气候变化领域集成服务门户(CCPortal): Iron colloids dominate sedimentary supply to the ocean interior

CCPortal

DOI	10.1073/PNAS.2016078118
	Iron colloids dominate sedimentary supply to the ocean interior
	Homoky W.B.; Conway T.M.; John S.G.; König D.; Deng F.; Tagliabue A.; Mills R.A.
发表日期	2021
ISSN	00278424
卷号	118 期号:13
英文摘要	Dissolution of marine sediment is a key source of dissolved iron (Fe) that regulates the ocean carbon cycle. Currently, our prevailing understanding, encapsulated in ocean models, focuses on low-oxygen reductive supply mechanisms and neglects the emerging evidence from iron isotopes in seawater and sediment porewaters for additional nonreductive dissolution processes. Here, we combine measurements of Fe colloids and dissolved δ56Fe in shallow porewaters spanning the full depth of the South Atlantic Ocean to demonstrate that it is lithogenic colloid production that fuels sedimentary iron supply away from low-oxygen systems. Iron colloids are ubiquitous in these oxic ocean sediment porewaters and account for the lithogenic isotope signature of dissolved Fe (δ56Fe = +0.07 ± 0.07‰) within and between ocean basins. Isotope model experiments demonstrate that only lithogenic weathering in both oxic and nitrogenous zones, rather than precipitation or ligand complexation of reduced Fe species, can account for the production of these porewater Fe colloids. The broader covariance between colloidal Fe and organic carbon (OC) abundance suggests that sorption of OC may control the nanoscale stability of Fe minerals by inhibiting the loss of Fe(oxyhydr)oxides to more crystalline minerals in the sediment. Oxic ocean sediments can therefore generate a large exchangeable reservoir of organo-mineral Fe colloids at the sediment water interface (a “rusty source”) that dominates the benthic supply of dissolved Fe to the ocean interior, alongside reductive supply pathways from shallower continental margins. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Iron colloid; Iron isotopes; Ocean sediment; Organo-mineral; Porewater
语种	英语
scopus关键词	calcium carbonate; carbon; ferric hydroxide; iron; nitrogen; organic carbon; oxygen; sea water; Article; Atlantic Ocean; benthos; carbon cycle; colloid; complex formation; crystal structure; diagenesis; dissolution; encapsulation; oxygen supply; precipitation; priority journal; sea; sediment; stone formation; water depth; weathering
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180045
作者单位	School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom; Department of Earth Sciences, University of Oxford, Oxford, OX1 3AN, United Kingdom; College of Marine Science, University of South Florida, Tampa, FL 33629, United States; Department of Earth Sciences, University of Southern California, Los Angeles, CA 90007, United States; School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom; School of Ocean and Earth Science, University of Southampton, Southampton, SO17 1BJ, United Kingdom
推荐引用方式 GB/T 7714	Homoky W.B.,Conway T.M.,John S.G.,et al. Iron colloids dominate sedimentary supply to the ocean interior[J],2021,118(13).
APA	Homoky W.B..,Conway T.M..,John S.G..,König D..,Deng F..,...&Mills R.A..(2021).Iron colloids dominate sedimentary supply to the ocean interior.Proceedings of the National Academy of Sciences of the United States of America,118(13).
MLA	Homoky W.B.,et al."Iron colloids dominate sedimentary supply to the ocean interior".Proceedings of the National Academy of Sciences of the United States of America 118.13(2021).