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Manganese (Mn) is a transition metal present at trace levels in the modern ocean where it cycles between three oxidation states, +2, +3, and +4. Mn is a cofactor in enzymes critical for life, including the oxygen-evolving complex of photosystem II involved in oxygenic photosynthesis and superoxide dismutase (SOD) that degrades oxygen radicals responsible for oxidative stress. Mn(IV) forms a suite of Mn oxide minerals found within marine ferromanganese crusts and nodules that scavenge trace metals and record paleoredox conditions throughout Earth’s history. Mn oxides form within a wide range of environments, including deserts, and on Mars as rock varnish and crusts.
Manganese (Mn) oxides are widespread on Earth, occurring as particles or grain coatings, rock varnish, cave deposits, and ferromanganese crusts and nodules. Rocks and sediments enriched in Mn oxides have been observed on Mars (Lanza et al. 2014) and in early Earth strata (Crerar...
KeywordsMetal Bacteria Fungi Metabolism Oxygen reduction Desert varnish Ferromanganese crusts Ferromanganese nodules Sediments Minerals Redox
References and Further Reading
- Crerar DA, Fischer AG, Plaza CL (1980) Metallogenium and biogenic deposition of manganese from Precambrian to recent time. In: Vanentsov IM, Grasselly G (eds) Geology and geochemistry of manganese. Volume III. Manganese on the bottom of recent basins. Verlagsbuchhandlung, Stuttgart, pp 285–303Google Scholar
- Hansel CM (2017) Manganese in marine microbiology. In: Poole RK (ed) Advances in microbial physiology. Academic Press, Oxford, pp 37–83Google Scholar
- Lanza NL, Fischer WW, Wiens RC, Grotzinger J, Ollila AM, Cousin A, Anderson RB, Clark BC, Gellert R, Mangold N, Maurice S, Le Mouelic S, Nachon M, Schmidt M, Berger J, Clegg SM, Forni O, Hardgrove C, Melikechi N, Newsom HE, Sautter V (2014) High manganese concentrations in rocks at Gale crater, Mars. Geophys Res Lett 41:5755–5763ADSCrossRefGoogle Scholar
- Morgan JJ (2000) Manganese in natural waters and earth’s crust: its availability to organisms. Met Ions Biol Syst 37:1–34Google Scholar