Dissolved carbohydrate in the central Arabian Sea

Abstract

Seawater samples (161), collected from 8 depths (0 to 1000 m) at 21 stations were analysed for total dissolved carbohydrate. Dissolved carbohydrate concentrations varied from 0.072 to 1.15 mg.l^-1. Carbohydrate concentrations did not decrease offshore in the upper 100 m but below 100 m horizontal variations were detectable. Vertical profiles showed a more or less uniform distribution in the upper 300 m and a slight increase below 300 m up to 1000 m. Carbohydrate was significantly correlated with chlorophyll a (P < 0.001) and phaeopigments (P < 0.001) suggesting its release from the former and zooplankton grazing in the latter. Inverse correlations with dissolved oxygen, phosphate and nitrate indicated the possibility of the release of carbohydrate from bacterial decomposition and the importance of these nutrients in regulating the concentration of carbohydrate in the marine environments.