Abstract
We determined the monosaccharide composition of dissolved organic matter (DOM) to evaluate the origin of DOM in Lake Kasumigaura. We applied high-performance liquid chromatography coupled with pulsed amperometric detection (HPLC-PAD) for the analysis of monosaccharides. We collected water samples from Lake Kasumigaura in 2004 and prepared samples from culture medium used for growing blue-green algae that are typically found in Lake Kasumigaura. The dissolved total saccharides (DTS) content of the lake water ranged from 1.8 to 3.0 μM. The DTS content of the DOM from lake water ranged from 3 to 6%. The monosaccharide composition in the lake water was uniform all year round. The main monosaccharides were fucose, rhamnose, arabinose, galactose, glucose, mannose, xylose and ribose. The algae released a large amount of DTS during the stationary phase. The concentration and composition of the released DTS differed substantially among the algal species. The released DTS was 43.2 to 126 μM. Glucose was the most predominant among the monosaccharides of the DTS. The DTS content of the algal DOM ranged from 11 to 33% depending on the type of algae. The monosaccharide composition was very different between the lake-water-derived and algal-derived DOMs.
