca 2+ in east China [Chen and Chen, 2008] and between SRP and nss-Ca 2+ in the Bay of Bengal [Srinivas and Sarin, 2012]. A lack of strong correlations with different source indicators in rain indicates that there was no predominant source of SRP in Miami or that rain P sources are relatively complex compared with those in eastern China, where anthropogenic aerosol concentrations are in general very high and intense pollution events very frequent.…”

“…However, Miami yielded higher N/P wet deposition ratios than Barbados because of higher N concentrations associated with the more frequent impact of terrestrial/polluted air masses. Higher N/P ratios in polluted areas have been previously predicted and observed [Chen and Chen, 2008;Mahowald et al, 2008].…”

“…Mineral dust is the primary source of soluble atmospheric P in the North Atlantic subtropical gyre region [Mahowald et al, 2008]. However, other sources of atmospheric P have been observed, as well, including biomass burning and anthropogenic combustion processes [Allen and Miguel, 1995;Artaxo et al, 2002;Baker et al, 2006a;Chen and Chen, 2008;Gaudichet et al, 1995;Mahowald et al, 2005;Ternon et al, 2011;Tsukuda et al, 2006;, primary biogenic particles [Graham et al, 2003;Mahowald et al, 2005], and sea spray [Chen et al, 1985;Graham et al, 1979]. Mahowald et al [2008] suggested that because anthropogenic P tends to be more soluble, it may have a larger impact on open-ocean processes relative to other P sources.…”

Satellite-Observed Transport of Dust to the East China Sea and the North Pacific Subtropical Gyre: Contribution of Dust to the Increase in Chlorophyll during Spring 2010

“…As a result, the atmospheric deposition of iron is seen to be the most important factor in phytoplankton growth in the ECS; nitrogen also plays an important part, whereas phosphorus has less impact. Previous studies have indicated that atmospheric phosphorus may not be a vital source of inorganic phosphorus in the ECS [62,67].…”

“…Soluble phosphorus (10.3 µg·m −2 ·d −1 ) was more than three times higher than the mean value of 3.3 µg·m −2 ·d −1 derived by Hsu et al [62] from dry deposition in the northeasterly monsoon period. The amount of soluble phosphorus of 10.3 µg·m −2 ·d −1 corresponds to 0.95 mg·m −2 in spring 2010, which accounts for 63% of the yearly dry deposition of dissolved inorganic phosphorus from dust storm samples (1.5 mg·m −2 ) obtained by Chen and Chen [67]. The total estimated deposition of total inorganic nitrogen supported by a mean dust deposition flux of 64.7 mg·m −2 ·d −1 was 0.6 mg·m −2 ·d −1 , which was comparable with the mean value of 0.69 mg·m −2 ·d −1 previously derived from dry deposition over the ECS [62].…”