DOI: 10.1016/j.epsl.2020.116297
论文题名: Reversible scavenging traps hydrothermal iron in the deep ocean
作者: Roshan S. ; DeVries T. ; Wu J. ; John S. ; Weber T.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 542 语种: 英语
中文关键词: dissolved iron
; hydrothermal iron
; numerical modeling
; reversible scavenging
; US GEOTRACES
英文关键词: Aerosols
; Hot springs
; Iron
; Stabilization
; Biological productivity
; East Pacific Rise
; Hydrothermal plume
; Hydrothermal vent
; Lateral dispersion
; Long range transport
; Mechanistic modeling
; Ocean circulation
; Oceanography
; colloid
; hydrothermal deposit
; hydrothermal vent
; iron
; long range transport
; marine environment
; scavenging (chemistry)
; speciation (chemistry)
; East Pacific Rise
; Pacific Ocean
; Pacific Ocean (South)
; Pacific Ocean (Tropical)
英文摘要: Recent studies suggest that seafloor hydrothermal vents could be an important source of iron (Fe) to the surface ocean, stimulating plankton growth and biological carbon export. However, quantifying the supply of hydrothermal Fe to the surface ocean requires accurately modeling its stabilization and removal processes, which are poorly known. Here, we determine the physical speciation of dissolved Fe along an oceanographic transect following a coherent hydrothermal plume that emanates from the East Pacific Rise (EPR) and persists westward over 4,000 km in the Tropical South Pacific. Our observations show that the plume persists horizontally, but descends vertically, and consists primarily of very large Fe colloids. Guided by these observations, we develop a new size-resolved mechanistic model of hydrothermal Fe dispersion in this region, in which the stabilization of hydrothermal Fe is explained by a reversible particulate exchange process. This model accurately captures the lateral dispersion, downward settling and physical speciation of hydrothermal Fe along this transect. An alternate model that uses a hydrothermal source of Fe-binding ligands to facilitate Fe transport within the deep ocean can reproduce the long-range transport of hydrothermal Fe, but does not reproduce the vertical descent of the plume. Our model shows that hydrothermal Fe vented from the EPR is trapped in the deep ocean, and only 1% of this iron ever makes it to the surface where it can stimulate biological productivity. At the global scale, 3-5% of hydrothermal Fe makes it to the surface ocean, the vast majority of which originates from Southern Ocean vents and upwells in the Southern Ocean. Our best estimate of the global supply of hydrothermal Fe to the surface ocean, based on data-constrained estimates of ocean circulation, mantle 3He venting, and the hydrothermal Fe:3He ratio from the EPR, is 0.12±0.07 Gmol yr−1. This is about 60-70 times lower than the supply of Fe from aerosol dust deposition, but could be regionally important in the Antarctic zone of the Southern Ocean. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165245
Appears in Collections: 气候变化与战略
There are no files associated with this item.
作者单位: Rosenstiel School of Marine and Atmospheric Science, University of Miami, Coral Gables, FL 33146, United States; Earth Research Institute, University of California, Santa BarbaraCA 93106, United States; Department of Geography, University of California, Santa BarbaraCA 93106, United States; Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, United States; Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14618, United States
Recommended Citation:
Roshan S.,DeVries T.,Wu J.,et al. Reversible scavenging traps hydrothermal iron in the deep ocean[J]. Earth and Planetary Science Letters,2020-01-01,542