Glacial deep ocean deoxygenation driven by biologically mediated air–sea disequilibrium

نویسندگان

چکیده

Deep ocean deoxygenation inferred from proxies has been used to support the hypothesis that a lower atmospheric carbon dioxide during glacial times was due an increase in strength of ocean’s biological pump. This relies on assumption surface oxygen (O2) is equilibrated with atmosphere such any O2 deficiency observed deep waters result organic matter respiration, which consumes and produces dissolved inorganic carbon. However, this shown be imperfect because disequilibrium. Here we Earth system model tuned suite observations, reproduces pattern glacial-to-Holocene oxygenation change seen proxy data, show disequilibrium plays important role deoxygenation. Using novel decomposition method track O2, found whole-ocean loss 33 Pmol preindustrial Last Glacial Maximum despite 27 gain increased solubility cooler temperatures. driven by biologically mediated disequilibrium, contributed 10% reduction inventory equilibrium compared 27% Maximum. Sea ice iron fertilization were largest contributors deoxygenation, occurs overall reduced production respiration ocean. Our results challenge notion caused stronger pump or more sluggish circulation, instead highlight importance previously underappreciated Lower than modern levels greater between ocean, according record-constrained modelling.

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ژورنال

عنوان ژورنال: Nature Geoscience

سال: 2021

ISSN: ['1752-0894', '1752-0908']

DOI: https://doi.org/10.1038/s41561-020-00667-z