Geochemical Journal, Vol. 7, pp. 215 to 230, 1973
Carbohydrates from lake sediments
NOBUHIKO HANDA and KEISUKE MIZUNO*
Water Research Laboratory, Faculty of Science, Nagoya
University, Chikusa, Nagoya, 464 Japan
(Received September 5, 1973; in revised form September 27, 1973)
Abstract Carbohydrate analysis of the sedimentary samples from Lake Suwa was conducted to ascertain the
total amounts of carbohydrates present and their chemical
nature, and to discuss the behavior of carbohydrates during the course of sedimentation.
Total carbohydrate was determined in the range from 5.92 to 8.321ng/g dry sediment in
the samples from the surface to 24cm depth of lake sediments. These values tended to
decrease with depth. Lake sediments gave rhamnose, fucose, ribose, arabinose, xylose,
mannose, galactose and glucose as the monosaccharide components when the sedimentary
samples were treated with sulfuric acid.
These monosaccharides were identified as
benzoylhydrazones or acetyl derivatives.
When alkali extracts of lake sediments were treated by gel filtration using sephadex
G-25, low molecular weight carbohydrates and polysaccharide were separated. The
polysaccharide, being major component of alkali extractable carbohydrate of lake sediment, was characterized by analyzing monosaccharide composition, degree of polymerization and type of glycosidic linkage between monosaccharide components. Results
indicate that this polysaccharide of lake sediment is originated from diatoms living
in this lake rather than from land vegetation.
Monosaccharide composition of sedimentary samples from various depths was
determined. Its vertical profile indicates that stabilities of monosaccharide components
of sedimentary carbohydrate to microbiological attack increase in following order;
glucose, galactose, fucose > mannose > ribose, rhamnose, arabinose.
Vertical profile
of low molecular weight carbohydrates indicates that the carbohydrates are intermediates during the decompositive processes of the polysaccharide in the sediment.