DOI: 10.1038/s41561-020-00667-z
论文题名: Glacial deep ocean deoxygenation driven by biologically mediated air–sea disequilibrium
作者: Cliff E. ; Khatiwala S. ; Schmittner A.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2021
卷: 14, 期: 1 起始页码: 43
结束页码: 50
语种: 英语
英文关键词: air-sea interaction
; biological pump
; carbon dioxide
; climate modeling
; deep water
; dissolved inorganic carbon
; global ocean
; Holocene
; Last Glacial Maximum
; organic matter
; respiration
英文摘要: Deep ocean deoxygenation inferred from proxies has been used to support the hypothesis that a lower atmospheric carbon dioxide during glacial times was due to an increase in the strength of the ocean’s biological pump. This relies on the assumption that surface ocean oxygen (O2) is equilibrated with the atmosphere such that any O2 deficiency observed in deep waters is a result of organic matter respiration, which consumes O2 and produces dissolved inorganic carbon. However, this assumption has been shown to be imperfect because of disequilibrium. Here we used an Earth system model tuned to a suite of observations, which reproduces the pattern of glacial-to-Holocene oxygenation change seen in proxy data, to show that disequilibrium plays an important role in glacial deep ocean deoxygenation. Using a novel decomposition method to track O2, we found a whole-ocean loss of 33 Pmol O2 from the preindustrial to the Last Glacial Maximum despite a 27 Pmol gain from the increased solubility due to cooler temperatures. This loss was driven by a biologically mediated O2 disequilibrium, which contributed 10% of the reduction of the O2 inventory from the solubility equilibrium in the preindustrial compared with 27% during the Last Glacial Maximum. Sea ice and iron fertilization were found to be the largest contributors to the Last Glacial Maximum deoxygenation, which occurs despite overall reduced production and respiration of organic matter in the glacial ocean. Our results challenge the notion that deep ocean glacial deoxygenation was caused by a stronger biological pump or more sluggish circulation, and instead highlight the importance and previously underappreciated role of O2 disequilibrium. © 2021, The Author(s), under exclusive licence to Springer Nature Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/169734
Appears in Collections: 气候变化与战略
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作者单位: Department of Earth Sciences, University of Oxford, Oxford, United Kingdom; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
Recommended Citation:
Cliff E.,Khatiwala S.,Schmittner A.. Glacial deep ocean deoxygenation driven by biologically mediated air–sea disequilibrium[J]. Nature Geoscience,2021-01-01,14(1)