Tracing natural and anthropogenic sources of aerosols to the Atlantic Ocean using Zn and Cu isotopes
Tracing natural and anthropogenic sources of aerosols to the Atlantic Ocean using Zn and Cu isotopes
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DOI：
10.1016/j.chemgeo.2022.121091
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发表时间：
2022-09
期刊：
影响因子：
3.9
通讯作者：
H. Packman;S. Little;A. Baker;Luke Bridgestock;R. Chance;B. Coles;K. Kreissig;M. Rehkämper;T. van de Flierdt
中科院分区：
文献类型：
--
作者：
H. Packman;S. Little;A. Baker;Luke Bridgestock;R. Chance;B. Coles;K. Kreissig;M. Rehkämper;T. van de Flierdt
人为活动大大增加了大气中金属对海洋的输入，这对海洋生态系统具有潜在的重要影响。本研究评估了锌和铜同位素组成的潜力，以区分自然和人为的大气输入这些金属的表面海洋。为此，锌和铜的同位素组成的气溶胶中收集的东热带大西洋的GEOTRACES GA 06巡航检查。富集因子和溶解度分数测量表明，在从北非尘羽最远的锌和铜收集的气溶胶中存在一个重要的人为成分。完全消化气溶胶的δ 65 CuNIST SRM 976平均值为+0.07 ± 0.39 ‰（n= 9，2 SD），与成岩值无明显区别，表明Cu同位素不是该地区气溶胶来源的有效示踪剂。全消化气溶胶的δ 66 ZnJMC-Lyon值为+0.17 ± 0.22 ‰（n= 11，2SD）。乙酸铵淋洗的气溶胶具有相似的Zn同位素组成，平均值为+0.15 ± 0.16 ‰（n= 7，2SD）。气溶胶是在矿尘盛行的地区采集的，尽管如此，其Zn同位素仍比岩生Zn轻，δ 66 Zn δ +0.3 ‰。当与先前发表的Pb同位素数据相结合时，气溶胶显示出耦合的Zn-Pb同位素系统，表明矿物粉尘（δ 66 Zn = +0.28 ‰和206 Pb/207 Pb = 1.205）和人为排放（δ 66 Zn =-0.22 ‰和206 Pb/207 Pb = 1.129）之间的混合。这表明锌同位素的潜力，以跟踪大气锌输入从人为来源的海洋表面。
Anthropogenic activities have significantly enhanced atmospheric metal inputs to the ocean, which has potentially important consequences for marine ecosystems. This study assesses the potential of Zn and Cu isotope compositions to distinguish between natural and anthropogenic atmospheric inputs of these metals to the surface ocean. To this end, the isotopic compositions of Zn and Cu in aerosols collected from the eastern tropical Atlantic Ocean on the GEOTRACES GA06 cruise are examined. Enrichment factors and fractional solubility measurements indicate the presence of a significant anthropogenic component in the aerosols collected furthest from the North African dust plume for both Zn and Cu. The mean δ65CuNIST SRM 976for the fully digested aerosols is +0.07 ± 0.39 ‰ (n= 9, 2 SD), which is indistinguishable from the lithogenic value, and implies that Cu isotopes are not an effective tracer of aerosol sources in this region. The mean δ66ZnJMC-Lyonvalue for the aerosols that underwent a total digestion is +0.17 ± 0.22 ‰ (n= 11, 2 SD). The aerosols leached with ammonium acetate have similar Zn isotope compositions, with a mean of +0.15 ± 0.16 ‰ (n= 7, 2 SD). The aerosols were collected in a region with prevalent mineral dust but, despite this, exhibit isotopically lighter Zn than lithogenic Zn with δ66Zn ≈ +0.3 ‰. When coupled with the previously published Pb isotope data, the aerosols exhibit coupled Zn-Pb isotope systematics that are indicative of mixing between mineral dust (δ66Zn = +0.28 ‰ and206Pb/207Pb = 1.205) and anthropogenic emissions (δ66Zn = −0.22 ‰ and206Pb/207Pb = 1.129). This demonstrates the potential of Zn isotopes to trace atmospheric Zn inputs from anthropogenic sources to the surface ocean.