干旱区生态环境知识资源中心(Arid): Reactive iron isotope signatures of the East Asian dust particles: Implications for iron cycling in the deep North Pacific

Arid

DOI	10.1016/j.chemgeo.2019.119342
	Reactive iron isotope signatures of the East Asian dust particles: Implications for iron cycling in the deep North Pacific
	Chen, Tianyu 1,2,3; Li, Weiqiang 1; Guo, Bai 1; Liu, Ruolin 1; Li, Gaojun 4; Zhao, Liang 4; Ji, Junfeng 4
通讯作者	Chen, Tianyu
来源期刊	CHEMICAL GEOLOGY
ISSN	0009-2541
EISSN	1872-6836
出版年	2020
卷号	531
英文摘要	Iron released from wind-blown dust has been widely suggested to be an important nutrient source for oceanic primary productivity. Once introduced into the seawater, the reactive Fe might get dissolved and impart its isotope signature into the water column. Characterization of the reactive iron isotope signatures of eolian dust will thus help to understand the budget of Fe in the global ocean. Yet, there are few systematic studies on the Fe isotope systematics of the dust sources across large spatial scale. Here, we report Fe isotope data from HC1 leaching experiment on surficial samples from deserts and loess deposits of different locations spanning > 3000 km spatially in east Asia, one of the most important dust source regions. Our data suggest most of the samples have relatively similar leaching signatures (delta Fe-56 = -0.09 +/- 0.07%o, n = 9, 2 SD). To understand the kinetics of Fe release during proton promoted leaching of natural particles, a synthetic model taking into account of different dissolution dynamics of easily dissolvable Fe and silicate Fe was developed. The model was tested by continuous leaching of two representative pelagic sediment samples recovered from core LL44-GPC3 in the North Pacific. When introducing only one tunable parameter (Le., the initial dissolution rate of Fe from hydro (oxides), with other parameters constrained by the dissolution kinetics), the model successfully reproduces leachate delta Fe-56 evolution and agrees reasonably well with Fe speciation in the studied marine sediment samples. We thus suggest that the leaching process can be well characterized by our kinetic model, while Fe isotopes in the initial leachates of the samples are dominated by endmember composition of the easily dissolvable Fe species. The small but distinct fractionation of Fe isotopes in the desert/loess samples from the parental upper continental silicate materials are suggested to record signatures of the secondary Fe species produced during weathering in the oxic environment. The significantly lighter Fe isotope compositions in the initial leachates of the North Pacific pelagic sediment samples compared to the east Asian desert/loess deposits indicate apparent isotope exchange of the dust reactive components with seawater dissolved species. The sedimentary light reactive Fe isotope signatures in turn point toward the contribution of sources characterized by low delta Fe-56 to the deep North Pacific and/or preferential uptake of Fe-56 by seawater ligands from the dust reactive components particularly at the seawater-sediment interface.
英文关键词	Dust Fe isotopes North Pacific East Asia Desert Loess
类型	Article
语种	英语
国家	Peoples R China
收录类别	SCI-E
WOS记录号	WOS:000499092800014
WOS关键词	DISSOLVED IRON ; HYDROTHERMAL PLUME ; OCEAN BIOGEOCHEMISTRY ; BIOTITE DISSOLUTION ; FRACTIONATION ; FE ; ATLANTIC ; KINETICS ; SOLUBILITY ; GEOCHEMISTRY
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
EI主题词	2020-01-05
来源机构	南京大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/312388
作者单位	1.Nanjing Univ, Sch Earth Sci & Engn, State Key Lab Mineral Deposit Res, Nanjing 210023, Jiangsu, Peoples R China; 2.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Geol, Qingdao 266071, Shandong, Peoples R China; 3.MNR, Key Lab Marine Sedimentol & Environm Geol, Inst Oceanog 1, Qingdao 266061, Shandong, Peoples R China; 4.Nanjing Univ, Sch Earth Sci & Engn, Key Lab Surficial Geochem, Minist Educ, Nanjing 210023, Jiangsu, Peoples R China
推荐引用方式 GB/T 7714	Chen, Tianyu,Li, Weiqiang,Guo, Bai,et al. Reactive iron isotope signatures of the East Asian dust particles: Implications for iron cycling in the deep North Pacific[J]. 南京大学,2020,531.
APA	Chen, Tianyu.,Li, Weiqiang.,Guo, Bai.,Liu, Ruolin.,Li, Gaojun.,...&Ji, Junfeng.(2020).Reactive iron isotope signatures of the East Asian dust particles: Implications for iron cycling in the deep North Pacific.CHEMICAL GEOLOGY,531.
MLA	Chen, Tianyu,et al."Reactive iron isotope signatures of the East Asian dust particles: Implications for iron cycling in the deep North Pacific".CHEMICAL GEOLOGY 531(2020).