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Title: Microbial oxidation of manganese in a North Carolina estuary

Journal Article · · Limnology and Oceanography; (USA)
;  [1]
  1. National Marine Fisheries Service, Beaufort, NC (USA)

Experiments were conducted with Mn-54 (++) to determine the kinetics of particulate manganese formation in seawater from the lower Newport River estuary, North Carolina. Dissolved Mn was rapidly converted into particles at constant rates that ranged from 0.36 to 6.2%/h, yielding turnover times of the dissolved manganese pool of 0.7-11 d. Dissolved Mn turnover rates increased with temperature up to a maximum at 25-35 C and also increased with the ratio of particulate to dissolved Mn. These two factors explained most of the variation in the observed turnover rates. The formation of particulate Mn appeared to result primarily from the oxidation of Mn(++) to manganese oxides. However, the oxidation rates were much too rapid to be accounted for by abiotic mechanisms, and the rate was reduced by 97% following heat sterilization of the seawater. In addition, the rates conformed to the Michaelis-Menten enzyme kinetics model, providing strong evidence that oxidation of Mn in the estuarine samples is microbially catalyzed. This catalysis appears to be instrumental in the rapid redox cycling of Mn and in the scavenging of dissolved Mn onto particles in aquatic systems. 35 refs., 8 figs., 2 tabs.

OSTI ID:
6898083
Journal Information:
Limnology and Oceanography; (USA), Vol. 32:3; ISSN 0024-3590
Country of Publication:
United States
Language:
English