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Appl Environ Microbiol. 1972 February; 23(2): 341-348
Copyright © 1972 American Society for Microbiology. All Rights Reserved.

Vitamin B₁₂ Production and Depletion in a Naturally Occurring Eutrophic Lake¹

Department of Microbiology, Oregon State University, Corvallis, Oregon 97331
Department of Oceanography, Oregon State University, Corvallis, Oregon 97331

ABSTRACT

The distribution of vitamin B₁₂ within Upper Klamath Lake was surveyed at approximately monthly intervals during a period from September 1968 to November 1969. High concentrations (up to 1.8 µg/g of dry sediment) characteristically occurred at the water-sediment interface, with a sharp decline below this area. A heavy bloom of Aphanizomenon flos-aquae occurred from the latter part of May through October 1969. B₁₂ concentrations of the uppermost sediments, from all but one sampling site, increased gradually through the bloom, followed by a drastic increase during the die-off period. B₁₂ is probably not a limiting factor for primary productivity, since sufficient levels of this vitamin were found to occur throughout the year. Of 42 cultures isolated from Upper Klamath Lake water and sediments, 20 were found capable of producing 50 pg or more of B₁₂/ml of medium. Phytoplankton samples were found to contain up to 5 µg of B₁₂/g of dry material. Degradation of B₁₂ occurred in sterilized as well as fresh sediment samples.

¹ Published as technical paper no. 3198, Oregon Agricultural Experiment Station. This paper was taken in part from a dissertation submitted in partial fulfillment of the requirements for the Ph.D. degree at Oregon State University. A portion of this paper was presented at the Annual Meeting of the American Society for Microbiology, Boston, Mass., 1970.