actively produced biotin and particularly most of the epiphytic bacteria isolated from
E.densa which produced three kinds of vitamins. Accordingly, it is thought that the
production of vitamins by these bacteria must be one of the most important autochthonous sources of vitamins in the pelagic zone of the lake.
That is to say, that role of B group vitamins must be very important to the increase of the
algal community and the primary productivity on the aquatic environment, and that far
more attention must be paid to the production and circulation of these vitamins in the
hydrosphere.
ACKNOWLEDGEMENTS
The author is very grateful to the members of Otsu Hydrobiological Station of Kyoto University for providing
us with kind technical assistance and critical discussion.
KURATA A., KAWASE T. and KADOTA H., 1982. Bull. Japan. Soc. Sci. Fish., 48 (3), 439-444.
KURATA A., SSARACENI C., RUGGIU D., NAKANISHI M., MELCHIORRI-SANTOLINI U. and KADOTA H 1976
Mem. Ist. Ital. Idrobiol., 33, 257-284.
POMMEL B., 1975. Ann. Hydrobiol., 6, 103-121.
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