气候变化领域集成服务门户(CCPortal): Rapid shift and millennial-scale variations in Holocene North pacific intermediate water ventilation

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DOI	10.1073/pnas.1714754115
	Rapid shift and millennial-scale variations in Holocene North pacific intermediate water ventilation
	Lembke-Jene L.; Tiedemann R.; Nürnberg D.; Gong X.; Lohmann G.
发表日期	2018
ISSN	0027-8424
起始页码	5365
结束页码	5370
卷号	115 期号:21
英文摘要	The Pacific hosts the largest oxygen minimum zones (OMZs) in the world ocean, which are thought to intensify and expand under future climate change, with significant consequences for marine ecosystems, biogeochemical cycles, and fisheries. At present, no deep ventilation occurs in the North Pacific due to a persistent halocline, but relatively better-oxygenated subsurface North Pacific Intermediate Water (NPIW) mitigates OMZ development in lower latitudes. Over the past decades, instrumental data show decreasing oxygenation in NPIW; however, long-term variations in middepth ventilation are potentially large, obscuring anthropogenic influences against millennial-scale natural background shifts. Here, we use paleoceanographic proxy evidence from the Okhotsk Sea, the foremost North Pacific ventilation region, to show that its modern oxygenated pattern is a relatively recent feature, with little to no ventilation before six thousand years ago, constituting an apparent Early–Middle Holocene (EMH) threshold or “tipping point.” Complementary paleomodeling results likewise indicate a warmer, saltier EMH NPIW, different from its modern conditions. During the EMH, the Okhotsk Sea switched from a modern oxygenation source to a sink, through a combination of sea ice loss, higher water temperatures, and remineralization rates, inhibiting ventilation. We estimate a strongly decreased EMH NPIW oxygenation of ∼30 to 50%, and increased middepth Pacific nutrient concentrations and carbon storage. Our results (i) imply that under past or future warmer-than-present conditions, oceanic biogeochemical feedback mechanisms may change or even switch direction, and (ii) provide constraints on the high-latitude North Pacific’s influence on mesopelagic ventilation dynamics, with consequences for large oceanic regions. © 2018 National Academy of Sciences. All Rights Reserved.
英文关键词	Holocene; Intermediate water; North Pacific; Oxygen minimum zone; Stable isotopes
语种	英语
scopus关键词	Article; biogeochemistry; carbon storage; controlled study; Holocene; latitude; nutrient concentration; ocean environment; oxygenation; paleoceanography; priority journal; sea ice; source sink relationship; water temperature
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/160509
作者单位	Lembke-Jene, L., Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, 27570, Germany; Tiedemann, R., Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, 27570, Germany; Nürnberg, D., GEOMAR Helmholtz-Zentrum fürOzeanforschung Kiel, Kiel, 24148, Germany; Gong, X., Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, 27570, Germany; Lohmann, G., Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, 27570, Germany
推荐引用方式 GB/T 7714	Lembke-Jene L.,Tiedemann R.,Nürnberg D.,et al. Rapid shift and millennial-scale variations in Holocene North pacific intermediate water ventilation[J],2018,115(21).
APA	Lembke-Jene L.,Tiedemann R.,Nürnberg D.,Gong X.,&Lohmann G..(2018).Rapid shift and millennial-scale variations in Holocene North pacific intermediate water ventilation.Proceedings of the National Academy of Sciences of the United States of America,115(21).
MLA	Lembke-Jene L.,et al."Rapid shift and millennial-scale variations in Holocene North pacific intermediate water ventilation".Proceedings of the National Academy of Sciences of the United States of America 115.21(2018).