Organic nitrogen in rain and aerosol in the eastern Mediterranean atmosphere: An association with atmospheric dust
Organic nitrogen in rain and aerosol in the eastern Mediterranean atmosphere: An association with atmospheric dust
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DOI：
10.1029/2002jd002997
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发表时间：
2003-05
影响因子：
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通讯作者：
K. Mace;N. Kubilay;R. Duce
中科院分区：
文献类型：
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作者：
K. Mace;N. Kubilay;R. Duce
[1] 2000年3月至5月初，在土耳其埃尔代姆利地中海东部的一个沿海地点收集了雨水和大气气溶胶样本，并对氮（N）物种进行了分析，包括硝酸盐（NO₃⁻）、亚硝酸盐（NO₂⁻）、铵（NH₄⁺）、水溶性有机氮、尿素和溶解的游离氨基酸。还分析了其他离子，包括Ca²⁺、Mg²⁺、K⁺、Na⁺、Cl⁻和SO₄²⁻。发现水溶性有机氮在雨水和大气气溶胶中分别约占水溶性总氮的17%和26%。雨水和大气气溶胶中的有机氮浓度与Ca²⁺离子呈现出具有统计学意义的线性关系（R²约为0.75，P < 0.05），这表明与大气尘埃中的方解石（CaCO₃）有关。运动轨迹分析表明，在70%的采样大气气溶胶中，风来自干旱地区，主要是北非。地球探测/臭氧总量测绘光谱仪的气溶胶指数数据也证实了在Ca²⁺浓度升高的日子里该地区大气尘埃的影响，并且轨迹分析表明北非是一个源区。综合离子、轨迹和气溶胶指数数据表明，该地区的有机氮与大气尘埃有关。尿素氮和氨基氮在有机氮组分中所占比例较小。在雨水和大气气溶胶中，尿素分别约占有机氮总量的11%和<1%。虽然氨基氮对有机氮总量的贡献极小（在大气气溶胶中约占有机氮总量的1%），但占氨基氮约75%的单个氨基酸表明了生物有机体的存在。需要进一步研究以解释生物以及人为产生的水溶性有机物的气相吸附对有机氮总量的影响。
[1] From March through early May of 2000, rain and bulk aerosol samples were collected at a coastal site on the eastern Mediterranean Sea at Erdemli, Turkey, and analyzed for nitrogen (N) species, including nitrate (NO3−), nitrite (NO2−), ammonium (NH4+), water-soluble organic N, urea, and dissolved free amino acids. Other ions were also analyzed, including Ca2+, Mg2+, K+, Na+, Cl−, and SO42−. Water-soluble organic N was found to contribute ∼17% and ∼26% of the total water-soluble N in rain and aerosols, respectively. Organic N concentrations within rain and aerosols exhibited statistically significant linear relationships to Ca2+ ion (Rsqr ∼ 0.75, P < 0.05), suggesting a relationship to calcite (CaCO3) in atmospheric dust. Kinematic trajectory analyses indicated the origin of winds from arid regions, mainly in northern Africa, in 70% of the aerosols sampled. Earth Probe/Total Ozone Mapping Spectrometer aerosol index data also confirmed the influence of atmospheric dust in the region on days when Ca2+ concentrations were elevated, and trajectory analyses suggested northern Africa as a source region. The combined ion, trajectory, and aerosol index data suggest that organic N is associated with atmospheric dust in this region. Urea N and amino N represented a small percentage of the organic N fraction. In rain and aerosols, urea represented ∼11% and <1%, respectively, of the total organic N. While amino N contributed minimally to organic N totals (∼1% of total organic N in aerosols), the individual amino acids contributing ∼75% of amino N were indicative of biological organisms. Further research is needed to decipher the influence from biology and gas phase adsorption of anthropogenically derived water-soluble organics on organic N totals.