Dissolved manganese in the Atlantic sector of the Southern Ocean

The first comprehensive dataset (492 samples) of dissolved Mn in the Southern Ocean shows extremely low values of 0.04 up to 0.64 nM in the surface waters and a subsurface maximum with an average concentration of 0.31 nM (n=20; S.D.=0.08 nM). The low Mn in surface waters correlates well with the nut...

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Bibliographic Details
Published in:Deep Sea Research Part II: Topical Studies in Oceanography
Main Authors: Middag, R., de Baar, H. J. W., Laan, P., Cai, P. H., van Ooijen, J. C.
Format: Article in Journal/Newspaper
Language:English
Published: 2011
Subjects:
Trace metals
GEOTRACES
Southern Ocean
Dissolved manganese
Biological uptake
Mn nutrient relation
CONTINENTAL-MARGIN SEDIMENTS
TRACE-METALS
SURFACE WATERS
HYDROTHERMAL MANGANESE
IRON LIMITATION
PACIFIC-OCEAN
SARGASSO SEA
INDIAN-OCEAN
WEDDELL SEA
BLACK-SEA
Ice Sheet
Weddell Sea
Online Access:https://hdl.handle.net/11370/7d09df84-c260-4f73-a441-5c316cfb3a41
https://research.rug.nl/en/publications/7d09df84-c260-4f73-a441-5c316cfb3a41
https://doi.org/10.1016/j.dsr2.2010.10.043
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Summary:The first comprehensive dataset (492 samples) of dissolved Mn in the Southern Ocean shows extremely low values of 0.04 up to 0.64 nM in the surface waters and a subsurface maximum with an average concentration of 0.31 nM (n=20; S.D.=0.08 nM). The low Mn in surface waters correlates well with the nutrients PO4 and NO3 and moderately well with Si(OH)(4) and fluorescence. Furthermore, elevated concentrations of Mn in the surface layer coincide with elevated Fe and light transmission and decreased export (Th-234/U-238 deficiency) and fluorescence. It appears that Mn is a factor of importance in partly explaining the HNLC conditions in the Southern Ocean, in conjunction with significant controls by the combination of Fe limitation and light limitation. No input of Mn from the continental margins was observed. This is ascribed to the protruding continental ice sheet that covers the shelf and shuts down the usual biological production, microbial breakdown and sedimentary geochemical cycling. The low concentrations of Mn in the deep ocean basins (0.07-0.23 nM) were quite uniform, but some elevations were observed. The highest deep concentrations of Mn were observed at the Bouvet Triple Junction region and coincided with high concentrations of Fe and are deemed to be from hydrothermal input. The deep basins on both sides of the ridge were affected by this input. In the deep Weddell Basin the input of Weddell Sea Bottom Water appears to be the source of the slightly elevated concentrations of Mn in this water layer. (C) 2010 Elsevier Ltd. All rights reserved.

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