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Manganese Oxidation by Organisms in Pinal Creek, Arizona by Eleanora I. Robbins (USGS)

Bacteria, cyanobacteria, algae, fungi, mosses, and protozoans living in Pinal Creek and oxidizing manganese. Photomicrograph images are from organisms that settled on glass slides or were collected in wet flocculates.

Details of this study are published in: Robbins, E.I., Corley, T.L., and Conklin, M.H., 1999, Manganese removal by the epilithic microbial consortium at Pinal Creek near Globe, Arizona: U.S. Geological Survey Water-Resources Investigations Report 99-4018A, p. 247-258.

Details of the Pinal Creek program and project can be found at:
http://toxics.usgs.gov/sites/pinal_page.html and http://wwwdaztcn.wr.usgs.gov/pinal/index.html

Photograph of manganese deposit in Pinal Creek, Arizona (photograph by James Eychaner, USGS). At Pinal Creek, the precipitation of manganese (Mn) results in deposits that may be more than 1 m thick. The brown ledges are older deposits that were not eroded away by a flood in 1993.
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 		Photograph of vegetation in Pinal Creek (photograph by Timothy L. Corley, University of Arizona, January 8, 1998). Manganese is actively being deposited in the vegetation, which is dominated by water speedwell (<em>Veronica anagallis-aquatica</em>). This study site is called the Left Hand Side (LHS) at study reach J2-5.
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 		Photograph of vegetation in Pinal Creek (photograph by Timothy L. Corley, University of Arizona, January 8, 1998). Manganese being deposited in the vegetation at study site Right Hand Site (RHS), which is dominated by water speedwell.
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 		Photograph of glass slides left in Pinal Creek. For a study conducted from October 1997 to January 1999, glass microscope slides were placed in the water for one month at a time and then retrieved to study microscopically how the manganese was being deposited. These glass slides were left monthly at site LHS-V1 where slides came into contact with the vegetation in the slower flow (10 cm/sec) near channel. Note that Mn oxidation is more intense in the summer.
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 		Photograph of glass slides left in Pinal Creek. These glass slides were left monthly at site LHS-V2 where faster flow in channel (25 cm/sec) provided an ideal environment for microbial colonization and Mn oxidation. Note that oxidation is more intense in the summer.
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Photograph of glass slides left in Pinal Creek. These glass slides were left monthly at site RHS-V1. Manganese oxidation is sparse in slow flow (5 cm/sec) where slides were in surface water above a mucky substrate. Note the presence of more oxidized Mn in the late winter and spring.
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 		Photomicrograph of oxidized manganese. The presence of oxidized Mn was tested with the redox dye, orthotoluidine, which turns blue in the presence of oxidized Mn. These holdfasts of the Mn-oxidizing bacterium <em>Leptothrix discophora</em> show the characteristic blue color of a positive response. (9/98-10/98, x630)
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 		Photomicrograph of green algae. Filamentous <em>Ulothrix</em> sp. actively oxidizes manganese on its holdfasts (brown spherical structures), which are used by the algae to attach to solid substrates such as rocks (and glass slides). (11/97-12/97, x100)
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 		Photomicrograph of green algae. Manganese-oxidizing <em>Ulothrix</em> sp. holdfasts (arrow) magnified from previous image. (11/97-12/97, x630)
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 		Photomicrograph of green algae. <em>Ulothrix</em> sp. filaments and their manganese-oxidizing holdfasts (arrow). (2/98-3/98, x250)
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Photomicrograph of green algae. A magnified filamentous green alga, <em>Ulothrix</em> sp., in its spherical, manganese-oxidizing holdfasts (arrow). (2/98-3/98, x630)
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 		Photomicrograph of green algae and bacteria. Two different organisms oxidize manganese on their holdfasts. The big one (big arrow) is the filamentous green alga, <em>Ulothrix</em> sp., and the smaller ones (small arrow) are those of the iron bacterium, <em>Leptothrix discophora</em>. Note that the basal cell of this <em>Ulothrix</em> is also coated with oxidized Mn. (12/97-1/98, x630)
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 		Photomicrograph of green algae. <em>Ulothrix</em> sp. filament (arrow) has manganese-coated cells and clear cells, as if this oxidation is algally mediated. (7/98-8/98, x250)
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 		Photograph of cyanobacteria in Pinal Creek. The cyanobacteria growing in Pinal Creek turn brown from oxidized manganese. (8/99)
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 		Photomicrograph of cyanobacteria. Brown clumps (arrow) of oxidized manganese on filaments of cyanobacteria. This type of oxidation is thought to be the result of photosynthetic elevation of pH to values above 8. (fresh mat, 9/98, x250)
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Photograph of dried moss, algae, and plant. Macrophytes turn blue (arrow) when orthotoluidine is applied, which shows that oxidized manganese is present. (fresh tissues, 9/98)
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 		Photomicrograph of moss. Oxidized manganese at a specific site on a moss protonema (at the intersection of cells) (arrow) suggests a biologically mediated process. (fresh moss, 9/98, x400)
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 		Photomicrograph of bacteria and moss. Holdfast of <em>Leptothrix discophora</em> (arrow) on moss leaf shows that the bacterium rather than the moss oxidized the Mn. (fresh moss, 9/98, x630)
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 		Photomicrograph of green algae. One cell of a <em>Ulothrix</em> filament is coated with oxidized manganese (arrow). The rest of the filaments are not coated. This suggests that a biologically mediated process may be in operation but the details of the process are unknown (senescence or aging?). (9/98-10/98, x630)
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 		Photomicrograph of bacteria and algae. Filamentous green alga (probably Spirogyra) colonized by manganese-oxidizing holdfast of <em>Leptothrix discophora</em> (arrow). (12/97-1/98, x630)
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U.S. Department of the Interior, U.S. Geological Survey
URL http://mam.er.usgs.gov/
Contact: Eleanora Robbins, USGS
Last modification: 03/10/2000 (mhh)