Diel variation of water-extractable carbohydrate composition of natural phytoplankton populations in Kinu-ura Bay

• Published in: Journal of experimental marine biology and ecology Vol. 162; no. 2; pp. 159 - 176
• Main Authors: Hama, J., Handa, N.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.1992; Elsevier Science
• Subjects: 13C incorporation into monosaccharides; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Carbohydrate; Diel variation; Fundamental and applied biological sciences. Psychology; GC/MS; Gel filtration; Marine; Phytoplankton; Sea water ecosystems; Skeletonema costatum; Synecology; Asia; Japan; 13C incorporation into monosaccharides; Gel filtration; Phytoplankton; Carbohydrate; Diel variation; GC/MS; Marine environment; Biochemical analysis; Algae; Circadian rhythm; Ecophysiology; Thallophyta
• ISSN: 0022-0981; 1879-1697
• DOI: 10.1016/0022-0981(92)90199-K

Natural phytoplankton populations from Kinu-ura Bay were incubated adding NaH 13CO 3 under natural light and temperature conditions for 24 h in July 1986, and diel changes in the production of water-extractable carbohydrates were investigated. The water-extractable carbohydrates were separated into fraction A (mol. wt. > 6000), B (mol. wt. 1000−6000) and C (mol. wt. < 1000) with Bio-Gel P6, and 13C incorporation into monosaccharide components in each fraction was analyzed by GC/MS. Fraction A consisted of glucose, xylose, galactose, fucose, mannose, rhamnose and arabinose. Only glucose was found in fraction B, which increased rapidly in the afternoon. Fraction C comprised mainly ribose, galactose and glucose. The monosaccharide composition and the molecular weight of the 3 fractions suggested that fractions A and B were cell wall heteropolysaccharide and storage glucan of algae, respectively, while fraction C consisted of low-molecular-weight cellular components, such as free glucose, oligosaccharides, simple glycosides, and coenzyme and/or nucleotides. These 3 fractions all increased during daytime, and decreased during nighttime. Fraction B increased quickly about 8-fold in the afternoon, but underwent an 80% decrease during nighttime. Diel specific variation of fractions A and C was less than that of fraction B. Monosaccharide components of fractions B and C were highly labelled with 13C in the daytime as compared with those of fraction A. A marked increase in 13C atom% of most monosaccharide components of fraction A was observed during nighttime, while 13C atom% of most monosaccharide components of fractions B and C tended to be constant or decrease. This result indicated that most carbohydrates in fraction A were synthesized not only during daytime, but also during nighttime by low-molecular-weight compounds which were highly labelled with 13C.