气候变化领域集成服务门户(CCPortal): Isotopic fingerprinting of biogeochemical processes and iron sources in the iron-limited surface Southern Ocean

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DOI	10.1016/j.epsl.2021.116967
	Isotopic fingerprinting of biogeochemical processes and iron sources in the iron-limited surface Southern Ocean
	Sieber M.; Conway T.M.; de Souza G.F.; Hassler C.S.; Ellwood M.J.; Vance D.
发表日期	2021
ISSN	0012821X
卷号	567
英文摘要	Iron (Fe) is an essential micronutrient that limits primary productivity throughout the surface of the Southern Ocean. Here, we present the first high-resolution depth profiles for dissolved Fe and Fe isotope ratios (δ56Fe) from all major zones of the Southern Ocean, collected during the Antarctic Circumnavigation Expedition in austral summer 2017. Open-ocean surface waters are characterized by remarkably high δ56Fe values (up to +1.6‰) and very low Fe concentrations (<0.05 nmol kg−1). We attribute the elevated δ56Fe values above the ferricline to the effect of continuous shallow cycling processes (uptake, recycling, and binding of Fe to organic ligands), with only a very limited resupply of Fe from below. Below the ferricline, δ56Fe values approach ∼0‰ and remain constant down to our deepest samples at 1000 m, with no obvious isotope signal from regeneration. This overall pattern in δ56Fe is modified near islands, continental shelves and hydrothermal vents, where distinct δ56Fe signatures are associated with different Fe sources. Near the volcanic Balleny Islands, elevated surface Fe concentrations associated with low δ56Fe are indicative of reductive release of isotopically light Fe from sediments. Elevated δ56Fe values at depth near the Balleny seamount chain and near the East Scotia Arc may reflect distal hydrothermal influences, caused by fractionation associated with precipitation or the loss of specific phases of Fe during long-range transport. Sedimentary sources of isotopically light Fe on the Antarctic Peninsula are important for shelf waters. Long-distance transport of this sediment-derived Fe and its influence on surface waters are strongly dependent on the regional circulation, and may ultimately be the source of light Fe previously observed within Antarctic Intermediate Water in the Atlantic sector of the Southern Ocean. © 2021 The Authors
关键词	Antarctic Circumnavigation Expedition biogeochemistry micronutrients nutrient cycling trace metals
英文关键词	Biogeochemistry; Hot springs; Iron; Isotopes; Nutrients; Oceanography; Submarine geology; Surface waters; Antarctic circumnavigation expedition; Biogeochemical process; Depth-profile; High-resolution depth; Iron sources; Isotopic fingerprinting; Nutrients cycling; Primary productivity; Southern ocean; Trace metal; Trace elements; biogeochemistry; iron; isotopic analysis; isotopic ratio; nutrient cycling; trace element; trace metal; Southern Ocean
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203296
作者单位	Institute of Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, Zurich, Switzerland; College of Marine Science, School of Geosciences, University of South FloridaFL, United States; Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Switzerland; Swiss Polar Institute, EPF Lausanne, Lausanne, Switzerland; Research School of Earth Sciences, Australian National University, Canberra, Australia
推荐引用方式 GB/T 7714	Sieber M.,Conway T.M.,de Souza G.F.,et al. Isotopic fingerprinting of biogeochemical processes and iron sources in the iron-limited surface Southern Ocean[J],2021,567.
APA	Sieber M.,Conway T.M.,de Souza G.F.,Hassler C.S.,Ellwood M.J.,&Vance D..(2021).Isotopic fingerprinting of biogeochemical processes and iron sources in the iron-limited surface Southern Ocean.Earth and Planetary Science Letters,567.
MLA	Sieber M.,et al."Isotopic fingerprinting of biogeochemical processes and iron sources in the iron-limited surface Southern Ocean".Earth and Planetary Science Letters 567(2021).