著者

福島 武彦 今井 章雄 松重 一夫 井上 隆信 小澤 秀明

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.20, no.6, pp.397-403, 1997-06-10 (Released:2008-01-22)

参考文献数

18

被引用文献数

11 6

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UV absorbance: DOC ratios were determined for the dissolved component of the water samples obtained from several specific sources, influent rivers and in-lake points of the three lakes as well as the evaluation of their changes during long-term incubations. There were significant differences in the ratios between influent rivers and in-lake points, which were consistently due to the difference between allochthonous sources mainly composed of pedogenic humic substances and autochthonous sources e.g. substances excreted through primary production. The nearly constancy of the ratio during the biodegradation process was confirmed for both allochthonous and autochthonous components; hence a two-component model could be applied to these lakes in order to calculate the proportion of DOC in each of the two components. Because of its usefulness to the model, easiness of measurement, and the close relation to trihalomethane productivity, this ratio could be one of the important indices for lake environmental management.

著者

今井 章雄 福島 武彦 松重 一夫

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.22, no.7, pp.555-560, 1999-07-10 (Released:2008-01-22)

参考文献数

30

被引用文献数

4 6

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Aquatic humic substances (AHSs) from the eutrophic Lake Kasumigaura were isolated using XAD-8 resin. The effects of these isolated AHSs on the growth of Microcystis aeruginosa cultures were evaluated. M. aeruginosa was isolated from algal blooms in Lake Kasumigaura and grown in a chmically defined medium under iron limitation. The production of siderophores, iron-specific complexing agents, by M. aeruginosa was also examined. Under iron limitation, M. aeruginosa was confirmed to produce hydroxamate-type siderophores; however, they were not effective to enable substantial recovery of the growth rate. The fulvic acid (lower molecular-size fraction of AHSs) isolated from Lake Kasumigaura was found to significantly inhibit the growth of M. aeruginosa. The fulvic acid at 2 mg dry weight l-1, the same level as in the lake, significantely inhibited the growth of M. aeruginosa even though siderophores were produced. This inhibition was probably due to a deficiency of iron caused by iron complexation with the fulvic acid. These results suggest that AHSs, through their iron complexation reactions, may play an important role in formation of M. aeruginosa algal blooms.