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Diel redox cycle of manganese in the surface Arctic Ocean
  • Yang Xiang,
  • Phoebe J. Lam,
  • Jong-Mi Lee
Yang Xiang
Department of Ocean Sciences, University of California at Santa Cruz, Department of Ocean Sciences, University of California at Santa Cruz

Corresponding Author:[email protected]

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Phoebe J. Lam
University of California, Santa Cruz, University of California, Santa Cruz
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Jong-Mi Lee
University of California, Santa Cruz, University of California, Santa Cruz
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Abstract

Knowledge of the chemical speciation of particulate manganese (pMn) is important for understanding the biogeochemical cycling of Mn and other particle-reactive elements. Here, we present the synchrotron-based X-ray spectroscopy-derived average oxidation state (AOS) of pMn in the surface Arctic Ocean collected during the U.S. GEOTRACES Arctic cruise (GN01) in 2015. We show that the pMn AOS is less than 2.4 when sampled during the day and more than ~3.0 when sampled at night. We hypothesize that an active light-dependent redox cycle between dissolved Mn and particulate Mn(III/IV) exists during the day-night cycle in the surface Arctic Ocean, which occurs on the timescale of hours. The magnitude of observed pMn AOS is likely determined by the net effect of the length of the previous night and integrated light level before the end of pMn sampling.
16 Dec 2021Published in Geophysical Research Letters volume 48 issue 23. 10.1029/2021GL094805