| The changes in concentration of thiamine, biotin and vitamin B sub(12) in water of the soaked bottles for 6 h in situ in the north basin of Lake Biwa were examined successively over 30 hours. The concentrations of the vitamins changed comparatively during 6 h. soaking in situ. Generally, the concentrations of thiamine, biotin and vitamin B sub(12) were in high levels in the morning and in low levels in evening both in the soaked bottles and in the surrounding water. The fluctuation ranges in concentration of vitamins in a 5 m deep layer were greater than those in thermocline. From the data obtained with the soaked bottles in situ, it was supposed that the decrease of vitamins in concentration during the daytime surpass consumption of vitamins by... |
