Temporal variabilities of the concentrations of intra- and extracellular microcystin and toxicMicrocystis species in a hypertrophic lake, Lake Suwa, Japan (1991-1994)
✍ Scribed by Park, Ho-Dong ;Iwami, Chie ;Watanabe, Mariyo F. ;Harada, Ken-Ichi ;Okino, Tokio ;Hayashi, Hidetake
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 278 KB
- Volume
- 13
- Category
- Article
- ISSN
- 1053-4725
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✦ Synopsis
Temporal variability in the concentration of toxic heptapeptide microcystin was studied ( ) ( ) during the warm season of four years 1991 -1994 in a hypertrophic lake Lake Suwa in central ( ) ( Honshu, Japan. Lake water samples ca. 5 L were filtered to separate intracellular microcystin cell ) ( ) fraction from extracellular microcystin filtered lake water fraction . These fractions were analyzed to measure the total quantity of microcystin in lake water. Total amounts of extra-and intracellular microcystin were measured with high performance liquid chromatography. Concentrations of intracellu-( ) lar microcystin usually exceeded concentrations of extracellular microcystin 24 out of 26 times . High concentrations of intracellular microcystin were found during the exponential growth phase of the blooms, whereas concentrations of extracellular microcystin were highest at the end of the blooms.
( ) However, concentrations of extracellular microcystin remained very small -4 g / L compared to the levels of intracellular microcystin. The relatively higher percentages of microcystin in filtered lake water ( ) )20% at the end of blooms suggests that release of microcystin from cells occurs during senescence and the decomposition period of Microcystis cells.