海水中での腸内細菌の消長に及ぼすし尿等の影響

Abstract

Effect of digested night soil, marine plankton and light on the viable count of intestinal bacteria in the seawater were examined in order to estimate the sanitary problems of ocean fertilization with night soil. One hundred ml each of aged seawater with or without digested night soil (1%), phyto-plankton Nitzschia closterium, Phaeodactyllum tricornutum, Dunaliella tertiolecta, Brachiomonas sp., Chlamydomonas sp., Platymonas sp., Nannochloris sp. and Chlorella sp. and zooplankton Tigriopus japonicus, were inoculated wiht 108 cells per ml each of Escherichia coli, Salmonella typhimurium or Vibrio parahaemolyticus, and rotary shaken with or without illumination (ca. 6, 000lx) for several days at 20°C. Bacterial cells were counted every day by using selective media. In the dark and clean seawater, E. coli and S. typhimurium survived more than 6 and 15 days, respectively, and V. haemolyticus rather propagated. On the other hand, the former two species and the latter one died off within 1 and 3 days, respectively, in the illuminated seawater containing digested night soil and marine plankton.