屈斜路湖堆積物にみる環境変動II

概要

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Lipid compounds were analyzed in three core sediments (16-19cm length) collected in 1993 from the south basin (Core 2), north basin (Core 1) and the northeastern part (Core 3) of Lake Kussharo-ko, Hokkaido Japan. The long-chain (>C23) anteiso compound series (alkanes, fatty acids and alcohols) were detected in every section of every core, which had been known to be unique in the moderately acidiic (pH=3-5) freshwater lake sediments. Abundances of the anteiso compounds varied significantly, showing maxima at the upper and the lower layers of the cores. The vertical variations accorded with variations in the composition of diatom valves remaining in sediments, suggesting a periodical pH fluctuation of the lake water. Only the northeastern core (Core 3) showed a decrease at the uppermost sections (0-2cm), which may probably reflect the recent rapid pH increase during the last decade. The fluctuations were considered to be caused by changes in relative proportion of the inflowing acid hot spring water to the bicarbonate-rich hot spring waters evolving along the lake coast.
日本有機地球化学会の論文
1996-05-30