Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 8, issue 10
Biogeosciences, 8, 2977–2991, 2011
https://doi.org/10.5194/bg-8-2977-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 8, 2977–2991, 2011
https://doi.org/10.5194/bg-8-2977-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 26 Oct 2011

Research article | 26 Oct 2011

Biogeochemistry of manganese in ferruginous Lake Matano, Indonesia

C. Jones1, S. A. Crowe1, A. Sturm2, K. L. Leslie2, L. C. W. MacLean3, S. Katsev4, C. Henny5, D. A. Fowle2, and D. E. Canfield1 C. Jones et al.
  • 1Nordic Center for Earth Evolution, Institute of Biology, Univ. of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
  • 2Dept. of Geology, Univ. of Kansas, Lawrence, KS 66047, USA
  • 3Canadian Light Source Inc., Univ. of Saskatchewan, Saskatoon, SK S7N 0X4, Canada
  • 4Large Lakes Observatory and Dept. of Physics, Univ. of Minnesota, Duluth MN 55812, USA
  • 5Research Center for Limnology, Indonesian Institute of Sciences (LIPI), Cibinong Bogor, Indonesia

Abstract. This study explores Mn biogeochemistry in a stratified, ferruginous lake, a modern analogue to ferruginous oceans. Intense Mn cycling occurs in the chemocline where Mn is recycled at least 15 times before sedimentation. The product of biologically catalyzed Mn oxidation in Lake Matano is birnessite. Although there is evidence for abiotic Mn reduction with Fe(II), Mn reduction likely occurs through a variety of pathways. The flux of Fe(II) is insufficient to balance the reduction of Mn at 125 m depth in the water column, and Mn reduction could be a significant contributor to CH4 oxidation. By combining results from synchrotron-based X-ray fluorescence and X-ray spectroscopy, extractions of sinking particles, and reaction transport modeling, we find the kinetics of Mn reduction in the lake's reducing waters are sufficiently rapid to preclude the deposition of Mn oxides from the water column to the sediments underlying ferruginous water. This has strong implications for the interpretation of the sedimentary Mn record.

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